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Group 4 diene complexes stabilized by phosphine donors Haddad, Timothy S. 1987

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Group 4 Diene Complexes Stabilized by Phosphine Donors  by Timothy S. Haddad B. Sc. University of Regina 1984 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE in THE FACULTY OF GRADUATE STUDIES (Department of Chemistry) We accept this thesis as conforming to the standard  THE UNIVERSITY OF BRITISH COLUMBIA May 1987 © Timothy S. Haddad, 1987  In  presenting  degree  at  this  the  thesis in  partial  University of  fulfilment  of  of  department  this or  publication of  thesis for by  his  scholarly purposes may be  or  her  representatives.  permission.  C  tl(=* l /  )  ^TrVf  The University of British Columbia 1956 Main Mall Vancouver, Canada V6T 1Y3 Date  DE-6(3/81)  Si  W81  that the  for  an advanced  Library shall make  it  agree that permission for extensive  It  this thesis for financial gain shall not  Department of  requirements  British Columbia, I agree  freely available for reference and study. 1 further copying  the  is  granted  by the  understood  that  head of copying  my or  be allowed without my written  Abstract  The synthesis of eight fluxional, diamagnetic group 4 complexes MR,(C4H6)[N(SiMe2CH PR2)2] (M = Hf, Zr; R' = Ph, CH2CMe3; R = Me) and (M = 2  Hf, Zr, R' = Cl; R = Me, CHMe^ has been achieved. The X-ray crystallographic results of two of these complexes (M = Hf, Zr; R' = Ph; R = Me) indicate that the bonding of the diene unit has a significantly higher degree of  T\ 4-TZ  character than is present in  Cp2M(diene) (M = Hf, Zr) complexes, and therefore the M(II) resonance structure has more contribution to the overall bonding scheme. Consistent with all the NMR data available is that these complexes maintain a meridional coordination of the tridentate amide-phosphine ligand both in solution and in the solid state. The observed fluxional process is best described as diene rotation. Two of the diene complexes (M = Hf; R1 = Cl; R = Me, CHMe^ were found to react with allylmagnesium chloride and subsequently undergo a unique C-C bond forming reaction and rearrangement to generate two new non-fluxional diene complexes I  1  Hf[(Ti4-CH2CHCHCH)CH2CH2CH2][N(SiMe2CH2PR )2] (R = Me or CHMe2). The 2  latter of these two complexes has been crystaUographically characterized.  iii T a b l e of C o n t e n t s :  Abstract  .  .  .  .  .  .  .  .  .  .  ii  L i s t of T a b l e s  .  .  .  .  .  .  .  .  .  iv  List of Figures  .  .  .  .  .  .  .  .  .  vi  .  .  .  viii  .  .  .  ix  List of Abbreviations  .  Acknowledgement .  .  .  .  .  .  .  .  .  .  C H A P T E R 1: I N T R O D U C T I O N  1  1.1 Late Transition Metal Diene Complexes . 1.2 Early Transition Metal Diene C 1.2.1 Synthesis  o  .  m  p  .  .  1.2.2 B o n d i n g Considerations  .  1.2.3 Fluxional Behavior 1.2.4 R e a c t i v i t y  .  .  . l  e  x  .  .  .  1  .  .  .  2.2 S  t  r  .  u  c  . t  u  2.3 Fluxional Behavior 2.4 R  e  a  c  t  . r .  i  v  s .  i  5  .  .  7  .  .  8  .  . .  . .  .  9  .  y  .  .  .  t  3  . 1 3 14  .  e  3  .  C H A P T E R 2 : RESULTS A N D DISCUSSION  2.1 Synthesis .  . .  .  .  .  .  .  1.4 Thesis Content  .  .  .  .  .  s  .  .  .  e  .  1.3 Phosphine Complexes of Group 4 Metals .  .  .  .  .  .  .  .  .  .  .  . .  .  . .  .  . . .  .  .  14  .  .  . .  .  16 22  .  30  C H A P T E R 3 : CONCLUSIONS  40  CHAPTER 4 : EXPERIMENTAL  41  4.1 Methods and Compounds  .  .  .  .  . 4 1  4.2 Tabulated N M R Data  . 4 6  CHAPTER 5 : REFERENCES  55  Appendix  .  . 5 8  iv List of Tables:  Table  I. Bond Length Data For a Series of Diene Complexes  Table  II. ^ C - H For a Series of Diene Complexes .  Table  HI. Selected Bond Angles For HfPh(ri4-C4H6)[N(SiMe2CH2PMe2)2],  .  . .  .  .  .  .  6  5a,  and ZrPh(Ti4.C4H6)[N(SiMe2CH2PMe2)2], 6a Table TV.  5  18  Selected Bond Lengths For HfPh(T|4-C4H6)[N(SiMe2CH2PMe2)2],  5a,  and ZrPh(Ti4-C4H6)[N(SiMe2CH2PMe2)2], 6a  19  Table  V. Comparison of Bond Lengths For Analogous Hf and Zr Complexes  Table  VI. AG* Calculated From Variable Temperature NMR  Table  VII. *H NMR data  47  Table  VIII. ^ C NMR data  49  Table  IX. 3*P fjH} NMR data  51  Table  X. Data for HfCl(ri4-C4H6)[N(SiMe2CH2PMe2)2]  3a  .  .  . 5 2  Table  XI. Data for ZrCl(ri4-C4H6)[N(SiMe2CH2PMe2)2]  4a  .  .  . 5 2  Table  XII. Data for HfCl(Ti4-C4H6)[N(SiMe2CH2P(CHMe2)2)2]  Table  XHI. Data for ZrCl(T|4-C4H6)[N(SiMe2CH2P(CHMe2)2)2]  4b  .  Table  XIV. Data for HfPh(ri4-C4H6)[N(SiMe2CH2PMe2)2]  .  .  . 5 3  Table  XV. Data for ZrPh(Ti4-C4H6)[N(SiMe2CH2PMe2)2]  .  .  . 5 3  Table  XVI. Data for Hf(CH2CMe )(Ti4-C4H6)[N(SiMe2CH2PMe2)2]  Table  XVII. Data for Zr(CH2CMe3)(rj4-C4H6)[N(SiMe2CH2PMe2)2]  Table  .  .  21  .  . 2 7  3b  5a 6a  3  52  7a .  .  53  .  54  8a .  . 5 4  XVIII. Bond lengths for HfPh(ri4-C4H6)[N(SiMe2CH2PMe2)2]  .  58  Table  XIX. Bond angles for HfPh(ri4-C4H6)[N(SiMe2CH2PMe2)2]  .  .  59  Table  XX. Bond lengths for ZrPhCri^^tNCSiMezCH^Me^J  .  .  60  Table  XXI. Bond lengths involving H atoms for ZrPh(-n4-C4H6)-  [N(SiMe2CH2PMe2)2]  61  Table X X I I .  Bond angles involving H atoms for ZrPh(Ti 4 -C 4 H 6 )-  [N(SiMe2CH2PMe2)2] Table X X H I .  Bond angles for ZrPh(Ti4-C4H6)[N(SiMe2CH2PMe2)2]  Table X X I V .  Bond lengths for Hf(Ti 4 -CH 2 CHCHCH)CH 2 CH 2 CH 2 -  .  [N(SiMe 2 CH 2 P(CHMe 2 ) 2 ) 2 ] Table X X V .  Bond angles for Hf(Ti 4 -CH 2 CHCHCH)CH 2 CH 2 CH 2 -  [N(SiMe 2 CH 2 P(CHMe 2 ) 2 ) 2 ] Table X X V I . Intra-annular torsion angles for HV(TI -CH CHCHCH)CH CH (5] 4  2  [N(SiMe 2 CH 2 P(CHMe 2 ) 2 ) 2 .  2  2  vi  List of Figures: Figure 1. T w o  proposed structures for F e ^ H ^ X C O ^  .  .  .  Figure 2. Three possible bonding schemes for butadiene bound to a transition Figure 3. Diene rotation and Berry pseudo-rotation. Figure 4. Envelope flip Figure 5. Tridentate  .  .  .  6  .  2  l  l  6a  17  .  .  .20  .  .  .  .  .  .23  spectra of HfPh(T| 4 -C4H )[N(SiMe CH2PMe2)2],  Figure 10. ^C{ R)  2  .10  structures based on the  .  "envelope flip" isomerization .  Figure 9. YL N M R  .  2  structurally characterized zirconocene dienes  7  .  . 2  2  .  4  4  1  metal  .  structure o f : Z r P h ( T i - C H ) [ N ( S i M e C H P M e ) ] ,  Figure 8. Possible octahedral solution  Figure 11.  .  .  hybrid-ligand bound to a metal centre .  Figure 6. X - r a y crystal Figure 7. T w o  mechanism .  .  1  .  2  6  5a  .  N M R spectra o f H f P h ( r j - C H ) [ N ( S i M e C H P M e 2 ) 2 ] , 4  4  6  2  2  24  5a .  25  31p{lH} variable temperature N M R spectra of H f P h ( r t - C H ) [ N ( S i M e 4  4  6  2  CH PMe2)2J, 5a, displayed in 10° intervals from 280 K to 210 K  .  .  Figure 12. Rotating  .  .  .  .28  .  .  .  .29  2  diene mechanism  Figure 13. Envelope flip Figure 14. * H N M R  .  mechanism.  .  3 1  4  .  .  .  2  6  .  .  .32  P { H } N M R spectra o f the reaction between H f C l ( t i 4 - C H ) !  4  [N(SiMe2CH2PMe2)2L 3a, and allylmagnesium chloride  Figure 16. * H  .  6  .  .33  N M R spectra o f H f ( r i - C H C H C H C H ) C H C H C H 4  2  2  2  2  35  [N(SiMe CH P(CHMe )2) ] 2  2  Figure 17.  26  spectra o f the reaction between H f C l ( T i 4 - C H ) [ N ( S i M e 2 C H -  PMe2)2], 3a, and allylmagnesium chloride  Figure 15.  .  .  2  2  Portion o f a 3 C - H heterocorrelation N M R spectrum showing the 1  1  connectivity o f the hydrogen and carbon atoms in the C7H1 \ fragment o f Hf(ri -CH CHCHCH)CH CH CH [N(SiMe2CH2P(CHMe2)2)2],9b 4  2  2  2  2  .  .  36  vii \  i — :  Figure 18. X-ray  crystal structure o f H f ( T l - C H C H C H C H ) C H 2 C H C H 2 4  2  2  [N(SiMe2CH2P(CHMe2)2)2], 9b  Figure 19. Stereoviews  o f Sa,  37  6a and 9b .  .  .  .  .  . 6 6  List of Abbreviations:  A  Angstrom  cmpd  Compound  Cp  Cyclopentadienyl  Cp*  Pentamethylcyclopentadienyl  dmpe  1,2 - bis(dimethylphosphino)ethane  dppe  1,2 - bis(diphenylphosphino)ethane  ESD  Estimated standard deviaiton  fac  Facial  AG*  Energy of activation  IR  Infrared  J  Coupling constant  L  Ancilary ligand  Me  Methyl  mer  Meridional  Mgini  [Mg(C4H6)(THF)2]n  NMR  Nuclear magnetic resonance  nOe  Nuclear Overhauser effect  Ph  Phenyl  R  Alkyl, aryl or halide  ref  Reference  Tc  Temperature of coalescence  temp  Temperature  THF  Tetrahydrofuran  UV-VIS  Ultraviolet - visible  Acknowledgement I would like to thank my proof-readers for their excellent criticism, my supervisor, Dr. Fryzuk, for endless patience and help and Dr. Steven Rettig for the three X-ray crystal structures he solved. In addition, thanks go to all m y co-workers, past and present, w h o make graduate studies so enjoyable.  1 C H A P T E R 1 : INTRODUCTION 1.1 Late 1 Transition Metal Diene Complexes  Thefirstbutadiene complex, FeCQHgXCO^, was synthesized in 1930 by Reihlen2 who proposed a 16-electron Fe(IT) species (A in Figure 1) as a possible structure. It was not until 19583 that comparison of the spectral features of Fef^HgXCO^ to those of cyclohexadiene iron tricarbonyl proved that the butadiene was bound to the iron in a cisoid fashion. At the same time an eighteen-electron Fe(0) structure (B in Figure 1) was proposed as a more reasonable formulation for this complex.  /TV %  Fe.  CO  CO  CO  CO CO  A  B  Figure 1. Two proposed structures for Fef^HgXCO^  Three possible bonding schemes for the diene moiety were suggested4 in 1959 (Figure 2). However, it was concluded that using solution spectroscopic methods it would not be possible to definitively distinguish among these possibilities.  C  D  E  Figure 2. Three possible bonding schemes for butadiene bound to a transition metal  The X-ray crystal structure of Fe(C4H6)(CO)3, solved a short time later5, showed that D was a fairly accurate representation. The C-C bond distances in the diene are essentially identical and all four carbons are approximately equidistant from the iron. The next development in this area was the discovery that in solution Fe(C4H6)(CO)(PF3)2 (a substitution product of Fe(C4H6)(CO)3 with PF3) was fluxional on the NMR timescale6. Rotation of the three non-diene ligands around the iron was proposed in order to explain the observed fluxional behavior. During the 1950's and 1960's, research into diene complexes of the late transition metals underwent a period of rapid growth. Several more fluxional systems were reported7 and subsequently a controversy developed over the nature of the fluxional process. Theoretical calculations8 were presented that allowed for diene rotation, but did not discount Berry pseudo-rotation. It was then verified experimentally7 that the fluxional process occurring for Fe(isoprene)[P(OMe)3]3 had to be either rotation of the diene ligand or cyclic exchange of the three phosphine ligands via Berry pseudo-rotation9 (Figure 3).  7>  Figure  .p«3 -PR3  3. Diene rotation and Berry pseudo-rotation  Diene rotation was the simplest explanation but it was indistinguishable on the NMR timescale from two sequential Berry rearrangements.  