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Structure determination of some di-(tertiary arsine) derivatives of metal carbonyls Roberts, Paul J. 1970

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THE  STRUCTURE  DETERMINATION  SOME D I - ( T E R T I A R Y A R S I N E ) OF M E T A L  OF  DERIVATIVES  CARBONYLS  by  PAIIL J . -ROBERTS B.Sc.(Hon.),  A THESIS THE  University  SUBMITTED  of British  IN PARTIAL  REQUIREMENTS DOCTQR OF  in  FOR  THE  Columbia,  FULFILLMENT DEGREE  OF  PHILOSOPHY  the Department of Chemistry  We  accept  required  this  thesis  as conforming  to the  standard  THE  UNIVERSITY  OF B R I T I S H  November,  1970  COLUMBIA  1967  OF  In p r e s e n t i n g t h i s t h e s i s  in p a r t i a l  f u l f i l m e n t o f the requirements  an advanced degree at the U n i v e r s i t y of B r i t i s h Columbia, I agree the L i b r a r y I further  s h a l l make i t f r e e l y  available for  agree t h a t p e r m i s s i o n f o r e x t e n s i v e  r e f e r e n c e and copying o f t h i s  It  i s understood that c o p y i n g o r  thesis  permission.  Department of  Chemistry  The U n i v e r s i t y o f B r i t i s h Columbia Vancouver 8, Canada  Date November l$  t  1970  or  publication  o f t h i s t h e s i s f o r f i n a n c i a l g a i n s h a l l not be a l l o w e d w i t h o u t my written  that  study.  f o r s c h o l a r l y purposes may be g r a n t e d by the Head of my Department by h i s r e p r e s e n t a t i v e s .  for  ABSTRACT  Supervisor:  Professor  The  structures  vatives  of  metal  lection  of  direct,  to  Mo-K  tri-iron  in  a  =  molecules by  per  the  R  of  reflections. Fe (CO)i ,  of  the  atom  two  of  cluster the  for  arsine)  determined  by  deri-  a  F o u r i e r methods,  2  c  =  i n which  A,  unit).  Fe-Fe bond  group  The  se-  applied  bent  i s more  74  a  Z =  total  carbonyl  ligand. of  nearly in  of as  8  (two refined  to  a  3234) a  derivative on  by  arsenic  an  each  central  Fe As 3  molecules  planar the  ,  group  The the  0  with  atoms)  i s replaced  distances  (CO) 1  3  P^/c,  described  i n one  .Fe  93.7°,  of  (of  terminal  arsine)  2  s t r u c t u r e was  (a t o t a l  atoms  2  3 =  i s best  iron  u n i t , but  The  space  22.11  one  di-(tertiary  asymmetric  2  molecule  is significantly  molecule.  and  2524 o b s e r v e d  equivalent  the  been  M e A s C = C (AsMe. ) C F C F  procedures  The  2  3  di-(tertiary  data,  asymmetric  0.09  of  have  monoclinic  20.04,  least-squares  final  four  bis(dimethylarsino)tetrafluorocyclobutene-  crystallizes b  Trotter  Patterson,  decacarbonyl,  11.60,  of  carbonyls  diffTactometer  —a  1,2-  =  James  in  iron  2  of  the  other  triangle  o  (2.53,2.65,2.65 in  the  parent  A)  do  not  of  8  are  from  those  bis(1,2- bis(dimethylarsino)tetrafluoro  cyclobutene)triruthenium 3  significantly  compound.  Crystals  Ru (CO) /  differ  octacarbonyl,(Me AsC=C(AsMe )CF CF )  orthorhombic,  2  space  group  Pbcn,  2  a  =  9.07,  2  2  b  =  18.53, c =  asymmetric squares (of  21.81  unit).  The  procedures  a total  of  1712)  ruthenium  of  and  ligand  was  R of  two-fold  axis,  by  arsine)  the  The and  ligands,  ruthenium  by  least-  molecule  observed  lies  on  i s best described  two  each  arsenic  refined  per  0.078 f o r 1507  i n which  2  c a r b o n y l on  b r i d g e s two  (one-half molecule  reflections.  3  atoms a r e r e p l a c e d di-(tertiary  4  structure  Ru (CO)i  one  Z =  to a final  a crystallographic a derivative  A,  c a r b o n y l s on  of the other  as  one  ruthenium  atoms o f t h e b i d e n t a t e  i n such atoms,  a way  and  one  that  each  Ru-Ru  bond o  remains  unbridged.  T h i s u n b r i d g e d Ru-Ru b o n d  (2.785  A) o  is  significantly  shorter  than  the b r i d g e d ones  (2.853  A) o  and  than  The  s k e l e t o n s of  deviate each  those of  the parent R u ( C O ) i 3  the d i - ( t e r t i a r y  significantly  ligand  from  being twisted  of  the ruthenium  is  2.407  18°  triangle.  with  The  do  not  the plane  respect to the  mean Ru-As b o n d  of  plane  length  bis(dimethylarsino)tetrafluorocyclobutene-  decacarbony1,  crystallizes  i n orthorhombic  8.594, b =  The  ligands  exact planarity,  triruthenium  18.795, c =  refined  0.076  arsine)  2.848A).  A. 1,2-  was  (average  2  by  f o r 1828  compound  equatorial  Me AsC=C(AsMe )CF CF .Ru (CO)i , 2  16.69  least-squares observed  2  Z =  c a r b o n y l group  on  4.  The  of  of  2028)  Ru3(CO)i  each  3  of  two  2  0  =  structure  p r o c e d u r e s .to a f i n a l  (of a t o t a l  i s a derivative  2  g r o u p . P 2 i 2 12 i , a  space A,  2  R  of  reflections.  i n which ruthenium  one atoms  is  replaced  ligand  by an a r s e n i c  i n such  a way  atom  that  of the di-(tertiary  the plane  of the ligand  arsine) i s twisted  0  18  with  respect  Ru-Ru b o n d  to the plane  distances  ference  between  tically  significant  1,2tetracarbonyl, in c by  observed is  Me AsCF(CF )CF AsMe .Mo(CO)4, 2  3  2  2  102.8°,  Z =  squares  methods  to a final  (of a t o t a l from  Two  being  statis-  bis(dimethylarsino)hexafluoropropanemolybdenum  the arsenic  ligand.  lengths  the d i f -  and e x p l i c a b l e i n terms o f t h e bonding  6 =  A,  a n d 2.858 A ,  bond  group  derived  with  and long  space  11.56 least  2.831,  triangle.  of the ligand.  the monoclinic =  a r e 2.831,  the short  characteristics  of the ruthenium  o f 1750)  Mo(CO)6 atoms  C2/c, a = 8.  crystallizes  25.06,  b =  T h e s t r u c t u r e was R o f 0.073  reflections.  13.27, refined  f o r 1510 ,  The m o l e c u l e  by r e p l a c i n g two c a r b o n y l  groups  of the chelating di-(tertiary  of the carbon-fluorine  bond  :  distances  arsine) (mean  o  1.505 and  A)  o  are significantly  the distance  between  longer  than  the carbon  the others  atoms  (mean  1.30  of the ligand ske-  o  leton bond  i s remarkably length  short  i s 2,572 A .  (1.40 A ) .  The w e i g h t e d  mean  Mo-As  A)  V  T A B L E OF  CONTENTS PAGE  TITLE  PAGE  i  ABSTRACT TABLE  i i V  OF CONTENTS  LIST  OF  TABLES  v i i  LIST  OF F I G U R E S  x  ACKNOWLEDGEMENTS I.  INTRODUCTION THE TECHNIQUE  B.  C H A R A C T E R I S T I C S OF M E T A L  C.  III.  1  A.  THEIR  II.  x i i  OF  X-RAY  CRYSTAL ANALYSIS CARBONYLS  2  AND  DERIVATIVES  R E S U L T S OF  PRELIMINARY  8 EXPERIMENTS  11  EXPERIMENTAL SECTION THE  STRUCTURE  DETERMINATION  16 OF M e A s C = C ( A s M e ) C F C F • 2  2  2  2  Fe (CO)i . 3  21  0  STRUCTURE  ANALYSIS  22  DISCUSSION IV.  THE  36  STRUCTURE  DETERMINATION  OF  (Me AsC=C(AsMe )CF CF ) • 2  2  2  2  Ru (CO) . 3  46  8  STRUCTURE  ANALYSIS  47  DISCUSSION V.  THE Ru  3  56  STRUCTURE  DETERMINATION  OF M e A s C = C ( A s M e ) C F C F • 2  2  2  2  (CO) io.  STRUCTURE  64 ANALYSIS  65  DISCUSSION VI.  THE  74  STRUCTURE  DETERMINATION  Mo (CO) it.. STRUCTURE  2  OF  Me AsCF CF(CF )AsMe • 2  2  3  2  79 ANALYSIS  80  vi  VII.  DISCUSSION  86  COMPUTER PROGRAMMING  97  A.  THE WEIGHTING  B.  IMPLEMENTATION "ORTEP".  VIII.  REFERENCES  SCHEME PROGRAM OF  THE  THERMAL  "UPDATE". PLOT  98  PROGRAM 103 106  vii  L I S T OF T A B L E S PAGE I. II.  INTRODUCTION EXPERIMENTAL SECTION II.I  C r y s t a l and e x p e r i m e n t a l  data  for a l l  structures. III.  THE S T R U C T U R E  .  1  9  D E T E R M I N A T I O N OF M e A s C = C ( A s M e ) C F C F • 2  2  2  2  Fe (CO)i . 0  3  III.I  C o m p a r i s o n o f 51 p o s s i b l e generated  by Hoge's s i g n  solutions determination  program. III.II  25  F i n a l measured  and c a l c u l a t e d  structure  factors. III.Ill  F i n a l p o s i t i o n a l and thermal with  III.IV  t h e i r standard  Equations  parameters  deviations.  31  o f w e i g h t e d mean p l a n e s f o r  iron  t r i a n g l e and d i - ( t e r t i a r y  III.V  Bond  d i s t a n c e s and v a l e n c y  III.VI  Magnitudes o f t h e p r i n c i p a l axes o f thermal and  IV.  29  THE S T R U C T U R E  33  angles.  vibration ellipsoids  arsenic  arsine).  34  of iron  atoms.  DETERMINATION  42 OF(Me AsC=C(AsMe )CF CF ) « 2  2  2  2  2  Ru (CO) . 3  IV.I  8  C o m p a r i s o n o f 16 p o s s i b l e generated  by Long's  sign  solutions determination  program. IV.II  F i n a l measured  49 and c a l c u l a t e d  structure  factors. IV.Ill  51  F i n a l p o s i t i o n a l and t h e r m a l with  t h e i r standard  parameters  deviations.  53  IV.IV  Bond d i s t a n c e s and v a l e n c e  IV.V  Equations  of weighted  ruthenium  triangle  angles.  54  mean p l a n e s f o r  and d i - ( t e r t i a r y  arsine). IV.VI  55  Magnitudes vibration  of principal f o r atoms  axes o f t h e r m a l  refined  aniso-  tropically. V.  55  THE S T R U C T U R E D E T E R M I N A T I O N OF  Me AsC=C(AsMe )CF CF • 2  2  2  2  Ru (CO)io• 3  V.I  Final  measured and c a l c u l a t e d  structure  factors. V.II  Final with  67  positional their  and t h e r m a l  parameters  standard deviations.  V.III  Bond d i s t a n c e s and v a l e n c e  V.IV  Equations  of weighted  ruthenium  triangle  69  angles.  71  mean p l a n e s f o r  and d i - ( t e r t i a r y  arsine). V.V  Magnitudes vibration  VI.  73 of principal f o rruthenium  THE STRUCTURE D E T E R M I N A T I O N OF  axes o f  thermal  and a r s e n i c atoms.  73  Me AsCF CF(CF )AsMe • 2  2  3  2  Mo ( C O ) . 4  VI.I  F i n a l measured and c a l c u l a t e d  structure  factors. VI.II  Final with  82  positional their  and t h e r m a l  standard deviations.  VI.Ill  Bond d i s t a n c e s and v a l e n c e  VI.IV  Magnitudes  VI.V  of principal  vibration  o f atoms  Equations  of weighted  molybdenum of  parameters  vector C(5)-C(6).  angles.  84  axes o f thermal  refined  octahedron  83  anisotropically.  85  mean p l a n e o f and d i r e c t i o n  cosines 8  8  ix  VII.  COMPUTER VII.I  PROGRAMMING Fortran  listing  o f program  "UPDATE".  101  LIST  OF  FIGURES PAGE  INTRODUCTION 1.1  Expected  structure  for  Me AsC=C(AsMe )CF CF • 2  2  2  2  Fe (CO)i . 3  1.2  12  0  Two  possible  structures  for  (Me AsC=C(AsMe )CF CF ) Ru (CO) . 8  14  Me AsC=C(AsMe )CF CF 'Ru (CO)io•  15  2  1.3  Two  2  possible  2  II. III.  THE Fe  2  3  for 3  OF  Me AsC=C(AsMe )CF CF • 2  2  2  2  io.  III.l  E-map w i t h  111.2  Molecular 3  heavy  positions  of  27  Me AsC=C(AsMe )CF CF • 2  2  2  2  37  of asymmetric carbonyl  111.4  Co-ordination angles  superimposed.  .  1 0  View  in  atom  structure  111.3  about arsenic  averaged  over  bridges. atoms,  the four  39  showing  arsenic  atoms  the asymmetric u n i t .  111.5  Intermolecular  111.6  Projection  THE  2  DETERMINATION  Fe (CO)  IV.  2  SECTION  STRUCTURE (CO)  3  2  structures 2  EXPERIMENTAL  2  contacts  of unit  cell  STRUCTURE DETERMINATION  OF  41 i n general down  view.  43  a-axis.  45  (Me AsC=C(AsMe )CF CF ) 2  2  2  2  2  Ru (CO) . 3  IV. 1  8  Molecular  structure  o f (Me AsC=C (AsMe )CF .CF ) • 2  2  2  2  2  Ru (CO) . 3  IV.2  Comparison of and  IV.3  57  8  (Me AsC=C(AsMe )CF CF ) Ru (CO) 2  2  2  2  2  3  (C H ) Ru (CO) . 8  8  Distortion  2  3  59  h  of co-ordination  8  about ruthenium.  60  xi  IV.4 V.  Projection  THE STRUCTURE  of the unit  cell  D E T E R M I N A T I O N OF  down a - a x i s .  63  Me AsC=C(AsMe )CF CF • 2  2  2  2  Ru (CO)io• 3  V.l  Molecular  structure  of  Me AsC=C(AsMe )CF CF • 2  2  2  2  Ru (CO)i .  VI.  75  0  3  V.2  Distortion of co-ordination  V.3  Projection  of unit  cell  THE STRUCTURE D E T E R M I N A T I O N OF  about ruthenium.  down a - a x i s .  77 78  Me AsCF CF(CF )AsMe • 2  2  3  2  Mo(CO)„. VI.1  Molecular Mo (CO)  VI.2  structure  o f Me A s C F C F ( C F ) A s M e • 2  2  3  2  87  ij.  View o f bond d i s t a n c e s  and d i h e d r a l  angles  around C(5)-C(6) bond. VI.3  Postulated  bonding  90  scheme  t o account f o r  anomalous o b s e r v a t i o n s . VI.4 VII.  Projection  of unit  cell  92 down c - a x i s .  96  COMPUTER PROGRAMMING VII.l  Stereo diagrams o f a l l four arsine) derivatives.  di-(tertiary 104  ACKNOWLEDGEMENTS I wish Trotter B.  for his  R. P e n f o l d  various  t o express continuous  aspects  this  Cullen  University paring  with  for reading  also  supplied  W.  R.  Cullen  the preliminary draft of suggestions.  the crystal  samples  used  work. The  grams  l i k e t o thank P r o f e s s o r s  t h e s i s a n d f o r m a k i n g many h e l p f u l  Professor in  and t o P r o f e s s o r  o f c r y s t a l l o g r a p h i c computing.  N. L . P a d d o c k  this  guidance  a n d D r . F . H. A l l e n f o r a s s i s t a n c e  I would and  my g r a t i t u d e t o P r o f e s s o r  co-operation  o f M r . T. V. T a y l o r  o f B r i t i s h Columbia Computing  ofthe  Centre  i n pre-  t a b l e s o f s t r u c t u r e f a c t o r s and l i s t i n g s o f proi s also greatly I  appreciated.  am i n d e b t e d  of  Canada f o r f i n a n c i a l  of  this  work.  to the National support  during  Research  Council  the entire  term  I.  INTRODUCTION  A.  THE  As organic tant the  revealed  compounds,  molecules,  sicists nique  and  has  pletely the  been  computers  be  methods, nitudes of  the  (F's)  of  technique  of  biochemists,  application  facilitated  mechanized obstacle of  by  have  in  phases  are  structure ought  the  been  clarify  the  phy  tech-  advent  way  of  method. the To  of  the  crystal  be  of  and  this  which  of  the  direct  from  (E's),  the  are  discussed  ensuing  lat-  overcome  squares  factors  com-  Although  devised,  determined  to  method  the  the  the  cannot.  uses  of  x-r  data c o l l e c t i o n .  d i f f r a c t e d waves,  and  in  magtwo  here  in  descriptions  of  determination. Since  transforms  the  examined  chemists,  which  the  the  to  been  impor-  for  methods  important, detail  have  in-  powerful  i t s phase  normalized  most  structure  of  lattice,  density  of  and  biologically  wave d i f f r a c t e d by  function,  i n which  sufficient  tal  the  several  Patterson  amplitudes  of  organic  extremely  The  one  ANALYSIS  an  applicability  measured,  difficulty, the  and  remains  universal  can  become  tremendously  there  innumerable  i t s discovery,  determination  amplitude  tice  has  CRYSTAL  products,  metallurgists.  electronic However,  the  X-RAY  a l l o y s which  since  analysis  structure  by  natural  and  sixty years  crystal of  T E C H N I Q U E OF  must  the  the (eq.  structure  periodic 1.1).,  therefore  amplitudes  electron  i t follows be  the  are  density that  Fourier  the  Fourier of  the  crys-  electron  transform  of  the  3  structure Fourier  amplitudes  series  efficients  of which  fP(Z'X'Z)  =  p(x,y,z)  phase, from  of the structure  the positions  a n d new  structure  application  by  parameters  However,  factors  factors  f a c t o r s , whose  process  atomic  a. f i n a l  An  approximate of the  phases w i l l  results  positions  s e t of phases.  i n a  complete  This  method  successful  i f t h e atoms o f t h e known  of  the molecule  constitute  a large  structure  cell.  portion  of the scattering  Apparently the sole  determination i s the i n a b i l i t y  are  final re-  particularly  i n the unit  be  The  of which  to yield  fraction  and  c a n be  is  matter  based  phases.  using these  l e a s t - s q u a r e s methods with  calculated  v a l u e s , c a n be c a l c u l a t e d .  