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Trifluoromethanesulfonates of iodine Dalziel, John R. 1975

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TRIFLUOROMETHANESULFONATES OF IODINE by • JOHN R. DALZIEL B.Sc. (Hons.)* Univers i ty of B r i t i s h Columbia, 1 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE in the Department of CHEMISTRY We accept t h i s thes is as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA May, 1975 In p r e s e n t i n g t h i s t h e s i s i n p a r t i a l f u l f i l m e n t o f t h e r e q u i r e m e n t s f o r a n a d v a n c e d d e g r e e a t t h e U n i v e r s i t y o f B r i t i s h C o l u m b i a , I a g r e e t h a t t h e L i b r a r y s h a l l m a k e i t f r e e l y a v a i l a b l e f o r r e f e r e n c e a n d s t u d y . I f u r t h e r a g r e e 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 c o p y i n g o f t h i s t h e s i s f o r s c h o l a r l y p u r p o s e s may be g r a n t e d by t h e H e a d o f my D e p a r t m e n t o r by h i s r e p r e s e n t a t i v e s . I t i s u n d e r s t o o d t h a t c o p y i n g o r p u b l i c a t i o n 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 n o t be a l l o w e d w i t h o u t my w r i t t e n p e r m i s s i o n . D e p a r t m e n t T h e U n i v e r s i t y o f B r i t i s h C o l u m b i a V a n c o u v e r 8, C a n a d a D a t e i i Abstract The invest igat ion of iodine tr i f luoromethanesulfonates was i n i -t ia ted by the synthesis of I ( S 0 3 C F 3 ) 3 v ia the react ion : HSO-CF-I 2 + 6HS03CF3 + 3 S 2 0 6 F 2 —4> 2 I ( S 0 3 C F 3 ) 3 + 6HS03F Iso lat ion of iod ine( I I I ) t r i s t r i f luoromethanesul fonate was poss ib le because of the very low s o l u b i l i t y of the compounds in the acid mixture. The yel low white s o l i d proved to be free of f l u o r o s u l f a t e . The compound was used subsequently in the synthesis of s a l t s of the general formula, M I [ I ( S 0 3 C F 3 ) 4 ] , with M1 = K, Rb, or Cs, using HS0 3CF 3 as the react ion medium. A l ternate routes to the t e t r a k i s ( t r i f l u o r o -methanesulfonate) iodate( I I I ) compounds were also r e a l i z e d . Reduction of I ( S 0 3 C F 3 ) 3 by an equimolar amount of I 2 at elevated temperature i n a sealed tube resulted in the formation of iodine( I ) t r i f luoromethanesulfonate. Poly iodine compounds of the type ^ 0 3 ^ 3 with n = 3 , 5 or 7 could not be obtained. The addi t ion of B r 2 to IS0*3CF3 resulted in the formation of the dibromoiodonium tr i f luoromethanesulfonate, I B r 2 S 0 3 C F 3 . Other t r ia tomic interhalogen polyhalogen cations such as ICl* or I*.could only be produced in solut ions of HSO-JCF-J . The s o l v o l y s i s of IS0 3 CF 3 in HS0 3CF 3 was found to lead to blue solut ions containing the- I 2 + c a t i o n . Attempts to prepare abromine(III) tr i f luoromethanesulfonate v ia three d i f f e r e n t routes, so l vo l ys i s of BrS0 3F in HS0 3 CF 3 , s o l v o l y s i s of BrF 3 in HS0 3CF 3 and oxidation of B r 2 in HS0 3CF 3 with S 2 0 g F 2 , were un-success fu l . The usual resu l t was a v io lent detonation of the reaction mixture. i i i The synthesis of iodyl trifTuoromethanesul fonate, IC^SOgCF^was effected by reacting H I 3 0 g and HS03CF3. S i m i l a r l y iodosyl t r i f Tuoro -methanesul fonate was obtained from and HI 3 0 g in HSOgCFg. Based on the resul ts of v ibrat ional spectroscopy, IOSO^CF^ is thought to be made up of d iscrete 10 units bridged by SO^CF^ groups. Structural studies based on inf rared and Raman spectroscopy were undertaken on a l l the products mentioned. In addit ion the previously synthesized compound CF^SO^CF^ was also studied as an example of a monodentate