3 1.2 Early Transition Metal Diene Complexes  1.2.1  Synthesis  Unlike the diene complexes of the late transition metals, complexes of the early transition metals incorporating diene ligands remained a rarity until the 1970's; group 3 diene complexes are in fact still unknown. [Zr(C4H )2(dmpe)]2(dmpe) (dmpe = l,2-bis(dimethylphosphino)ethane), reported 6  in 1979 1 0 , was the first example of a group 4 diene complex. In 1980 Wreford 1 1  C H TiCI (dmpe) 4  1-1— Na/Hg  Ti(C H ) (dmpe) 4  6  2  [ij  synthesized the first titanium diene complex Ti(C4H5)2(dmpe) in an analogous manner (Equation l ) . W r e f o r d 1 2 was also among the first to make use of the "magnesium butadiene" reagent [Mg(C 4 H5)(THF)2] , generating a wide variety of cw-diene complexes n  of T i , Zr, Hf, Nb, W and Fe. Except for some vanadium compounds reported 1 3 in 1960, group 5 diene complexes  are  also  extremely  scarce.  Ta(C4H6)(C2H4)(PMe3)Cl  and  C p * T a C H 2 C H 2 C H C H 2 ( C 4 H 6 ) were briefly reported in 1979 1 4 and 1982 1 5 respectively. 2  Nakamura made the most extensive report in 1985 1 6 on a series of tantalum diene complexes utilizing the "magnesium butadiene" method of preparation. Another method of early transition metal diene formation is photolysis of diarylzirconocenes17 in the presence of a trapping diene (equation 2). The low temperature photolysis generates the highly reactive zirconocene fragment which is trapped by  4 butadiene while in a trans -conformation. It was with this method that Erker first isolated a  Cp ZrPh + C H 2  2  4  h 6  v  ,  Cp Zr(t/ans- C H ) + biphenyl 2  4  [2]  6  -30° C  diene bound in a trans-fashion  to a single metal centre. Later it was shown  18  that the  "magnesium butadiene" method would generate a trans-bound butadiene complex as the kinetic product if the reaction was carried out at low temperature (equation 3).  Cp MCL, + Mg I] 2  Cp M( trans- C H ) + MgCL  fl —  2  4  6  [3]  10° C  M = Hf, Zr  Coupling of alkenyl ligands (equation 4) and thermally induced exchange of diene 19  ligands (equation 5) are two other methods that have been used to generate /rans-dienes 20  2Cp Zr'  Cp Zr'  2  •Ph  2  •Ph  Ph  .Ph CpgZr'  Cp Zr^^ 2  •Ph  'Ph  [4]  Ph'  Ph  Cp M(isoprene) + 2  M = Hf, Zr  Ph.  + isoprene  Ph Ph'  [5]  5 bound to zirconocene. However, the generality of these procedures has not yet been established.  1.2.2 Bonding Considerations  The bonding of the diene changes from a delocalized, 7C-bound rj4-diene as seen for FefX^HgXCO^ to emphasis of the o2-rc (see D and E respectively in Figure 2) type of bonding for these early metal complexes. Evidence for a2-rc bonding comes from crystallographic and N M R spectroscopic studies. A notable exception 21 to the bonding modes of D and E in Figure 2 is Mo(C 4 Hg)3 which, being intermediate between an early and a late transition metal complex, shows a short-long-short C-C bond length pattern for the diene unit (see C in Figure 2). Crystallography has shown that when the diene is bound to Zr, H f or Ta, the C-C bond lengths of the diene unit show a long-short-long bond sequence. In addition, the two outer carbons (which have partial sp 3 bond character) are closer to the metal than the inner  Table L  Bond length3 data for a series of diene complexes.  Compound  M-Cl M-C4  M-C2 M-C3  C1-C2 C4-C3  C2-C3 ref  Cp2Zr(C6H10)b  2.300(3)  2.597(3)  1.451(4)  1.398(4) 17  Cp2Hf(C6H10)b  2.267(5)  2.641(5)  1.471(8)  1.378(8) 22  Cp* Th(C^  2.56(3)  2.74(3)  1.46(4)  1.44(3)  23  Mo(C4H6)3  2.29(1)  2.29(1)  1.32(2)  1.55(3)  21  Fe(CO) 3 (C 4 H 6 )  2.14(4)  2.06(3)  1.46(5)  1.45(6)  5  2  a) bond lengths in A b) Cp = 7 i 5 - C 5 H 5 , C g H ^ = 2,3-dimethylbutadiene c) C p * = Ti5-C5Me5  A \ ;  sp2-like carbons. Table I contains crystallographic data representative of cw-bound dienes; included are data from one late transition metal complex and the molybdenum compound mentioned earlier. An intriguing thorium complex, for which the authors were unable to explain why the diene bond lengths were so similar, is also included. However, large estimated standard deviations preclude any definitive conclusions about this derivative. Five crystal structures of bis(cyclopentadienyl)zirconium diene complexes have been completed. In a recent review24, Erker has carefully examined the subtle differences between these five zirconocene compounds and determined that there are only three parameters which vary consistently with the degree of a- andft-bondingexpected from the diene. The first is the Zr-C2, Zr-C3 bond distance, representing the 7t-interaction. The second is the C1-C2, C4-C3 bond distance, strongly affected by the o-interaction. The third parameter is the Zr-Cl-C2, Zr-C4-C3 bond angle. The larger these three parameters are, the larger the CS/K ratio is for the bonding of the diene to the metal centre. These trends also hold for the two hafnocene-diene complexes for which X-ray data are available. Table II. ^ C - H f ° r a series of diene complexes3 Compound  ref.  Si(C H )Me  125  25  Cp*Th(CH)  142  23  Cp Hf(C H )  140  18  Cp2Zr(C H )  144  18  Cp Ta(C H )  149  16  (CCOsFeCQHs)  168  26  4  6  2  2  2  4  4  4  2  4  6  6  6  6  a) couplings in Hz  7 The NMR spectroscopic evidence for  a -7i 2  bonding comes from the 1 J C - H coupling  constant of the outer diene carbons. In general, the magnitude of this coupling is diagnostic of the particular hybridization at the carbon centre, this coupling being smaller for an sp3 carbon than for an sp2 carbon27; Table II contains some representative data. Si(C4Hg)Me2 is expected to have the outer carbons as pure sp3 hybrids, while the iron complex will have pure sp2 hybridized carbons. This gives a ^ C - H range of 125 to 168 Hz for the transition between a purely o-bound diene to one that is onlyrc-bound.The data clearly show that the early metal complexes are somewhat intermediate between the two. 1.2.3 Fluxional Behavior Just as diene complexes of the late transition metals exhibit fluxional behavior so too do those of the early transition metals. However, the dynamic process occurring is fundamentally different for these early transition metal complexes. While diene rotation is often presented as the operative mechanism when the diene is bound to late transition metals, the process that the early transition metal complexes undergo has been described as the "envelope flip" mechanism 28 > 29 « 24 (Figure 4). The energy of activation at the coalescence temperature has been calculated24 to be in the range of 6.5 to 14.3 kcal mol-1. Hs  H Ha  H  Figure 4. Envelope flip mechanism: H = mew-hydrogen; Hg = syn-hydrogen; H = anft'-hydrogen m  a  The evidence for this process is obtainedfromNMR spectroscopy. Above the coalescence temperature, the spectral data indicate an averaged planar metallocycle; both the cyclopentadienyl rings are equivalent, the syn- and a/ifz-protons of the diene in fast  exchange are equivalent and the two meso-protons are equivalent. Below coalescence, the two cyclopentadienyls become inequivalent, and there are three multiplets for the syn-, antiand meso-diene protons. Diene rotation cannot explain these spectroscopic data since in the rotating diene mechanism syn- and a/ir/-protons never exchange and are therefore always inequivalent.  1.2.4  Reactivity The rich chemistry of these early metal dienes has been recently reviewed by  Erker and Nakamura . The diene fragment has been found to undergo a thermal reaction 24  29  with ketones, aldehydes, esters, nitriles, alkynes and alkenes as shown in Scheme 1. CpjZrfisoprene)  R o  C  P  2  &  X  \ H*  RCN  RCOOR'  j RR-CO  R  R'  \ //  o  C  P2 ^ &  J  D  OR  \  X  J  =-R  R_C=  CpjZr CpzZr  y)  H*  R HO R"  Scheme 1. Reactivity of Cp2Zr(isoprene) with unsaturated molecules.  Erker claims that the reactive species is an r| -diene compound which coordinates 2  the unsaturated organic reactant and subsequently undergoes an electrocyclic ring closure followed by rearrangement to the observed product. This is illustrated in equation 6 using dimethylacetylene as an example. These types of reactions generate useful organic products  9 after hydrolysis, and serve to illustrate the use of these diene reagents in organic synthesis30.  1.3 Phosphine Complexes of Group 4 Metals Until recently, the coordination and organometallic chemistry of zirconium and hafnium were dominated by complexes stabilized by traditional hard31a ligands such as nitrogen- and oxygen-donor types. The first literature reports of zirconium and hafnium phosphine complexes were made in 1974 3 2 and 197533 when two poorly characterized  PhZrCI + dppe 3  • PhZrCI (dppe)  [7]  3  dppe adducts (dppe = l,2-bis(diphenylphosphino)ethane) were reported (equations 7 and 8). While the 1974 paper reported an elemental analysis, a Zr-C IR stretch and some low resolution 1 H NMR data, the 1975 paper reported only one broad C-N IR stretch and the given formula was "empirical".  {HfCI [C(CI)=NCMe ][C S N C M ] } 3  3  e3  2  • HfCI [C(CI) =NCMe ][dppe] 3  3  [8]  10  It was not until 1979 that two papers describing some well defined phosphine complexes were published. First34 was the trapping of the elusive zirconocene fragment with tertiary phosphines (equation 9). This established the ability of the soft31a phosphine  Cp Zr(H)R + 2L 2  R = alkyl  RH + Cp Zrl_ 2  [9]  2  L = dmpe, 2Ph PMe, 2PhPMe 2  2  2  donor to stabilize low oxidation states of group 4 metals. The second report11 (equation 10) was of the dmpe adduct of ZrCl4. This adduct was then reduced with Na/Hg amalgam in  ZrCI + dmpe — - ZrCI (dmpe) 4  4  2  - [(C H )2Zr(dmpe)] (dmpe) Na/Hg 4  6  2  [io]  the presence of butadiene to generate a formally Zr(0) butadiene complex stabilized by the chelating phosphine. It was partly the paucity of thermally stable group 4 phosphine complexes that led to an ongoing research project to study the chemistry of zirconium and hafnium complexes incorporating the potentially tridentate ligand shown below (Figure 5). The ligand was Me2 Si  RP _ M „ 2  Me2 Si  P  R  2  Figure 5. Tridentate hybrid-ligand bound to a metal centre  designed such that it would be capable of stabilizing metals both in high and low oxidation states. The amide donor was expected to stabilize high oxidation state metals3 l b while the phosphine ligands were expected to bind strongly to low oxidation state metals3l b . With regard to the hard early metals, it was anticipated that the amide portion would anchor the chelating ligand and therefore reduce the tendency for phosphine dissociation. This strategy was successful and several crystalline Hf(IV) and Zr(IV) complexes have been synthesized, a few of which are shown in Scheme 2. The ligand is capable of both facial and meridional coordination (F&G), although in solution meridional coordination is favored35 (F&F'). It is possible to generate both mono- and bis-ligand complexes35*36 (F&I); mononuclear and dinuclear compounds have also been isolated37 (J&K). Several alkyl, hydride and borohydride compounds (HJ,K&L) have been successfully characterized38. Many of the aforementioned compounds exhibit dynamic behavior as revealed by their solution !JH,31P{1H} and ^C^H) NMR spectra. The organometallic chemistry of hafnium and zirconium (up to 1984) is the subject of a recent monograph39. Included in this text are numerous examples of the now common group 4 phosphine complex as well as three chapters on low oxidation state complexes. An interesting trend is that many of these low valent complexes are stabilized with phosphine ligands. Recently phosphines have been used to isolate some novel low valent group 4 organometallic compounds. Thermolysis of C p 2 Z r P  n  2  in the presence of PMe3 results in  the isolation of a mono-phosphine benzyne complex40 (equation 11). Another interesting  Cp2ZrPh2  >10PMe.  