the approximate  refined  be  a d d i t i o n a l elements  of this  (1.2)  atoms c a n be c a l c u l a t e d structure  calculated  }  quantities.  structure  (1.1)  associated  cannot  to the correct  to reveal  to the correct  structure,  fined  calculated  map  i s expected  iterative  then  of these  density  structure closer  o f t h e s e known  has an  density  i s known,  t o be a p p r o x i m a t i o n s  electron  are co-  + k y + £z)}dv.  amplitude  experimentally observed  on  phases  structure  and t h e e l e c t r o n  part  assumed  amplitudes  of a  e x p { - 2 7 r i ( h x + ky_ + Zz)  hkl  if  the phases  exp{2iri(hx  = ~ EZZ F  However, each  directly  the structure  i n terms  (eq. 1.2). -hk£  unknown  and c a n be w r i t t e n  obstacle  to locate  a  of starting  4  segment i n t h e u n i t now  turn  our  was  of  a Fourier  between atomic  group  in  = I  of  peak  a few  to  locate  and  a map  | cos  the  which  drawbacks tend  t o be and  then  atoms.  Since the  of  i t corresponds, heavy  ravelled  and .atomic p o s i t i o n s We  have seen  that  cell. Peaks  broader  the  the v e c t o r  atomic  numbers  i t i s obvious  can  appear  that much  atoms.  Pro-  a relatively usually  assigned to these  the presence  can  contains  of  by  a t o m s , t h e v e c t o r map  the straight-  t h e v e c t o r map  atoms w i l l  i s dominated  of  seem a  v e r y much  vided  structure  (1.3)  t o the method.  intensity  to the product  Iz)  +  i n the u n i t  lighter  number o f h e a v y  contained  requirements  more i n t e n s e t h a n v e c t o r s b e t w e e n t h e the  the  amplitudes  2rr(hx + k y  the molecule  between r e l a t i v e l y  that  we  ends o f v e c t o r s  i t would  distribution  atoms t o w h i c h  vectors  of  of which  complicated i f the molecule  i s proportional  the  squares  2  h k £  crystallization,  i n the e l e c t r o n  more t h a n  ( e q . 1.3)  t h e symmetry  a r e , however, s e v e r a l  become d i f f u s e  of  E££|F  the vector d i s t r i b u t i o n  than  that  positions.  considering  forward matter There  problem  crystallography''",  corresponding to the  P(x,y,z)  space  series  waves, produced  at positions  By  of x-ray  were the p h a s e l e s s  the d i f f r a c t e d  peaks  i t i s to this  i n the h i s t o r y  shown t h a t  coefficients  and  attention.  Early it  cell  of  a  be  small un-  atoms.  large  number  o f atoms o f s i m i l a r  atomic  ease w i t h which a s o l u t i o n t e r s o n map,  but  number i s d e t r i m e n t a l t o can be  e x t r a c t e d from  the  t h a t a s m a l l number o f r e l a t i v e l y  atoms makes t h i s  a p o w e r f u l method.  The  the Pat-  heavy  reverse i s true for  d i r e c t methods, by w h i c h p r o c e s s p h a s e s a r e a s s i g n e d  from  a statistical  The  analysis 2  theory  i s formulated  atoms b u t has  of the s t r u c t u r e  amplitudes.  3  '  on  a random a r r a n g e m e n t o f  been s u c c e s s f u l l y  applied  t o many  s t r u c t u r e s w h i c h c o n t a i n atoms o f e x t r e m e l y atomic  crystal  different  numbers. The  symmetric g  c o r n e r s t o n e o f d i r e c t methods i n c e n t r o -  space  hkl  where ,  groups i s the  relation  ^hkl h k £ ~k. £ £  =  l  I  i s a simple  t h a t one  F can be  ,  ,  ,  scaling  determined  * -h-h'k-k  ,  term.  l-V  1  Although  strongly  i n one  and  this  (1.4)  i t appears  o n l y i f the magnitudes  p h a s e s o f a l l o t h e r s a r e known, t h e s e r i e s must  large,  similar  direction  (+ o r -)  i f F^]^ is  direction  i s determined  by  and  tend  sufficiently  t h e agreement i n  3  signs  among p r o d u c t s  write  the  S  following  ( £  hk£  }  ~  S ( f  o f l a r g e F's  .  We  can t h e r e f o r e  relation.  h'k'£  where S means " t h e s i g n  | )  '  S (  o f " and  -h-h'  k-k-  l-V  ]  ~ means " i s p r o b a b l y  (  1  '  5  )  equal  4 to".  The  p r o b a b i l i t y with which t h i s  equation holds  depends  6  on the magnitudes o f the three r e f l e c t i o n s and i s given by  P = h + htanh{os/al  |E.., . E, , , ,  /2  -hk£  * -h' k' V  -  . E, , , . , , , , \ } -h-h' k-k' l - V P  (1.6) where a / a |  / / 2  3  i s a parameter dependent on the contents o f the  u n i t c e l l and independent  o f t h e i r l o c a t i o n and where E's  are d e f i n e d by  % k £ = IW / | i 2  £  -  f  (1  7)  where e i s an i n t e g e r which takes on d i f f e r e n t values f o r d i f f e r e n t classes of r e f l e c t i o n s . A s l i g h t l y more rigourous treatment  of eq.  r e s u l t s i n the most commonly used form of Sayre's  S (  -hkl  }  ~ h-k'I'^-h'k'i'*  '  S ( I  equation.  h - h ' k-k' l - V ^  with corresponding p r o b a b i l i t y P  W  ( +  : = h  +  ^  tanh(a3  +  (  1  *  8  )  ;  /^ ^hk£lg,|,|,%'k'£- • /2  Vh'k-k'H' where P  1.4.  i s the p r o b a b i l i t y  t h a t the s i g n of  1  ( 1  +  w i l l be l e s s than h and w i l l imply t h a t the s i g n of ^^ikt i s negative with a p r o b a b i l i t y +  In p r a c t i c e , phases are assigned to a s m a l l number o f r e f l e c t i o n s and Sayre's  9 )  i s positive.  I f the value, of the summation i n eq. 1.9 i s n e g a t i v e , P  P_ = 1 - P  '  equations are a p p l i e d .  7  to determine o t h e r s . An  T h i s can be achieved  i n i t i a l s e t of ten very  i n s e v e r a l ways.  l a r g e r e f l e c t i o n s can  be allowed to take on a l l p o s s i b l e combinations of and minus s i g n s .  T h i s would r e s u l t i n 2  of which s e v e r a l w i l l be more c o n s i s t e n t p r o b a b i l i t i e s ) than the o t h e r s .  1 0  plus  possibilities, ( i . e . have higher,  Each of these h i g h l y pro-  bable combinations i s then taken as a s t a r t i n g s e t  and  phases are generated f o r the remaining r e f l e c t i o n s by applying  Sayre's An  equations.  a l t e r n a t i v e approach a r i s e s as a consequence  of the f a c t t h a t the o r i g i n of a centrosymmetric u n i t can be a r b i t r a r i l y  l o c a t e d a t any  centre of symmetry.  cell Three  or sometimes fewer r e f l e c t i o n s , depending on the space group, can be assigned  a r b i t r a r y phases, corresponding to  choice of o r i g i n .  Three or four other  the  r e f l e c t i o n s are  allowed to take a l l p o s s i b l e combinations of p l u s  and  minus s i g n s , r e s u l t i n g i n 8 or 16 p o s s i b l e s o l u t i o n s . E i t h e r method i s completed by c a l c u l a t i n g an e l e c t r o n d e n s i t y map  using  of h i g h e s t p r o b a b i l i t y .  the phases of those s o l u t i o n s  B.  CHARACTERISTICS AND T H E I R  Numerous bing  reviews  metal-carbon bonding,  structure  of metal  OF M E T A L  DERIVATIVES  have appeared 5-7  carbonyls,  CARBONYLS  recently  preparation, 8 9 ' metal  descri-  p r o p e r t i e s , and  atom c l u s t e r s  10  and  11-14 Lewis base s u b s t i t u t e d cipal  conclusions  briefly  of these  as background  following  parts  carbonyl  studies  of this  their  compounds  The  o u g h t ' t o be  to the material  prin-  reviewed  t o be p r e s e n t e d i n  thesis.  The m o s t r e g u l a r and  complexes.  feature  of the metal  carbonyls  d e r i v a t i v e s i s t h e adherence o f most o f t h e s e t o t h e " e f f e c t i v e a t o m i c number"  o r " i n e r t gas"  15 law  which  ligands around For to  requires  sufficient the metal  example,  that  t h e c e n t r a l atom a c c e p t  electrons  that  the total  atom r e s u l t s i n a c l o s e d  t h e compound  Fe(CO) (NO) 2  2  number  shell  c a n be  total  and two n i t r o s y l  o f 36 e l e c t r o n s ,  various  ligands  co-ordination  donate  number  groups  the krypton  of  electrons  configuration. considered  c o n s i s t o f F e ( 0 ) (26 e l e c t r o n s ) , t w o c a r b o n y l  electrons)  from t h e  (2x2  groups  (2x3 e l e c t r o n s ) , f o r a configuration.  Since,  from one t o a dozen e l e c t r o n s , t h e  f o ra given  metal  atom w i l l  vary  from  one compound  t o another depending on t h e c o m b i n a t i o n o f  ligands  t o complete  used  instance, with five  t h e i n e r t gas c o n f i g u r a t i o n .  i n e r t gas c o n f i g u r a t i o n  co-ordination  species  For  e x i s t f o r iron-  numbers o f f o u r ( d i c a r b o n y l d i n i t r o s y l i r o n ) ,  (pentacarbonyliron)  and s i x ( d i - i o d o t e t r a c a r b o n y l i r p n ) .  9  I t i s obvious t h a t an i n t e g r a l number o f p a i r - d o n a t i n g l i g a n d s can complete  the valence s h e l l of a metal of even  atomic number, whereas metal atoms of odd atomic number must r e c e i v e an a d d i t i o n a l s i n g l e e l e c t r o n . ment can be accommodated i n s e v e r a l ways.  This  require-  A ligand  which  donates an odd number of e l e c t r o n s can be employed, r e s u l t i n g i n compounds e x e m p l i f i e d by Co (NO) (CO)  3  and HCo(COK, or  the odd e l e c t r o n on each atom can be shared w i t h another such atom, r e s u l t i n g i n a metal-metal bond, as i n Co2(CO) . 8  Besides t h i s r e g u l a r i t y i n s t o i c h i o m e t r y , metal carbonyls and t h e i r d e r i v a t i v e s are c h a r a c t e r i z e d by the a c t u a l nature of the m e t a l - l i g a n d bond.  The carbon atom of  carbon monoxide possesses an sp h y b r i d i z e d  lone p a i r of  e l e c t r o n s which forms a a-bond by o v e r l a p w i t h a vacant t r a n s i t i o n metal o r b i t a l of the proper symmetry.  The  carbon monoxide group a l s o has vacant 7T-antibonding which form a TT-bond by o v e r l a p w i t h f i l l e d d o r b i t a l s on the metal atom.  orbitals  non-bonding  The metal-carbon bond o r d e r  i n these complexes must thereby be g r e a t e r than u n i t y , r e q u i r i n g a c o n c u r r e n t decrease i n carbon-oxygen  bond o r d e r .  The presence of m u l t i p l e bonding between metal and carbon atoms i s r e f l e c t e d by the f a c t t h a t x-ray s t u d i e s show t h a t the metal-carbon bond l e n g t h i s d i s t i n c t l y s h o r t e r than the sum  of the s i n g l e bond  radii.^  Other l i g a n d s found i n s t a b l e s u b s t i t u t i o n complexes o f metal carbonyls a l s o possess both a-donor and  ir-acceptor p r o p e r t i e s .  On  phines  acceptor properties  d  and  arsines,  o r b i t a l s on It  ligands  the has  contain  explained  the  phosphorus or been found  metals  i n terms of  above, s i n c e  site  the  presence of  effects.  required  but  Since  of  from  states.  ir-bonding  complexes,  This  bonding  a metal  can  four  been chosen s i n c e , metal carbonyls, and  discussion  this  presented  atom enhances i t s  charge produces  ir-bonding  the  appear  presence of  negative,  will  the to  an  oppobe  electronic  inhibit  this  type  systematic  and  as  L  1  represent  i n terms of  the  2  ligands will  respectively.  in this  arsine)  thesis  have  derivatives  a unified topic  for  the  complexity  of  often  be  2  d e n o t e d by  2  the  in  their  Me AsC=C(AsMe )CF CF 2  of  study  principles established  Because of  names, the 2  included  di-(tertiary  they  Me AsCF(CF3)CF AsMe 2  ,  structures  introduction.  be  i t s back-bonding c a p a b i l i t y  a negative and  empty  complex formation. The  L  oxidation  decreases  charge, e i t h e r p o s i t i v e or  arise  phos-  atoms.  d e s c r i p t i o n of  b o t h a-  for stable  substituted  t h a t most complexes of  i n low the  s u c h as  arsenic  a p o s i t i v e c h a r g e on  acceptor properties whereas  ligands  2  and;  symbols  C.  R E S U L T S OF  Before  an  x-ray  PRELIMINARY analysis  other  experiments  are  often  these  experiments  can  lead  the  compound u n d e r  o f -the cations  will  now  i s undertaken,  c a r r i e d out, to  some i d e a  investigation.  compounds i n t h i s be  EXPERIMENTS  thesis  of  This  and  and  the  the  i s the  these  several results  of  structure  of  case  for  three  structural indi-  discussed. 17  The LFe (CO)io  i n f r a - r e d , n.m.r. and  suggest  3  a  structure  Mossbauer  i n which  two  spectra  of  terminal  car18  bonyl are  groups  of  the  two  replaced  by  the  arsenics  ligand in  (Figure  the  are  I.l).  would  The  n.m.r. s p e c t r u m  equivalent, be  viously ligand  so  expected  i s bent  as  of  t o be  the  presence  the  planar,  r e s u l t of  of  only  one  a l l the  LFe (CO) , 2  1 9  3  arsine) F  resonance  to  ligand  the  pre-  i n which  6  formation  2  f l u o r i n e atoms  arsine)  i n contrast  the  Fe (CO)i  di-(tertiary  di-(tertiary  structure of a  i r o n atoms of  indicates that  that  determined  equivalent  of  a  the  Tr-bond 19  from  the  cyclobutene The  singlets,  X  H  system  to  one  n.m.r. s p e c t r u m  of  of  i n d i c a t i n g a moderately  the  iron  atoms.  L Ru (CO)scontains 2  two  3  symmetrical  structure  2 0  for  the  ligand.  arrangement of spectrum of  The  1 9  F  fourteen  LFe(CO)i , (  n.m.r. s p e c t r u m peaks w i t h  where o n l y  is a  complex  some s i m i l a r i t y  one  arsenic  to  atom of  the the  21  ligand  i s bonded  evidence,  and  reluctant  to  the  to  the  i r o n atom.  observation  chelate,  favour  that the  T h e s e two the  ligand i s  structure  pieces-of normally  shown i n  Figure  Figure I . l  Structure expected  of Me AsC=C(AsMe )CF CF «Fe 2  on  the basis  2  2  2  of preliminary  3  (CO) i  0  experiments.  I . 2a  rather  than  The consist for  this  ligand in  of  an  the  F  and  singlets,  complex.  1  U  Figure  n.m.r. s p e c t r a  This  could  3  of  i n the  the  involving  the  of  The  of  I.3a)  or  latter  carbonyl  the  double bond of  3  symmetrical by  i s favoured of  chelate  cyclobutene  the  (Figure because 0  because without ring.  both  structure  LFe3(CO)i and  0  having  bridging  region  ligand to the  LRu (CO)i  accomplished  infra-red spectra  terminal  known r e l u c t a n c e  be  (Figure  equatorial position.  similarity  I.2b.  indicating a highly  either chelating  LRu (CO)io the  1 9  that of  and of also  I.3b) of  Figure  1.2  Two  possible  structures  for  (Me A s C = C ( A s M e ) C F 2  2  2  CF ) • R u 2  2  3  (CO)  F i g u r e T.3  Two  possible  structures  f o r Me AsC=C(AsMe )CF CF •Ru 2  2  2  2  3  (CO) 1 . 0  EXPERIMENTAL  SECTION  LFe (CO)i 3  mixture  i s o b t a i n e d by  0  of products  formed by  chromatography  ultraviolet  of  irradiation  the of  17 Fe (CO)i 3  and  2  the  di-(tertiary  are black needles were c o l l e c t e d 0.04  elongated  arsine).  along  a.  The The  crystals  intensity  u s i n g a sample of dimensions  0.3  data  xp.03  x,  mm. L Ru (CO) 2  products  of  3  the  i s prepared  8  reaction  of  by  chromatography  Ru (CO)i 3  with  2  the  of  the  ligand  20 refluxed was  an  were  xn  hexane.  irregular  0.05  mm.  The  plate  with  parallel  Ru (CO) 3  formation of  i 2  of  with  the  3  ether  A  in intensity  Mo(CO)  6  ether-benzene  with  colourless recorded  the  needles  using a Unit  were o b t a i n e d parameters ment o f  ligand  the  elongated  and  z  2  a d i f f r a c t o m e t e r w i t h Mo-K  —a  across.  ;  quantities  the  in  the  compound from  measurements. recrystallization f o r m e d by The c.  methods  for thirty  of  data  dimensions  recrystallized  0.16  by  and  from  refluxing  crystals  Intensity  space group data  photographic  values  was  dimensions  f o r each were determined  sin 8/A  flake  products 22  along  mm.  arsine) results  i n toluene.  specimen of  cell by  of  by  0.2  Its  equimolar  single  L'Mo(CO)q. i s p r e p a r e d petroleum  of  x 0 . 4 4 x 0 . 2 5 mm.  f o r use  to record the  developed.  di-(tertiary 20 0  0.07  used  about  irradiation  LRu (CO)i .  dimensions  diethyl  {001}  t o c and  Ultraviolet of  crystal  are;  data  xo.07  f o r each accurate  xo.57  mm.  compound lattice  least-squares  reflections 23 radiation.  were  treat-  measured  on  Reflection automated G e n e r a l scintillation  i n t e n s i t i e s were m e a s u r e d on  Electric  XRD  c o u n t e r , Mo-K  a Datex-  6 diffractometer, with  radiation  (Zr f i l t e r  a  and  pulse^  —a height was  a 9-20  a n a l y s e r ) , and  (1.80  at both  + 0.86  culated  tan8) degrees  ends o f e a c h The from  the  and  The  scan  20  range i n  b a c k g r o u n d s were m e a s u r e d  scan.  standard  d e v i a t i o n o f an  counting s t a t i s t i c s a (I)  = S + B +  2  where S- = s c a n  scan.  (dS)  intensity  was  cal- .  using 2  count  B = background, c o r r e c t e d t o time  of  scan  I = S - B d = an e m p i r i c a l c o n s t a n t w h i c h a l l o w s experimental  errors;  v a l u e s used  f o r unknown  f o r each s t r u c t u r e  are given i n Table I I . I R e f l e c t i o n s whose i n t e n s i t i e s were c l a s s i f i e d  as u n o b s e r v e d .  f a c t o r s were a p p l i e d and derived.  Absorption  Lorentz  were l e s s and  than l a  polarization  the s t r u c t u r e amplitudes  were  c o r r e c t i o n s were n o t a p p l i e d .  C r y s t a l d a t a and are given i n Table I I . I .  parameters of data  collection  Table I I . I Crystal  and e x p e r i m e n t a l  L Ru (CO)  LFe (CO)io  2  3  C i H i A s Fi^Fe. 01  formula  8  molecular weight crystal  2  2  (gm.)  3  0  system  dimensions  (A,deg.)  a =  11.60(2)  b =  2 0 . 0 4 (2)  c  22.11(2)  =  (A )  measured  density  flotation  3  CC£ /CH I 4  Z (gm./cm .) 3  F(000)  (cm. space  - 1  2.02 3040  absorption )  group  Ci H i A s F 8  2  2  l t  Ru O 3  a =  9.07(1)  a  b =  18.53(1)  b =  c  21.81(1)  c  =  coefficient y  2  6  l t  monoclinic a =  25.06(2)  18.795(5)  b  =  13.27(2)  = 16.69(5) •  c  =  11.56(2)  3 =  102.8(2) 3749  2. 0 4 ± 0 . 0 2  2.22±0.02 3  2  8.594(3)  2696  2.14±0.02 4  o C i 1H1 A s F M o 0 567.7  orthorhombic  CC£ /CHBr  i  917.3  orthorhombic  =  L'Mo(COKt  CC^/CHBr  3  CC^^/CHBrs  3  8 density  2  3666  (gm./cm .) 2 . 0 1 ± 0 . 02  i n  calculated  itH i t A s i j F s R u s O s  (CO) i o  3  93.7(2) 5129  3  LRu  8  1195.3  monoclinic  B = volume  2  781.2  o  cell  C  3  data.  45  4  4  8  2.17  2.26  2.01  2272  1736  2096  51  43  45  (Mo-K^)  F_ i/£ 2  ^2h^  P b c n (D*£)  P2i2i2i  (Dj)  C2/c  (Cj ) h  KD  Table absent  spectra  26 (Mo-K_ ) max.  II.I  (continued)  hOl  I =  2n+l  Okl  k  =  2n+l  hOO  h  =  2n+l  hkl  h+k  =  OkO  k  2n+l  hOl  I  =  2n+l  OkO  k  =  2n+l  hOl  I  2n+l  hkO  h+k  =  001  I  =  2n+l  2n+l  =  35  40  45  40  minimum i n t e r p l a n a r spacing (A)  1.18  1.04  0.93  1.04  number with  of 26  reflections < 26 max.  3234  1712  2028  1750  number  of unobserveds  710  205  200  240  0.04  0.02  0.02  0.02  a  d  i n a  axis to  (deg.)  =  expression  2  mounted  ct a x i s  parallel  of  diffractometer  scan  speed  time  f o r background L  and  2n+l  4  2  2  2  10  20  20  20  (deg./min.)  L'  (sec.)  represent  the ligands  Me AsC=C(AsMe )CF CF 2  2  2  2  and  Me AsCF(CF )CF AsMe 2  3  2  2  respective  III.  THE  STRUCTURE  DETERMINATION  OF M e A s C = C ( A s M e ) C F C F • F e 2  2  2  2  3  (CO) i  0  1  STRUCTURE A N A L Y S I S The that,  with  asymmetric  t e n heavy  complicated.  unit  atoms,  Two p o s s i b l e  the Patterson function orientations  origin  region,  peaks,  i t was n o t i m m e d i a t e l y  further  c o n t a i n s two m o l e c u l e s , so  appeared  b u t as a r e s u l t o f t h e l a r g e possible  was  i nthe  number o f  to derive  any  information. An  attempt  was t h e n made t o s o l v e  the  structure 24  by  d i r e c t methods u s i n g Hoge's s e r i e s  which  apply Sayre  relationships  of four  programs  i n two d i m e n s i o n s  i nthe  25a Vand  and Pepinsky  version  o f t h e Cochran  and  Douglas  25b procedure.  The i n i t i a l p r o g r a m  first  calculates  a  2 Wilson plot  f o rthe data  and outputs  and  an o v e r a l l t e m p e r a t u r e  and  outputs  values  those  The s e c o n d and s o r t s  program reads  the data  reflections  The n e x t  termination of  stage of t h i s  o f a l l Sayre  the probability with  (E's).  Sayre  solutions,  possible  groups, a  including  specified the de-  and t h e c a l c u l a t i o n  holds.  The t h i r d  relationships  rejecting  dis-  output of  program involves  these  determine  to indicate the  | E | exceeds  each  Average  electron  parity  which  scale  calculates  t h e tape  relationships  uses  any i i  into  f o rwhich  gram o f t h e s e r i e s  for  factors  o r absence o f a centrosymmetric  first  value.  and then  calculated  2  tribution.  only  normalized structure  o f | E |and | E | a r e then  presence  the  factor  an o v e r a l l  those  pro-  to  f o r which,  SMAX = I h  | Eg-1 " |  | - | EJJ_  (where ri i s a r e f l e c t i o n c o n t a i n e d which  fails)  correctly involved  exceeds  a preset  the probability  given  by t h e Sayre  P(S)  =  from  i n a Sayre  that  the sign  relationships  relationship  o f Eg i s  i n which  i t i s  the expression  J2tanh(o- /o-!/  % +  O.D  value.  Since  i s calculated  |  £ |Eg| • |Ej^| • |Eg_j>| )  2  3  (3.2)  Jc then in  i f only  Sayre  relationships  which  t h e s u m m a t i o n , e q . 3.2 b e c o m e s  sign  o f i ii s opposite  by  setting  of  0.985,  the  a value  t o that  given  f o r which  extent of this probability Those s o l u t i o n s  tity  attained  out with  t h e number o f p l u s  of  the following SEEE**2  =  any s i g n  c a n be  and  Hence  probability  i s incorrect  to  rejected.  are within  the limits of of this  solution,  i n the solution  quanas w e l l  and t h e v a l u e  Z(^|Ejv|.|E^|.|Eg_j>|)  2  (3.3)  k  S i s a r e f l e c t i o n contained  i n a Sayre  relationship  fails. The most p r o b a b l e s o l u t i o n  to  that the  expression h  which  to a  t h e maximum v a l u e  signs  included  i n the solution.  f o rany r e f l e c t i o n i n each  as  where  which  are  the probability  o f SMAX c o r r e s p o n d i n g  a l lsolutions  SMAX a r e p r i n t e d  fail  be t h a t  which  minus s i g n s  has approximately  would  t h e n be e x p e c t e d  e q u a l numbers  and t h e minimum v a l u e s  of plus  f o r SMAX a n d S E E E * * 2 .  24  The program  and  suitable taining  number o f  malized III.l  the  to the  to  In  the  present  and  the  signs  acceptance  29,  and  a  i t is  of  criteria  outstanding  34  this  of  the  With of  the  terson the  two  heavy  as  input  a Fourier  arsenic  atoms,  the  meters  utilized  the  by  projection  the  with  was  norTable  solutions which  above.  Sets  meet  17,18,24,26,  a Fourier calculation. lowest and  probability  the  revealed  atoms on  E-map the  in  the  and  refocussed  fluorine  remaining  III.l)  unit.  z-parameters on  the  Pat-  structure  Sixty-one  of  atoms were  phases based  the  positions,.in  asymmetric  y-  Set  (Figure  i n the  derived.  and  three  subsequent e l e c t r o n density Preliminary  a-axis  three-dimensional  summation w i t h and  to  signs  oxygen,  con-  only  51  test,  a t o m u n i t s was  carbon,  specified  the  a t t e n t i o n was the  tape  were determined.  the  heavy  a  first  1.4  information  f u n c t i o n , and  sixty-four from  ten  the  program  reflections  mentioned  set of  atoms,  heavy  Okl  i n having  this  from  generated. the  |E| >  opposite-indication-of-sign computed w i t h  E's  to produce  once,  comparison of  were used  projection,  third  work,  structure factor  33  the  the  a Fourier calculation  s o l u t i o n as  contains  was  from  s i x solutions at  the  29  signs  for input up  examined  f o u r t h program uses  on  the  atoms were  of the  located iron  and  found  on  map.  least-squares  block-diagonal  refinement  of  approximation,  the  para-  and  re  -  a  Table  III.I  C o m p a r i s o n o f 51 s o l u t i o n s Hoge's Set  Number o f pluses  sign  SMAX  determination  SEEE**2  Set  from  program  Number o f pluses  SMAX  SEEE** 2  1  21  12.4  1026  22  18  12. 4  1525  2  22  12. 8  985  23  20  12.8  1449  3  20  12.4  992  24  16  12. 3  710  4  21  12. 8  951  25  17  12.3  1192  5  23  12.9  1450  26  16  12.0  587  6  20  12.4  1355  27  17  12.0  1005  7  21  12.8  1275  28  25  11.9  1269  8  20  12.4  1072  29  17  10.2  686  9  22  12. 4  1200  30  21  12. 8  1409  10  17  12.4  1196  31  22  12.9  1612  11  21  12. 8  1159  32  20  12. 8  169,0  12  21  12.4  1213  33  20  12.8  878  13  16  12.4  1578  34  21  12.8  1380  14  20  12. 8  1173  35  24  12. 8  1437  15  19  12.3  1204  36  23  12.3  1239  16  22  12. 3  1069  37  24  12.8  1342  17  21  11. 8  541  38  19  11.3  1091  18  20  11.3  969  39  18  12. 8  1194  19  23  12.8  1147  40  18  12.9  1254  20  22  12.9  1671  41  17  12.3  1080  21  21  12.4  1529  42  17  12.8  924  Table I I I . l Set  Number o f pluses  SMAX  43  16  12. 8  44  24  45  (continued) Set  Number o f pluses  SMAX  SEEE**  1416  48  19  12. 8  1415  12.8  1606  49  16  12.0  1241  16  11.2  940  50  15  12. 8  1275  46  22  12.8  1773  51  18  12.7  1084  47  18  12.3  1381  SEEE**2  duced R t o 0.11. A t t h i s stage, a t h r e e - d i m e n s i o n a l d i f ference  map showed e l e c t r o n d e n s i t y  f l u c t u a t i o n s around  the i r o n and a r s e n i c atoms which i n d i c a t e d thermal motion.  Refinement was continued using  f u l l - m a t r i x procedure. w i t h w = {A + B | F reflections.  a modified  The f u n c t i o n minimized was Zw(F -kF ) Q  c  | + Q | F | + D | F | } - f o r the observed 2  3  1  Unobserved r e f l e c t i o n s were excluded from the  refinement but i n c l u d e d culation.  anisotropic  i n the f i n a l s t r u c t u r e f a c t o r  cal-  The c o e f f i c i e n t s A, B, C, and D were adjusted by  a short least-squares  program w r i t t e n by the author (see  S e c t i o n VII) t o achieve best of £w(F -kF ) o c  2  constancy o f l o c a l averages  over the f u l l range of I F I , the f i n a l values -o J  1  1  being 600, 0.3, -0.06, and 0.00027 r e s p e c t i v e l y . f a c t o r s were from r e f . 26 and i n c l u d e d dispersion correction.  Scattering  the r e a l p a r t of the  The v a r i a b l e s r e f i n e d were the  p o s i t i o n a l parameters, a n i s o t r o p i c thermal parameters f o r . the t e n heavy atoms, i s o t r o p i c thermal parameters f o r the other atoms, and a s i n g l e o v e r a l l s c a l e f a c t o r , a t o t a l of.  Figure  III.l  E-map w i t h heavy  atoms  final  refined  superimposed.  positions  of  347 v a r i a b l e s .  Since the dimensions  o f the computer pro-  gram used were l i m i t e d t o 249 v a r i a b l e s , to vary d i f f e r e n t combinations cycles.  necessary  o f parameters i n s u c c e s s i v e  No parameter c o r r e l a t i o n c o e f f i c i e n t s g r e a t e r than  0.35 were observed, six  i t was  cycles.  and f u l l convergence was reached  F i n a l values o f R and R ^ were 0.090 and 0.096 — —w  1  respectively  f o r the 2524 observed  and 0.117 r e s p e c t i v e l y  r e f l e c t i o n s and 0.131  f o r a l l data.  A final  difference;  s y n t h e s i s showed maximum f l u c t u a t i o n s of +0.8 e/A . 3  observed  after  and c a l c u l a t e d  Final  s t r u c t u r e f a c t o r s are g i v e n i n i  Table I I I . I I . F i n a l p o s i t i o n a l and thermal parameters are g i v e n i n Table I I I . I l l , calculated cycle.  together with t h e i r standard d e v i a t i o n s  from the i n v e r s e matrix o f the l a s t  The weighted  refinement  mean planes of the i r o n t r i a n g l e and  d i - ( t e r t i a r y a r s i n e ) l i g a n d of each molecule  are g i v e n i n  Table I I I . I V , and the bond d i s t a n c e s and valency angles are i n Table I I I . V .  t  ^ R = £ IF -F I/I|F I; — '-o - c " '-o 1  R = {Ew(F -F ) /2wF } -w - -o -c —o 2  /  2  l / z  Table Final  measured  reflections  and c a l c u l a t e d  have an a s t e r i s k  29  III.II structure after  the  factors. F  -o t im r.Air  o  1*  107  114  10  1"»T  117  ^  i  i 1*1 m  is*  Z"  11  !«•>  0 -1?  1  ZOI 2QT  Z6<1  I?  I"*  157  10  101  10*  1'  nss c u e  L  nss C*LC  Unobserved  value. l OBS CAIC  30 Table  i  cm  III.II  CMT,  (continued)  t  nos  C»L<"  -I 111 IJ*  -1 iza 111 • -4  1*0  1*9  Table Final  positional  (fractional, deviations  Molecule ATOM  X  3759 Fed) Fe(2) 1932 Fe(3) 1871 A s (4) 0196 A s (5) 012 3 4694 C ( 6) 4249 C ( 7) C ( 8) 3046 C ( 9) 4546 C (10) 1994 C (11) 2881 C (12) 2732 C (13) 1908 C(14) 1945 C (15) 0999 C (16) 0063 C (17) -0819 C (18) 0165 C(19) -0710 C (20) -0903 C (21) -0919 C (22) -2184 C (23) -2172 F (24) -2237 F (25) -2908 F (26) -2951 F (27) - - 2 3 4 1  0773 0822 0053 0762 -0490 1330 0122 1380 0498 1685 0779 -0627 0271 -0133 0868 -1445 -0300 0405 1564 0172 -0222 -0009 -0456 -0284 0507 -0304 -109 8  x 10 )  and t h e r m a l  h  are given  parameters.  Molecule z  ( 2) ( 2) ( 2) ( 2) ( 2) (18) (20) (19) (15) (17) (15) (15) (16) (18) (16) (19) (18) (17) (19) (12) (14) (18) (21) (11)  (ID (ID  (11)  1986 2646 1738 3092 1633 2313 2501 1537 1421 2609 329 2 1691 0975 2620 1849 1706 0884 3903 3118 2681 2224 2810 2266 3355 2770 1840 2398  B(A ) 2  ( 2) ( 2) ( 2) ( 1) ( 1) (16) (18) (17) (14) (14) (14) (13) (16) (16) (14) (17) (16) (16) (17) (12) (13) (16) (18) (11) (10) (10) ( 9)  5 .7 6 .7 6 .2 4 .0 4 .5 4 .1 3 .6 4 .9 5 .2 4 .6 7 .1 6 .4 5 .8 7 .3 2 .3 3 .9 5 .3 7 .2 8 .5 8 .6 8 .5 7 .7  Standard  i n parentheses.  1  y (. 3) ( 3) ( 4) (3) ( 3) (31) (33) (30) (25) (27) (25) (26) (27) (29) (27) (31) (30) (29) (32) (21) (25) (29) (35) (19) (19) (19) (17)  III.Ill  ( 8) (10) ( 9) ( 7) ( 8) (7) ( 7) ( 8) [ 8) ( 7) (10) ( 9) ( 9) (10) ( 6) ( 7) ( 8) (10) ( 6) (6) ( 6) ( 5) -  X 8370 6462 6492 4616 4683 9362 7881 8602 9233 7087 6759 6756 7265 5772 6281 3993 4406 3900 4256 3474 3508 2143 2195 1544 1874 1897 1612  2 z  y ( 4) ( 4) ( 4) ( 3) ( 3) (36) (31) (28) (33) (25) (29) (29) (34) (27) (27) (31) (33) (27) (29) (29) (24) (31) (28)" (17) (18) (17) (18)  2441 3155 2248 3527 2109 2764 1830 3035 1892 3905 3031 1425 2323 2228 3266 1239 2319 3356 4471 3127 2691 3240 2755 3078 3854 2950 2176  (3) ( 2) ( 2) ( 2) ( 2) (20) (19) (18) (20) (16) (18) (20) (20) (16) (17) (18) (19) (16) (17) (18) (15) (19) (18) (10)  (ID  (10)  (ID  0695 0738 -0048 0792 -0529 1247 1184 0172 0354 0714 1546 0014 -0694 0699 -0138 -0461 -1404 1546 0625 0239 -0202 0099 -0377 0555 -0066 -0961 -0322  B(A ) 2  ( 2) ( 2) ( 2) ( 1) ( 1) (19) (17) (16) (17) (13) (18) (15) (19) (15) (15) (16) (17) (14) (15) (16) (13) (17) (16) ( 9) (10) (10) (10)  7 .5 (10) 6 .3 ( 9) 5 .4 ( 8) 6 .7 ( 10) 3 .9 ( 7) 6 .3 ( 9) 5 .6 ( 9) 7 .4 ( 10) 4 .7 ( 8) 4 .6 ( 8) 6 .6 ( 9) 7 .2 ( 10) 5 • K 8) 5 .7 ( 9) 5 .9 ( 9) 3 .7 ( 7) 6 . 