SOoCF- group. iv TABLE OF CONTENTS PAGE Abstract i i Table of Contents i v L i s t of Tables L i s t of Figures Acknowledgements CHAPTER I INTRODUCTION 1 A. The interhalogens 4 B. Pclyhal.ides and Pos i t i ve Polyhalogen Complexes 6 C. Halogen Oxyacid Compounds 9 D. Tr i f luoromethanesulfonic acid and i t s der ivat ives 10 II EXPERIMENTAL 15 A. Chemicals 15 1. Reagents a. Commercial 15 b. Prepared 16 2. Products a. Iodine(I I I ) and Iodine(I) t r i f luromethane-sulfonates 18 b. A l k a l i metal t e t r a k i s tr i f luoromethane-sulfonate iodate( I I I ) sa l ts - 19 c. Iodyl and Iodosyl tr i f luoromethanesulfonate 19 d. Dihalo iodine trif luoromethane sulfonate 20 continued V TABLE OF CONTENTS, Continued. PAGE B. Apparatus 21 1. Vacuum 1ines 21 2. Metal Fluorine Line 22 3. Dry Atmosphere Box 22 4. Reactors 22 5. Miscellaneous 25 C. Spectrophotometers 28 1. Infared Spectrometer 28 2. Raman Spectrophotometer 28 3 . V i s i b l e and U l t r a v i o l e t Spectrophotometer 29 II I RESULTS AND DISCUSSION 30 A. Introduction 30 B. Synthesis 30 1. Iodine(I I I ) t r is t r i f luoromethanesul fonate 30 2. I (S0 3 CF 3 )2 cat ion 37 3. A l k a l i metal tet rakis ( t r i f luoromethanesul fonate) iodate( I I I ) 37 4. Iodine monokistrif luoromethanesulfonate 39 o 5. Polyhalogen and Interhalogen tr i f luromethane sulfonates 42 6. Iodine-Oxygen tr i f luoromethanesulfonates 46 7. Bromine t r is t r i f luoromethanesul fonate 50 C. V ibrat ional Spectroscopy 52 1. General Introduction 52 2. M[ I (S0 3 CF 3 ) 4 ] 59 conti nued TABLE OF CONTENTS, Continued. 3. I ( S 0 3 C F 3 ) 3 4. IS0 3 CF 3 5. IB r 2 S0 3 CF 3 6. I0 2 S0 3 CF 3 7. I0S0 3CF 3 8. CF 3 S0 3 CF 3 IV GENERAL CONCLUSIONS vi i LIST OF TABLES Table PAGE 1 A l l red Rochow E lec t ronegat i v i t i es for Selected Elements 3 2 AG° (Kcal/mole) for the Interhalogens 5 3 Cat ionic Compounds of Oxyacids 11 4 Elemental Analys is and Melt ing Points 36 5 A comparison of S03X inf rared v ib rat iona l frequencies in (C 2 H5) 2 Sn(S0 3 F) 2 and ( C 2 H 5 ) 2 Sn (S0 3 CF 3 ) 2 58 6 V ibrat ional Frequencies for Rb[ I (S0 3 CF 3 ) 4 ] and (CH 3 ) 3 GeS0 3 CF 3 60 7 V ibrat ional Spectrum of I ( S 0 3 C F 3 ) 3 65 8 V ibrat ional Spectrum of IS0 3 CF 3 67 9 Infrared Spectra of IBr 2 S0 3 CF 3 and AgS0 3CF 3 69 10 V ibrat ional Frequencies for IBr 2 in IBrS0 3 CF 3 and IBr 2 S0 3 F 71 11 V ibrat ional frequencies for I0 2 S0 3 CF 3 and I0 2 S0 3 F 73 12 V ibrat ional Frequencies for I0S0 3 CF 3 77 13 1-0 Stretching Frequencies in Several Compounds 79 14 V ibrat ional Spectra of CF 3 S0 3 CF 3 81 15 S-0 Stretching Frequencies in i o n i c , monodentate, and bidentate S0 3F and S0 3 CF 3 groups 83 v i i i LIST OF FIGURES Figure PAGE 1 The Structure of [ IC l^ lLSbClg - ] 8 2 Metal Fluorine l i n e 23 3 Pyrex Glass Reactors 26 4 Monel Metal Reactor 27 5 The System ^ ^ O ^ 41 6 Corre lat ion Diagram of SO^X 53 7 Normal Vibrat ions of SO3CF3 groups with C3 V Symmetry 55 8 Raman Spectrum of USO^CF^)^ 63 9 Infrared Spectra of (10 JSO^CF^ and (I0 2)S0 3 C F 3 from 1500-250 cm"1 75 i x Acknowledgements I would l i k e to acknowledge my extreme indebtedness to Dr. F. Aubke for his supervision throughout the course of th i s work. From i t s inception to i t s completion his suggestions and encouragement have been of immeasurable help. I w i l l never be able to express f u l l y the gratitude that he deserves. I would also l i k e to thank a l l of my coworkers in Lab. 457 for t h e i r f r iendship and ass is tance, without them the l a s t four years would not have been as pleasant as they were. F i n a l l y I would l i k e to thank a l l those who taught me Chemistry, p a r t i c u l a r l y Dr. R.F. Grant, who when I was considering many al ternate