Cp2Zr(C6H4)(PMe3) + C6H6  [11]  12  Scheme 2. Some well characterized group 4 complexes incorporating the hybrid [N(SiMe2CH2PR2)2]" ligand. An asterisk denotes crystallographically characterized complexes.  13  compound is the mono-phosphine titanocene carbene c o m p l e x  41  (equation 12), which has  been recently isolated and crystallographically characterized. In this reaction the phosphine has trapped the titanocene methylidene which is thought to be the reactive f r a g m e n t i n 42  olefin metathesis, olefin polymerization and methylene transfer reactions.  L L = PMe , PMe Ph, PEt 3  2  3  1.4 Thesis Content  Since  i t h a d been  demonstrated  that  the p h o s p h i n e  arms  o f the  [N(SiMe2CH2PR2)2]" ligand can bind strongly to early transition metal centres, it appeared reasonable that lower oxidation state chemistry of H f and Z r should be accessible with this ligand system. A s an initial route into this field, the formation o f early metal diene complexes was examined. It was during the full characterization of these compounds that a unique fluxional process was uncovered. The question of lower formal oxidation states is also addressed in view o f some of the X-ray crystallographic results.  14  CHAPTER 2 : RESULTS AND DISCUSSION 2.1 Synthesis The basic synthetic method employed was to react various group 4 mono-ligand metal trichlorides with the magnesium-butadiene reagent [Mg^HgXTHF)^ (equation 13). The colourless starting materials react instantly with the butadiene reagent to generate  N Me,S,'  MCI, I  .P  la lb lc 2a 2b 2c  _i—1—  N  M  .  N  Me,S,'  >  M^ I VII  • MgCl, [13]  ^_  w  M = Hf, M = Hf, M = Hf, M = Zr, M = Zr, M = Zr,  „  R = Me R = CHMe2 R = CMe3 R = Me R = CHMe2 R = CMe3  3a 3b 4a 4b  orange hafnium and red zirconium complexes as crystalline solids. These colour changes appear to show some d-electron density for the metals in these compounds indicating that the M(II) resonance structure has some significant contribution to the overall bonding scheme. The visible spectrum of 4a shows one very broad absorption at 350 nm (e = 9001 mol^cm"1) while 3a and 3b both show one absorption at 420 nm and 450 nm respectively (e = 510 and 350 1 moHcm"1). In addition, a shoulder is apparent for 3a and 3b at 350 and 360 nm. This reaction is facile when the phosphorus alkyl groups are methyls or isopropyls, but for the t-butyl substituted derivatives, isolation of the diene complexes was never achieved. The most probable reason for this is the increased bulk of the t-butyl groups which, from molecular models, do show severe steric interactions with the diene moiety. When [Mg(C4H6)(THF)2]n is added to a colourless THF solution of either l c or  2c the solution immediately turns red indicating the formation of a new compound. However, both *H and 31P{ *H} NMR spectra of the crude reaction mixture (extracted with C6D6 and filtered through Celite) indicated the presence of numerous species. Resonances attributable to the expected diene complex are not observed. For compounds 3a and 4a the remaining chloride is labile and can be metathesized with phenyllithium or neo-pentyllithium to generate the corresponding hydrocarbyl derivatives in equation 14. In addition, 3a and 3b were reacted with allylmagnesium chloride generating transient allyl-diene species which rearrange via a C-C bond formation  3a 4a  3a 4a  M = Hf, M = Zr, M = Hf, M = Zr,  R = Ph R = Ph R = CH2CMe3 R = CH2CMe3  5a 6a  7a 8a  reaction and a 1,3 - proton shift to give the hafnium species shown below (equation 15). At  3a  3b  R = Me R = CHMe2  9a  9b  room temperature, this reaction takes a week for the complete conversion to 9a (an allylspecies can be detected spectroscopically). For 3b the reaction and rearrangement is over in one hour and all that is isolated is the crystalline product 9b. The details of this reaction are discussed in Section 2.4  16 2.2 S t r u c t u r e s  Throughout this thesis the structures of the diene complexes are drawn with the tridentate amide-phosphine ligand bound to the metal in a meridional mode of ligation and the diene coordinated to the metal in a cisoid manner, this is based on the results of two crystal structures that have been solved by Dr. Steven J. Rettig of the UBC X-ray crystallographic service. The formation of HfCl(C4H6)[N(SiMe2CH2PMe2)2], 3a, was monitored by low temperature (-78° C) 31P{1H} NMR spectroscopy to check if resonances due to any intermediate species might be present. Specifically, a compound was expected with the diene coordinated in a fra/is-configuration. However, only resonances due to HfC^[N(SiMe2CH2PMe2)2l and 3a were detected. This is in direct contrast to the low  temperature reaction of (T| -C5H )2ZrCl2 with [Mg(C4H )(THF) ]n where the trans-diene 5  6  5  2  compound18 is isolated. The X-ray results show that HfPh(C4H6)[N(SiMe2CH2PMe2)2], 5a, and ZrPh(C4H 6 )[N(SiMe2CH 2 PMe2)2]» 6a, are isostructural. Four different views of the  zirconium compound are given in Figure 6. The full crystallographic data and stereoviews of both compounds are given in Appendix 1. Some pertinent bond angles and bond lengths are given in Tables IH and TV. If the diene is assigned a coordination number of two then a distorted octahedral environment is apparent. The two phosphines are almost rra/w-disposed to one another with P-M-P bond angles of 149° in both structures; this corresponds to a 31° deviation from the ideal. This deviation has been observed before in other complexes (for example the P-M-P bond angle is 159° for ZrCl [N(SiMe2CH P(CHMe2) )2]) where the solution 3  2  2  spectral data are consistent with fra/w-phosphines and the crystal structure deviates from ideality. The explanation37 advanced for this deviation is that the small bite size of the chelating ligand prevents pure rrans-coorclination.  17  Figure 6. X-ray crystal structure of ZrPh(C4H6)[N(SiMe2CH2PMe2)2]» 6a, a) numbering scheme for 6a and 5a b) ligand backbone removed showing transoidal phosphines c) view showing metallocyclic structure of the metal diene unit d) view showing rj4-coordination of the diene  18 Table III. Selected Bond Angles3 For HfPh(C4H )[N(SiMe2CH PMe2)2l, 5a, 6  2  and ZrPh(C4H6)[N(SiMe CH2PMe2)2], 6a. 2  Angle  5a  6a  P1-M-P2  149.36(6)  149.43(7)  P1-M-C5  89.9(2)  91.9(2)  Pl-M-N  74.00(14)  73.36(15)  Pl-M-B  93.47(13)  93.4(2)  P2-M-C5  77.5(2)  77.7(2)  P2-M-N  84.12(14)  83.66(15)  P2-M-B  116.30(13)  111.3(2)  C5-M-B  128.3(2)  124.8(3)  C5-M-N  110. (2)  111.3(2)  N-M-B  120.4 (2)  122.8 (2)  a) angles in degrees The ipso-carbon of the phenyl group and the amide nitrogen are in the equatorial plane with N-M-C5 bond angles of 110° and 111° for M = Hf and Zr respectively; the deviation from ideality is only 20° - 21°. The diene ligand has been "frozen out" in a twisted fashion. The sum of the angles N-M-C5, N-M-B and C5-M-B (B is the "centre of gravity" for the diene ligand) is 358.8° and 358.9° for M = Hf and Zr respectively; this represents a deviation of only 1.2° to 1.1° from "coplanarity". There is nothing unusual about the metal-phosphorus or the metal-nitrogen bond lengths as they are typical of what has been found in several other complexes35-36'37-43 containing this hybrid ligand. From a survey of six structures, a range of M-N and M-P bond lengths is obtained; 2.096 to 2.264 A for the former and 2.706 to 2.806 A for the latter.  The metal to ipso-phenyl carbon bond length (M = Hf, 2.290 A; M = Zr, 2.317 A) gives a value for a metal sp2-carbon sigma bond while a structure43 [N(SiMe2CH2PMe2)2]  offac-HfMey  has a range of 2.243 A to 2.272 A for a hafnium sp3-carbon sigma  bond. This is somewhat unusual, since a metal sp2-carbon bond is expected to be the shorter of the two.44'310 It may be that these structures are not comparable since the former structures are 14-electron systems, meridional and have some degree of M(II) character, Table IV. Selected Bond Lengths3 For HfPh^HgXNKSiJ^C^PMe^J, 5a, and ZrPh(C4H6)[N(SiMe CH2PMe2)2], 6a. 2  Bond  5a  6a  M-Cl  2.380(8)  2.410(12)  M-C4  2.338(7)  2.350(10)  M-C2  2.464(7)  2.481(11)  M-C3  2.447(7)  2.450(9)  M-C5  2.290(6)  2.317(7)  M-N  2.157(5)  2.190(6)  M-Pl  2.720 (2)  2.752(2)  M-P2  2.707 (2)  2.730(2)  C1-C2  1.415(10)  1.40(2)  C2-C3  1.337(12)  1.354(15)  C3-C4  1.442(12)  1.442(15)  a) bond lengths in A  while the latter compound is 12-electron, facial and Hf(IV). However viewed, a bond length of 2.24 A to 2.32 A is an acceptable Hf or Zr to carbon o-bond for these amidephosphine complexes. The metal to Cl and C4 bond lengths are longer than this standard,  20 indicating that the bonding of the diene in these complexes has a high degree of 7C-bonding character to it Several differences exist between the structural data of these complexes and those of the Cp2M(diene) (M = Hf, Zr) type. Typically with these metallocenes the outer carbons Cl and C4 are 0.23 A to 0.43 A closer to the metal than the inner carbons C2 and C3 of the diene. This has been explained24 as being due to a larger contribution from a-bonding over 7C-bonding. In 5a and 6a this difference is only 0.10 A for Hf and 0.09 A for Zr, indicating a larger contribution from the M(II) resonance form than is seen for the Cp2M(diene) complexes. As was stated in Section 1.2.2, the three most sensitive structural features for detecting the ratio of O~/K bonding in the metallocene complexes are the Zr-C2, Zr-C3 bond lengths, the C1-C2, C4-C3 bond lengths and the Zr-Cl-C2, Zr-C4-C3 bond angles. The larger these values the greater the ratio of a/rc bonding. The Cp2Zr(diene) with the highest degree of 7c-bonding (M in Figure 7) has values45 of 2.550 A, 1.445 A and 81.8° for these three parameters, while the Cp2Zr(diene) with the lowest degree of nbonding (N in Figure 7) has values46*24 of 2.855 A, 1.48 A and 95.8° respectively. 