1 ( 9) 5 • K 8) 7 .6 ( 5) 8 . 1 ( 6) 7 .6 ( 5) 8 .2 ( 6) h-  1  Table Molecule ATOM  x  0(28) 0 (29) 0(30) 0(31) 0 (32) 0 (33) 0(34) 0(35) 0(36) 0(37)  Molecule  z 2543 2820 1218 1018 1590 0464 3745 2615 2926 1602  k_2  2  X  B(A ) 2  (11) (12) (10) (11) (11) (12) (11) (10) (10) ( 9)  b_3 3  6 . 9 ( 6) 7 .1 ( 6) 5 .8 ( 5) 6 . 2 ( 6) 7 . 1 ( 6) 6 • 8 ( 6) 6 • 6 ( 6) 6 . 6 ( 6) 6 . 1 ( 6) 4 . 8 ( 5)  b  i  2  2  9953 (25) 7 6 6 8 (22) 8924 ( 2 2 ) 9 7 5 3 (21) 6 9 0 5 (21.) 7665 (25) 6826 (20) 7446(21) 5238 (18) 6110(19)  3063 1444 3447 1455 0838 2401 2973 4475 1911 3625  b 13  b  2  3  B(A  z  y  1 5 8 4 (13) 1 5 6 0 (12) - 0 1 5 5 (12) 0 1 5 8 (11) 0083 ( I D - 1 1 6 7 (14) 2 0 6 2 (12) 0 6 6 7 (11) 1 0 2 3 (10) -0531(11)  (15) (14) (14) (14) (14) (14) (12) (13) (11) (12)  *  53 44 56 48 59  26 27 30 21 24  22 21 17 20 21  -4 -6 -6 -4 -10  4 4 4 5 0  0 -10 - 5 - 6 - 7  48 66 54 65 71  41 27 30 21 26  26 31 26 23 19  0 -1 3 1 -2  -1 -6 2 5 -4  3 -8 -6 -3 -3  .4  1  1  2  2  1  2  Fe(l) Fe(2) Fe(3) A s (4) A s (5) M e a n -a  COEFFICIENTS  I N THE T E M P E R A T U R E  EXPRESSION:,  exp-10"  (b i i h  2  + b  2  2  k  +  2  + b  3 3  2bi h£ 3  l  2  +  + 2b  2b i h k 2  2 3  2  )  9 • 3 ( 8) 8 • 2 ( 7) 8 • 0 ( 7) 7 • 5 ( 6) 7 . 4 ( 6) 9 . 2 ( 8) 7 • 2 ( .6) 7 • K 6) 5 . 3 ( 5) 6 . 3 ( 6)  1  Fed) Fe(2) Fe(3) A s (4) A s (5) Molecule  Molecule  1724 ( 1 2 ) - 0 2 6 3 (.13) 1789 (12) 0279(11) -1087(13) 0403 ( 1 2 ) 0789 (12) 2253 ( 1 3 ) -0608 (12) 1 2 1 5 ( 9)  b 11  (continued)  1  y  5 3 5 9 (21) 4 5 9 2 (21) 2 6 6 4 (19) 5 0 4 0 (20) 3 3 2 8 (21) 1 8 7 5 (20) 3 4 2 6 (20) 1 9 4 5 (20) 1 9 1 6 (19) 0301(18)  III.Ill  k£)  Table Equations  Equations X',  Y,  axes  of planes  I I I . IV  of weighted  i n the form  Z_' a r e c o o r d i n a t e s  i n A,  IX'  planes  + mY  referred  + n_Z' = p_, w h e r e to  orthogonal  a,b,c*  m Iron  mean  n  triangle  Maximum displacement (A)  (3 F e a t o m s ) Molecule  1  0.3477  •0.7384  0.5778  2.8059  0  Molecule  2  0.3921  0.6 513  •0.6497  5.9574  0  Di-(tertiary (2 A s  arsine)  and 4 C atoms)  Molecule  1  0.2872  -0.7502  0.5956  2.8559  0.009  Molecule  2  0.2296  0.7076  -0.6683  5.0354  0.037  34  Table Bond d i s t a n c e s  III.V  (A) and v a l e n c y a n g l e s  otherwise s p e c i f i e d ,  (degrees).  standard deviations  o f bond  Unless lengths  a r e 0.03-0.04 A; o f a n g l e s a t F e and A s , 0.7-1.8° ; and o f a n g l e s a t C,  2.2-3.4°.  Molecule Fe Fe Fe Fe Fe  (1) -Fe (2) (1) - F e ( 3 ) (2) - F e ( 3 ) (2) - A s ( 4 ) (3) - A s ( 5 )  1 Molecule 2  2. 652 (8) 2. 651(7) 2. 527 (6) 2. 301 (7) 2. 300 (6)  Fe (1) -C(6) 1. 69 F e d ) -C(7) 1. 80 F e d ) -C(8) . 1.74 Fe (1) -C(9) 1. 69 Fe (2) -C(10) -.1. 73 Fe (2) - c d i ) 1. 75 Fe (3) -C(12) . 1.70 Fe (3) -C(13) 1. 75 AVERAGE F e -G  term F e ( 2 ) -C(14) • 1.91 F e ( 2 ) -C(15) 2. 01 Fe (3) -C(14) 1. 98 F e ( 3 ) -C(15) 1. 94 As (4) -C(18) As (4) -C(19) As (5) -C(16) As (5) -C(17)  2. 643 (7) 2, 671 (9) 2. 517(7) 2. 278 (6) 2. 307 (7) 1. 75 1. 75 1. 69 1. 70 1. 67 1. 81 1. 68 1. 74  1.73 2. 02 1. 95 1. 90 2. 06  1. 93 1. 92 1. 92 1. 96  1. 94 1. 97 1. 93 1. 98  Molecule 1 Molecule 2 As (4)-C (20) As ( 5 ) - C ( 2 1 )  1. 92 1. 91  1. 92 . 1.97  C (20)-C(21) C (20)-C(22) C(21)-C(23) C ( 2 2 ) - C (23)  1. 28 1. 58 1. 54 1. 50  1. 31 1. 57 1. 55 1. 44  C(22).-F(24) C ( 2 2 ) - F (25) C ( 2 3 ) - F (26) C ( 2 3 ) - F (27)  1. 33 1. 33 1. 30 1. 34  AVERAGE C-F  1. 33  C(6)-0(28) C (7)-0(29) C ( 8 ) - 0 (30) C ( 9 ) - 0 (31) C ( 1 0 ) - O (35) C(ll)-0(34) C(12)-0(32) C (13)-0(33) C(14)-0(36) C ( 1 5 ) - 0 (37)  1. 19 1. 10 1. 15 1. 18 1. 14 1. 15 1. 18 1. 16 1. 17 1. 18  AVERAGE AVERAGE A s -Me  1.94  C-0  1.16  ;  1. 30 1. 32 1. 37 1. 35  1. 15 1. 17 1. 17 1. 16 1. 22 1. 14 1. 20 1. 18 1. 17 1. 13  35  Table  III.V  Molecule 1 C ( 6 ) -F e ( l ) C ( 6 ) -F e ( 1 ) C(6)- Fe(1)C(6)- F e ( l ) C(7)- Fe(1)C(7)- Fe(1)C(7)- Fe(1)C(8)- Fe(1)C ( 8 ) -F e ( 1 ) C ( 8 ) -F e ( l ) C(9)- F e ( l ) Fe(2) - F e ( l )  C(7) C(8) C(9) F e (2) C(9) F e (2) Fe(3) C(9) F e (2) Fe(3) F e (3) -Fe(3)  (continued) Molecule 1 2  2  92 93 100 105 94 85 88 94 86 85 96 56.9(2)  93 95 100 107 93 93 90 92 79 81 97 56.5(2)  F e (2) - A s ( 4 ) -C ( 1 8 ) F e (2) - A s ( 4 ) - C ( 1 9 ) Fe(2) -As(4) -C(20) C ( 1 8 ) - A s (4) - C ( 1 9 ) C(18) -As(4) -C(20) C ( 1 9 ) - A s (4) -C ( 2 0 ) F e (3) - A s (5) -C ( 1 6 ) F e (3) - A s ( 5 ) - C ( 1 7 ) F e (3) - A s (5) - C ( 2 1 ) C (16) - A s ( 5 ) - C ( 1 7 ) C(16) -As(5) -C(21) C(17) -As(5) -C(21)  119 118 114 104 99 100 120 116 113 104 101 100  116 120 116 104 99 99 116 121 113 103 99 102  C ( 1 0 ) - F e (2) - C d l ) 94 C ( 1 0 )- F e ( 2 ) - C ( 1 5 ) 86 C ( 1 0 )- F e ( 2 ) - A s ( 4 ) 97 C ( l l ) - F e (2) - C ( 1 4 ) 88 C ( 1 1 ) - F e (2) - A s ( 4 ) 100 C ( 1 4 ) - F e (2) - F e ( 3 ) 51 C ( 1 4 )- F e (2) - A s ( 4 ) 88 C ( 1 5 ) - F e (2) - F e (3) 49 C ( 1 5 ) - F e (2) - A s ( 4 ) 87 F e (1) - F e ( 2 ) - C ( 1 0 ) 89 88 F e ( l ) -Fe(2) - C ( l l ) F e (1) - F e (2) - C ( 1 4 ) 87 F e (1) - F e (2) - C ( 1 5 ) 86 F e (1) - F e (2) - F e ( 3 ) 6 1 . 5 (2) F e (3) - F e ( 2 ) - A s ( 4 ) 1 0 9 . 1 ( 2 )  96 83 97 88 96 48 86 53 89 97 82 80 94 62.3(2) 109.1(2)  A s (4) -C ( 2 0 ) - C ( 2 1 ) A s (4) - C ( 2 0 ) -C ( 2 2 ) C (21) -C ( 2 0 ) - C ( 2 2 ) A s (5) -C ( 2 1 ) - C ( 2 0 ) A s (5) -C ( 2 1 ) -C ( 2 3 ) C (20) -C ( 2 1 ) - C ( 2 3 )  137 131 92 137 127 96  134 134 92 136 130 93  C ( 2 0 ) - C ( 2 2 ) -F (24) C (20) -C ( 2 2 ) - F ( 2 5 ) C ( 2 0 ) -C ( 2 2 ) -C ( 2 3 ) F (24) - C ( 2 2 ) - C ( 2 3 ) F (24)- C ( 2 2 ) - F ( 2 5 ) F (25)- C ( 2 2 ) - C ( 2 3 )  111 114 86 119 109 117  112 114 88 117 109 117  C ( 1 2 ) - F e (3) - C ( 1 3 ) C ( 1 2 ) - F e (3) - C ( 1 4 ) C ( 1 2 ) - F e (3) - A s ( 5 ) C ( 1 3 ) - F e (3) - C ( 1 5 ) C ( 1 3 ) - F e (3) - A s ( 5 ) C ( 1 4 ) - F e (3) - F e ( 2 ) C ( 1 4 ) - F e (3) - A s ( 5 ) C ( 1 5 ) - F e (3) - F e ( 2 ) C ( 1 5 )- F e ( 3 ) - A s ( 5 ) F e (1) - F e ( 3 ) - C ( 1 2 ) F e (1) - F e ( 3 ) - C ( 1 3 ) F e (1) - F e (3) - C ( 1 4 ) F e d ) - F e (3) - C ( 1 5 ) F e (1) - F e (3) - F e ( 2 ) F e (2) - F e (3) - A s ( 5 )  93 90 94 84 98 52 88 49 89 87 93 82 90 61.2(2) 110.7(2)  C(21) -C(23) -F(26) C(21) -C(23) -F(27) C ( 2 1 ) -C ( 2 3 ) -C ( 2 2 ) F ( 2 6 ) - C ( 2 3 ) -C ( 2 2 ) F (26)- C ( 2 3 ) - F ( 2 7 ) F ( 2 7 ) - C ( 2 3 ) -C ( 2 2 )  120 118 86 114 106 113  116 113 88 119 103 118  F e (1) -C ( 6 ) -0 ( 2 8 ) F e (1) - C ( 7 ) - 0 ( 2 9 ) F e (1) - C ( 8 ) - O ( 3 0 ) F e (1) - C ( 9 ) - 0 ( 3 1 ) F e (2) - C ( 1 0 ) - 0 ( 3 5 ) .Fe (2) - C ( l l ) - 0 ( 3 4 ) Fe(3) -C(12) -0(32) F e (3) -C ( 1 3 ) - 0 ( 3 3 )  180 177 174 176 174 173 176  170 172 170 171 174 173 177 172  (2) -C ( 1 4 ) - 0 ( 3 6 ) (3) - C ( 1 4 ) - 0 ( 3 6 ) (2) - C ( 1 5 ) - 0 ( 3 7 ) (3) - C ( 1 5 ) - 0 ( 3 7 )  143 136 139 142  134 146 147 136  95 86 97 88 96 48 90 51 87 88 90 85 87 61.6(2) 110.4(3)  Fe Fe Fe Fe  173  DISCUSSION The  molecule  (Figure  I I I . 2)  i s best  described  as  18 a  d e r i v a t i v e of  g r o u p on by  the  In  each  each  Fe (CO)i 3  of  the  a r s e n i c atoms of  the  two  and  carbon  III,IV)  in contrast the  of  the  the  this  present  of  the  l i g a n d i s not  in  the  two  arsine)  l i g a n d are  the  The  the  distance  1.30(3) A  (standard  retention  of  (Table  III.V)  the  iron so  atoms; .  that  the  planarity  3  character, while  the  bonding  C=C  in LFe (CO)i  deviation i n parentheses),  double-bond  cyclo-  difference in  compounds i s f u r t h e r i n d i c a t e d by  lengths;  latter  of  0  (Table 19  2  the  3  the  LFe (CO)6.  in  in LFe (CO)i ,  unexpected.  unit,  i n the  of  ligand.  coplanar  involvement  t o one  carbonyl  replaced  asymmetric  d e v i a t i o n from p l a n a r i t y  i s not  atoms  non-planarity  iT-electrons i n bonding  bonding  iron  i n the the  compound i s a s s o c i a t e d w i t h butene  equatorial  di-(tertiary  atoms o f  to  one  equivalent  molecules  arsenic  Presumably  two  / with  2  bond is  0  indicating  r  corresponding  o  length  i n LFe (CO) 2  involvement  of In  the  each  asymmetric u n i t , iron  triangle,  different between  Since  the  the  the  two  the  two  LFe (CO)io  amount o f  molecules.  angle  quite  bending  is different  bent,  i n the  two  an  iron  is  the  with  the  slightly 1 the  i s only the  atom.  in  coplanar  In molecule  ligand planes  2 i s more s i g n i f i c a n t l y  to  the  molecules  3  l i g a n d i s not  t h e - t r i a n g l e and  molecule  consistent with  iT-electrons i n bonding of  and  i n the  i s 1 . 5 1 ( 4 ) A,  6  angle  3.7°,  angle  but  being  molecules,  the  9.9°.  to  38  s m a l l d e v i a t i o n s from p l a n a r i t y are probably c r y s t a l packing The  a r e s u l t of  forces.  bond lengths  and valency  angles  i n the two  L F e ( C O ) i o molecules i n the asymmetric u n i t are not s i g 3  nificantly different  (Table I I I . V ) .  The Fe-Fe d i s t a n c e s  i n the i s o s c e l e s i r o n t r i a n g l e are 2.65(1) A f o r the o  e q u i v a l e n t bonds, and 2.53(1) A f o r the c a r b o n y l - b r i d g e d bond.  These lengths  are c l o s e t o the d i s t a n c e s o f 2.67(1) A  o  and  T O  2.56(1) A f o r the parent  Fe (CO)i 3  molecule,  2  so t h a t  replacement of two t e r m i n a l c a r b o n y l groups by the d i ( t e r t i a r y a r s i n e ) l i g a n d has apparently l i t t l e disturbance  proceeded  of the bonding i n the i r o n  with  triangle.  The mean Fe-C(terminal) to the d i s t a n c e found m  d i s t a n c e i s 1.73 A, c l o s e 27-30 r e l a t e d compounds, and a l l 31  the Fe-C-0 are c l o s e t o l i n e a r , as expected. (bridging) d i s t a n c e s are c o n s i d e r a b l y bridges  appear t o be s l i g h t l y  longer,  asymmetric  and the  (Figure I I I . 3 ) .  The mean o f the f o u r longer F e - C ( b r i d g i n g ) standard  The Fe-C  bonds  (with  d e v i a t i o n of the mean) i s 2.02(2) A, w h i l e  the :  a  average of the s h o r t e r bonds i s 1.93(2) A, the d i f f e r e n c e being g r e a t e r than 3a and probably asymmetry i s s i m i l a r t o , although  significant.  This  not as pronounced as  t h a t found i n P h P F e 3 ( C O ) i i (average F e - C ( b r i d g i n g ) , 2.04 '27 27 and 1.87 A).. As Dahm and Jacobson p o i n t out, this asymmetry need not be the r e s u l t of c r y s t a l packing f o r c e s , but c o u l d be i n h e r e n t i n the bonding of the parent F e ( C O ) i , 3  0  3  2  Figure  III.3  View  of  asymmetric  carbonyl  bridges. oo  in  which  there  carbonyl and  the  i s some  groups.  18  evidence  The  C-0  d i s t a n c e s i n the  nificantly  longer  than  bond  the  other  bond  (Table  III.V)  are  quite  similar  pounds.  The  to  i n Ph P F e 3 ( C O ) 1 1  i n the  arsine)  average  carbonyls  lengths to  and  ° A,  1.17  are  not  valency  those  Fe (CO)io  sig-  angles  in related  moiety  3  are  com-  similar  27 and  3  di-(tertiary  bridging  average.  the  those  lengths  bridging  All  angles  f o r unsymmetrical  ligand  are  the  dimensions  close  to  of  those  the •  in LCo (CO) 2  6  ^  19 and  LFe (CO)6 2  non-planarity valency  apart  from  the  ligand  of  differences  i n the  latter  at  arsenic  show d e v i a t i o n s  tetrahedral  value  (Figure  III.4),  121°)  being  larger  Fe-As  bond  in  angles  the  lengths  LFe (CO) 2  The thermal are  and  1 9 6  i n Table  approximately  the  (mean  C-As-C o  2.297 A)  of  the  ellipsoids III.VI.  of The  perpendicular to  the  the  The exact  angles  (113-.  (99-104°).  correspond  to  those  found  3 3  principal iron  largest the  from  angles  the  by  compound.  Fe-As-C  {Fe(CO)3}2(AsMe3)*.  magnitudes  vibration  given  than  the  caused  axes and  of  the  arsenic  vibrations  plane  of  the  atoms  are  iron  t r i -  angle. All normal  van  the  der  intermolecular distances correspond  Waals  interactions,  the  closest  to  approaches  D  being so  about  that  molecule  an  3.1  A.  oxygen  i n the  The atom  molecules of  asymmetric  are  a bridging unit  arranged  (Figure  c a r b o n y l group  i s approximately  of  III.5) each  equidistant  42  Table Magnitudes the  III.VI  (A, a = 0 . 0 0 5 - 0 . 0 0 8 A) o f t h e p r i n c i p a l a x e s o f  thermal v i b r a t i o n  ellipsoids of the iron  Molecule Axis  1  Axis  2  1  and a r s e n i c Molecule  Axis  3  Axis  1  Axis  2  atoms  2 Axis  Fe(l)  0.186  0.233  0.235  0.179  0.249  0.292  F e (2)  0.165  0.175  0.277  0.195  0.223  0.298  FeO)  0.190  0.192  0.261  0.190  0.222  0.273  A s (4)  0.177  0.179  0.249  0.194  0.212  0.243  As (5)  0.166  0.218  0.260  0.193  0.232  0.240  43  a  Figure  III.5  Intermolecular  contacts  i n general  view.  from  three  iron  atom  of  the  of of  the the  molecular  four other  terminal  carbonyl  molecule.  packing  i s shown  groups  Another, i n Figure  of  the  simplified III.6.  unique view  IV.  THE  STRUCTURE  DETERMINATION  {Me AsC=C(AsMe )CF CF } -Ru (CO) 2  2  2  2  2  3  OF 8  STRUCTURE The requiring graphic  asymmetric  that  the  symmetry  i t was  at  (0,y_,%)  of  of  three  Pbcn.  The  219  f a c t o r |E| >  be  i n which  l o c a t e d on  a  the  by  Sixteen  were  not  atoms  solved  Long's  relationships  is  two-fold  normalized by  molecule,  crystallo-  ruthenium  methods.  having  a  molecule  l i e on  determined  Sayre  the  three  to  direct  were  half  s t r u c t u r e was  reflections  1.50  contains  Since  expected  dimensional  for  gram,  molecule  ( i t contains  triangle),  signs  unit  element.  centrosymmetric  ANALYSIS  in  a  axis the  sets  use  of  structure  computer  pro-  applied i n  an  34 iterative of  seven  with  procedure. signs  other  and  c o n d i t i o n s imposed The  first  origin  can  be  The  other  four  negative  signs  way  the  by  that the  From signs  of  allowed  in turn.  starting  the  The  set  sorted  bottom  of  the  starting  set  changes  with  are and  list  not the  the  on  on  are the  sets,  below  E's  the  both  of  positive  |E|.  predicts new  to  change).  signs  the  newly  (the The  the  prelist.  iteration  reflection  a  followed  Each  the  and  i n such  decreasing program  the  signs.  f u r t h e r down  eighth  group  specify  ordered  i s reached,  number  space  to  set  conjunction  positive  list.  signs  in  beginning,  of  the  allowed  starting  by  chosen  take  i s at  determine  starting  are  E's  a  equation  the  i n order  starting  uses  assigned  to  to  the  sign  E's  i s used  repeated, the  are  for reflections  diction When  of  three  on  arbitrarily  remainder,  each  program  a p p l i e s Sayre's  symmetry. and  The  is  signs number  determined  of  48  are  counted  converged list  for  when  each  cycle  there  and t h e i t e r a t i o n  a r e no a d d i t i o n s  i s said  t o o r changes  t o have i n the  of signs. A  consistency  U  = <  index,  U, i s d e f i n e d  as  34  (4.1)  J_Jli_Jl2Jl3i_ |ES1I=IEKJ |E |> ga  where and  t h e sums  where  solution will  <> m e a n s will  have  correct verges  a comparison  a  that  and  numbers  positions  o f four  (assigned  this  independent  and thermal  persion  factors  i n three  of ref.  c o r r e c t i o n was a p p l i e d .  cycles to  index  signs.  (0.95) An  was  as expected. four  improved  refinement, 26.  