professions made my f i r s t year of Chemistry the f i r s t of many. Introduction From a f i r s t year general chemistry text the fo l lowing descr ipt ion of the halogens i s t a k e n 1 : "The halogen atoms a l l have seven electrons in t h e i r outer she l l and are fo l lowed, in each case, in the per iodic table by a noble gas. Consequently the i r most stable oxidat ion number i s - 1 . A l l the halogens except f l u o r i n e are known to e x i s t in several ox idat ion s t a t e s . " This prel iminary d e f i n i t i o n i s followed by a descr ip t ive chemistry of the halogens which i s exc lus ive ly the chemistry of the ha l ides , X~. Most f i r s t year chemistry students when asked to describe the chemistry of the halogens respond with a descr ipt ion of hal ide chemistry. Very few are aware of the pos i t i ve character which a l l halogens except f luo r ine can and do d isp lay . Since the compounds synthesized here are a l l c a t i o n i c halogen compounds, a short int roduct ion of the subject i s in order. Cat ion ic halogen compounds are ones in which the halogen X can be considered to have a pos i t i ve ox idat ion number, e i ther 1, 3 , 5 or 7 and to occupy formal ly a c a t i o n i c p o s i t i o n . An example i s c h l o r i n e n i t r a t e , ClN0\j, where in analogy to potassium n i t r a t e KNO^ the ch lor ine occupies the c a t i o n i c p o s i t i o n . In general the halogen w i l l not e x i s t as a true cation as found in an ion ic compound but rather i t w i l l be the p o s i t i v e l y polar ized part of a covalent molecule of general formula x - y~ or in 6 + 6 - + the example CI - ONC^  rather than K NO^". There are several important consequences of t h i s covalent nature of c a t i o n i c halogen compounds which may r e s u l t : a) The compounds may be v o l a t i l e , in p a r t i c u l a r when the halogen is c h l o r i n e . 2. b) The symmetry of the "anion" may be reduced (e .g . for NOj Ufo to C^y or even lower) C. ) hydrolysis of the compound w i l l be complex resu l t ing in more than jus t simple ion formation. H20 + e . g . NaNCL - — - N a (solv) + NO- (solv) (1) HO C1N03 - - 2 H + (solv) + N 0 3 ' CIO" (2) The halogen most l i k e l y to form c a t i o n i c halogen compounds i s * iodine (with the possible exception of a s t a t i n e ). This i s apparent from the e l e c t r o n e g a t i v i t i e s of the halogens l i s t e d in table 1. On purely e lec t ronegat i v i t y grounds p o s i t i v e l y po lar ized iodine i s expected for bonds with the fo l l ow ing : the halogens Br , CI and F; the chalcogenides Se, S and 0 ; the group V element N and the group IV element C. For bromine and chlor ine only F, 0 and N remain as potent ia l partners . F luor ine , as expected from i t s e lec t ronegat i v i t y has not been found to form any c a t i o n i c halogen compounds. In sp i te of a wide array of possible anion sources in pract ice only oxygen, the halogens themselves, and a to a l i m i t e d extent nitrogen have been found to produce binary c a t i o n i c halogen compounds. The com-pounds are the internalogens, halogen oxides, and halogen n i t r i d e s . Only the f i r s t two categories w i l l be discussed. * Astat ine should have a greater c a t i o n i c tendency than Iodine,.however, i t s very short ha l f l i f e , only 8.3 hours fo r the most stable isotope, has prevented any deta i led chemical i n v e s t i g a t i o n . TABLE 1 Allred-Rochow E lec t ronegat i v i t i es for selected Elements Group IV A V A VI A VII A C N 0 F 2.50 3.07 3.50 4.10 P S CI 2.06 2.44 2.83 Se Br 2.48 2.74 I 2.21 Values taken from: J . Inorg. Nuc l . Chem., 5_, 264 (.1958). 