6a has Me  Figure 7. Two structurally characterized zirconocene dienes lower values (2.466 A, 1.42 A and 76.3") for all three parameters indicating an increased degree of jc-bonding and therefore more Zr(II) character. The same pattern emerges for the hafnium analogue (2.456 A, 1.429 A, 76.3") in that values for all three of these parameters are lower than in any hafnocene(diene) complex. Some interesting differences between the crystal structures of 5a and 6a are also apparent. For the two pairs of isostructural hafnium and zirconium diene complexes for  21 which X-ray data are available, it has been shown that Hf-C c-bonds are shorter than the corresponding Zr-C a-bonds, while 7t-type bonds are shorter for zirconium. These differences are summarized along with some new data in Table V. Comparison of the MCl, M-C4 and M-Ph bonds shows that the magnitude of the differences between analogous Table V . Comparison of Bond Lengths3 For Analogous Hf and Zr Complexes Complex  M-Cl M-C4 Diffb M-Phc Diffb  M^C2 M-C3 Diffb  ref  Cp2Hf(C6H10)d  2.267  2.641  22  Cp2Zr(C6H10)d  2.300 .033  2.597 .040  17  Cp2Hf(C8H12)e  2.255  2.72  22  Cp2Zr(C8H12)e  2.279 .024  2.635 .08  22  5af  2.359  2.456  h  6a8  2.380 .021 2.317 .027  2.466 -.010  h  2.290  a) bond lenghts in A b) diff = differences in A between isostructural pairs of complexes c) metal to i/wo-carbon bond length d) CgHiQ = 2,3-dimethylbutadiene e) CgH12 = l,2-bis(methylene)cyclohexane f) HfPh(C4H6)[N(SiMe2CH2PMe2)2] g) ZrPh(C4H6)[N(SiMe2CH2PMe2)2] h) this work structures for the metal carbon a-bonds is similar in all six structures; in all cases hafnium having slightly shorter bonds than zirconium. However, there is a large discrepancy in the differences of therc-interaction(M-C2 and M-C3 bond lengths) between analogous compounds. For the cyclopentadienyl complexes zirconium is much better at 7t-bonding than hafnium, while the data on the diene complexes containing the hybrid ligand clearly show that hafnium has a shorter ^-interaction than does zirconium. The fact that compounds 5a and 6a have comparable Tt-type interactions is perhaps due to the presence  22  of the phosphine donors which should make the metals more susceptible to lower formal oxidation states. 2.3 Fluxional Behavior Information on the solution structure and fluxional behavior of these compounds was obtained from careful analysis of lH, 13C{ lH] and 31P{ 1H} NMR data. Based on an octahedral geometry there are three limiting structures (excluding enantiomers): there are one meridional and two facial isomers. Assuming that these compounds undergo the well documented "envelope flip" isomerization seen for Cp2M(diene) (M = Hf, Zr, U, Th) complexes, there are six isomeric compounds to be considered (Figure 8). The upper three isomers (fac-O, fac-P, mer-Q) have metallocyclopentene structures, which represents the average chemical environment the atoms would experience above the coalescence temperature. The lower three isomers (fac-O',fac-P\  mer-Q')  show one of the two  possible limiting structures for each isomer below the coalescence temperature. Fac-0  has a mirror plane bisecting the diene and passing through the R'-M-N  bonds; this symmetry element remains independent of the "envelope flip" process, as is true for/ac-O'. Both/ac-P and fac-P' have no symmetry; all the atoms are chemically inequivalent47 irregardless of any fluxional process. Finally, mer-Q has a mirror plane because the diene, N, M, and R' atoms are all coplanar, while below coalescence (mer-Q') this symmetry element is lost and the molecule has all atoms chemically inequivalent. Representative variable temperature *H, 13C{1H}, 31P{1H} NMR spectra are shown in Figures 9, 10 and 11. Initially the room temperature (above coalescence) NMR spectra indicated that/ac-O was the high temperature structure. The amide-phosphine ligand resonances immediately ehminated/ac-P as there are only two silyl-methyl and two phosphorus-methyl resonances; fac-P would require four of each. Mer-Q was dismissed since the diene ligand would require four signals in both the 13C{JH} and *H NMR, whereas two 1 3 C and three lH signals are observed.  23  Figure 8. Possible octahedral solution structures based on the "envelope flip" isomerization a) above coalescence metallocyclopentene averages b) low temperature limiting structures  Figure 9. 400 MHz *H NMR spectra of HfPh(C4H6)[N(SiMe2CH2PMe2)2i\ 5a, a) room temperature NMR spectrum in C 6 D 6 b) -80° C NMR spectrum in C 7 D 8 (An asterisk denotes solvent resonances)  Ci.C  N  Hf  PCH Si 2  4  \  PMe,  C, C 2  I  b)  SiMe,  3  ^^^•w^^^^^^* ^^^^^^  J  Figure 10. 75 MHz ^C{^H)  NMR spectra of HfPh^HgHNCSiMezCHjPMe^J, 5a,  in C 7 D 8 a) room temperature NMR spectrum b) -83" C NMR spectrum (An asterisk denotes solvent peak)  Figure  11. 121 MHz 31p{lH} variable temperature NMR spectra of HfPh(C4H6)-  [N(SiMe2CH -PMe2)2L 5a, in 2  to 210 K (bottom trace)  C 7 D 8 displayed in 10° intervalsfrom280 K (upper trace)  The low temperature N M R data are consistent with either fac-P' or mer-Q'. Inspection of the various representative spectra (Figures 9-11) shows that below coalescence all atoms are inequivalent thereby eliminating/ac-O'. Fac-P' can be eliminated as a possibility on the basis of the two crystal structures that were solved. Since it is reasonable to assume that the low temperature NMR data are consistent with the solid state structure, mer-Q' is the isomer whichfitsthe data best. In addition, at low temperature the Jp.p coupling constant is in the range of 53 to 80 Hz. This is a typical2J trans-phosphine  2  coupling constant for these group 4 complexes and supports the mer-Q' structure. Table VI. A G * Calculated From Variable Temperature NMR 3  Compound  AG*(kcal mol"1) T c b difference0 Nucleus  HfCl(C4H6)[N(SiMe2CH2P(CHMe2)2)2] 3b  9.1  220  ZrCl(C4H6)[N(SiMe2CH2P(CHMe )2)2] 4b  9.6  223  HfCl(C4H6)[N(SiMe2CH2PMe2)2] 3a  10.7  240  ZrCl(C4H6)[N(SiMe2CH2PMe2)2] 4a  11.3  247  HfPh(C4H6)[N(SiMe2CH2PMe2)2] 5a  10.9  260  ZrPh(C4H6)[N(SiMe2CH2PMe2)2] 6a  11.5  257  HfPh(C4H6)[N(SiMe2CH2PMe )2] 5a  10.3  220  ZrPh(C4H6)[N(SiMe2CH2PMe2)2] 6a  11.5  250  HfPh(C4H6)[N(SiMe2CH2PMe2)2] 5a  10.6  250  ZrPh(C4H6)[N(SiMe2CH2PMe2)2] 6a  11.0  260  Hf(CH2CMe3)(C4H6)[N(SiMe2CH2PMe2)2] 7a 11.4  275  12.3  280  2  2  Zr(CH2CMe3)(C4H6)[N(SiMe2CH2PMe2)2]8a  a) AG-i- calculated from the procedure given in Section 4.2.3 b) T c = temperature of coalescence in K c) difference = difference between isostructural complexes  31  0.5  P  31p 31p  0.6  3lp 31p  0.6  31p  ^  1.2  0.4  iH 13  C  13  C  31p  0.9  31p  28 This then leaves the problem of explaining how the molecule would undergo the rearrangement of fac-O to mer-QJ with such small energies of activation (Table VI). A simple solution is arrived at when an earlier assumption is re-examined. The assumption was that these compounds would undergo the "envelope flip" isomerization that is so well documented for the bis(cyclopentadienyl)metal(dienes) (M = Hf, Zr, U, Th). If the C4H6 fragment is instead allowed to rotate about the metal (Figure 12) then it is seen that this type  Figure 12. Rotating diene mechanism of process is entirely consistent with all the NMR data. At low temperature the structure is mer-Q',  while at high temperature Cl and C4, C2 and C3, Ha and Ha', Hs and Hs', and  Hm and Hm' all exchange. This results in the molecule having a mirror plane passing through the R'-M-N bonds, so the number of resonances expected for the tridentate ligand is that observed: two silylmethyls, two phosphorus alkyls and two methylenes. There are a number of other points which are consistent with these molecules having a rotating diene rather than any process which would involve the "envelope flip" isomerization (Figure 13). First, consider the variable temperature1 3 C {*H} NMR. The "envelope flip" process requires the four diene carbons to be chemically inequivalent above and below the coalescence temperature. Consequently, as the temperature is varied four distinct1 3 C resonances would be expected irregardless of the temperature. This is in direct contrast with the observed behavior (Figure 10). In order for the "envelope flip" process to occur, an isomerization to fac-0  would also have to take place above the coalescence  temperature. A room temperature nOe difference experiment was run in order to determine  F i g u r e 13. Envelope flip mechanism  the coordination geometry of the tridentate ligand. When the downfield silyl-methyl resonance of HfPh(C4H^)[MSiMe2CH2PMe2)2] is irradiated (see Figure 9 for the normal * H N M R spectra) a large enhancement of the ortho-phenyl  protons is observed. This  evidence supports meridional coordination as the above coalescence temperature structure.  Fac-0 is discredited since with the phenyl ring trans- to the nitrogen no enhancement of the orr/io-phenyl protons would be expected. It has been well documented24 that the AG$ for the dynamic behavior of these early metal diene complexes is always less (3.2 to 4.5 kcal mol" 1 ) for the hafnium compounds versus those of zirconium. This has been attributed to the zirconium compounds forming stronger 7t-bonds and therefore requiring more energy to undergo the "envelope flip" process. Since it was shown earlier that in the solid state H f P h ^ H g ) [N(SiMe2CH PMe2)2], 5a, and ZrPh(C4H6)[N(SiMe2CH2PMe )2], 6b, have TC-bonds of 2  2  comparable strength (hafnium having a slightly shorter ^-interaction) similar solution behavior is to be expected. However, this is not what is observed; for the four pairs of isostructural compounds synthesized, the AG$ (Table VI) for the observed dynamic process is slighdy larger for the zirconium compounds. One interpretation for this is that the "envelope flip" process is not the dynamic process observed. A final point concerns data collected on numerous Hf and Zr compounds containing this potentially tridentate chelating ligand. For all the M[N(SiMe2CH2PR2)2]Ln ( M =  Zr;  R  = Me, CHMe2, CMe3)  ^  compounds isolated (with the possible exception of the  trimethylmonoligand compounds) the tridentate ligand shows only meridional coordination in solution. All of the crystal structures which have been solved show meridional geometry when the phosphine-alkyl groups are the bulky iso-propyls or t-butyls. Only when this substituent is the less sterically demanding methyl group has facial geometry been seen in the solid state. However, as all the NMR spectral data are virtually identical on changing from the methyl-phosphine complexes to those with iso-propyl substituents (3a to 3b or from 4a to 4 b) and both crystal structures of 5a and 6a (containing the least sterically demanding alkyl group) have meridional geometry, it is difficult to envisage these diene complexes as having facial geometry in solution. 2.4 Reactivity The reactivity of these complexes has not been extensively investigated as the focus of this work has been to clarify the nature of the dynamic process that these compounds undergo. These complexes do react with H2, CO and acetone, in each case losing their intense red colour, but all attempts to isolate and characterize the organometallic product(s) have so far failed. Attempts were made to react HfCl(C4H6)[N(SiMe2CH2PMe )2]» 3a, and 2  HfPh(C4H6)[N(SiMe2CH2PMe )2]» 5a, with ethylene; the expected insertion product is 2  shown below (equation 16). However, only pure starting material was isolated, and no other organometallic derivative was detected.  