outstanding  indicated the  o f these  a s t w o A s a n d t w o Ru) w e r e  9 was  one o f which  rotation axis  parameters  solutions  consistency  atoms,  equally  Table IV.I  Solution  s e tof signs  full-matrix least-squares  scattering  possible  converged  the highest  on t h e two-fold  positions  of  procedure  i t  and con-,  are approximately  structure.  The t r u e  o n e , i.e.  cycles  o f p o s i t i v e and negative  E-map c a l c u l a t e d w i t h  situated  which  2  Usually the  iterative  of the sixteen  having  of hi".  index.  fewer  ri +ri3=Fii  f o r which  3  a l l values  p o s i t i v e and negative.  the iteration  equal  and ia  consistency  f o rt h e p r e s e n t  s e to f signs  2  consistent  requires  between  over  n"  be t h e most  t o a s e to f signs  generated in  usually  solution  a l l pairs  "average  the highest  distributed gives  a r e over  The r e a l  i  The  atoms b y two c y c l e s  with  use o fthe  part  of the dis-  A difference  synthesis  Table I V . I Comparison Long's Set  Signs o f starting set  o f t h e 16 s o l u t i o n s  sign  determination  from  program  Number o f cycles  Number o f pluses  Number o f minuses  Consist! inde: U  1  +++++++  7  109  110  0.539  2  ++++++-  8  103  116  0.464  3  +++++-+  12  112  107  0 .641  4  +++++—  5  117  102  0. 8 9 6  5  ++++-++  12  116  103  0.588  6  ++++-+-  6  108  111  0.638  7  ++++—+  5  108  111  0.691  8  ++++  8  103  116  0.543  9  +++-+++  3  109  110  0.954  10  +++-++-  6  109  110  0.909  11  +++-+-+  5  110  . 109  0.684  12  +++-+—  10  108  111  0.481  13  +++—++  7  106  113  0. 899  14  +++—+-  8  102  117  0.557  15  +++  7  110  109  0.680  16  +++  12  105  114  0.424  +  ;  phased all  on  the  twenty  r e f i n e d parameters  carbon, Two  mization for  of  cycles Ew(F  observed  -F  constant  range of and  If  w  2  =  matrix  peaks  and  final  values  arsenic  treating cycles  this  the  of  At  atoms.  stage  R  C,  and  w(F -F ) Q  37.32,  stage  around  the  the  thermal parameters scale  for  the  factor, for  convergence of  the  and  0.098 r e s p e c t i v e l y ,  and  0.088 and  and  calculated  0.114  the  1.09,  a  -0.0159,  positions cycles  A  1507  respectively,  map  of  refinement,  factors  showed  map  of  of  difference  necessity  the  fullfor  map  of  also  Two  thermal  a t o m s , and  total  the  whole  final, varying  parameters  f l u o r i n e atoms, i s o t r o p i c  other  for  structure  difference  and  adjusted  thermal parameters  anisotropic  arsenic,  from  a difference  further  0.089.  3 -1  cal-  over  2  c  I}  DlF  f u l l - m a t r i x r e f i n e m e n t were c a r r i e d out  ruthenium,  mini-  D were  f l u o r i n e atoms a n i s o t r o p i c a l l y .  the  final  of  indicated  for  A  B,  Two  to  p o s i t i o n a l parameters,  final  +  2  factor  A,  anisotropic  the  overall  I  C|F  structure  being  of  atoms.  I +  BlF  this  troughs  atoms r e d u c e d  computed a t  +  0.124.  refinement using  heavy  {A  in final  to  and  positions  (unobserveds were excluded  0.00008 r e s p e c t i v e l y .  ruthenium  fluorine  average values  |, the  showed s m a l l  the  ) ,  R  and  the  f u l l - m a t r i x refinement, with  included  culation) , reduced give  of  reflections  refinement but  to  oxygen,  revealed  133 R —  a  single  variables.  and  R  were  0.078  —w  observed r e f l e c t i o n s ,  f o r a l l data. are  At  listed  Measured  i n Table  f l u c t u a t i o n s around  the  IV.II. heavy  Table Final  measured  reflections  and c a l c u l a t e d  have  an a s t e r i s k  IV.II  51  structure  factors.  after the 1  L  0 0 0 C  0  OBS C«LC  L  * D» 37 6 1*5 159 « 94 109 10 51 *S 12 111 UT 14 111 »s* 1* 121 121 IB 4* •> 10 112 101 0 456 4 31 1 216 191 2 10) 10*  6 I • 9 10 11 12 11 14 14 16 IT 11  290 30T 224 231 91 48 161 192 266 291 215 227 1B9 Z07 159 ITT 159 ISM *• IB 152 152 0* ' 1 102 91  B  116 121  11  1 2  15  101  0  ll It  OBS CALC  OBS C»LC  L 1* 15 16  102 I0B 51 51 109 |09  5  1*4 13T  1  195 190  0  11*  OBS CALC  L  OBS C*LC  153 14*  11* III IB0 |T4  2  106  Ml  2  211 21T  11  142 142  10  146 lfcT  S  26  111  116 504 199 192  14)  114  I  IT0  B  191 1*7  |0  105 11*  IS  102  11  122 114  1*  112 110  5  120 120  I TO 120  126  •  0* 14 40 4T 144 150 10  11T 12*  I  2  value,  It  0  tl  t  F —o  Unobserved  121 112  0  10  15  **  0 0  IB 20 O  23 44 594  16 41 4U  1> 16  102 106  IB  200 140  5  ?45 226  12  6  111 111  B  142 16T  111 121  I  MS  HI  162 14B  116 169  31  atoms  o f +1.5  elements of  e/A,  which  of the structure  random e x p e r i m e n t a l Table  IV.Ill  c o u l d n o t be a t t r i b u t e d and were  gives the f i n a l  parameters,  the  inverse matrix of the last  Standard  deviations  tribution  from  parameters. mean p l a n e s and  carbon  angles  are given i n Table  triangle  of the d i - ( t e r t i a r y  ellipsoids  include  of the  from Bond  IV.IV. a  of the  and t h e  con-  weighted  arsenic  arsine) ligand.  IV.VI. .  ther-  lattice  axes o f a n i s o t r o p i c  are i n Table  and  calculated  IV.V g i v e s t h e e q u a t i o n s  of the ruthenium atoms  result  of refinement.  f o r these q u a n t i t i e s  magnitudes of the p r i n c i p a l vibration  cycle  the standard deviations  Table  a  positional  with standard deviations  and v a l e n c e  t o be  error.  mal  distances  assumed  t o any  The  thermal,  Table Final  positional with  ATOM Ru(l) Ru(2) AS (1) A s (2) F(l) F(2) F(3) F(4) C(l) C(2) C(3) C(4) C(5) C(6) C(7) C(8) Me (1) Me (2) Me (3) Me (4) 0(1) 0(2) 0(3) 0(4)  X  0 0686 0189 2288 2657 0652 1952 3968 2102 2281 0225 -0948 1275 1734 2003 2448 1250 -1618 2171 4427 3360 3278 -0111 -1890  coefficients  1014 -0329 1847 0000 2546 2200 1013 1332 0973 -0586 -1266 0081 1560 1978 0956 1294 2780 2147 -0563 0051 1028 -0782 -1861 0271  standard  z  y  ( 2) ( 3) ( 2) (22) (23) (19) (22) (29) (25) (28) (26) (25) (32) (23) (31) (35) (39) (29) (33) (22) (19) (22) (19)  (fractional,  ( 1) ( 1) ( 1) ( 1) (10) (12) (10) (11) (14) (12) (1.4) (13) (12) (15) (12) (14) (17) (20) (14) (17) (10) ( 9) (11) (10)  2500 3071 3340 3909 4549 4981 5378 4931 2434 2560 3311 3505 4054 4623 4265 4843 3192 3771 4650 3766 2400 2276 3432 3810  i n the temperature  B  ( 1) ( 1) ( 1) ( 8) (10) ( 8) ( 9) (12) (10) (11) (11) (10) (12) (10) (12) (13) (16) (12) (13) ( 8) ( 8) ( 9) ( 8)  IV.Ill x  10 )  deviations  or b i i  1 0 1 4 ( 39) 1 0 1 3 ( 29) 1 3 8 6 ( 41) 1 0 0 3 ( 35) 3493(319) 3799(392) 4149(310) 2783 (363) 4.5 (6) 3.6(5) 4.3(5) 3.8(5) 3.3(5) 5.4(6) 3.2(4) 5.2(5) 6.2(7) 7.4(8) 4.6 (6) 6.0 (7) 5.7(4) 5.1(4) 6.5(5) 5.2(4)  expression:  and t h e r m a l  4  parameters,  i n parentheses.  b  2  2  1 0 1 ( 8) 113 ( 6) 1 1 0 ( 7) 162 ( 8) 267 (79) 623 (94) 414(72) 294 (83)  2  + b 2]S 2  2  +  b  _  b i3  1 8 9 ( 7) 0 28 ( 9) 187 ( 5) 2 4 5 ( 7) 72 ( 1 3 ) 1 8 8 ( 6) 66(13) 463 (53) - 2 9 8 ( 1 3 0 ) 396 ( 6 6 ) 617 (163) 210(51) 181 (120) 571(58) 128(140)  exp - 1 0 ~ ( b i i h 5  bi 2  b_33  3 3 :  £  - 6 8 ( 12) - 44( 9) - 1 2 5 ( 13) - 6 1 ( 11) -637(111) -107(136) -122(100) -691(111)  2  +  2b  2bi h£ 3  1 2  +  hk 2b  0 8 ( 4) - 3 5 ( 5) - 1 5 ( 5) 7(53) -158 (66) - 10(51) - 91(56)  + 2 3  23  k£)  54 Table Bond  distances with  IV.IV  o (A) a n d v a l e n c e  angles  (degrees),  standard deviations i n parentheses.  R u ( l ) -Ru(2) Ru CD- -As(1) R u t 1) - C ( l )  2.853 (3) 2.401(3) 1.91(3)  Ru Ru Ru Ru Ru  2.785 (4) 1.89 (2) 1.86 (3) 1.92(2) 2.413 (3)  (2) -Ru(2' ) (2) - C ( 2 ) (2) -C(3) (2) -C(4) (2) - A s (2)  A s (1) -Me(1) A s (1) - M e ( 2 ) A s (1) -C(5)  2.00 (3) 1.97 (4) 1.92 (2)  A s (2) -Me(3) A s (2) -Me(4) A s (2) - C ( 7 )  1.93 (3) 1.97 (3) 1.95 (2)  C(5)C(5)C(6)C(7)-  C(7) C(6) C(8) C(8)  1.39(3) 1.52(3) 1.46 (3) 1.46 (3)  C(6)C(6)C(8)C(8)-  F(l) F(2) F(3) F(4)  1.35 (3) 1.32 (3) 1.36(3) 1.39 (3)  C(l)C(2)C(3)C(4)-  0(1) 0(2) 0(3) 0(4)  1.15 (3) 1.15 (2) 1.17 (3) 1.14 (3)  c ( l ) - Ru(l)-Ru(2) C ( l ) - Ru(l)-Ru(2') c ( D - R u ( l ) - A s (1) ' c ( D - R u ( l ) - A s (ID c ( D - Ru ( l ) - C ( l ' ) A s (1) - R u ( l ) - A s (ID A s (1) - R u ( 1 ) - R u ( 2 ) Ru(2) - R u ( l ) - R u ( 2 ' )  77.3(8) 98.6(8) 90.7 (8) 92.3 (8) 175.4 (16) 100.0(1) 102.3(1) 58.42 (9)  Ru(2) - A s (2)-C(7) Me (3)- A s ( 2 ) - M e ( 4 ) Me (3) -As(2)-C(7) Me (4)-As(2)-C(7)  116.8 (6) 102.3 (12) 98.6(10) 98:7.(H)  A s (1) - C ( 5 ) - C ( 7 ) A s (1) - C ( 5 ) - C ( 6 ) C(7)- C(5)-C(6)  137.9(17) 131.5(17) 90.6(18)  C ( 2 ) - R u ( 2 ) - R u (2') C(2)- Ru(2)-Ru(1) C ( 2 ) - Ru (2) - A s ( 2 ) C(2)- Ru(2)-C(3) Ru (2 ) - R u ( 2 ) - R u ( l ) Ru(2')-Ru(2)-C(3) Ru(2' )-Ru(2)-C(4) C ( 3 ) - Ru (2.) - A s (2) C ( 3 ) - R u ( 2 ) - C (4) C ( 4 ) - R u ( 2 ) - A s (2) C ( 4 ) - R u ( 2 ) - R u (1) Ru(l) -Ru(2)-As(2)  79.3 (7) 97.4 (7) 92.8(7) 95.9(10) 60.79 (4) 98.7 (8) 95.5(7) 99.1(8) 93.3 (11) 89.5 (7) 72.6 (7) 104.0(1)  A s (2) - C ( 7 ) - C ( 5 ) A s (2) - C ( 7 ) - C ( 8 ) C(5)- C(7)-C(8)  131.9(17) 134.0 (17) 94.1(19)  C(5)- C(6)-F(l) C ( 5 ) - C(6)-F(2) C (5) -C(6)-C(8) F (1) -C ( 6 ) - C ( 8 ) F (1) - C ( 6 ) - F ( 2 ) F (2)- C(6)-C(8)  117.8 (23) 116.0(24) 87.K19) 115.3(23) 106.8(23) 113.3(24)  R u ( l ) - A s ( 1 ) - M e (1) Ru(l) -As(1)-Me(2) R u ( l ) -As ( 1 ) - C ( 5 ) Me (1)- A s ( 1 ) - M e ( 2 ) Me (1) - A s ( 1 ) - C ( 5 ) Me (2)- A s ( 1 ) - C ( 5 )  117.8 (8) 119.0(10) 118.5 (7) 103.5(14) 97.1(11) 96.8(12)  C(7)- C ( 8 ) - F ( 3 ) C(7)- C ( 8 ) - F ( 4 ) C(7)- C ( 8 ) - C ( 6 ) F (3) -C ( 8 ) - C ( 6 ) F ( 3 ) - C ( 8 ) - F (4) C (6) - C ( 8 ) - F (4)  119.0 (22) 114.4(22) 88.2 (19) 117.1(23) 103.2 (21) 115.4(23)  Ru(2) -As(2)-Me(3) Ru(2) -As(2)-Me(4)  117.8 (8) 119.1(9)  0(1)- C d ) - R u ( l ) 0 (2) - C ( 2 ) - R u ( 2 ) 0 ( 3 ) - C(3)-Ru(2) 0(4)- C ( 4 ) - R u ( 2 )  172.5 (23) 175.1(20) 176.1 (23) 172.6(21)  1  i  55  Table Equations  of planes  i n the form  IV.V ZX  + mY  + nZ_ = p_, w h e r e  o  X, Y,  Z_ a r e c o o r d i n a t e s i n A,  a, b,  c.  referred  Z Ruthenium  to orthogonal  m  n  axes  maximum displacement (A)  p  triangle  (3 Ru a t o m s ) Di-(tertiary (2 A s a n d 4C  0.8945  0  -0.4471  -2.4377  -0.4364  -1.9683  0  arsine) atoms) 0.8442  0.3112  Table Magnitudes the  IV.VI  (A) o f t h e p r i n c i p a l  thermal vibration  Axis  1  Axis  axes  of  ellipsoids 2  Axis  Ru(l)  0.13  0.19  0.22  Ru(2)  0.14  0.20  0.22  As(l)  0.13  0.21  0. 27  A s (2)  0.16  0.19  0.23  F(l)  0.19  0.27  0.44  F(2)  0.24  0.32  0. 45  F(3)  0.22 ,  0.26  0. 42  F(4)  0.22  0.24.  0.45  3  0.04  DISCUSSION The IV.1. fold  The  molecular  molecule  axis,  and  stereochemistry  i s s i t u a t e d on  i s conveniently  a  i s shown  in  Figure  c r y s t a l l o g r a p h i c two-  described  as  a derivative  35 of  Ru3(CO)i  i n which  2  and  one  carbonyl  are  replaced  ligands, ruthenium  in  by  on  two  a way  atoms, The  each  the  such  two  and  one  changes.  A l l Ru-Ru b o n d  the  between  L Ru (CO) 2  four-membered  ligand  is  3  two  8  carbonyl  no  arsine)  ,  two  groups  from  structural  longer  atoms w h i c h  atoms  unbridged.  several  are  ruthenium  ruthenium  remains  causes  the  one  ligand bridges  lengths  of  two  on  di-(tertiary  four  ruthenium  bridge  2.853(3)  each  of  groups  other  Ru-Ru b o n d  replacement form  the  that  to  distance  of  bidentate  Ru (CO)i2 3  carbonyl  equal.  are  di-(tertiary  linked  The by  arsine)  A  (standard d e v i a t i o n i n parentheses), o compared w i t h 2.785(4) A f o r t h e u n b r i d g e d Ru-Ru d i s t a n c e a n d 2 . 8 4 9 , 2 . 8 5 9 , a n d 2 . 8 3 7 A. ( e a c h a = 0.006 A.) f o r t h e 35 three  Ru-Ru d i s t a n c e s  significant in  shortening  u-acceptor  relative  to  has  used  been  carbonyl  other  ruthenium  which  with  one  LFe (CO)i 3  0  short  the  to  distance  This  to  of  This  from d i f f e r e n c e s  di-(tertiary  electronic the  ranged  3  from  difference  increase 17  been  isomer  studied"^  2.853  2.782 r e p o r t e d  in  Several  2  have  :  arsine)  Fe (CO)i .  compounds  lengths  molecule.  arises  explain  relative  cluster  Ru-Ru b o n d  of  groups.  previously  of  parent  probably  character  shift  in  i n the  to  f o r the  2.956  ^ A,  Ru(2)-  57  [(CH ) AsC=C(As(CH3)2)CF CF ] R U ( C O ) Q 3  2  0  Figure  IV.1  2  1  2  Molecular  3  4  structure  2  2  3  A  of L Ru (CO) 2  3  Ru(3)  bond  distance  i n  bis(cyclo-octatetraene)triruthenium 40  tetracarbonyl between and on  (Figure  Figures  IV.2a  the d i - ( t e r t i a r y the bonding  Ru-Ru  bonds  number the  IV.2a).  and IV.2b would arsine)  properties  involving  of carbonyl  The marked  as an e x t r a c t o r  bonding  d orbitals  the  di-(tertiary  are  weaker  the  arsine)  expected  structure  does  on t h e m e t a l  Tr-acceptors As  than from  n.m.r.  of the ligand  plane  of the ruthenium  other  from  non-  observations  from  i s twisted  exact  words, ligands  and  from,  of the ligand planarity.  18.2° w i t h  t r i a n g l e and t h i s  displacements  (  group.  the skeleton  significantly  greatest  reflecting  In other  the carbonyl  3  plane  the  to the  density  atom.  8  cases,  and c y c l o - o c t a t e t r a e n e  of LFe (CO)io/  not d i f f e r  significant  of electron  8  In both  atoms w i t h  relative  C H  effect  are the shortest,  s u p e r i o r i t y of the carbonyl  that  t h e same  i n the c l u s t e r .  ligands  ligands  suggest  are exerting  the ruthenium  similarity  The  respect  to the  twisting  causes  of the carbonyl  groups  from 35  their  positions  axial  carbonyl  the to  plane  as  whereas  the carbonyl  shown  retain  groups  are very  of the ruthenium  89.9°),  causes  i n the parent  i n Figure  carbonyl. nearly  triangle  i n L2RU3(CO) groups IV.3.  an a p p r o x i m a t e l y  8  In  Ru3(CO)i  perpendicular  (angles  vary  the twisting  t o be b e n t Nevertheless,  octahedral  from  2  to  from  88.0  of the ligand  axial  ruthenium  co-ordination  positions, does' i n the,  complex. The  arsenic  atoms  also  s u f f e r minor  distortions  Ru Figure  IV.3  As  Co-ordination  about  and  and  (b)  Ru(l)  C  ruthenium  (e) R u ( 2 )  atoms  (a)  i n parent  of d i - ( t e r t i a r y  compound  arsine)  complex.  o  of  their  co-ordination.  of  t h e m e t a l atom causes  OAs-C  angles  Figure  III.4).  As i n L F e ( C O ) i , t h e l a r g e  size  Ru-As-C a n g l e s t o be l a r g e r  than  3  0  ( a v e r a g e s 1 1 8 . 1 a n d 99.5° Ru-As b o n d d i s t a n c e s  2.308 - 2.472 A r e p o r t e d  of.  respectively;  are within  t h e range  f o r Ru{ (PhzAsCeHi,) A s } B r . 3  4  Our  1  2  o  mean v a l u e would  (2.407  A) i s i n a c c o r d w i t h  be p r e d i c t e d  the d i f f e r e n c e  from  t h e Fe-As bond  distance bond  length,  and  o f R u a n d F e ; e.g.  of atomic r a d i i  which from  the  ,  i n L F e ( C 0 ) i p i s 2.30 A , t h e R u - R u ° 35 i n Ru (CO)i i s 2.85 A , and t h e u n b r i d g e d Fe-Fe ° 18  Fe-As bond d i s t a n c e distance  the distance  3  3  2  i n Fe (CO)i 3  length  i s 2.65 A  2  o f {2.30 + ^(2.85  giving  - 2 . 6 5 ) } = 2.40  None o f t h e o t h e r s t r u c t u r a l particularly  surprising.  a predicted  Average  Ru-C  Ru-As  A.  parameters i s a n d C-0  distances  ©  a r e 1.89 a n d 1.15 A , a s i n t h e p a r e n t c o m p o u n d , a n d t h e Ru-C-0 a n g l e s show t h e same s l i g h t d e v i a t i o n s f r o m l i n e a r i t y 31 which of  a r e found  t h e double bond  indicated  scheme.  