4. A. The interhalogens The general formula fo r any interhalogen i s XY n when Y i s always the l i g h t e r halogen and n i s odd, e i ther 1, 3 , 5 or 7. In a l l , 13 i n t e r -halogens are known to be stable and are l i s t e d in table 2. Note that f luor ine only acts as the Y group. The major i ty of interhalogen com-pounds are halogen f l u o r i d e s . Iodine i s the c a t i o n i c halogen for the largest number of interhalogens and i t exh ib i ts i t s highest ox idat ion number, +7 with f l u o r i n e . A l l these are expected from the electronega-t i v i t y arguments. The thermal s t a b i l i t y of the diatomic interhalogens, XY, i s due to a combination of two main f a c t o r s . F i r s t there i s the i n t r i n s i c bond energy of the X-Y bond. This can be estimated from the standard free energies AG° given in table 2. Second there i s the tendency f o r XY to undergo d i s p r o p o r t i o n a t e into nX 2 and x v ( 2 n + l ) ' This tendency i s apparent from the AG of react ion and i s indicated by an increased AG° of the products. From thermodynamic data and measured or estimated 2 bond energy values accumulated by Wiebenga et a l . i t can be seen t h a t , although the bond energies f o r XY were less for the l i g h t e r c a t i o n i c , X, halogens, the corresponding XY^ and XY^ compounds were also much less s t a b l e . For the diatomic f luor ides formed from the heavier halogens, i . e . IF,the greater s t a b i l i t y of IF,- and IF^ e f f e c t i v e l y n u l l i f i e d the s t a b i l i t y fac tor of the high bond energy for IF. 5IF AG*= r3%Z Kcal (3) 7IF Kcal (4) 5. TABLE 2 AG°f(Kcal/mole) for the Interhalogens' X XY AG0 X Y 3 AG° X Y 5 AG° XY7 CI c l F ( g ) - 1 3 . 4 C lF 3 (g ) - 3 8 . 8 C lF 5 (g ) - -Br B r F ( g ) - 1 4 . 7 B r F 3 ( l ) -75 B r F 5 ( l ) -127.5 -B r C 1 ( g ) - 3 . 4 6 - - -- -I I F ( g ) - 2 2 . 7 I F 3 - IF S (1) -205.3 I F 7 ( g ) I C ' ( s ) - 7 . 6 7 I C l 3 ( s ) -21 .1 - - -I B r ( s ) -" - - - -AGC 6. As a r e s u l t , while the order of s t a b i l i t y fo r the binary interhalogens with respect to the elements i s IF > BrF > C1F >IC1 7 IBr > B r C l , iodine monofluoride which has supposedly the most stable bond has been detected only in flames where iodine i s brought into contact with f l u o r i n e . That i s at high temperatures where I-F bonds are cleaved quite read i l y and the d i s p r o p o r t i o n a t e reactions mentioned above do not occur i r r e v e r s i b l y . B. Polyhal ides and Pos i t i ve Polyhalogen Complexes Interhalogens are c lose ly re lated to two kinds of i ons ; the poly -hal ide anions, and the polyhalogen cat ions . An interhalogen such as BrF^ can act as a hal ide ion acceptor to form a polyhal ide anion, BrF^", or a hal ide ion donor to form a poly -halogen c a t i o n , B r F 2 + according to . excess SbF,- KF BrF 2 SbF 6 " 2. B r F 3 »-K BrF^" (5) - 3 Except fo r short l i v e d rad ica ls such as C l 2 and FC1 polyhalogen anions are diamagnetic and thus contain general ly an odd number of atoms. In the exceptions, the even polyhal ides i . e . Cs l^ the observed diamagnetism indicates that at least two empir ical units make up the real formula. This has been confirmed by X-ray d i f f r a c t i o n studies^ . The chemistry, s t ruc ture , and bonding of polyhal ide anions has been reviewed recent ly by 5 Popov and sha l l not be discussed fu r ther . Polyhalogen ca t ions , as shown by the above example (eq. 5 ) , may be formed from the neutral interhalogens on in te rac t ion with strong Lewis acids such as SbF .