On the assumption that these compounds could be considered as M(TJ) complexes, oxidative addition of Cir^Br to 3a was attempted. However, no reaction occurred and once again only pure starting material was isolated. The most interesting reaction occurred when 3a and 3b were reacted with allylmagnesium chloride (equation 17). For3b, the intermediate allyl species was not  3a  R = Me  9a  3b  R = CHMe2  9b  detected and only purple crystals of the C-C coupled product 9b were isolated. When R = Me, the initially isolated product mixture was impure and could not be crystallized. However, spectra run on a sealed NMR tube of the crude reaction product (after separation from MgCl2) clearly showed a gradual change from an allylic compound, to a complex mixture, to mostly C-C coupled product (Figures 14 and 15). The ! H and 31P{1H} NMR spectra shown are of the reaction mixture a day and then a week after workup. The phosphorus data are the most informative as they shows the presence of two compounds along with some decomposition. Both the31P{1H} and the H NMR spectra show that as l  the resonances for the allyl-complex disappear those due to the coupled product increase. (The3 1 P resonances around -60 ppm are typical for decomposition products). The P{1H} NMR spectrum of pure 9b shows only the sharp AB quartet pattern with a  31  coupling constant of 65 Hz. Further evidence for the reaction sequence shown in equation 17 is obtained from the gated decoupled 1 3 C NMR spectrum of 9b. Two of the seven inequivalent carbons  32  1  F i g u r e 14. IJH N M R spectra (in C 6 D 6 ) of the reaction between H f C l ( C 4 H 6 ) [N(SiMe2CH2PMe2)2l, 3a, and allylmagnesium chloride a) 400 M H z spectrum after 1 hour b) 300 M H z spectrum after 1 day c) 300 M H z spectrum after several days (* denotes "A4X" pattern for the allylic protons)  33  I  a)  '  I  I  I  I  I  | i  -10  I  I  i I  I  I  i  —  I  |  -20  -I I I I  I  I  I  i i | -30  I  I—I—i—r-i—i—I—i—i—I—i—i—i—i—i—i—I—i—i—r | i ' ' -40  ' I i '  -50  A-  b) i i i i i—i | i i i i—i i i i i |—i—i i i i i i i i—|—i i i i—i—i i i—i—|—i—i—i—i—i—i—i—i—i—|—i -10  Figure 15. 121  •  -20  -30  -40  -50  -i—i—i—|—i—i-  M H z ^ P ^ H ) N M R spectra.(in C D ) o f the reaction between 6  6  HfCl(C4H )[N(SiMe2CH2PMe2)2], 3a, and allylmagnesium chloride a) spectrum after 1 6  day b) spectrum after several days (* denotes signals for the allyl species)  from the unsaturated organic fragment have coupling constants of 124 and 129 Hz, indicating that they are sp3-hybridized and not bonded to the metal. The lH and ^f31?} NMR spectra (Figure 16) show that the compound has C; symmetry, but the spectra are sufficiently complex that only 10 of the 11 protons due to the organic fragment can be identified. To aid the assignment of these resonances a 2D Heterocorrelation ^C^H NMR spectrum was obtained for 9b (Figure 17). All 11-proton and 7-carbon resonances are assigned from combining these data with some lH NMR homo-decoupling data. Initially compound 9b was assigned structure S (see Scheme 3 below), the expected product from the C-C coupling of an "olefin" and butadiene. However, it was clear that this assignment was in error since decoupling the proton resonance at 5 ppm causes the resonance at 6.4 ppm to collapse into a doublet, not the doublet of doublets expected. Fortunately, crystals suitable for X-ray diffraction were isolated from hexanes and the structure was solved. The reason for the aforementioned NMR data is explained by a 1,3 - proton shift that has occurred. The X-ray crystal structure of 9b, recently completed by Dr. Steven Rettig is shown in Figure 18. A stereo-view and the complete crystallographic details are contained in the Appendix. These results are somewhat similar to the other two structures presented earlier. The phosphines are coordinated in a transoid fashion (The Pl-Hf-P2 bond angle is 150.3°) and the sum of the three angles C25-Hf-N, N-Hf-B and B-Hf-C25 (where B is the "centre of gravity" for the diene portion) is 359.7°. The coordination of the T|4-diene unit is interesting since the metal is significantly closer to one end of the diene than the other (HfC19 = 2.32(2), Hf-C20 = 2.36(2), Hf-C21 = 2.56(3), Hf-C22 = 2.58(3)). The bond lengths within the diene moiety show a similar distortion (C19-C20 = 1.43(3), C20-C21 = 1.45(5), C21-C22 = 1.36(5)). Unfortunately, large ESD's preclude the drawing of any conclusions about the bonding of the diene unit.  Figure 16. 400 MHz H NMR spectra of Hf[(ri 4 -CH2CHCHCH)CH 2 CH 2 CH2]l  [N(SiMe2CH2P(CHMe2)2)2]in C 6 D 6 a) normal *H NMR spectrum b)  spectrum  l  H[^P}  NMR  36  MeSi 2  MeSi 2  I  7 CO  I  'I  I I [ I I I I  6  I  I I 11  I  I I I I  I  5  I I I I  4  I  I I I I  ) 3  I  II I  l|  2  M I I  I  I I I I  1  I  I I I I  I  I I I I  I  M I I  I  0 PP)  3  CL - Q.  o o O  o  O o —o  m O  Figure 17. Portion of a  C- lK  li  heterocorrelation 75-300 MHz NMR spectrum showing  the connectivity of the hydrogen and carbon atoms in the C7H11 fragment of I  "  —1  H f [ ( T l - C H 2 C H C H C H ) C H 2 C H 2 C H 2 ] [ N ( S i M e C H 2 P ( C H M e 2 ) 2 ) 2 ] . 9b, 4  2  resonance is indicated by an asterisk)  (The C 6 D 6  I I I I  37  a)  b)  Figure  18. X-ray crystal structure o f H V [ ( T I 4 - C H C H C H C H ) C H 2 C H C H 2 ] 2  2  [ N ( S i M e 2 C H - P ( C H M e 2 ) 2 ) 2 L 9b, a) numbering scheme b) v i e w looking down H f - N 2  bond showing the coordination o f the tridentate hybrid ligand (silyl- and phosphine-alkyl groups have been omitted for clarity)  38  9a or 9b  Scheme 3 Possible Mechanism for the Formation of 9a and 9b. A possible mechanism for the formation of 9a and 9b is postulated in Scheme 3. The allyl-diene R could form species S via an electrocyclic C-C bond formation step analogous to the reaction observed between ethylene and Cp2M(diene) (M = Hf, Zr) complexes. Compound S would then undergo a 1,3-proton shift to achieve the observed product. P-hydrogen elimination from S to the hafnium hydride complex T, followed by migratory insertion between the olefin and hydride achieves this step. This coupling reaction has several ramifications for this thesis. First, these products represent thefirsttime that temperature invariant (-90' to +90° C)C] symmetry complexes  containing the amide-phosphine ligand have been observed. This proves that these metal complexes can have strong metal phosphorus bonds such that the ligand is rigidly bound to these early transition metal centres. This is of course one of the necessary conditions for the diene rotation interpretation of the dynamic NMR data. Also, the 2Jp.p coupling constant of 65 Hz for 9b indicates that the fluxional diene complexes have rra/w-phosphines at low temperature (the observed 2J p.p for these diene compounds is 53 to 80 Hz).  40 CHAPTER 3 : CONCLUSIONS  The successful synthesis of eight fluxional, diamagnetic group 4 complexes M R ' ( C 4 H ) [ N ( S i M e 2 C H P R 2 ) 2 ] ( M = Hf, Zr; R' = Ph, C H C M e ; R = Me) and ( M = 2  6  2  3  Hf, Zr, R' = Cl; R = Me, C H M e 2 ) has been achieved. The X-ray crystallographic results of two of these complexes ( M = Hf, Zr; R' = Ph; R = Me) indicate that the bonding of the diene unit has a significantly higher degree o f T|-7C character than is present i n the 4  Cp2M(diene) ( M = Hf, Zr) complexes, and therefore the M(II) resonance structure has more contribution to the overall bonding scheme.  Consistent with  all the N M R  data available is that these complexes maintain a  meridional coordination of the tridentate amide-phosphine ligand both in solution and in the solid state. The observed fluxional process is best described as diene rotation. That this fluxional process i s more akin to that found for an electron-rich, late transition metal complex provides support for the proposal that phosphine donors can stabilize lower oxidation states o f the early transition metals. Two  of the diene complexes ( M = Hf; R' = Cl; R = Me, C H M e ^ were found to  react with allylmagnesium chloride and subsequently undergo a unique C-C reaction and rearrangement  to generate two new  bond forming  non-fluxional diene complexes  Hf[(Ti4_CH2CHCHCH)CH2CH CH2][N(SiMe2CH2PR2)2] (R = Me, C H M ^ ) . The latter 2  o f these two compounds has been crystallographically characterized. Presumably these two compounds are non-fluxional because the diene cannot rotate when one end of it is tied down to the metal via a three-carbon bridge.  41 CHAPTER 4 : EXPERIMENTAL  4.1 Methods and Compounds  4.1.1.General  Information.  All manipulations were performed under prepurified nitrogen in a Vacuum Atmospheres HE-553-2 glovebox equipped with a MO-40-2H purification system or in standard Schlenk-type glassware on a dual vacuum/nitrogen line. Z1CI4 and HfCl4 (Aldrich) were sublimed prior to use. LiCH2CMe348, LiPh49, [Mg(C4H6)(THF)2]n12> and MCl3[N(SiMe2CH2PR2)]35 (M = Hf or Zr, R = Me, CHMe2 or CMe3) were prepared according to the literature procedures. Allylmagnesium chloride was prepared from magnesium and allylchloride. 1,3-butadiene, CO, and ethylene (Matheson) were used as received. H 2 was purified by passing it through a column of molecular sieves and MnO. Hexanes and THF were initially dried over CaH2 followed by distillationfromsodiumbenzophenone ketyl. Diethyl ether and toluene were distilled from sodium-benzophenone ketyl. C6Dg, C7Dg and spectral grade hexane were dried overnight with activated 4A molecular sieves, vacuum transferred to an appropriate container, "freeze-pump-thawed" threetimesand stored in the glovebox. Carbon, hydrogen and nitrogen analysis were performed by P.Borda of this department. J H NMR spectra (referenced to CgD5H at 7.15 ppm) were performed on one of the following instruments depending on the complexity of the particular spectra: Broker WP-80, Varian XL-300 or a Broker WH-400. 1 3 C NMR spectra (referenced to CgDg at 128.0 ppm or CD3C6D5 at 20.4 ppm) were run at 75.429 MHz and 3 I P NMR spectra (referenced to external P(OMe)3 at 141.0 ppm) were run at 121.421 MHz, both on the XL-300. UV-VIS spectra were obtained on hexane solutions with a Perkin - Elmer 552A spectrophotometer using a sealable quartz cell equipped with a Kontes teflon needle valve.  42 4.1.2 HfCl(Ti4.C4H6)[N(SiMe2CH2PMe2)2] 3a To a rapidly stirred solution of HfCl^NtSiMe^H^Me^J (0.960 g, 1.70 mmol) in THF (90 mL) was added a slurry of Mg(C4H6)(THF)2 (0.378 g, 1.70 mmol) in THF (10 mL) dropwise over a period of 5 minutes at room temperature. An instantaneous reaction occured as the colourless Hf(IV) solution became deep red. After stirring for 20 minutes the solvent was removed under vacuum and the resulting oil was extracted with hexanes (50 mL). MgCl2 was removed by filtration through Celite and crystallization of the product was induced by cooling a saturated solution to -30 °C; yield 0.746g (80 %). Anal. Calcd. for C 14 H 34 ClHfNP 2 Si 2 : C, 30.66; H, 6.25; N, 2.55. Found: C, 30.41; H, 6.10; N, 2.46. 