to allow  i n the ligand  different  from  The  retention  between C(5) and C(7) i s  l e n g t h o f 1 . 3 9 ( 3 ) A., n o t s i g -  the value f o r the s p  The compound L R u ( C O )  2  hybridization  forms d u r i n g t h e 20 of the present derivative, i s assumed t o be 19 2  preparation analogous  a l lthe metal carbonyls.  by t h e s h o r t bond  nificantly  one  m  t o LFe (CO)6 2  6  which  i n which  this  double bond  the involvement of the ir-electrons  of the iron  i s broken  i n bonding  to  atoms.  Intermolecular  c o n t a c t s range  from  2.9 t o 3.5  A  62  and are normal van der Waals i n t e r a c t i o n s .  The most  important of these are shown i n a p r o j e c t i o n of the structure  (Figure  IV.4).  63  V.  THE  STRUCTURE  DETERMINATION  Me AsC=C(AsMe )CF CF 2  2  2  2  «Ru (CO)1 3  0  STRUCTURE  ANALYSIS  The p o s i t i o n s o f t h e t h r e e arsenic the  atoms  factors these  of  least-squares  refinement  carbon,  full-matrix  revealed  oxygen,  refinement,  atoms  a l l atoms were g i v e n  which,  along  with  according  Ew(F ~F ) .  atoms.  One  cycle  thermal  f o r each  R t o 0.126.  At  of this  a n i s o t r o p i c temperature parameters, were  factors  improved  least-squares  R e f l e c t i o n s were  2  c  on  the positions of a l l  reduced  positional  o  scattering  parameters  s i x cycles of block-diagonal  minimizing  using  and f l u o r i n e  and t h r e e p o s i t i o n a l  thirty-two light  from  two c y c l e s o f  v a r y i n g an i s o t r o p i c  point,  by  two  A d i f f e r e n c e s y n t h e s i s phased  r e f i n e d parameters  parameter the  f u n c t i o n and improved w i t h  f r o m r e f . 26.  thirty-two  and  i n the asymmetric u n i t were determined  Patterson  full-matrix  ruthenium  refinement,  given  weights  t o t h e f o l l o w i n g scheme. /w  = 1  I  i f |F  < F*  o /w  =  F  and For approximately range of  |F  this  *  /  /w  At final  fractions  deviations  a n d R a n d R^  t h e 1828 o b s e r v e d  q  |  i f  |  were  Q  | >  F  *  o f F * = 70 r e s u l t s i n  for w(F ~F ) o  convergence,  of their  F  f o r unobserveds  a choice  values  were s m a l l  for  F  = 0.5  data,  constant |.  |  2  c  over  parameter  corresponding  the whole shifts  standard  0.076 a n d 0.096 r e s p e c t i v e l y  reflections  a n d 0 . 0 8 8 a n d 0.100 f o r  all  data.  given  M e a s u r e d and  i n Table V.I.  tuations  A  Table V.II  from of  from  d i f f e r e n c e map ±1.8  e/A  showed 3  which  random e x p e r i m e n t a l  l i s t s the  parameters with  structure factors  final  standard  angles  final  refinement  cycle.  deviations  the equations triangle  and  di-(tertiary  axes o f a n i s o t r o p i c  T a b l e V.V  carbon  The  thermal  f o r the three ruthenium  valence  the  standard  T a b l e V.IV  mean p l a n e s  o f t h e a r s e n i c and arsine) ligand.  matrix  d e v i a t i o n s of  from  c e l l parameters.  of the weighted  have  and  Bond d i s t a n c e s and  contain a contribution  of the u n i t  fluc-  deviations calculated  are given i n Table V . I I I . Standard  these q u a n t i t i e s  are  error.  positional  t h e i n v e r s e s o f t h e d i a g o n a l terms o f t h e  the  cipal  final  a r o u n d t h e heavy atoms o f  b e e n assumed t o a r i s e  thermal  calculated  of the  atoms o f  ruthenium the  magnitudes of the vibration and  two  gives  prin-  are given i n  a r s e n i c atoms.  Table Final  measured  reflections  K *  and  have  calculated  an  V.I  structure  asterisk  after  I  Unobserved  F| value. o  K  OBS C » I X 16  the  factors.  II  *999  9  211  0 0 0  12 11 14  100 J>  11  0 0  16 II  55 SJ  56 52  12  221  0  156  U  311  2 72  Ul  1 SB  10 7  109  0  ]  UB  12  131  101  5  1)6  110  105  1I  151 110  160 116  1  I IS  126  108  243  210  124  18 5  261  0 0 0 0 21 2 78  9 a  2>B  219  13 11  121 150  lis 136  4 5  3  Ul 160 112  142 162 11S  10  161  162  106  101  21  LIB  112  i  12  26  140  11  10  102  13  5*  2  1  OBS C*LC  19  117  11 * 1 (45  125  1  1 I  112 116  206  171 214  6  107  106  5  106  101  198  48 2  104  171 226  129  109  11  2 1  125  19  15  10*  11  102  17 1)  159  111  10  68  Table  K  3  14*  127  OBS CALC  V.I  (continued)  K  OBS  CAI  Table V . I I Final  positional with  ATOM RU(1) Ru(2) Ru(3) A s (1) A s (2) F(l) F(2) F(3) F(4) 0(1) 0(2) 0(3) 0(4) 0(5) 0(6) 0(7) 0(8) 0(9) 0(10) C(l) C(2) C(3) C(4) C(5) C(6) G(7)  jx  Y  1378 2 4 9 5 ( 3) 2 1 9 0 ( 2) - 0 0 1 1 0432 0 2 9 5 ( 2) - 0 7 1 3 ( 3) - 0 6 9 0 0 9 3 4 ( 3) - 1 0 9 8 - 3 6 7 2 (20) -1923 -2541 - 1 9 4 1 (23) - 2 3 3 9 (30) -2315 -2873 - 0 5 6 7 (27) - 0 4 0 0 (35) 1991 2162 (38) 2506 5 3 9 1 (22) 0701 2079 4 6 1 8 (32) 2 7 0 3 (26) 0368 - 1 6 7 2 (35) 1406 0464 - 2 1 4 8 (25) 0784 0550 (32) 3 8 1 4 (26) -0830 -0163 5086 (24) 0 6 3 1 (59) 1713 2083 2240 (34) 0904 4218 (35) 3816 (42) 1816 1905 (31) 0391 - 0 8 3 4 (30) 1053 - 1 1 2 4 .(.38). .'. 0 470  (fractional  x  10 )  standard deviations z  ( 1) 0 8 0 0 ( 2) ( 1) 1 4 3 8 ( 1) ( 1) 0 1 2 1 ( 1) ( 1) - 0 3 5 9 ( 2) ( 2) 1 8 6 0 ( 2) 0 4 4 0 (15) (11) ( 9) - 0 1 5 8 (10) (12) 1 8 4 9 (16) ( 9) 1 2 0 4 (14) (14) 1 6 3 1 (20) (14) - 0 5 1 5 (15) (12) 0 0 3 1 (12) (15) 1 9 7 5 (16) (18) - 1 2 0 6 (15) (12) - 0 9 0 8 (15) (16) 1 4 5 2 (14) (13) 2 7 4 0 (15) 0 0 5 2 (14) (11) (16) 2 4 6 0 (16) (18) 1 3 5 0 (26) (19) - 0 0 4 3 (17) (16) 0 3 5 5 (18) (15) 1 5 6 1 (19) (16) - 0 6 8 2 (18) (13) - 0 4 8 7 (19) (17J. . 1 0 6 8 (17).  b ll 120 72 72 72 92 104 239 292 341 280 339 128 285 127 343 120 276 214 69 296 129 138 285 56 202 ,176  ( 3) ( 2) ( 2) ( 3) ( 3) (24) (33) (44) (41) (49) (56) (26) (45) (30) (56) (30) (51) (35) (24) (93) (39) (43) (54) (35) (35) (48)  and t h e r m a l  k  parameters  i n parentheses b 22  23 25 21 22 29 53 35 53 37 61 67 70 82 118 43 88 43 39 102 15 82 39 41 35 28 63  ( 1) ( 1) ( 1) ( 1) ( 1) ( 7) ( 5) ( 7) ( 5) ( 9) ( 9) ( 8) (10) (14) ( 7) (12) ( 8) ( 6) (13) (10) (14) ( 9) ( 8) (9) ( 7) (11)  b 33 52 43 44 45 46 100 53 93 103 129 84 62 74 63 69 62 61 94 71 65 39 46 48 44 106  ( 1) ( 1) ( 1) ( 1) ( 1) (12) ( 7) (12) (ID (18) (11) ( 8) (12) (10) (11) (10) (11) (11) (10) (20) (11) (12) (13) (13) (14) 4 4 (10.)  b 12  b 13  - 1 3 ( 1) - 7 ( 1) - 3 ( 1) - 1 ( 1) - 1 3 ( 1) -38 (12) -19 (11) -64 (16) -28 (13) 73 ( 1 7 ) -40 (21) -16 (26) -57 (18) -48 (20) 34 ( 1 9 ) 12 ( 1 9 ) - 1 (18) 8 (13) 11 (18) 47 ( 2 7 ) -29 (21) -10 (18) - 9 1 (16) -24 (17) -19 (13) -rl8 (22)  - 4 ( 2) - 1 ( 2) - 1 ( 2) - 6 ( 2) - 6 ( 2) -22 (16) 6 (15) 11 (24) -50 (19) 22 ( 2 8 ) -16 (23) 11 (28) 11 (23) 49 ( 1 6 ) -48 (22) 35 ( 1 6 ) 26 ( 2 2 ) 25 ( 1 8 ) -43 (14) 54 ( 4 1 ) -30 (20) -10 (21) - 2 1 (26) 23 ( 1 9 ) -56 (18) 28 ( 2 0 )  b 2  3  +  0 ( 1) 1 ( 1) 0 ( 1) - 1 ( 1) - 6 ( 1) 5 ( 9) - 5 (11) 15 ( 9) 9 ( 7) -22 (11) 41 ( 7) -16 (14) -14 (10) -13 (11) 13 ( 9) -13 (11) - 4 ( 9) -22 (14) - 1 (11) - 1 (13) -11 (11) 14 ( 9) 5 ( 9) - 5 (10) 13 ( 9) - 1 6 ( 9)  Table ATOM C(8) C(9) C (10) C(ll) C(12) C(13) C(14) Me (1) Me (2) Me (3) Me (4)  X 1163 3080 4002 -1048 -0510 -2106 -1443 -0484 2253 -2629 0547  y (41) (35) (42) (29) (29) (38) (45) (44) (40) (33) (35)  ^Coefficients  z  0506(14) 2233 -0520(15) 0569 -0089(21) 2096 -1417 (14) 0429 -1577(13) 1125 -2062(14) -0439 -2249(19) 1196 -1033(20) 2796 -1881(18) 2084 - 0 7 1 1 ( 1 4 ) -0924 -1257(14) -1083  i n the  V.II b ll  (18) (18) (27) (16) (20) (22) (27) (18) (26) (23) (19)  284 163 100 80 68 157 166 254 125 44 278  b  b_2 2  (56) (43) (51) (32) (32) (47) (57) (60) (46) (36) (44)  t e m p e r a t u r e >e x p r e s s i o n :  (continued)  27 ( 7) 30 ( 8) 44 (13) 3 5 ( 8) 2 3 ( 7) 2 1 ( 7) 38 (11) 71(13) 40 (11) 37(12) 29 ( 7)  exp - 1 0  - , t  55 57 60 36 76 84 98 36 86 73 100  (12) (12) (21) (10) (14) (16) (22) (12) (21) (19) (14)  ( b i i h - 42  b i  3 3  b  2  bi  2  2(25) - 7 1 (19) -19(31) -13(33) -21(19) 13 (26) 13 ( 3 4 ) 29(25) -13(31) -52 (25) 63 ( 1 9 )  - 5(19) -42 (18) -59 (25) - 8(32) -21(13) -12 (17) -23 (24) -36 (25) 3 (22) -11(20) 10(17)  2k  2  +  b  3  3  b  3  £  2  +  3  -  4 ( 8) 1 ( 9) - 4(16) -24(16) - 2 ( 9) 15 ( 9) 34(14) -13(11) 22(14) 6 (14) 0 ( 9)  2b_i hk  + 2bi h£ 3  2  2  +  2b  2 3  k£)  Table  V.III  o  Bond  distances with  (A) a n d v a l e n c e  standard  R u (1) - R u ( 2 ) Ru (1) - R u ( 3 ) R u (1) - C ( l )  deviations  2.831(3) 2 . 8 3 1 (3) 1.95(5) 1.95 (3) 1.88(3) 1.89 (3)  R u ( l ) -C(2) R u (1) - C ( 3 ) R u (1) - C ( 4 )  R u (2) - R u ( 3 ) R u (2) - A s ( 2 ) Ru(2) -C(8) Ru (2) - C ( 9 ) Ru (2) - C ( 1 0 )  2 . 8 5 8 (6) 2.417 (4) 1.87(3) 1.90(3) 1.91(4)  R u (3) - A s ( 1 ) R u (3) - C ( 5 ) R u (3) - C ( 6 ) Ru (3) - C ( 7 )  2.417 (3) 1.93 (3) 1.83(3) 2.00 (.3)  A s (1) - C ( l l ) A s (1) - M e ( 3 ) A s (1) - M e ( 4 )  1.92 (3) 1.90 (3) 1.94 (3)  A s (2) - C ( 1 2 ) A s (2) - M e ( 1 ) A s (2) - M e ( 2 )  1.96(3) 1.98(3) 1.90 (3)  Ru Ru Ru Ru Ru Ru Ru  (2) - R u ( l ) (2) - R u ( l ) (2) - R u ( l ) (2) - R u ( l ) (3) - R u ( l ) (3) - R u ( l ) (3) - R u ( l ) C(l)- Ru(l)C(l)- Ru(l)C(2)- Ru(l)C(2)- Ru(l)C(3)- Ru(l)Ru(l) Ru(l) Ru(l) Ru(l) Ru(3)  -Ru(3) -C(l) -C(3) -C(4) -C(l) -C(2) -C(3) C(2) C(4) C(3) C(4) C(4)  60.64(11) 93(1) 78(1) 102(1) 81(1) 94(1) 94 (1) 92(1) 92 (2) 97(1) 105(1) 90 (1)  -Ru(2) -Ru(3) -Ru(2) -C(8) -Ru(2) -C(9) -Ru(2) -C(10) - R u (2) - A s ( 2 )  5 9 . 6 8 (9) 80 (1) 98(1) 102(1) 102.48(11)  angles  (degrees),  i n parentheses  C(13) C(13) C(14) C(14)  -F(l) -F(2) -F(3) -F(4)  1.37(4) 1.35(4) 1.34 (5) 1. 3 9 ( 4 )  C ( l ) - 0(1) C ( 2 ) - 0(2) C ( 3 ) - 0(3) C ( 4 ) - 0(4) C ( 5 ) - 0(5) C ( 6 ) ~ 0(6) C ( 7 ) - 0(7) C ( 8 ) - 0(8) C ( 9 ) - 0(9) C(10) -0(10)  1.13(6) 1.12(4) 1.21(4) 1.09 (4) 1.11(4) 1.21(4) 1.09(4) 1.13(4)  C ( l l ) -C(12) C ( l l ) -C(13) C(12) -C(14) C(13) -C(14)  1.29 (4) 1.52 (4) 1.50(4) 1.43 (6)  R u (3) - A s ( 1 ) - C ( l l ) R u (3) - A s ( 1 ) - M e ( 3 ) R u (3) - A s ( 1 ) - M e ( 4 )  117 (1) 120(1) 119(1) 101(1) 97 (1) 99 (1)  C ( l l ) - A s ( 1 ) -Me(3) C (11) - A s ( 1 ) - M e ( 4 ) Me (3) - A s ( 1 ) - M e ( 4 )  R u (2) - A s ( 2 ) - C ( 1 2 ) R u (2) - A s ( 2 ) - M e ( 1 ) R u (2) - A s ( 2 ) - M e ( 2 )  1.22(4)  1.12 (5)  C(12) - A s ( 2 ) -Me(1) C(12) - A s ( 2 ) -Me(2) Me (1) - A s ( 2 ) - M e ( 2 )  119(1) 117(1) 117(1) 98(1) 98 (1) 105 (2)  A s (1) - C ( l l ) - C ( 1 2 ) A s (1) -C (11) - C ( 1 3 ) C(12) - c ( i i ) -C(13)  137(2) 132(2) 91(2)  i  72  Table  V.III  Ru(3) -Ru(2) -C(8) Ru(3) -Ru(2) -C(9) A s (2) - R u ( 2 ) - C ( 8 ) A s (2) - R u ( 2 ) - C ( 9 ) A s ( 2 )- R u ( 2 ) - C ( 1 0 ) C ( 8 ) - Ru(2)- C(10) C ( 9 ) - R u ( 2 ) - C(10)  97(1) 78(1) 91(1) 89(1) 97(1) 91(2) 94 (2)  R u ( l ) -Ru(3) -Ru(2) Ru (1) -Ru (3) - C ( 5 ) R u ( l ) - R u (3) - C ( 6 ) R u ( l ) -Ru(3) -C(7) R u (2) - R u ( 3 ) - A s ( l ) Ru (2) - R u ( 3 ) - C ( 5 ) Ru (2) - R u ( 3 ) - C ( 7 ) A s (1) - R u ( 3 ) - C ( 5 ) A s ( 1 )- R u ( 3 ) - C ( 6 ) A s (1) - R u ( 3 ) - C ( 7 ) C ( 5 ) - R u ( 3 ) - C(6) C ( 6 ) - R u ( 3 ) - C(7.)  5 9 . 6 7 (9) 80(1) 100(1) 94(1) 101.80(12) 97(1) 76(1) 90 (1) 101(1) 94(1) 91(1) 95(1)  (continued) A s (2) - C ( 1 2 ) - C ( l l ) A s (2) - C ( 1 2 ) - C ( 1 4 ) C ( l l ) -C(12) -C(14)  133 (2) 132 (3) 94(3)  F (1) -C ( 1 3 ) - F ( 2 ) F (1) -C ( 1 3 ) - C ( l l ) F (1) -C ( 1 3 ) - C ( 1 4 ) F(2)- C(13)- C ( l l ) F ( 2 ) - C(13)- C(14) C ( l l ) -C(13) -C(14)  103 (3) 116(2) 116(3) 118 ( 3 ) 116 ( 3 ) 88 ( 2 )  F(3)- C(14)F(3)- C(14)F(3)- C(14)F(4)- C(14)F(4)- C(14)C(12) -C(14)  103 (3) 117(3) 1 2 1 (3) 115(3) 116 (3) 86 ( 3 )  Mean Ru-C-0  F(4) C(12) C(13) C(12) C(13) -C(13)  173 1  73  Table Equations  of planes  V.IV  i n t h e f o r m iX + mY  + nZ = p_, w h e r e  o  X, Y, a,  Z_ a r e c o o r d i n a t e s i n A , r e f e r r e d  b, c. I  Ruthenium (3  t o o r t h o g o n a l axes  Ru  m  n  maximum displacement (A)  p  triangle  atoms)  0.6940  Di-(tertiary  -0.3306  -0.6396  -0.2223  -0.5311  -0.3961  0.4677  0  arsine)  (2 A s a n d 4 C  atoms) 0.7490  Table  0.06  V.V  o  Magnitudes  (A) o f t h e p r i n c i p a l  ellipsoids  o f t h e heavy atoms. Axis 1  axes o f t h e thermal  Axis  2  vibration  Axis  Ru(l)  0.18  0.23  0.27  Ru(2)  0.16  0.21  0.25  Ru(3)  0.16  0.20  0.25  As(1)  0.16  0.20  0.25  As(2)  0.17  0.22  0.27  3  DISCUSSION In  t h e same way  that  LFe3(CO)i  i s related  0  to  18 Fe (CO)i , 3  As  t h e complex  2  atoms  di-(tertiary strengths  arsine)ligand.  than  cluster,  metal-metal  electron  bonds  groups  r e p l a c e d by t h e s e  longer  than  carbonyl and  i s related  i s i n evidence  are  Although singlet  plane this  ligand  both  solution), assumes  or that  i n L Ru (CO) ,  Ru-Ru-C  3  3  8  angles  Ru (CO)i  2  H  has been  and  1  9  F  atoms  This  of packing  forces  for axial  i s flexing  i A)  (2.858(6) A ) . consist  upon  respect  to;the  either  that  of the  triangle i n i n solution  and  crystallization.  of the ligand  skewed  2.831(3)  (the plane  c a r b o n y l s t o change  to the severely  The bond  implies  the ruthenium  the twisting  only  of the d i - ( t e r t i a r y  triangle.  configuration  t o be  previously,  spectra  t w i s t e d 18.4° w i t h  the ligand  at  carbonyl  observed  n.m.r.  acceptor  having  structure.  plane  of the  the metal  having  (both  2  o f two  efficient  Ru(2)-Ru(3),  t h e mean  co-planar with  a stationary 2  J  i s i n fact  i s a result  being  effect  3  be e x p e c t e d  involving  s h o r t e r than  o f the ruthenium twist  would  and R u ( l ) - R u ( 3 ) ,  resonances,  ligand  atoms  Ru (CO)i .  o f lower  are less  i n the present  Ru(l)-Ru(2)  significantly  arsine)  This  bonds  atoms  ligands  between  to  on each  d e n s i t y from  ligands  metal-metal  groups.  distances  Since  the c a r b o n y l group  ir-antibonding  in  0  i s r e p l a c e d by t h e a r s e n i c  removing  As  3  shown i n F i g u r e V . l , one c a r b o n y l g r o u p  ruthenium  of  LRu (CO)i  again from  configurations  causes n e a r l y 90° shown  Figure  V . l  Molecular  structure  of  LRu (CO)i . 3  0  76  i n F i g u r e V.2.  Mean Ru-C  and C-0  bond d i s t a n c e s are i n  e x c e l l e n t agreement w i t h p r e v i o u s l y r e p o r t e d and Ru-C-0 angles  complexes.  Ru-As bond d i s t a n c e s  (both 2.417  agreement w i t h the values  -  4 3  2.401  and  2.413  A)  are i n good  A found  for L Ru3(CO) 2  8  are w i t h i n the range 2.308 to 2.472 A r e p o r t e d f o r  Ru((Ph AsC6EU) As)Br . 2  3  than C-As-C angles due  3  (mean 172.8°, a(mean) 1.3°))are s i g n i f i c a n t l y  n o n - l i n e a r as i n most c a r b o n y l  and  values ^ ^'^'  4 1  2  Ru-As-C angles  (averages  118.2  and  are again  99.7° r e s p e c t i v e l y )  t o the s t e r i c e f f e c t of the ruthenium atom The  larger  dimensions of the d i - ( t e r t i a r y  (of.  Figure  III.4).  arsine) ligand 32  are e s s e n t i a l l y i d e n t i c a l to those i n other s i m i l a r s t r u c t u r e s . The  double bond i n the cyclobutene  ring  (1.29 A)  and other carbon-carbon d i s t a n c e s are reasonable. f l u o r i n e bond d i s t a n c e s The  (mean 1.36  A) are a l s o as  i s retained Carbonexpected.;  e x t e n t of a n i s o t r o p y of the thermal v i b r a t i o n s  of the heavy atoms i s shown i n Table V.V.  The  principal  axes of v i b r a t i o n show no r e g u l a r i t i e s i n o r i e n t a t i o n w i t h respect to intramolecular v e c t o r s . I n t e r m o l e c u l a r van 2.96  to 3.48  der Waals contacts ranging  A are shown i n the a-axis p r o j e c t i o n of  structure i n Figure  V.3.  