^ or Al CI 3 e f f e c t i n g hal ide ion t ransfer from the neutral interhalogen. Recently some f luorosu l fa tes with t r ia tomic cations of the type IX,, or (with X = CI or B r ) , have been reported, suggesting an a l ternate route to i n t e r - and polyhalogen ca t ion ic com-pounds. Deta i ls w i l l be discussed l a t e r . A word of caution i s necessary regarding the use of the term "cat ion" in re fe r r ing to these i n t e r - and poly-halogen compounds. From the bond distances for IC l 2 -SbC lg 7 given in f igure 1 i t can be seen that the use of the term cat ion fo r the ICl^ moiety i s somewhat misleading because appreciable anion-cat ion in te rac t ion i s present. In th i s case the in te rac t ion involved chlor ine bridges which r e s u l t in a d is tor ted anion and a polymeric s t ructure . The true structure i s somewhere between a genuine ion ic s o l i d and a two dimensional polymer. Anion cat ion in teract ions of varying degrees have been found for a l l compounds of th i s type. They are most e a s i l y detected by X-ray g structure analys is but are also apparent from v ib ra t iona l spectral 9 10 analys is or from N.Q.R. studies . The observed anion-cat ion i n t e r -act ion in the s o l i d state may be broken up by d i sso l v ing the compound in strong protonic ac ids , e . g . : HSO3F BrF 0 SbF c- - B r F 0 , . * + SbF c ~, , ^ 2 6 2 (solv) 6 (solv) In summary, whereas monoatomic halogen cations of the type X + + + are nonexistent, polyhalogen or interhalogen cations X n or XY n do e x i s t . However, some degree of a n i o n i c - c a t i o n i c associat ion in the s o l i d state and s t a b i l i z a t i o n by su i tab le strong protonic acids in s o l u -t ion i s necessary for t h e i r ex is tence. An addit ional group of compounds e x i s t where a p o s i t i v e l y charged halogen i s s t a b i l i z e d by Lewis bases 1 1 such as pyr idine or qu ino l ine . The Structure of [iCl^fSbClg] a 2 . 2 6 •Cl4 2 . 3 4 116.8 V.. CI 8 3.00'*.. ^85J0? N / 2 . 8 5 f\ A 913° J_ 68.7° ' Cl, Cl; 9. These compounds, commonly c a l l e d s t a b i l i z e d halogen compounds are ob-tained by react ion such as I 2 + AgN03 + Zpy ^ - A g l + [ I (py) 2 ] [NO3] (7) where the d r i v ing force of the reaction is the formation of the inso luble s i l v e r s a l t . They are mentioned here for the sake of completeness. C. Halogen Oxyacid Compounds Of greater relevance to th i s study are halogen oxy der ivat ives 12 of oxyacids such as I0(N0 3) . They have been known fo r a long time 13 and were commonly referred to as basic s a l t s . For example, as shown 14 recently by T. K ik indai the in te rac t ion product between fuming n i t r i c acid and I 2 i s best regarded as IONO^. This compound was o r i g i n a l l y 12 obtained by M. Mi 11 on . The oxides of iodine and I^O^ have long been forumlated as iodosyl and iodyl iodates . These and re lated compounds such as the iodosyl der ivat ives of H2S0^ and H2SeO^ are wel l s tud ied . Although bromine oxygen analogues to 10 and I 0 2 compounds appear to be thermally unstable, some chlor ine oxygen compounds containing the 15 ch lory l group, C10 2 are known. Compounds such as C10,,S03F and 16 ( C 1 0 2 ) 2 S 3 0 - | Q , in marked contrast to the highly polymeric I0 2 compounds, are found to be soluble in strong ac ids , and produce q u a n t i t a t i v e l y the chloronium cat ion C 1 0 2 + . Generally iodine ( I I I ) compounds as well as i o d y l , I 0 2 , and i o d o s y l , 10, compounds are formed by a number of strong to medium strong acids such as the monobasic oxyacids, H02CCF3 and HN03 and inc luding d i -basic acids l i k e H 2 S0 4 and H,,Se04 and even t r i basic H-^ PO .