4.1.3 ZrCI(Ti4.C4H6)[N(SiMe2CH2PMe2)2] 4a The identical procedure described above for the analogous hafnium compound was employed using ZrCl3[N(SiMe2CH2PMe2)2] (1.487 g, 3.111 mmol) and Mg(C4H6)(THF)2 (0.693 g, 3.11 mmol) yielding 0.736 g (51 %) of product. Anal. Calcd. for C14H34ClNP2Si2Zr: C, 36.46; H, 7.43; N 3.04. Found: C, 36.36; H, 7.50; N, 3.07. 4.1.4 HfCl(Ti4.C4H6)[N(SiMe2CH2P(CHMe2)2)2] 3b The identical procedure described above for compound 3a was employed using HfCl3[N(SiMe2CH2P(CHMe2)2)2] (2.163 g, 3.193 mmol) and Mg(C4H6)(THF)2 (0.752 g, 3.38 mmol) yielding 1.763 g (83 %) of product. Anal. Calcd. for C22H50ClHfNP2Si2: C, 39.99; H, 7.63; N 2.12. Found: C, 40.00; H, 7.53; N, 2.08.  43 4.1.5 ZrCl(r|4.C4H6)[N(SiMe CH2P(CHMe2)2)2] 4b 2  The identical procedure described above for compound 3a was employed using ZrCl3[N(SiMe2CH2P(CHMe2)2)2] (0.590 g, 1.000 mmol) and Mg(C4H6)(THF)2 (0.233 g, 1.047 mmol) yielding 0.448 g (78 %) of product. Anal. Calcd. for C22H50ClNP2Si2Zr: C, 46.08; H, 8.79; N 2.44. Found: C, 44.83; H, 6.60; N, 2.35. 4.1.6 Attempted synthesis of HfCl(n. 4 -C4H 6 )[N(SiMe2CH P(CMe3)2)2] 2  The identical procedure described above for compound 3a was employed using HfCl3[N(SiMe2CH2P(CMe3)2)2] (0.456 g, 0.622 mmol) and Mg(C4H6)(THF)2 (0.138 g, 0.620 mmol).H and31P{1H} NMR spectra of the crude reaction mixture are complex l  and suggestive of decomposition. 4.1.7 Attempted synthesis of ZrCl(ti 4 -C 4 H 6 )[N(SiMe2CH2P(CMe3)2) 2 ] The identical procedure described above for compound 3a was employed using ZrCl3[N(SiMe2CH2P(CMe3)2)2] (0.595 g, 0.921 mmol) and Mg(C4H6)(THF)2 (0.205 g, 0.921 mmol).H and31P{1H} NMR spectra of the crude reaction mixture are complex l  and suggestive of decomposition. 4.1.8 HfPh(Ti*-C4H 6 )[N(SiMe 2 CH2PMe2)2] 5a Phenyllithium (0.025 g, 0.30 mmol) in ether (5 mL) was slowly added dropwise to a rapidly stirrred ethereal solution (25 mL) of HfCl(Ti4-C4H6)[N(SiMe2CH2PMe2)2] (0.161 g, 0.294 mmol). After stirring for 15 minutes the product was separated from the LiCl produced by removing the ether under vacuum, extracting with hexanes and filtering through a short column of Celite, Crystallization from minimum hexanes yielded 0.127 g of product (73 %). Anal. Calcd. for C2oH39HfNP2Si2: C, 40.71; H, 6.66; N, 2.37. Found: C, 40.38; H, 6.60; N, 2.35.  44 4.1.9 ZrPh(T| 4 -C 4 H 6 )[N(SiMe 2 CH 2 PMe 2 ) 2 ] 6a The identical procedure described above for the analogous hafnium compound was employed using ZrCl(ri -C4H6)[N(SiMe2CH2PMe2)2] (0.328 g, 0.711 mmol) and 4  phenyllithium (0.060 g, 0.714 mmol) yielding 0.289 g (81 %) of product. Anal. Calcd. for C 2 oH 39 NP 2 Si2Zr: C, 47.77; H, 7.82; N, 2.79. Found: C, 48.00; H , 7.79; N, 2.79.  4.1.10 Hf(CH 2 CMe )(ri4.C4H 6 )[N(SiMe2CH 2 PMe )2] 7a 3  2  To a hexane solution (20 mL) of HfCl(Ti -C4H )[N(SiMe2CH PMe2)2] (0.095 g, 4  6  2  0.17 mmol) neo-pentlylithium (0.013 g, 0.17 mmol) in hexanes (5 mL) was added dropwise with rapid stirring. After 15 minutes the cloudy solution was filtered through Celite to remove the LiCl produced and the hexanes were removed under vacuum. Addition of a few drops of hexanes to the resulting oil induced instant crystallization. Enough hexanes were added to just redissolve these crystals and cooling to -30 °C overnight yielded 0.077 g (76 %) of pure product. Anal. Calcd. for C H45HfNP Si2: C, 39.06; H , 7.76; 19  2  N, 2.40. Found: C, 38.80; H, 7.86; N, 2.35.  4.1.11  Zr(CH2CMe3)(r|4-C4H6)[N(SiMe2CH2PMe2)2] 8a The identical procedure described above for the analogous hafnium compound was  employed using ZrCl(rj4-C4H6)[N(SiMe2CH2PMe2)2] (0.200 g, 0.434 mmol) and neopentyllithium (0.034 g, 0.44 mmol) yielding 0.125 g (58 %) of product. Anal. Calcd. for C 1 9H4 5 NP 2 Si2Zr: C, 45.93; H, 9.13; N, 2.82; Found: C, 45.60; H , 9.28; N, 3.10. I 4.1.12  1  Hf[(Ti 4 -CH 2 CHCHCH)CH 2 CH 2 CH 2 ][N(SiMe 2 CH 2 PMe 2 ) 2 ]  9a  To a red THF solution (20 mL) of HfCl(Ti4-C4H6)[N(SiMe2CH2PMe2)2] (0.270 g, 0.492 mmol) 0.73 M allylmagnesium chloride (0.67 mL, 0.49 mmol) in THF was added dropwise with rapid stirring. The red solution initially faded to orange and then over a period of days became a dark burgundy colour. After one week the solvent was removed  under vacuum, the residue was extracted with hexanes and filtered through Celite to remove MgC^. Thus far this compound has not been obtained in crystalline form. '  1  4.1.13 Hf[(Ti4.CH2CHCHCH)CH2CH2CH2][N(SiMe2CH2P(CHMe2)2)2] 9b The identical procedure described above for the compound 9a was used except that the reaction only requires two hours of stirring prior to workup. HfCl(rj4-C4H6)[N(SiMe2CH2P(CHMe2)2)2] (0.300 g, 0.454 mmol) and 0.70 M allylmagnesium chloride (0.65 mL, 0.46 mmol) were used to yield 0.248 g (82 %) of product. Anal. Calcd. for C25H55HfNP2Si2: C, 45.06; H, 8.32; N, 2.10; Found: C, 45.09; H, 8.50; N, 2.24.  4.1.14 General Method for Substrate Reaction with the Diene Complexes In the glovebox a heavy-walled glass reaction vessel equipped with a Kontes needle valve (enables the reaction vessel to be isolated from external atmospheres) and a B-24 ground glass socket (enables the reaction vessel to be connected to a nitrogen/vacuum line) was charged with = 50 mg of butadiene compound and ~ 20 mL of toluene. The flask was sealed, removed from the glovebox, attached to a vacuum line and "freeze-pump-thawed" at least once. The substrate was then either syringed into the flask under a strong flow of nitrogen, or condensed into the cooled (-196° C) evacuated reaction vessel. The reaction mixture was then stirred at room temperature for various lengths of time prior to removing the volatiles under vacuum. Theflaskwas then removed to the glovebox where the residues were either extracted with C£>6 (if the reaction was a new one) and filtered through Celite into an NMR tube (a31P{1H) spectrum and/or lH NMR spectrum was promptly obtained) or else extracted with hexanes, filtered and cooled to -30" C in order to induce crystallization.  46 4.2 Tabulated N M R Data  4.2.1 Guide to the N M R Data Tables  In this section the room temperatureH, 1 3 C, 3 1 P and the low temperature 3 1 P l  N M R data are tabulated. In general the coupling constants (when it has been possible to obtain them) are quoted below the chemical shift. The 1 JC-H coupling has been placed in square brackets under the carbon in question. For the C4FLJ fragment H , A  H  S  and H  M  are  the anti-, syn- and meso-protons while Q and Ct are the inner and the terminal carbons respectively. Similarly, for the CgFLj unit HQ, H resonances while, Q, C 0 ,  M  and H are the ortho-,  and C p are the ipso-,  P  ortho-, meta-  meta-  and para-  and para-carbons. The  numbering scheme used for the C7H11 fragment is shown in Figures 16 and 17, pp 35-36. Below, is a guide for the tables stating the compound with its number (#): #  Compound  3a  HfCl(C4H6)[N(SiMe2CH2PMe2)2]  4a  ZrCl(C4H6)[N(SiMe2CH2PMe2)2]  3b  HfCl(C4H6)[N(SiMe2CH2P(CHMe2)2)2]  4b  ZrCl(C4H6)[N(SiMe2CH2P(CHMe2)2)2]  5a  HfPh(C4H6)[N(SiMe2CH2PMe2)2]  6a  ZrPh(C4H6)[N(SiMe2CH2PMe2)2]  7a  Hf(CH2CMe3)(C4H6)[N(SiMe2CH2PMe2)2]  8a  Zr(CH2CMe3)(C4H6)[N(SiMe2CH2PMe2)2]  9a  Hf[(Ti4-CH2CHCHCH)CH2CH2CH2] [N(SiMe2CH2PMe2)2]  9b  !  \  1  \  Hf[(Ti4-CH2CHCHCH)CH2CH2CH2][N(SiMe2CH2P(CHMe2)2)2]  4.2.2 Chemical Shift Data  47 Table VII. *H NMR data Cmpd SiMe2 PCH2Si  PMe2 or P(C//Me2)2 & P(CHMe2)2  Other  3a  0.20(s) 0.64(dt) 0.97(t) 0.26(s) Jgem=12 Japp = 3.5 0.70(dt) 1.21 (t) ^app= 3.5  H a = 0.63(m) H s = 2.03(m) H m = 6.04(m)  4a  0.14(s) 0.65(m) 0.22(s)  H a = 0.78(m) 1^ = 2.57^) H m = 5.85(m)  3b  0.40(s) 0.81(dt) 0.44(s) Jgem = 1 4 J a p p = 3.5 0.97(dt) J app = 3-5  2.05(m) 2.34(m)  4b  0.25(s) 0.75(dt) 0.30(s) J g e m =14 Japp = 3.5 0.9(obscured)  1.95(m) 2.30(m)  5a  0.20(s) 0.70(dt) 0.79(t) 0.30(s) J a p p = 4.5 J a p p = 3.0 0.97(t) Japp = 3.0  H a = 0.53(m) Hf(C6H5) H s = 2.24(m) H p = 7.15(d) H m = 6.02(m) J a p p = 7.0 H m =7.32(d) Japp = 7-0 H 0 = 7.81(d) Japp = 7.0  6a  0.13(s) 0.61(dt) 0.24(s)  H a = 0.46(m) Zr(C6H5) H s = 2.64(m) H p = 7.14(d) H m = 5.86(m) J a p p = 7.0 H m =7.28(d) Japp = 7-0 H 0 = 7.76(d) JJ app =70 '•v  0.94(t) Japp = 3.5 1.20(t) Japp = 3.5  1.10(m) Ha=1.00(m) 1.1 l(m) H s = 2.19(m) 1.13(m) H m = 6.37(m) 1.30(dt) 3  J -H =  7  H  Japp = 7  0.75(t) Japp = 3.0 0.88(t) J a p p = 3.0  1.10(m) 1.13(m)  H a = obscured H s = 2.53(m) H m = 6.02(m)  48  Table VII. * ! ! NMR data continued Cmpd SiMe2 PCH2Si  PMe2 or P(C//Me2)2 & P(CHMe2)2  Other  7a  0.22(s) 0.58(dt) 0.96(t) 0.30(s) J a p p = 4.0 J a p p = 2.8 Jgem=14 1.12(t) 0.74(dt) Japp = 2.8 Japp =4.0  H a = 0.20(m) HfCH2CMe3 H s = 1.78(m) H a = 0.05(t) H m = 6.17(m) J a p p = 5.0 rL^l.lOCs)  8a  0.18(s) 0.66(m) 0.30(s)  H a = 0.32(m) ZrCH2CMe3 H s = 2.31(m) H a = obscured H m = 6.17(m) rlv=1.10(s)  9a  0.07(s) 0.14(s) 0.16(s) 0.24(s)  0.94(t) Japp = 3.0 1.11 (obscured)  0.34(dd) 0.91(d) 2 J P . H = 9.5 2Jp_H = 6 Jgem= 14 0.93(d) )0.50(dd) 2JP.H=6 2 1.17(d) Jp_H = 8 Jp-H =8 1 • 17(d) 2 0.73(dd) J P . H =6 2 Jgem=14 JP.H=6 0.73(obscured)  C7Hn Hlb=-.41(m) HJa= obscured H7a=1.41(m) H7b= 1.57(m) H2b= 1.96(m) H 4 =2.10(m) H3a=2.10(m) H3b=2.78(m)  2  11^=3.20(171)  H6=4.48(m) H 5 =6.00(m) 9b  0.21(s) 0.21(s) 0.24(s) 0.27(s) 0.32(s)  0.57(d) 0.57(d) J .H=7.6  2  P  0.84(dd) Jgem =14  1 1..9 94 4((m m)) 1.96(m) 2.23(dsept) 3  J -H = 7  2  Jp-H=8  2  0.98(dd)  Jp-H = 2  2.30(dsept)  Jp-H=8  3  2  2  H  J H - H = 7  Jp-H = 2  1 1..0 01 1((d dd d)) 1.03(dd) 1.06(dd) 1.08(dd) 1.15(dd) 1.16(dd) 1.26(dd) 1.27(dd) {For all 8 peaks} 3  3  Jp-H = 4 J H - H = 7  C7Hn Hlb=0.06(m) Hla=1.05(m) H7a=1.30(m) H75=1.54(m) H2b=2.44(m) H 4 =2.52(m) H3a=2.66(m) H3b=2.74(m) H6=4.98(m) H 5 =6.36(m)  49 Table VIII. " C NMR data Cmpd SiMe2 PCH2Si 3a  PMe2 or P(CHMe2)2 & P(CHA/e2)2 Ct= 56.87 [t, 141.9] C i = 114.76 [d, 156.5]  5.55(s) 17.64(s) 13.48(t) 6.18(s)  J pp = 6.8 a  13.87(t)  Japp 8.5 =  4a  5.36(s) 17.99(s) 5.85(s)  3b  5.77(s) 9.72(br) 6.40(s)  Ct= 60.21 Q= 114.76  13.62(t) Japp = 6.9  24.73(0 Japp  =  4.2  25.11(0  Japp = 5.1  4b  25.04(t)  5.7 l(s) 10.47(0  Japp = 4.8  6.46(s) Japp 2.7 _  25.24(t)  Japp =37 -' J  5a  5.83(s) 17.72(s) 14.05(t) 6.24(s) app = -6 14.45(t) J  J  6a  7  app = 6.7  5.91(br) 17.87(s) 13.99(0  Japp = -6 6  14.45(t)  J  7a  5.85(s) 17.76(s) 6.05(s)  5.91(s) 17.95(s) 5.95(s)  3  18.62(s) 19.16(s) 19.45(s) 19.57(s)  Ct= 57.91 [t, 145] Q= 114.62 [d, 164.1]  18.72(s) 19.09(s) 19.42(s) 19.60(s)  Ct= 61.64 [t, 146.0] C i = 113.06 [d, 157.7] Ct=57.1 [t, 145.2] Ci= 112.1 [d, 154]  Hf(C6H5) Cp = 124.5 C m = 126.9 C D = 137.2 Q = 197.9  Ct=59.8 Q= 115.0  Zr(C6H5) Cp = 124.7 C m = 126.4 C 0 = 135.6 Q = 191.8  Ct= 54.93 [t, 143.0] C i = 115.0 [d, 157.0]  HfCH2CMe3 C a = 83.06 [t, 101.0] Cp = 30.18 Cy= 35.07 [t, 124.0]  Ct= 56.30 Q= 109.54  ZrCH2CMe3 C a = 82.51 Cp = 36.35 Cy= 35.41  app 5-6 =  13.52(t) J = 6.3 14.22(0 a p p  J  8a  Other  app = 6-1  13.8(t) J = 5.1 14.26(0 a p p  Japp = 5.1  Table VIII 1 3 C NMR data Cmpd SiMe2 PCH2Si 5.98(s) 17.20(s) 6.03(s) 18.35(s) 6.12(s) 6.50(s)  continued  PMe2 or P(CHMe2)2 & P(CHMe )  2 2  QHg  13.95(d) ^P-C = 9.9 14.12(d) 1J _C = 15.4 14.48(d) ^P-C = 9.3 15.08(d) 1J _C = 15.2  C 1 = 63.41 [t, 109] C2= 39.75 [t, 124] C 3 = 35.71 [t, 126] C4= 81.82 [d, 161] C5= 126.14 [d, 149] C 6 = 93.42 [d, 144] C 7 = 49.21 [t, 141]  P  P  6.08(s) 8.63(d)  6.1 l(s) ^P-C = 3.8 6.3 l(s) 11.03(d) 6.40(s) Jp-C =4.0 !  