the  from  80  98  (b)  o C Figure  V.2  Co-ordination  around  Ru(2)  and  (b)  Ru(3)  of  LRu (CO)i 3  0  THE S T R U C T U R E  DETERMINATION  M e A s C F C F (CF ) A s M e 'Mo (CO) i, 2  2  3  2  STRUCTURE The atoms  and improved w i t h  refinement, difference revealed  using  all  EwA  2  R t o 0.116.  from  the following  thermal  B, C,  were  {A + B|F  to anisotropic fluorine  R t o 0.083.  assigned  | + c|f |  best  B, C,  f i t to constant  At  weights  and D e q u a l  and  r e s p e c t i v e l y (unobserved  from refinement  factor  calculation),  convergence,  3  reduced  least-squares wA  2  over  a l l | this  1.5458,  reflections i n final  a n d 0 . 0 8 5 a n d 0.148 shifts  F 0  |.  weighting -0.0186  are ex-  structure  R and R t o 0.073 a n d — —w  a l l parameter  1  Q  t o 7.1341,  but included  reflections  D|F | }~  (142 v a r i a b l e s ) u s i n g  A,  cluded  +  2  o  scheme w i t h  final  f o r a l l ob-  scheme.  of refinement  observed  refinement  a r s e n i c , and  and D a r e c a l c u l a t e d by  to give  0.00008  oxygen,  paremeters f o r  Converting  reflections  w =  At  parameters  u n i t weights  f o r one c y c l e r e d u c e d  point, observed  cycles  A  least-squares  f a c t o r s f o r molybdenum,  and r e f i n i n g  treatment  using  and i s o t r o p i c  this  for  Patterson  full-matrix  phased on t h e r e f i n e d  of  atoms r e d u c e d  temperature  Two  two c y c l e s o f  cycle of f u l l - m a t r i x  reflections  w h e r e A,  from the  atoms.  minimization  atoms  arsenic  the p o s i t i o n s of a l l twenty-one carbon,  One  served  and  s c a t t e r i n g f a c t o r s from ref.26.  synthesis  fluorine  with  o f t h e molybdenum  i n space group C2/c were d e r i v e d  function  and  coordinates  ANALYSIS  0.094  f o r a l l data.  were  small  fractions Fourier  of  revealed  atoms w h i c h error. given and  their  can  Measured  standard  r e s i d u a l s of only  be  and  inverse  distances  and  deviations  of  matrix  extent  of  f o r the  trifluoromethyl  of  and  are  cell  and  the  heavy  are  final positional  deviations  calculated  refinement  cycle.  of  the  Bond  standard  i n t o account the  parameters.  Table  stanVI.IVi  thermal motion of The  bond d i s t a n c e s  corrections  the  anisotropy those of should  for libration.  the  be  However,,  oxygen atoms were r e f i n e d i s o t r o - •  the  Although  present molecule  comparisons with  account of  factors  the  f l u o r i n e atoms.  and  the  i n Table. V I . I l l ;  c o r r e c t i o n s w e r e made.  comparisons w i t h i n  take  unit  group,  carbon  tailed  last  difference  experimental  f l u o r i n e atoms, p a r t i c u l a r l y  since  no  the  anisotrppy  somewhat by  pically,  of  angles  the  increased the  random  standard  these quantities take  molybdenum, a r s e n i c , large  as  final  around  3  T a b l e VI.II g i v e s  valence  dard deviations shows t h e  e/A  A  calculated structure  i n T a b l e VI.I.  the  ±1.5  explained  thermal parameters with  from  is  deviations.  possible  distances libration  are  i n other  bond  length  valid, molecules  corrections.  deshould  82  Table V I . I Final  measured  reflections  and c a l c u l a t e d  have an a s t e r i s k K  -I  10 12 I* I*  0 3 0 0  »1T 2Z» 21* 21)  10  12*  |4»  K  -*l  21  F  I  value.  DBS C»IC  107 190 J74  2B  15*  OBI C4LC  a f t e r the.  Unobserved  17  S71 2*0 7)1 24'  11 11 11  Ul  20  structure factors.  lt>B *1 Ul  |B0 35 120  0  200  225  0  27b  298  0  204  lis  0  25B  27*  200 17B 249  o m  in  0 0 0  227 9B 2)«  258 105 25B  0  108  115  40  55  -1!  -18  -»£ 120 111 247  1 10  Ul 261  11 i'. 17* «  10  i)  -ia  - H  12  t.6 251  244  69  B7  -i<  -i;  -2! 107  104  -H  Table Final  positional with  ATOM  Mo A s (1) A s (2) F(l) F(2) F(3) F(4) F(5) F(6) C(l) C(2) C(3) C(4) C(5) C(6) C(7) Me (1) Me (2) Me (3) Me (4) 0(1) 0(2) 0(3) 0(4)  X  1503 1563 0840 0328 0396 1460 1441 0775 0680 2134 2014 1430 0917 0682 1109 1010 0073 1055 1333 2249 2529 2331 1372 0572  standard  Y. ( 1) ( 1) ( 1) ( 9) ( 9) ( 7) (10) (13) (13) (12)  (ID (  9)  (ID  (15) (13) (16) (14) (13) (15) (14) (9) ( 9) ( 8) (10)  Coefficients  1128 2939 1960 3159 3916 3969 5343 5515 4909 1379 0691 -0220 0826 3327 3859 4916 1565 2251 3248 36 45 1517 0453 -1066 0590  (fractional  z  ( 2) 1 8 6 3 ( 2) ( 2) 2 6 7 5 ( 2) ( 2) 0 1 1 2 ( 2) (16) 1540 (21) (15) - 0 2 3 6 (17) (13) 0 5 0 5 (17) (14) 2 3 5 7 (29) (17) 0 9 5 5 (24) (17) 2533 (28) (22) 1 1 6 1 (25) (21) 3 2 4 5 (25) (19) 1 1 9 3 (20) (21) 2679 (24) (28) 0 6 6 3 (32) (23) 1399 (28) (29) 1860 (33) (27) - 0 4 1 6 (29) (25) - 1 3 6 4 (29) (29) 4 1 1 3 (34) (26) 2 9 0 3 (31) (18) 0 7 4 9 (20) 4112 (21) (18) 0 8 4 8 (19) (16) (18) 3 2 0 6 (21)  i n the temperature  VI.II x  IO *) a n d t h e r m a l  deviations B orb  ii  2 2 ( 1) 2 8 ( 1) 2 4 ( 1) 4 7 ( 6) 5 9 ( 6) 3 6 ( 4) 50 .( 7) 86(10) 102(11) 6.9 (6) 6.3 (6) 5.1(6) 6.3 (6) 8.8(8) 7.6 (7) 8.5(8) 8.7(8) 8.4(8) 9.9 (9) 8.9 (8) 9.4(6) 9.5(6) 8.2 (5) 9.8 (6)  parameters,  1  i n parentheses b_2  b  2  66 ( 2) 63 ( 2) 8 1 ( 2) 159(20) 139(17) 113 (14) 81(13) 118(18) 115 (18)  e x p r e s s i o n : exp -10  - l +  3  bi  3  bi  2  77 ( 2) 0 ( 1) 8 3 ( 3) - 1 ( 1) 7 3 ( 3) 0 ( 1) 299 (32) 1 9 ( 8) 171(21) 46 ( 9) 216(23) 6 ( 6) 512 (56) 1 4 ( 9) 286(35) 29(11) 455 (51) 24 ( 1 2 )  (b_i i h  2  +  b 2k 2  2  +  K  3  £ 2  3  t  8( 1) K 1) 6 ( 1) - 3 ( 2 ) 4 ( 1) 7 ( 2) 78 (12) 25 (20) - 27(10) 39(15) 3 5 ( 8) 71(15) 2 ( 1 5 ) -48 (22) 17(15) 42(21) 156(22) - 5(25)  b_3 3|- + 2 b 1 h k  + 2b_!3 h J  2  2  + 2 b kJ.) 23  00 LO  Table Bond d i s t a n c e s with  VI.Ill  (A) a n d v a l e n c e  standard deviations  Mo-C(1) Mo-C (2) Mo-C(3) Mo-C ( 4 ) Mo-As(1) Mo-As (2)  1.96 ( 3 ) 1.90 ( 3 ) 1.94 ( 3 ) 1.96(3) 2.573(4) 2.569(7)  As(l)-Me(3) As(1)-Me(4) As (l)'-C (6) As(2)-Me(1) As(2)-Me(2) As(2)-C(5)  1.92 ( 4 ) 1.92(3) 2.06 ( 3 ) 1.95(3) 1.94(3) 1.99(4)  C (1)-Mo-As (1) C (1)-Mo-As (2) C ( l ) - M o - C (2) C(l)-Mo-C(3) C ( 4 ) - M o - A s (1) C ( 4 ) - M o - A s (2) C ( 4 ) - M o - C (2) C ( 4 ) - M o - C (3) As(1)-Mo-C(2) As(1)-Mo-As(2) As(2)-Mo-C(3) 0 ( 3 ) - M o - C (2)  90(1) 92(1) 87 ( 1 ) 90(1) 90 ( 1 ) 93 ( 1 ) 88(1) 89(1) 90(1) 82.1 (2) 95(1) 92(1)  Mo-As ( 1 ) - M e ( 3 ) Mo-As(1)-Me(4) Mo-As(1)-C(6) Me ( 3 ) - A s ( D - C ( 6 ) Me ( 3 ) - A s ( l ) - M e ( 4 ) Me(4)-As (1)-C(6)  121(1) 119(1) 108(1) 106(1) 102(2) 98(1)  Mo-As ( 2 ) - M e (1) Mo-As(2)-Me(2) M o - A s (2) -C ( 5 ) Me(l)-As(2)-C(5) Me(l)-As(2)-Me(2) Me(2)-As(2)-C(5)  123(1) 122(1) 106 (1) 95(1) 103(1) 102(1)  angles  (degrees),  i n parentheses C(l)-0(1) C (2)-0(2) C(3)-0(3) C(4)-0(4)  1.20 ( 3 ) 1.18 ( 3 ) 1.19 ( 3 ) 1.20(3)  C(5)-C(6) C(6)-C(7) C(5)-F(l) C ( 5 ) - F (2) C(6)-F(3) C ( 7 ) - F (4) C(7)-F(5) C(7)-F(6)  1.40 ( 4 ) 1.54(4) 1.50 ( 4 ) 1.37(4) 1.51(4) 1.24 ( 4 ) 1.34 ( 4 ) 1.26 ( 4 )  As ( 2 ) - C ( 5 ) - F ( l ) As ( 2 ) - C ( 5 ) - F ( 2 ) As ( 2 ) - C ( 5 ) - C ( 6 ) F(l)-C(5)-F(2) F(l)-C(5)-C(6) F(2)-C(5)-C(6)  106(2) 113(2) 118(3) 108 ( 3 ) 99 ( 3 ) 112 (3)  As ( 1 ) - C ( 6 ) - C ( 7 ) As(l)-C(6)-F(3) As ( 1 ) - C ( 6 ) - C ( 5 ) C(7)-C(6)-F(3) C(7)-C(6)-C(5) F(3)-C(6)-C(5)  113 (2) 104(2) 111(2) 108 (3) 121 (3) 97 ( 3 )  C(6)-C(7)-F(4) C(6)-C(7)-F(5) C(6)-C(7)-F(6) F (4)-C (7)-F(5) F(4)-C(7)-F(6) F.(5)-C(7)-F(6)  113 ( 3 ) 110(3) 113 ( 3 ) 106 ( 3 ) 110 ( 3 ) 105(3)  Mo-C (1) - 0 ( 1 ) Mo-C(2)-0(2) M o - C ( 3 ) - 0 (3) M o - C ( 4 ) - 0 (4)  178(3) 178 (3) 176 ( 2 ) 176 ( 2 )  85  Table  VI.IV  o  Magnitudes vibration  (A) o f  the p r i n c i p a l  ellipsoids  axes  of  the  o f a n i s o t r o p i c atoms. Axis 2 Axis 1  thermal  Axis  MO  0.22  0.24  0 . 26  AS(1)  0.23  0,24  0,30  A s (2)  0.21  0.27  0.28  F(l)  0.26  0.37  0.49  F(2)  0.19  0.38  0.51  F(3)  0.24  0.32  0.42  F(4)  0.25  0.39  0.61  F(5)  0.29  0.44  0.53  F(6)  0.26  0.37  0.65  3  . ..DISCUSSION The molecule  1,2-bis(dimethylarsino)hexafluoro-  propanemolybdenum t e t r a c a r b o n y l (Figure VI.1) 44 molybdenum hexacarbonyl  i s d e r i v e d from  45 '  by replacement of two  carbonyl  groups by the a r s e n i c atoms of the c h e l a t i n g d i - ( t e r t i a r y arsine) ligand.  The  c o - o r d i n a t i o n around molybdenum remains  e s s e n t i a l l y octahedral. and As(2)  The  f i v e atoms C(2), C ( 3 ) , Mo,  are s i t u a t e d i n the l e a s t - s q u a r e s plane  Table VI.V  with C ( l ) and C(4)  t h i s plane.  C-0  The As-Mo-As angle i s 82.1°, and  bond l e n g t h s , 1.18-1,20(3), mean 1.19  to v a l u e s r e p o r t e d p r e v i o u s l y . ^ ^ 4  2  below  the other,, angles  (Table V I . I I I ) .  bond d i s t a n c e s , 1.90-1.96(3), mean 1.94  are almost e x a c t l y l i n e a r ,  given, i n  e q u a l l y spaced above and  at molybdenum are i n the range 87-95° Mo-C  As(l)  A,  A, are  and  The  the  similar  The Mo-C-0 groupings  176-178(3)°.  The Mo-As bond d i s t a n c e appears to be measured f o r the f i r s t time, the mean value being  2.572(4) A.  This  d i s t a n c e i s c l o s e to t h a t which would be p r e d i c t e d from a ;  knowledge of other m e t a l - a r s e n i c  bond l e n g t h s , and  from  d i f f e r e n c e s i n c o v a l e n t r a d i i ; e.g. the Fe-As bond d i s t a n c e o 49-52 i s 2.30 A, the Mo-Mo d i s t a n c e s i n v a r i o u s compounds o  average 3.25  2.65  h (3.25  and  the unbridged Fe-Fe d i s t a n c e i n F e ( C O ) i 3  2  18  0  is  A,  A,  g i v i n g a p r e d i c t e d Mo-As bond l e n g t h of  - 2.65)) = 2.60  (2.30  +  A.  The As-Me bond lengths are 1.92-1.95(3), mean 1.93  o  A, and  the As-C  (fluorocarbon) bond d i s t a n c e s are 1.99(4)  00  Table (a.)  Equation  C(2)  and  Z/  are  a,  b,  C(3)  pf weighted i n the  of  the  As-C  cosines of a,  m e a n 2.03  bond  are  which  angles  carbon)  1  As(2),  = p_ w h e r e  X',Y, axes  involving  a n g l e s , 106  influence  of  0.5895)  t h e mean v a l u e s  of  different.  the  The  t h e molybdenum atom a r e only  and  i n the  referred  c*,  0.5014,  carbon  atoms.  five-membered  The  are  ring,  t h e Mo(CO)i+ g r o u p .  as  are  at than  Mo-As-C(fluoroinfluenced  but  the  a result  There  types  angles  a l lsignificantly  angle, presumably  two  larger  108(1)° , a r e p r o b a b l y  1 1 9 - 1 2 3 mean 121°,  tetrahedral  2.2605  the v e c t o r C(5)-C(6) h,  A;  maximum displacement (A) 0.03  p_  significantly  involve  presence  angles, the  nZ  As(l),  to the orthogonal  -0.4361  o r t h o g o n a l axes  2.06(3),  their  +  n  0.1876  Direction  arsenic the  referred  m  (0.6333,  and  + mY  o f Mo,  c*.  0.8801  to  mean p l a n e £X'  form  c o o r d i n a t e s i n A,  £  (b.)  VI.V  two  Mo-AsrMe larger  of  the  distinct  angles  a t each  arsenic  106(1)° a t A s ( l ) ,  95  102(1)°  a t A s (2) , p r o b a b l y  as two  a result methyl  of  differing  groups A  table  steric  a t each of  a  and  interactions  arsenic  and  (the d i h e d r a l  than  steric  Me-As-C(fluorocarbon) and  by  atom,  98  between  and  the  the f l u o r o c a r b o n . angle  between  the  plane  c o n t a i n i n g the r i n g carbon atoms and  the metal atom and  plane c o n t a i n i n g the r i n g n i t r o g e n atoms and atom) and  the  the metal  8 (the angle between the n i t r o g e n atoms as  one  looks down the carbon-carbon bond) has been compiled  for  a number of M(en>3 complexes. are 24.8  and  Average values  48.6° r e s p e c t i v e l y .  r i n g i n L'Mo (CO) p l a c e d by -0.40  The  0.14  plane, so t h a t the C-C  and C(6)  bond i s t w i s t e d 23.2° with  from r e f . 5 3 ) , The  the than* d i h e d r a l angles  a l l being c l o s e to 180°  179°).  (47°,  bond may  bond with  (178,  175,  cf. 48.6°,  i s reduced from an i d e a l 60° as a.  r e s u l t of the formation of the c h e l a t e r i n g . t r i f l u o r o m e t h y l and  ( cf. 24.8°  arrangement i s staggered,  The As-C-C-As d i h e d r a l angle  average from r e f . 53)  respect  A view along the C-C  i s shown i n F i g u r e VI.2.  and  dis-  A r e s p e c t i v e l y from the As-Mo-As  to the c e n t r a l plane of the molybdenum octahedron average of values  3  five-membered  i s non-planar with C(5) and  of a and  The  one  three f l u o r i n e s u b s t i t u e n t s of the  be c l a s s i f i e d as a x i a l or e q u a t o r i a l with  C-C  respect  to the c h e l a t e r i n g ; the b u l k i e r t r i f l u o r o m e t h y l group occupies  a less s t e r i c a l l y - h i n d e r e d equatorial p o s i t i o n  (Figures VI.1  and  VI.2).  The bond d i s t a n c e s and valence f l u o r o c a r b o n group  and  i n the  (Table V I , I I I ) show some unusual  interesting features. 1.50  angles  The  C - F ( a x i a l ) bond d i s t a n c e s  and are  1.51(4), mean 1.51(3) A, the C - F ( e q u a t o r i a l ) bond o length i s 1.37(4) A, and the C - F ( t r i f l u o r o m e t h y l ) bonds  measure 1.24, 1.26, and 1.34(4), mean 1.28(2) A. 54 C-F bond d i s t a n c e  The normal  ° i s 1.33 A.  The e q u a t o r i a l and t r i f l u o r o -  methyl C-F bond lengths do not d i f f e r s i g n i f i c a n t l y from the normal v a l u e ; the e q u a t o r i a l C-F bond cannot be claimed t o be s i g n i f i c a n t l y  longer than the t r i f l u o r o m e t h y l bonds, as ;  i t d i f f e r s from the mean t r i f l u o r o m e t h y l l e n g t h by only 2a and from the l o n g e s t observed t r i f l u o r o m e t h y l bond by only 0.5a.  The C - F ( a x i a l ) bonds are however very s i g n i f i c a n t l y  longer than a normal C-F bond t o r i a l ) bond  (by 6a), than the C-F(equa-;  ( by 2.8a), and than the mean of the C - F ( t r i -  f l u o r o m e t h y l ) bonds  (by 6a). a  The C-C bond d i s t a n c e i s 1.40(4) A, s i g n i f i c a n t l y shorter  (by 3.5a) than a normal C-C s i n g l e bond  The v a l e n c e angles a t C(5) and C(6) are a l s o  (1.54 A ) .  informative.  Those angles not i n v o l v i n g the a x i a l f l u o r i n e atoms are a l l g r e a t e r than the t e t r a h e d r a l v a l u e , range 111-121(3), mean 115°; the angles i n v o l v i n g the a x i a l f l u o r i n e s are c o r r e s p o n d i n g l y l e s s than the t e t r a h e d r a l v a l u e , w i t h the C - C - F ( a x i a l ) angles b e i n g 97 and 99(3)°. A l l of these unusual f e a t u r e s are e x p l i c a b l e i n •. terms o f a bonding system which, i n v a l e n c e bond language, c o n t a i n s a c o n t r i b u t i o n not only from the normal Ia  (Figure V I . 3 ) , but a l s o from the s t r u c t u r e l b , which  i n v o l v e s d o n a t i o n o f molybdenum non-bonding via  structure  d-electrons,  the a r s e n i c 4d o r b i t a l s , i n t o o r b i t a l s o f the f l u o r o -  carbon group.  The m o l e c u l a r dimensions are b e s t e x p l a i n e d  by an equal c o n t r i b u t i o n of the two c a n o n i c a l forms I a and  92  Figure  VI.3  Proposed for  bonding  anomalous  scheme  to  observations.  account  93  lb  to the resonance  bond  character,  1.40  A,  pected  and  i n agreement w i t h  about  bond  thus has  50%  would  than  s i n g l e bond  a normal  the tetrahedral  as o b s e r v e d  bond d i s t a n c e  be p r e d i c t e d  o f t h e no-bond  double  the observed distance  midway between  (120°) v a l u e s ,  tribution  t h e C-C  the angles not i n v o l v i n g F ( a x i a l ) would  t o be  trigonal  hybrid;  ( 1 . 