25.07(d) iJp.c = 7.8 25.18(d) ijp.c = 6.4 25.48(d) 1J .C = 5.2 25.95(d) Jp-C = 7.7 P  1  Other  19.00(s) 19.25(s) 19.34(s)  19.41(d)  J -C = 3.7 19.70(s)  2  P  20.19(d)  2 J _ = 5.3 P  C  20.25(d)  2 J . = 4.5 P  C  Q = 69.42 [t, 110] C 2 = 37.85 [t, 121] C 3 = 34.72 [t, 127] C 4 = 88.10 [d, 148] C5= 123.48 [d, 147] C 6 = 90.22 [d, 160] C 7 = 51.52 [t, 139]  51 T a b l e I X . 3 * P {lH} N M R data  Cmpd  Temp (K)  3a  293 180  -10.29 -5.17 -14.28  79.3  270 180  -18.02 -15.08 -20.99  76.1  293 180  +26.83 +30.07+13.03  76.9  293 180  +16.53 +19.00+11.65  78.9  280 180  -13.78 -7.33 -18.95  53.2  288 180  -18.76 -17.21 -19.16  62.3  303 190  -11.95 +4.74 -15.36  77.0  296 180  -17.46 -13.25 -19.36  78.8  9a  298  -8.81 -16.63  75.9  9b  298  +22.79+17.31  65.1  4a  3b  4b  5a  6a  7a  8a  4.2.3  Chemical Shift (ppm)  D a t a f o r t h e C a l c u l a t i o n of  2jp.p(Hz;  AG*  The AG* are calculated from the Eyring equation where the rate constant50 is given by kg = TC Aoc IV2. Therefore AG* = -R T c ln [(TC AVC h)(\2 k Tc)-]] where R is the gas constant, T c is the temperature of coalescence, h is Planck's constant, k is the Boltzman constant and Auc is the peak seperation at coalescence. The two variables Avc and T c are obtained as follows. For *H and 13C{ lH) NMR data Auc is taken to be the peak separation (in hertz) at low temperature. However, for 31P{ *H} NMR data it is observed that a linear dependance between Ax> and temperature exists. Consequently, Ax> are obtained from a c  least squares plot of Av and temperature by extrapolation to T c . Al) for these plots are  calculated from the four frequencies in the observed A B quartet pattern. The formula51 used is ( D A - D E )  = [U1-I4III2-I3] / . 1 2  The data for each compound are tabulated below.  Included is the correlation coefficiant r for the least squares plots, the observed Tc, the calculated A D c and the calculated AG*. In all cases T c , obtained by inspection of the various spectra, remains the largest source of error. If the error in T c for the 31P{ lH) NMR data is estimated to be ± 5 K (this is definitely an overestimation) then the error in AG* is ± 0.22 kcal mol"1. T a b l e X . D a t a f o r H f C I ( r i - C H 6 ) r N ( S i M e 2 C H P M e 2 ) 2 ] 3a 4  2  4  Nucleus 31  P  128.11 118.34 106.14 97.59 91.49  Frequency (Hz) X -1 207.45 197.69 186.70 178.16 173.27  423.52 428.40 434.50 440.61 446.27  502.86 507.75 515.07 522.40 528.55  Results  (v -DB)Temp(K) A  284.56 299.73 318.33 333.90 345.70  180 190 200 210 220  r = 0.9975 T c = 240 K Auc= 379.0 Hz AG* = 10.7 kcal mol"1  T a b l e X I . D a t a f o r Z r C l ( r t 4 - C H 6 ) [ N ( S i M e C H P M e ) ] 4a 4  Nucleus 31  P  1794.4 1829.2 1867.7 1897.0 1928.2 1964.8  Frequency (Hz) x -1 1867.7 1906.2 1942.9 1975.8 2010.6 2047.3  2509.2 2474.3 2435.8 2401.1 2366.3 2327.8  2588.0 2551.4 2511.0 2479.9 2446.9 2412.0  2  ( A V  — V  2  2  2  Temp (K) Results  B)  713.5 640.6 563.1 487.9 429.5 354.2  180 190 200 210 220 230  r = -0.9997 T c = 247 K Avc = 233.7 Hz AG* = 11.3 kcal moH  T a b l e X I I . D a t a f o r H f C l ( r i - C 4 H 6 ) [ N ( S i M e C H P ( C H M e ) ) ] 3b 4  2  Nucleus 31  P  3688.1 3685.6 3679.8 3673.9  Frequency (Hz) 3615.1 3600.4 3596.9 3592.8  1622.8 1620.0 1618.4 1623.7  2  CDA-UB) Temp  1542.1 1542.3 1540.7 1542.1  2067.7 2057.2 2057.2 2048.8  180 185 190 200  2  2  2  (K) Results r =-0.9860 TC = 220K A\)c = 1966.7 Hz AG* =9.1 kcal mol"1  53  Table XDX Data for ZrCI(ti -C4H6)[N(SiMe2CH2P(CHMe )2)2] 4b 4  2  Nucleus  Frequency (Hz)  CUA-DR)  3lp 2346.6 2267.7 1453.9 1375.1 2348.8 2271.4 1463.1 1385.2 2359.4 2280.5 1479.6 1400.7  889.2 882.5 876.3  Temp (K) 180 190 200  Results r =-0.9997 TC = 223K Auc= 1966Hz AG* = 9.6 kcal moH  Table XIV. Data for HfPh(ri -C4H6)[N(S.Me2CH2PMe )2] 5a 4  2  Nucleus 31  P  -863.2 -854.0 -846.7 -839.4  !H  Frequency (Hz) -916.4 -905.3 -899.9 -892.4  -2274.6 -2292.9 -2314.9 -2335.0  ("OA-DR) Temp  -2327.8 -2346.1 -2368.1 -2390.1  1842.9 1710.6  (K)  Results  1410.4 1438.9 1467.3 1495.7  180 190 200 210  r= 1.0000 TC = 260K Auc= 1638Hz AG* = ll.Okcal mol"1  132.3  183  TC = 220K AG* = 10.3 kcal moH  13  C  9122.38 7841.60  1280.78  190  TC = 250K AG* = 10.6 kcal mol"1  Table XV. Data for ZrPh(ri4-C4H6)[N(SiMe2CH2PMe )2] 6a 2  Nucleus 31  P  lH  -2058.3 -2049.1 -2036.2 -2028.9 -2021.7 -2016.1  Frequency (Hz) -2120.6 -2294.7 -2357.0 -2111.4 -2313.1 -2375.4 -2098.6 -2335.0 -2397.3 -2091.2 -2353.4 -2415.7 -2083.9 --2375.4 -2437.8 -2078.5 -2395.5 -2456.1 1854.9 1662.0  (DA-DR) Temp  (K)  Results  228.0 256.5 292.2 318.4 348.2 373.5  180 190 200 210 220 230  r = 0.9989 T c = 258 K Av = 458.5 Hz  192.9  183  T c = 250 K  c  AG* = 11.5 kcal moH  AG* = 11.5 kcal mol-1 13C  9095.30 7632.36  1462.94  188  T c = 260 K AG* = 11.0 kcal mol"1  Table XVI. Data for Hf(CH 2 CMe 3 )(ii 4 -C4H 6 )[N(SiMe2CH PMe2)2] 7a 2  Nucleus  Frequency (Hz)  CUA"""^) Temp (K) Results  3lp +612.81 +537.65-1825.08-1903.88 2438.50 190 +574.32 +499.16-1832.49-1907.65 2405.64 200 +535.83 +460.67-1836.13-1911.29 2370.77 210 +497.34 +420.36-1841.59-1918.57 2337.66 220 +458.85 +383.69-1848.88-1922.22 2305.62 230  r =-0.9999 TC = 275K Auc= 2154.7 Hz AG* = ll.Okcal mol'1  Table X V n . Data for Zr(CH2CMe3)(ri4-C4H6)[N(SiMe2CH2PMe )2] 8a 2  Nucleus 3lp 1568.9 1583.6 1605.5 1627.5 1651.3 1664.2 1689.8  Frequency (Hz) x-1 1647.7 1662.3 1684.4 1706.3 1726.5 1743.0 1766.6  2311.2 2313.1 2324.1 2331.4 2338.7 2347.9 2358.8  2390.1 2395.5 2402.9 2410.2 2417.5 2423.1 2432.2  (DA-DR)  738.2 726.9 714.2 699.5 688.6 677.5 663.1  Temp (K) Results 180 190 200 210 220 230 240  r = -0.9993 T c = 280 K Avc=  613.7  Hz  AG* = 11.5 kcal mol  55 CHAPTER 5 : REFERENCES (1) For the purposes of this thesis groups 3,4 and 5 metals are considered as early transition metals, those in groups 8,9 and 10 as late transition metals while groups 6 and 1 are intermediate between these two classifications. (2) Reihlen, H.; Gruhl, A.; Hessling, G. v.; Pfrengle, O. Annalen.  1930,482,  161. (3) Hallam, B. F.; Pauson, P. L. /.  Chem. Soc. 1958, 642.  (4) Green, M. L. H.; Pratt, L.; Wilkinson, G. /. Chem. Soc. 1959, 3757. (5) (a) Mills, O. S.; Robinson, G. Proc. Chem. Soc. 1960, 421. (b) Mills, O. S.; Robinson, G. Acta. Cryst. 1963,16, 758. (6) Warren, J. D.; Clark, R. J. Inorg.  Chem. 1970,9,  (7) VanCatledge, F. A.; Ittel, S. D.; Jesson, J. P.  373.  J.Organomet.Chem.  1979, 168,  C25. (8) Albright, T. A.; Hofmann, P.; Hoffmann, R. /.  Am. Chem. Soc. 1977, 99,  7546. (9) Berry, R. S. /.  Chem. Phys. 1960,32,  933.  (10) Datta, S.; Wreford, S. S.; Beatty, R. P.; McNeese,T. J.  1979,101,  1053.  (11) Datta, S.; Fischer, M. B.; Wreford, S. S.; Beatty. /.  1980,188,  353.  (12) Wreford, S. S.; Whitney, J. F. Inorg.  Chem. 1981, 20,  (13) Fischer, E. O.; Kogler, H. P.; Kuzel, P. Chem.  J. Am. Chem.  Organomet.  Chem.  3918.  Ber. 1960,93,  (14) Fellmann, J. D.; Rupprecht, G. A.; Schrock, R. R. /. 5099.  1979,101,  (15) Mayer, J. M.; Bercaw, J. E. /. Am.  Soc.  Chem. Soc. 1982,104,  3006.  Am. Chem.  Soc.  2157.  (16) Yasuda, H.; Tatsumi, K.; Okamoto, T.; Mashima, K.; Lee, K.; Nakamura, A.; Kai, Y.; Kanehisa, N.; Kasai, N. /. Am. Chem. Soc. 1985,107, 2410. (17) Erker, G.; Wicher, J.; Engl, K.; Rosenfeldt, F.; Dietrich, W.; Kruger, C. J. 6346.  Am. Chem. Soc. 1980,102,  (18) Dorf, U.; Engl, K.; Erker, G. Organometallics  1983,2, 462.  (19) Czisch, P.; Erker, G.; Korth, H.; Sustmann, R.  Organometallics  1984,3,  945. (20) Yasuda, H.; Kajihara, Y.; Mashima, K.; Nagasuna, K.; Lee, K.; Nakamura,  A. Organometallics,  1982,1,  388.  56 (21) Skell, P. S.; McGlinchey, M. J. Angew. Chem. Internat. Ed. 1975,14, 195. (22) Kruger, C; Muller, G.; Erker, G.; Dorf, U.; Engel, K. 1985,4, 215.  Organometallics,  (23) Smith, G. M.; Suzuki, H.; Sonnenberger, D.; Day, V. W.; Marks, T.  Organometallics, 1986, J,  549.  (24) Erker, G.; Kruger, C; Muller, G. Adv. 137,  Organomet. Chem. 1985,24,  (25) Filleux-Blanchard, M. L.; An, N.; Manuel, G. J. 11. (26) Bachmann, K.; von Philipsborn, W. Org.  Soc.  Organomet. Chem.  Mag. Reson. 1976,8,  (27) Maciel, G. E.; Mclver, J. W.; Ostland, N. S.; Pople, J. A. 1970, 92, 1. (28) Faller, J. W.; Rosan, A.M. J.  Am. Chem. Soc. 1977,99,  (29) Yasuda, H.; Tatsumi, K.; Nakamura, A. Acc.  1. 1977,  648.  J. Am. Chem.  4858.  Chem. Res. 1985,18,  120.  (30) a) Yasuda, H.; Kajihara, Y.; Mashima, K.; Nagasuna, K.; Nakamura, A.  Chem. Lett., 1981, 671.b) Yasuda, H.; Kajihara, Y.; Nagasuna, K.; Mashima, K.; Nakamura, A. Chem. Lett., 1981, 1980.c) Akita, M.; Yasuda, H.; Nakamura, A. Chem. Lett., 1983, 217.d) Mashima, K.; Yasuda, H.; Asami, K.; Nakamura, A.Chem. Lett., 1983, 219.e) Yasuda, H.; Nagasuna, K.; Asami, K.; Nakamura, A.Chem. Lett., 1983,  955.  (31) a) "Inorganic Chemistry"; Huheey, J. E.,3rd Ed., Harper and Row Publishers: New York, NY., 1983, 312 - 325. b) ibid., 569 - 572. c) ibid., 113-121. 106,  (32) Clarke, J. F.; Fowles, G. W. A.; Rice, D. A. /. 349. (33) Crociani, B.; Nicolini, M.; Richards, R. L. /.  Organomet. Chem.  1976,  Organomet. Chem. 1975,101,  349. (34) Gell, K. I.; Schwartz, J. J.  Chem. Soc.  1979, 244.  (35) Fryzuk, M. D.; Carter, A.; Westerhaus, A. Inorg. Chem. 1985,24, 642. (36) Fryzuk, M. D.; Williams, H. D.; Rettig, S. J. Inorg. Chem. 1983,22, 863. (37) Fryzuk, M. D.; Rettig, S. J.; Westerhaus, A.; Williams, H. D. Inorg. Chem. 1985,24,4316. (38) Fryzuk, M. D.; Williams, H. D. Organometallics, 1983,2,162. (39) "Chemistry of Organo-Zirconium and -Hafnium Compounds"; Cardin, D. J.; Lappert, M. F.; Raston, C. L. Ellis Howard Ltd.: Toronto, Canada., 1986.  57 (40) Buchwald, S. L.; Watson, B. T. J.  Am. Chem. Soc.  (41) Gilliom, L. R.; Grubbs, R. H. Organometallics,  1986,108, 7411.  1986,5, 721.  (42) Brown-Wensley, K. A.; Buchwald, S. L.; Cannizzo, L.; Clawson, L.; Ho, S.; Meinhardt, D.; Stille, J. R.; Straus, D.; Grubbs, R. H. Pure and Appl. Chem. 1983, 55, 1733. (43) Fryzuk, M. D.; Carter, A.; Rettig, S. J. unpublished results. Chem.  (44) Hunter, W. E.; Atwood, J. E.; Fachinetti, G.; Floriani, C. /. 1981,204, 67.  Organomet.  (45) Erker, G.; Engel, K.; Kruger, C; Muller, G. Organometallics,  1984,5,  128. (46) Lappert, M. F.; Martin, T. R. /. Chem.  Soc. Chem. Commun.  1980, 476.  (47) For the purposes of this discussion the freely rotating alkyl groups (which are unaffected down to -90° C) are each considered as one inequivalent "atom". For example, at low temperature 4 inequivalent silyl methyl singlets are observed. (48) Collier, M. R.; Lappert, M. F.; Pearce, R. J.  Chem. Soc. Dal. Trans.  1973,  445. (49) Schlosser, M.; Ladenberger, V. J.  Organomet. Chem.  1967,8, 193.  (50) Thomas, W. A. Ann. Rev. NMR Spectrosc. 1968,1, 43-89. (51) "The Chemists Companion"; Gordon, A. J.; Ford, R. A. John Wiley & Sons: Toronto, Canada, 1972, 309.  58  Appendix  Table XVIII Bond lengths for rIfPh(Ti -C4H£)[N(SiMe2CH PMe )2l 4  2  2  o  Bond l e n g t h s  (A) w i t h  standard deviations Bond  Length(A)  estimated  i n parentheses Bond  Length(A)  Hf  -P(l)  2 .720(2)  Si(1)-C(11)  1 .889(8)  Hf  -P(2)  2 .707(2)  S i d )-C(17)  1 .880(8)  Hf  -N  2 .157(5)  Sid  1 .865(7)  Hf  -C(1)  2 .380(8)  Si(2)-N  1 .731(6)  Hf  -C(2)  2 .464(7)  Si(2)-C(12)  1 .883(7)  Hf  -C(3)  2 .447(7)  Si(2)-C(l9)  1 .877(8)  Hf  -C(4)  2 .338(7)  Si(2)-C(20)  1 .874(8)  Hf  -C(5)  2 .290(6)  C d )-C(2)  1 .415(10)  Hf  -B  2 .047(4)  C(2)-C(3)  1 .337(12)  P ( 1 ) -con  1 .803(7)  C(3)-C(4)  1 .442(12)  P(D - C ( 1 3 )  1 .839(8)  C(5)-C(6)  1 .403(9)  P(1 )- C ( 1 4 )  1 .818(8)  C(5)-Cd0)  1 .418(9)  P(2) -C(12)  1 .797(7)  C(6)-C(7)  1 .376(10)  P(2) -C(15)  1 .817(8)  C(7)-C(8)  1 .376(13)  P(2) -C(16)  1 .825(9)  C(8)-C(9)  1 .354(13)  Si(1)-N  1 .735(5)  C(9)-C(10)  1 .387(10)  )-Cd8)  59 Table XIX. Bond angles for  HfPh(ri -C4H 6 )[N(SiMe2CH2PMe2) ] 4  2  Bond a n g l e s  (deg) w i t h e s t i m a t e d  standard d e v i a t i o n s Bonds Pd)-Hf P(l)-Hf  -P(2) -N  P(D-Hf  -C(5)  P(l)-Hf -B P(2)-Hf -N P(2)-Hf -C(5) P(2)-Hf -B N -Hf - C ( 5 ) N -Hf -B C(5)-Hf -B Hf -P(1)-C(11) Hf -P(1)-C(13) Hf -P(1)-C(14) C(11)-P(1)-C(13) C(11)-P(1)-C(14) C(13)-P(1)-C(14) Hf -P(2)-C(12) Hf -P(2)-C(15) Hf -P(2)-C(16) C(12)-P(2)-C(15) C(12)-P(2)-C(16) C(15)-P(2)-C(16) N -SiO)-C(ll) N -Si(1)-C(17) N -Si(D-C(l8)  Angle(deg) 149. 3 6 ( 6 ) 74. 0 0 ( 1 4 ) 89. 9 ( 2 ) 93. 4 7 ( 1 3 ) 84. 12(14) 77. 5(2) 1 16.30(13) 110. 1 (2) 120. 4 ( 2 ) 128. 3(2) 100. 9 ( 2 ) 126. 9 ( 3 ) 1 16.3 ( 3 ) 107. 7 ( 4 ) 102. 5 ( 4 ) 100. 0 ( 4 ) 97. 9 ( 2 ) 125. 3(3) 119. 3 ( 3 ) 105. 8 ( 4 ) 104. 6 ( 4 ) 101 . 5 ( 4 ) 107. 1(3) 1 15.2 ( 3 ) 112. 1 (3)  i n parentheses Bonds C( 11 ) - S i ( 1 ) - C ( 1 7 ) C(1l)-Si(D-C(l8) C(!7)-Si(1)-C(l8) N -Si(2)-C(l2) N -Si(2)-C(V9) N -Si(2)-C(20) Cd2)-Si(2)-C(l9) Cd2)-Si(2)-C(20) Cd9)-Si(2)-C(20) Hf -N -Si(1 ) Hf -N -Si(2) Si(D-N -Si(2) C( 1 ) - C ( 2 ) - C ( 3 ) C(2)-C(3)-C(4) Hf -C(5)-C(6) Hf -C(5)-C(10) C(6)-C(5)-C(10) C(5)-C(6)-C(7) C(6)-C(7)-C(8) C(7)-C(8)-C(9) C(8)-C(9)-C(10) C(5)-C(10)-C(9) P(1)-C(H)-Si(1) P(2)-C(l2)-Si(2)  Angle(deg) 105. 8 ( 4 ) 110. 1 (4) 106. 4(4) 109. 6 ( 3 ) 112. 1(3) 1 13.6 ( 3 ) 108. 7 ( 4 ) 105. 6(3) 106. 9(4) 120. 4(3) 120. 2(3) 119. 2(3) 123. 4 ( 8 ) 120. 8(8) 124. 6(5) 122. 3(5) 112. 7 ( 6 ) 124. 4(7) 119. 2(8) 120. 3(7) 119. 6 ( 8 ) 123. 7 ( 8 ) 107. 4 ( 4 ) 1 13.2 ( 4 )  60 Table XX. Bond  lengths for ZrPh(ri -C4H )[N(SiMe2CH2PMe2)2] 4  6  Bond l e n g t h s standard Bond  (A) w i t h  deviations  Length(A)  estimated  i n parentheses Bond  Length(A)  Zr  -P(1)  2.752(2)  SiO)-C(11)  1.866(9)  Zr  -P(2)  2.730(2)  SiO)-C07)  1.884(8)  Zr  -N  2.190(6)  S i (1 )-C(18)  1.865(8)  Zr  -CO)  2.410(12)  Si(2)-N  1.719(6)  Zr  -C(2)  2.481O1)  Si(2)-C(12)  1.905(7)  Zr  -C(3)  2.450(9)  Si(2)-C(l9)  1.860(9)  Zr  -C(4)  2.350(10)  Si(2)-C(20)  1.872(9)  Zr  -C(5)  2.317(7)  C(1)-C(2)  1.40(2)  Zr  -B  2.056(7)  C(2)-C(3)  1.354(15)  P O ) - C O 1)  1.818(7)  C(3)-C(4)  1 .44205)  PO  )-C(l3)  1.829(9)  C(5)-C(6)  1 .422(1 1 )  P O ) ~ C O 4)  1.823(8)  C(5)-C(10)  1 .398(10)  P(2)-C(12)  1 .800(8)  C(6)-C(7)  1.386(12)  P(2)-C(15)  1.839(8)  C(7)-C(8)  1.365(14)  P(2)-C(16)  1 .81800)  C(B)-C(9)  1 .370(14)  S i (1 )-N  1.733(5)  C(9)-C(10)  1.376(11)  61 Table XXI.  Bond lengths involving H atoms for ZrPh(ri4-C4H6)[N(SiMe2CH2PMe2)2]  Bond l e n g t h s i n v o l v i n g estimated Bond  hydrogen  standard deviations  Length(A)  atoms  (A) w i t h  i n parentheses  Bond  Length(A)  C(l)-H(1a)  1.09(8)  C(3)-H(3)  0.93(8)  C(l)-H(1b)  0.70(10)  C(4)-H(4a)  1.11(8)  C(2)-H(2)  0.88(7)  C(4)-H(4b)  0.93(7)  Table XXIL Bond angles involving H atoms for ZrPh(ri -C H )[N(SiMe2CH2PMe )2] 4  Bond a n g l e s i n v o l v i n g estimated Bonds  4  hydrogen  standard deviations  Angle(deg)  6  2  atoms  (deg) w i t h  i n parentheses Bonds  Angle(deg)  C(2)-C(1)-H(1a)  126(5)  C(2)-C(3)-H(3)  120(5)  C(2)-C(1)-H(1b)  110(11)  C(4)-C(3)-H(3)  117(6)  H(1a)-C(1)-H(lb)  114(12)  C(3)-C(4)-H(4a)  111(5)  C(1)-C(2)-H(2)  123(6)  C(3)-C(4)-H(4b)  105(5)  C(3)-C(2)-H(2)  111(5)  H(4a)-C(4)-H(4b)  133(7)  62 Table XXHI. Bond angles for ZrPh(Ti -C H )[N(SiMe2CH2PMe )2] 4  4  2  6  Bond a n g l e s  (deg) w i t h e s t i m a t e d  standard deviations Bonds >-Zr P(l • -Zr P ( 1 • -Zr P ( 1 >-Zr P ( 1 • -Zr P d • -Zr P d >-Zr P(2 • - Z r P ( 2 • -Zr P ( 2 ] • -Zr P(2 • - Z r P ( 2 ] • -Zr P ( 2 ] -Zr N -Zr N -Zr N -Zr N -Zr N -Zr C ( 1 ] • -Zr C ( 1 ] -Zr c d ]• - Z r C ( 1 ] -Zr C(2] - Z r C ( 2 ) -Zr C ( 2 ) -Zr C(3) - Z r C(3] - Z r C(4] - Z r Zr -Pd) Zr -P(1) Zr -P(0 P(1  -P(2) -N  cd) -C(2) -C(3) -C(4)  -C(5) -N  -cd) -C(2) -C(3) -C(4) -C(5) -cd) -C(2) -C(3) -C(4) -C(5) -C(2) -C(3) -C(4)  -C(5) -C(3) -C(4) -C(5) -C(4) -C(5) -C(5)  -C(11)  -C(13) -C(14) C(11)-P(l)-C(l3)  C(11)-P(l)-C(14)  C(13)-P(1)~C(14) Zr -P(2) -C(12) Zr -P(2) -C(15) Zr -P(2) -C(16)  i n parentheses  Angle(deg)  149.43(7) 73.36(15) 83.5(4) 74.6(3) 91.2(3) 125.5(3) 91.9(2)  83.66(15)  123.7(4)  135.7(3) 113.5(3) 79.0(3) 77.7(2)  151.1(4)  121.0(3) 102.1(3) 103.6(4) 111.3(2)  33.2(4) 60.5(5) 75.8(5) 86.1(4) 31.9(4) 60.6(4) 118.0(4) 34.9(4) 145.9(4) 135.0(4) 99.9(2) 127.0(3) 115.9(3) 108.2(4) 102.0(4) 101.2(4) 97.4(2) 125.2(3) 118.7(4)  Bonds  C(12)-P(2)-C(15) C(12)-P(2)-C(16) C(15)-P(2)-C(16) N -Sid)-C(H) N -Si(D-C(l7)  N  -Si(D-C(l8)  C( 1 1 )-Si(1)-C(17) C(1D-Si(1)-C(l8) C ( l 7 ) - S i ( 1 )-Cd8) N -Si(2)-C(12) N -Si(2)-Cd9) N -Si(2)-C(20) C(12)-Si(2)-C(l9) C(l2)-Si(2)-C(20) C(l9)-Si(2)-C(20) Zr -N -Sid) Zr -N Si(1)-N  -Si(2) -Si(2)  Zr -C(1)-C(2) Zr - C ( 2 ) - C ( 1 ) Zr -C(2)-C(3) C(1)-C(2)-C(3) Zr -C(3)-C(2) Zr  -C(3)-C(4)  C(2)-C(3)-C(4) Zr -C(4)-C(3) Zr -C(5)-C(6) Zr -C(5)-C(10) C(6)-C(5)-C(10) C(5)-C(6)-C(7) C(6)-C(7)-C(8) C(7)-C(8)-C(9) C(8)-C(9)-C(10) C(5)-C(10)-C(9) Pd)-C(1l)-Si(1) P(2)-C(12)-Si(2)  Angle(deg)  105. 1 [4) 104. 5 [4) 103.1 [5) 107. 7 [3) 114. 3<[3) 112. 6 1 I3) 105. 6<[4) 109. 5<[4) 106. 81[4) 109. 8 [3) 112. 5 [4) 112. 7 (3) 109. 1 (4) 105. 3 (4) 107. 0 [5) 119. 51[3) 119. 91[3) 120. 2 1 [3) 76. 217 ) 70. 61!6) 72. 8 [ 7 ) 125. 7 (13) 75. 3 (6) 68. 8 (5) 121 .4 (12) 76. 4 (6) 121 .1 (6) 125. 3 (6) 113. 4 ( 7 ) 123. 7 (9) 119. 0 (10) 120. 0 (9) 120. 4 (9) 123. 4 (9) 108. 0 (4) 112. 5<(4) r  r  1  Table XXIV. Bond lengths for Hf(rj4-CH2CHCHCH)CH2CH2CH2[N(SiMe2CH2P(CHMe2)2)2] Bond l e n g t h s standard Bond  (A) w i t h  deviations  Length(A)  estimated  i n parentheses Bond  Length(A)  Hf  -P(1)  2 .767(6)  Si(2)-N  1.72(2)  Hf  -P(2)  2 .812(6)  Si(2)-C(2)  1.88(3)  Hf -N  2 .129(13)  Si(2)-C(9)  1.87(2)  Hf  -C(19)  2 .32(2)  Si(2)-CdO)  1.90(3)  Hf  -C(20)  2 .36(2)  C(3)-C(11)  1.49(4)  Hf  -C(21)  2 .56(3)  C(3)-C(12)  1.47(4)  Hf  -C(22)  2 .58(3)  C(4)-C(13)  1.54(3)  Hf  -C(25)  2 .22(3)  C(4)-C(14)  1.55(3)  P(1)-C(1)  1.81(2)  C(5)-C(15)  1.51(4)  P(1)-C(3)  1.83(3)  C(5)-C(16)  1.45(4)  P(1)-C(4)  1.86(2)  C(6)-C(17)  1.47(3)  P(2)-C(2)  1.79(3)  C(6)-C(18)  1.54(3)  P(2)-C(5)  1.88(2)  C(19)-C(20)  1.43(3)  P(2)-C(6)  1.82(3)  C(20)-C(21)  1.45(5)  Si(1)-N  1.77(2)  C(21)-C(22)  1.36(5)  Si(l)-C(l)  1.83(2)  C(22)-C(23)  1.44(4)  Sid)-C(7)  1.90(3)  C(23)-C(24)  1.53(4)  Si(1)-C(8)  1.88(2)  C(24)-C(25)  1.52(4)  64 Table XXV. Bond angles for Hf(ti4-CH2CHCHCH)CH2CH CH2[N(SiMe2CH22  P(CHMe2)2)2] Bond a n g l e s  (deg) w i t h e s t i m a t e d  standard d e v i a t i o n s i n parentheses Bonds -P(2) P(1)-Hf P(1)-Hf -N P(1)-Hf -C(19) P(1)-Hf -C(20) -C(21) P(1)-Hf P(1)-Hf -C(22) P(1)-Hf -C(25) P(2)-Hf -N P(2)-Hf -C(19) P(2)-Hf -C(20) -C(21) P(2)-Hf P(2)-Hf -C(22) P(2)-Hf -C(25) N -Hf -C(19) N -Hf -C(20) N -Hf -C(21) N -Hf -C(22) N -Hf -C(25) C(l9)-Hf -C(20) C(l9)-Hf -C(21 ) C(l9)-Hf -C(22) C(l9)-Hf -C(25) C(20)-Hf -C(21 ) C(20)-Hf -C(22) C(20)-Hf -C(25) C(21)-Hf -C(22) C(21)-Hf -C(25) C(22)-Hf -C(25) Hf - P ( 1 )- C O ) Hf - P ( l )- C ( 3 ) Hf - P ( 1 )- C ( 4 ) C ( 1 ) - P ( 1 ) -C(3) C ( 1 ) - P ( 1 ) -C(4) C(3)-P(1) -C(4) Hf - P ( 2 )- C ( 2 ) Hf - P ( 2 )- C ( 5 ) Hf - P ( 2 )- C ( 6 ) C(2)-P(2) -C(5) C(2)-P(2) -C(6) C(5)-P(2) -C(6) N -Si(1)-C(l)  Angle(deg) 150.3 (2) 77.8 (4) 84.4 (6) 119.0 (7) 125.2 [10) 100.3 (7) 87.8 (7) 74.6 (4) 112.9 [7) 84.1 (7) 84.4 (10) 108.1 (7) 94.6 [7) 105.1 (7) 118.4 [9) 148.1 [14) 174.9 [8) 115.9 (8) 35.6 (8) 61.3 (10) 69.9 (9) 135.4 (9) 34.1 (12) 58.4 (10) 123.0 (12) 30.7 (12) 89.0 (12) 68.5 (9) 94.8 (7) 129.9 (10) 113.3 (7) 108.5 (12) 103.2 (11) 103.8 (12) 94.1 I(8) 129.61(11) 115.5 (7) 107.3 (14) 102.0 (11) 104.0 (13) 106.3i (8)  Bonds N -SiO)-C(7) N -Si(1)-C(8) C( 1 ) - S i ( 1 ) - C ( 7 )  C(D-SiO)-C(8)  C(7)-Si(1)-C(8) N -Si(2)-C(2) N -Si(2)-C(9) N -Si(2)-CO0) C(2)-Si(2)-C(9) C(2)-Si(2)-CO0) C(9)-Si(2)-CO0) Hf -N -SiO) Hf -N -Si(2) SiO)-N -Si(2) P(l)-CO)-SiO) P(2)-C(2)-Si(2) P( 1 ) - C ( 3 ) - C ( 1 1 ) P(1)-C(3)-C(12) C O 1 )-C(3)-C(12) P(1)-C(4)-C(13) P(1)-C(4)-C(l4) C(13)-C(4)-C(14) P(2)-C(5)-C(15) P(2)-C(5)-C(16) C(15)-C(5)-C(16) P(2)-C(6)-C(17) P(2)-C(6)-C(18) C(17)-C(6)-C(18) Hf -C(19)-C(20) Hf -C(20)-C(19) Hf -C(20)-C(21) C(19)-C(20)-C(21 ) Hf -C(21)-C(20) Hf -C(21)-C(22) C(20)-C(21)-C(22) Hf -C(22)-C(21) Hf -C(22)-C(23) C(21)-C(22)-C(23) C(22)-C(23)-C(24) C(23)-C(24)-C(25) Hf -C(25)-C(24)  Angle(deg) 112. 61 9) 111. 81 8) 109. 41 11) 110. 01 10) 106. 71 12) 105 .01,9) 1 17.91 10) 109 ,3<H O ) 107..71 12) 109 .51 12) 107..3< 13) 120 .21[8) 121 .51,9) 118 . 1 8) I 112 .8! 11) 111.. 1 < 13) 1131 [2] [2] 1 15< 113 [3] 113 [2] 1 14[2] 112 [2] 1101 [2] 1181 [3] 118 [3] 114 [2] 1161 [2] 1091 [2] 73. 8< 13) 70. 61 13) 80 [2] 120 [3] 65.,5\ 14) 76![2] 1181 [4] 741 [2) 1141 i 2 ] 1221 [4] 1071 2) 1101 3) 121 < 2) r  r  65 T a b l e X X V I . Intra-annular torsion angles for H f ( r i - C H 2 C H C H C H ) C H 2 C H 2 C H 2 [ N 4  (SiMe2CH P(CHMe2)2)2] 2  Intra-annular  torsion  standard d e v i a t i o n s Atoms  angles  (deg)  i n parentheses Value(deg)  N -Hf -P(1)-C(1) Hf -P(l)-C(D-Si(l) N -Si(1)-C(1)-P(1) C(l)-Si(1)-N -Hf P(1)-H£ -N -Si(1)  -44.5(8) 45.0(11) -23.8(13) -22.9(11) 39.9(7)  N -Hf -P(2)-C(2) Hf - P ( 2 ) - C ( 2 ) - S i ( 2 ) N -Si(2)-C(2)-P(2) C(2)-Si(2)-N -Hf P(2)-Hf -N -Si(2)  -48.3(9) 47.1(12) -23.7(15) -28.3(12) 45.4(7)  C(22)-Hf -C(19)-C(20) Hf -C(19)-C(20)-C(21) C(19)-C(20)-C(21)-C(22) C(20)-C(21)-C(22)-Hf C(l9)-Hf -C(22)-C(21)  -63(2) 66(2) -5(4) -51(2) 67(2)  C(25)-Hf -C(22)-C(23) Hf -C(22)-C(23)-C(24) C(22)-C(23)-C(24)-C(25) C(23)-C(24)-C(25)-Hf C(22)-Hf -C(25)-C(24)  -11(2) 34(4) -48(4) 44(4) -18(2)  Figure 19.  Stereoviews of 5a, 6a and  9b  

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