3 3 A)  The  considerably  as a r e s u l t  ex-  (110°)  (mean 1 1 5 ° ) .  t o be  be  and  C-F(axial) longer  of the  s t r u c t u r e , l b , a g a i n as  of  con-  observed  o  (1.51 A ) .  In molecular orbital  a d e l o c a l i z e d ir-bond s y s t e m , w h i c h  contains  molybdenum orbital normal  4d o r b i t a l ,  on e a c h  It expected  total  empty  carbon  sp  i s difficult  bond  However,  o r d e r o f 0.5,  the chelate involves  4d o r b i t a l s ,  approximates  a-bonding  2  bonds  since  on  a p  filled an  orbital,  t h e bonds  have  would  be  would  of the a  s i n g l e bond  which change value  distance  i s the shortening  predicted  longer  than  i n bond of  1.51  order.  o  ( 1 . 3 3 A) noted  This  be  above  o  the  ring  system.  the basis  the distance  a  and  t o p r e d i c t what d i s t a n c e  f o r the C-F(axial) scheme.  arsenic  atom w h i c h  t o an a p p r o x i m a t e  bonding  terminology,  by  a p p r o x i m a t e l y 0.14  i n t h e C-C  bond  A,  for a related  i s i n agreement w i t h  the observed  A.  ;  More r e l i a b l e  comparison  may  b e made w i t h  CHF=CF*Mn(CO)5 55  o  i n w h i c h l o n g C-F b o n d s , 1 . 4 8 ( 2 ) A, h a v e b e e n o b s e r v e d . ; These l o n g bonds have been r a t i o n a l i z e d i n terras o f s t r u c t u r e s +  involving where  i.r.  Mn  11  =C  F  spectra  .  Another  have been  comparable  s t r u c t u r e i s Mn(CO)sCF3  interpreted ^  i n terms  o f weak  C-F  bonds  Mn =CF  F  +  have  resulting  2  been  .  from  resonance  Contributions  supported  by  from  structures  structures  the observance  of the type  of this  of a short  type  Mo-C F 3  7  47 in  7 T - C H M o (CO) 3C 3F7 , 5  were  found  compound carbon any  5  i n t h e C-F b o n d s .  i s similar,  atom  effect  must  by  atom  be  tends  back-donation  bonding the  orbitals  ligand  this  to force  even  i n compounds  for  a high  where  n.m.r.  I t would i s able  antithat  to function i n o f t h e C-F appears  a favourable axial  atom. 57  favour  an  2  t o be  position equatorial  In Me AsCHFCH AsMe  indicate  the  charge  or  appear  bonding  factors  that atoms.  negative  non-bonding  Such  so  complex,  of the presence  steric  studies  that the  the arsenic  formal  into  positions. into  i n the present  feature  i n a metal  compound  f o r the fluorine  example,  that  by v i r t u e  C-F bonds  abnormalities  to the metal,  through  of the ligands.  i n the present  able  bonded  of electrons  i n the axial  position  known  to reduce  back-donation  bonds  t h e added  transmitted  i s well  no r e l a t e d  The s i t u a t i o n  but with  i s not directly  It metal  although  2  an a x i a l  2  « C r (CO) it  fluorine  atom. At  first  glance,  undesirable  feature  denum m i g h t  be e x p e c t e d  and  C-0  result for  bonds  that  this  the positive t o cause  t o be s h o r t e r  of the u n a v a i l a b i l i t y  back-bonding.  model  than  Mo-C  appears charge bonds  those  shifts  on t h e molybt o be  o f Mo(CO)  o f non-bonded  Corresponding  t o have t h e  metal  o f C-0  6  longer as a electrons  stretching.  frequencies  to higher  However,  the  can  be  also  -rr-acceptor the  level  between in  wavenumbers  charge d i s t r i b u t i o n interpreted  strength of  the  and  would  C-0  be  also  pictured  a mechanism  group, bond  expected.  i n Figure  arsine)  i n which  lengths  be  VI.3.1b  for increasing  the d i - ( t e r t i a r y  carbonyl  t h e Mo-C  L'Mo(CO)it  of  as  might  ligand  case,  i n Mo(CO)  the  no  difference  and  6  to  those  expected. o  The is  a  normal  slightly smaller  C-CF  single  larger, than The  bond  3  bond,  and  the  i n the present t h e C-C-F  t h e F-C-F  tetrahedral  thermal  angles,  angles,  VI.IV)  so  t h e maximum v i b r a t i o n s  are  restraint, The  solely  by v a n  structure, shown  i.e.  between  intermolecular d e r Waals  with  i n Figure  the  VI.4.  slightly  or  are  f o r those  atoms  i n general  oriented  i n directions of perpendicular  packing  interactions.  shorter  A,  110-113(3)° , a r e  105-110(3)°  vibration ellipsoids  a n i s o t r o p i c a l l y (Table  steric  1.54 (4)  value.  treated that  compound,  appears A  to  t o be  projection  intermolecular  least bonds. governed of  distances,  the i s  VII.  COMPUTER  PROGRAMMING  A  During squares  program,  is  where  EwA  and be  2  o"  .  P  R  made  G  standard  P  D  A  T  E  "  by o u r f u l l - m a t r i x quantity  k/a  =  being  2  constant  The program c a n  °  —  =  A  - > , \ B 1  correct over  I  I  F  —o ' ~  +  C1 | F  — —o  +  2  of  1  requires  | | .  a range  i s p r o p o r t i o n a l t o t h e mean wA  be e q u a l  numbers  Since  for  a n d we  can say that  a n d make  them  (7.1)  3  ~  t o have  the range  |  D 1 F 1  — —o  scheme  ranges  equal  1  ~  weighting  local  1  b e made  must  minimized  (k i s a  can  of  least-  d e v i a t i o n s i n F ' s from  8  2  jl  constant  U  equation  F  be  "  deviation i n F) .  5  A  M  and w  I f ^ - F ^ J  to assign  a  A  the residual  A =  Cruickshank's  R  refinement  i s the standard  F  O  that  2  a l l equal  2  a l l ranges  of reflections,  t h e <wA >  EwA  £wA  2  , <wA >,  2  2  f o r a l l range  t o <A > 2  o f t h ef i r  range. <wA >  =  2  but  s i n c e w = k/a  —  where  a  2  F  i  squares  (7.3)  r  i s calculated  (a*y we  must  (7.2)  2  2  Therefore,  and  <A >i  calculate  f i tof  f o r t h e mean  by = k A ,  F I of the I—oI  range. ^  transposing, <A > /<A > 2  2  i  B ,  C,  1  and D  (7.5) f o r the best  least-  °F^i to  t  o  k  <  A  2  >  i /  the program  B  2  >  i  over  NGRP  ranges,  where  r ,  z{A  n  leads  C  ,  D  i  + B<|F —  —  to the familiar  | > .+ C<|F  '—o  NGRP  i s input  cards. normal  NGRP  _ ,  A  from  This  •3 A  <  l  1  —  | > . - lii ili}2= o  | > . + D<|F 2  '-o  l  1  —  '-o  equations  3  A  <A  x  1  >i  (7.6) or /  i n matrix  notation,  E<IF I>. i '-o' i  NGRP  E < I F |>. Z < I F |> i "~2 i ~~2 1  E<  I>  z<  2  z<IF —o i . —o 1 X — x — Z < F -|>? Z < | F |>f . —O 1 . —O X E < I F 1  .  1  1  I  1  >  3  1  1  X  I  .  1  K  E < I F |  .  2  i  ?  A  ^  1  ~2.  i  X  1  >  x  E < I F  1  \ >  F  - O  |  F  |>f  B  1  >  C  ? 1  z<IF | > ?  I  1  | > ?  2.  i  I  i  ~°  E<IF  2  1  z<  F  i  . x  1  —  1  —o 1 — 1  Z<A >./<A >i 2  2  i  x'  I  E<IF >.<A 2 >./<A 2 >i i '—o' x x'  E< | F  i  \ or .and and  T W/k we  = S  solve  (7.7)  |>. <A >./<A >i 2  1  2  2  x  \'  1  |>. <A >./<A >J  E<|F  3  and  W/k  2  = T"  2  S  1  (7.9)  f o r A / k , B / k , C / k , a n d D/k b y i n v e r t i n g  T  m u l t i p l y i n g b y S. The  standard  so  (7.8)  '—o  1  that  achieve  best  deviations  i f we  choice  i n the derived  can evaluate  the best  of weights,  weighting  which  parameters  the constant scheme  gives  the lowest  i sw = —  1/a r  2  k i n ( 7 . 3 ) we c a n  by m u l t i p l y i n g t h e  solution  o f t h e normal  theoretically  that  e q u a t i o n s b y k.  I t can be  the constant k i s ERROR = Z w A / ( N R E F - N V )  (7.10)  2  w h e r e NREF number  shown  i s t h e number  of variables  of reflections  a n d NV  i n the least-squares  i s the  crystal  structure  refinement. The six  (of.  stages i)  read  increasing is  "UPDATE"  Table  structure  magnitude  factor  of F  of the array  according the  Each  adaptation M  the  structure contain  reflection. g r a m , we  I F ^ J  have  data. and  from  with  additional  ASORT(A,I,N,M,K) sorts  t h e M by K N by  i n the f i r s t i t sf i r s t  i s dimensioned  column  element.  elements  |F_ |, r e s p e c t i v e l y , c  of this  A(NREF,2) w h i c h  of ;For  1 0 , 0 0 0 b y ;2  of reflections  The a r r a y  K)  read  from  A(J,1)  and  f o r the J t h  ,  stage of the proi s sorted  i n order  I F ^ J . t h e number  o f ranges  gram  ranges  with  A  i n order of  i s dimensioned  t h e number  an a r r a y  determine  number  formulated i n  and s o r t  which  located  At the completion  increasing ii)  (which  program,  factor  be  Subroutine  routine  keys  i s s e t t o NREF,  A(J,2)  .  data  row i s moved  to this  and  The  A  t o one-word  array.  c a n now  VII.I).  an a s s e m b l e r - l a n g u a g e  fragment  of  program  cards.  desired  Each single  i f NREF/NGRP  range  of reflections (NGRP)  i s given  reflections  i s n o t an  i s input  range.  to the pro-  NREF/NGRP  added  integer.  i n each  reflections  to the f i r s t  few  Table Listing  VII.I  o f t h e program  OF At MOL SO. HE ANFO.I INFO • HA XFU iM tinLSQ , M Nl)LS PEAL M I D ' - C - : , ? l , VtM [T t. SIGII^l,YCI K I t S I L l 1)1, AC ( 10|,ASI I'll PIWFNSISN S l l - U ' l .NU-Mflt I , * ( « . .41 Df'ENST.CN HJ11?),HKU<-'J .Hit .FSCALf I 171 ,ktr N|lt<) .1110) ,VI4) 9E*L*» X,V,SU .T INT[i;rR-2 HJ.HR ,HL .F SCALF ,RFFN 6 FORMAT I i x , 'THIS l)A!A SF T t.ANUCT HE M M F O T O a FOUR P A^ AMFIE K CURV lt'l 7 FORMAT( 1 K,'BY LEAST SUUAffS METHODS WITMIH1T NEGATIVE WEIGHTS') F0fiW*T(///» A = ' . F 1 S . C , ' R . >,F15.1,' C > • »F 15. "3, ' Q • ' . F 1 1 . 9 I FCIkHAl | / / ' F SIT, SO SU« IM • ,/ I F0RMAT(3X,F4..",?Fir.,4l * F C r t « A T ( > ',///)  YISCKLTMX.)YBCUM| KP61  -  FOK . MAH4FI:>. :,2I5» R I  I ,2X,IS|  CALL «£wiNl< 4  X T-NRF. -NV Swr)LSl}«u. Oil 4L 1 J - 1, 1 r  ,Ft-. J ,2X ,Fh . >?X,Fo ,3 ,2X , F 5 . Z , ?x ,  1FIS3.?,X,I5> • f (]R AT( * ' , 2 U ' R K.'WDKLSOVI fUF»"AT(///«WCIGHTlN READ(5,3R1 F I N L F L I RNGRP-NGRP JKP." nri ?ir [ j . i , . SU*< IJ 1 = 0. NRF F =~ W  RS  -'DLSU-t.-DLTAS': Skl)LSC"SW['LSi-J»Wp| 50 ' TF K F • ISwDL S ti/ XT I nr- 1?! ( J K - 1 , 4 Yl I JM= TF "*-V | I JK I *°lTH|h.l"2I h » l T F ( 6 , 12) IY(I I ,1 « l .*) WPITFtf., 3?) WHIT SFWl\r> • Sw[)LStj»,..f SnF?StJ«l'.  NREF V 4 6  : SCJUARED'I I  OH 31 1 J , -NG.<P  K P-V.IMII«1R,PJl SIGSJ"Y11  tr  WD1 <,Q*r, wrn. j , MFTSO"".  iM) i jnn = i , ucri-  OEADI ?,END=Q^) CYDIKl, S1GIK I , YC|K I, STL IK) .AC) K I t H J U l .MRU) ,HLIL| , F S C 4 L H L t .REFHIL) , 1 - 1 , l l ) DO 1 1=1,R  1 H HJ( 11 »t';E1 r,n T : J qo  , A 5 ( K ) , 1 "  r>r> 32 RCAPt-il It TASJ.FO )*YI? )•FM*Y[3 If t SIGSQ.i f .".'"'I Gi- rr J *.»l.'j/SIGSO hfr'S'JuhrnsOtti'TLi* f M • OL 5i:)*V.nL V j i « 'OL lAlv)  I F I YCII I t I 1,1,4234 4 NHEF'NRFF*! ft(N^Er ,1 I=Y n( I ) A ( N » E F ,2|*YCI I I CONT 1NUE CALL A SORT t A, 1. lr-:";-.' ,NW rf , ? )  i  » E^n i ^Hfi FR^[!H>S(jRT{ ( •VOL SC3 11 • T t i K » s e « T ih iu sc/.*ri:sg (  ,r.r.r  Of-TfMUNF MOTHER TF •< CFLFC T  nn i J=I,NGP°  ICNS  SwllLS(J"SwOLSQ*wni SO SwFUS'J«S^FOS J*WK1S(? CONTIMJE T"NF1»SS(JMF{l/XNt' r f TR,SSHl TA/SSU^Fl. rr TwTOH*Sy>'T ( S^nLSLVS^i-^.'SOl TMW^S-SrtOL ';u/ <^«CF TF?M« ,tJBT ( Sk.1t.S0/xT |  'IM  [h T-ACH Ri  XNREf-NKFF 1NHFF=NRFF/NCHP J F = NH FF-C^GRP" INRFf I  ,  t,  HI' I TE (  IFIJ-IFI 4,4,5 NHrMJlmlNRtr Gil TO 4 MJM|JI=INWrF*l CONTINUE C ALCUl AT F WEIGHT INC. ANALYSIS IN FIJRM A T III S SiriLTA - O . r iiUMFtl-* .f 00 6 J = l , NGPP su«*rn=>-, SOt(.TA=;-. • • OLSO- . KP=NU"IJ) III) 7 I > 1 . KP fltLTA-AilSI AC JKPH ,1 l-A( JKP* [ ,2 ) I r>LT ASl>t)tL T A«"OEt TA DLSO = DLSO*DlT ASO SOn TAtSfl LTA*nnrA SUMfO-SllMFO.AI J X P .| , I 1 M « l TE 141 OL TASO.A I JK*"*I ,1 I . "INFtl-AI JKP*1 IF I 1 .FU.MJM I J )] n A » F O " A I ' J n P * l , 11  IE  1) MIH SO = 0LS0/M)MIJI ,  fHAX»l.j -,f |-Llf'«rM x t  4  l » f *"( 1-1  l**- . n  S0RTW 11 v? 1 re 1 6, ?i i r, sir.sy 1 S I K tw I F If .f,f . v » l x ) T O 2i )r tF . G F . F l * I r,o TC L  22  INUC  20? 2C-3 2G6  22  r,n 3CC ' KH I IE « tt 31 f,) H"I If I 6,3'. 7 ( SUHRITUT INE SHI.TNI A.U, N.x.OCT, ' 1 FNO SUPfiOllTlNE TO SOI VF H A T ° t t C0UAT1CN TIMEnsicN  A M ,  OP <>>.'  r>ET-i)fT-A(i,ii  IFtArtSlDf TI .1. T  K*2,^  X(2 . M = S U » ( Kl XI3,3)>SUMIH Xt 3, t)-SUMI •>) = S"H(6) t>0 11 1-2,4 IKl-1-1  C .1 1 ) F I N 1 • S . •*'  . L T .  1-..2 1 = 1,'.  SC1H  K«1=K-1 XII . K l - S U M l K H l l  00 f K*2,<.  I], Th rnu , liwDS.Tfat ,  IF IFIN? .LT. i ' IM'-I-; . :.• W « | T F F F S I G S 'U '.-i!FI(SIC= S G S!>S I S * I Y ( I M SO.LTS .O ^IR . ITr.n G D/i'.C 2* SI CS TI F • Ff»NF2«INT IO G O F »F| G D H I C: N T D STO° PEAL'P"UA,LTr t»i:  SUFf/ rMJM(JI  no 19  IFlM  I f (FMflX ,L T, f . . - ] ) I F IFl.tl ,LT. C6,2^1 INI  trtt.ru.1>  Iff J .CO. 11 *• I NDL S'rOLSO MFANFt) = P-SDEITA/SU^FO " D L S ' J » MOLSD/MINIILS SSOMFr-SSIlMFO^SOMFO SSOl TA.SSpLTAtSOELTA J*r = J K P*KP WRITE I) I MINFC,MA*FC.,HEANfn,R,H[JLSO ENOFRF 3 SFW IND 3 DO H JOfl = l t NGBP P.FA013,ENIJ» 161 E , F , H , G , A N T <1)=R su"i 1»- sum 11 11 DO 15 J-2,h J«1=J-1 T)Jl = T(JM11 *B S11M)JI-SU>-IJI*T(JI CONTINUE T(7 L A N SUM< 7 I=SUMl7 I*T(7 I no u L=fl,ic LM1=L-1 ICLI-TILMll'H SUM(L)=S1JV.(L|*T(L» CUNTINUE CONTINUF CONTINUE BEWIND 3 K(1.11=RNGRP  1 T-*, T * W  LALCULATF 1. S'lO SIO''* A* HINtTIlIN O FF  1-  *T(  X"-  R £ Al) I *•, FNn.i, •? I OL' AS a, TO s n , s « - Y i i i * y i 2 i ' *U»Y< a i- f iv F H * Y ( 4 i M-WVStGSO  At I I H , M . 1 , 3 M - ,F f . 1.3*.Fft. i, 2X.F*,, 1 . 2 X . F 6 . 3 . 2 X . F 5 . 2 , 2 X , F 6 . *  FKRC1H  "UPDATE"  224 22S 226 127 22B 229  HI J 1 "P 1 J) - B I I 1 «Mi'LT CCNTINUE CON'IMUF 00 < 1=1.  B tI -lEU ll/AlI,Ll flFTURN  MftlTEIAil?) FORMAT(•DETCPMINANI RETURN 1 FNfl  Nn tlNIOl'F SOLO  102  iii) each  the following five  range  and s t o r e d  M I N F O , MAXFO, mean  quantities arecalculated f o r  temporarily a n d MEANFO,  iv)  theratio  2  matrix  for  A / k , B/k, C / k , a n d D/k.  v) ERROR  o f normal  using  corrected MAXFO, and  these  values  F^  values  from input bad  justed being  i s solved  {EwA /ZwF^} 2  NUM(J)  = number  value.  Using  thevalues  these  o f MINFO,  a n d NUM(J)  i s compiled  1  /  2  "  2  from  where  t o t h eprogram  ERROR,  scheme  <wA > of reflections  arecalculated  of FINl  by s m a l l  weighting  range.  =  t o FMAX  used  t o s e tup  i s a subroutine f o r  of the four  by t h i s  MWDLSQ  2  fit,  SOLTN  WTDR, MWDLSQ,  f o reach  w and a  FLIM  and t h e system  o f A , B, C, a n d D, a t a b l e  R, MEANFO,  i n steps  a r e used  f o r A , B, C , a n d D, t h e c o n s t a n t  and each  WTDR =  vi)  a n d MDLSQ  equations  i smultiplied  printed  2  I  equations.  i s evaluated  parameters  maximum a n d  <A > /<A >i  the  matrix  t h e minimum,  E|A.|/E|F^| f o r the range.  index  t h e q u a n t i t i e s MEANFO  solving  file.  |F^|i n t h e range.  R, t h e d i s c r e p a n c y MDLSQ,  on a data  from of a  changes  in. s t r u c t u r e  and p r i n t e d  FIN1 t o FLIM FINl,  2  i n the,Jth  FLIM,  cards.  as a f u n c t i o n o f  and i n steps  FIN2,  refinement.  because o f  and should  t o theweighting  o f FIN2  a n d FMAX a r e  Sometimes  arenegative  range,  be a d -  parameters  before  B. During t h e Oak R i d g e  PROGRAM  the course  "ORTEP"  o f t h e work f o r t h i s  National Laboratory  thermal  thesis,  ellipsoid  plot  59 p r o g r a m , ORTEP, programs  w a s made  are  with our existing  and i m p l e m e n t e d on t h e IBM 360/67 by t h e a u t h o r . Stereo views  thesis  compatible  are given  represented  vibration.  of the four structures i n this  i n F i g u r e V I I . l as p l o t t e d by 50% p r o b a b i l i t y  b y ORTEP.  ellipsoids of  Atoms  thermal  Figure Stereo  VIi.l  views  of  LFe (CO)io  (c)  LRu (CO)  L Ru (CO)8  (d)  L'Mo(CO)  3  2  3  (a)  (b)  3  105  (d)  VIII.  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