^ 10. As can be seen from table 3 , the formation of Br( I ) and Br(111) and CI(I) oxyacid der ivat ives are r e s t r i c t e d to r e l a t i v e l y strong mono-basic ac ids . F i n a l l y , only one stable 1(1) d e r i v a t i v e , ISO^F, has been made. It seems that i n analogy to the d i s p r o p o r t i o n a t e of IF into IF 5 and ^ e q u a t i o n v t h a t the I (111) compounds are thermodynamically favoured. There i s a r i ch chemistry of pos i t i ve halogens. Of the halogens, iodine has the most extensive chemistry inc luding binary oxyacid d e r i -vat i ves . The occurrence of ca t ion ic halogen compounds appears to be connected with the acid strength of the given oxyacid. A b r i e f d i s -cussion of HSO^CFg, the acid used i n t h i s work, fo l lows . D. Tr i f luoromethanesulfonic Acid and i t s Der ivat ives Tr i f luoromethanesulfonic acid i s a strong monobasic protonic a c i d . It was o r i g i n a l l y prepared in 1954 1 7 by the oxidat ion of b is ( t r i f luoromethy l th io ) mercury and p u r i f i e d by treatment of barium bis tr i f luoromethanesulfonate with fuming s u l f u r i c a c i d . This method i s not pract icable for producing large q u a n t i t i e s . HSO^CF^ i s now manu-factured commercially by the e l e c t r o f l u o r i n a t i o n of CH2SO2CI and d i s -t r ibuted as Fluorochemical Acid by the Minnesota Mining and Manufac-tur ing Company. In respect to acid strength t r i f luoromethanesulfonic 14 acid has been claimed to be the strongest monobasic acid known based on the conduct i v i t ies of various acids in acet ic a c i d . On the other hand, HSO^CF^ reacts with organotin compounds in much the same 1 g manner as HSO^F . The resu l t ing organotinsulfonates are i sos t ruc tu ra l 11 TABLE 3 Cat ionic Compounds of Oxyacids Acids H^ Y Groups Compounds formed by Oxyacids and Halogens CH3C00H CFgCOOH H 2 S0 4 H 3 P0 4 H 2 Se0 4 H 2Te0 4 HOTeFr-H0SeFe HN03 HC104 HS03F 1 2 1 2 1 2 1 2 1 2 3 Group 1 IY 3 IOY I0 2Y Group 2 C1Y BrY BrY, Group 3 IY ¥ IX2Y CX=C1 or Br) 12. and have completely ident i ca l •£< Sn Mossbauer parameters. I t , there-fo re , seems reasonable to assume HSO^CF^ i s as strong an acid as HSO^F or HC10 4. Some physical propert ies of HS0 3CF 3 would indicate t h i s . A b r i e f review of the chemistry of HS0 3CF 3 up to 1965 has been given k c • 19 by Senmng No deta i led s t ructura l studies (e .g . X-ray d i f f r a c t i o n ) of t r i f luoromethanesulfonic ac id der ivat ives have been undertaken. How-ever, there are two in f rared and Raman studies involv ing normal co -20 21 ordinate analyses and force f i e l d ca lcu la t ions on the S0 3 CF 3 anion ' The problem of assigning bands i s complicated by a near coincidence of CF 3 and S0 3 v ib ra t iona l modes and extensive v ib ra t iona l mixing of modes. The proposed assignments in the two studies d i f f e r widely . The tr i f luoromethanesulfonate group can act as a monodentate, b identate, or even t r identate l igand through oxygen. In the a l k a l i metal s a l t s the S0 3 CF 3 group i s an anion S0 3CF 3~ while in the t i tanium chloro s a l t s i t acts as a bidentate l igand in T i C ^ S O - j C F . ^ or a 22 t r identate l igand i n T i C l 3 S 0 3 C F 3 . In a manner s i m i l a r to the f l u o r o -22 23 su l fates of t i taniam and t i n ' the tr i f luoromethanesulfonates have bidentate or t r identate S0 3 CF 3 groups which act as br idging l igands rather than as chelat ing groups. In Organic chemistry the acid strength of HS0 3CF 3 i s u t i l i z e d in s i tuat ions where perch lor ic acid has been used. In th i s respect t r i f luoromethanesulfonic acid i s of comparable strength but i s not nearly such a strong ox id i ze r and i t s use reduces hazards. Two examples of th i s use a re ; f i r s t , the use of HS0 3CF 3 as a t i t r a n t in g l a c i a l 13. 24 acet ic acid so lu t ion and second, as a replacement for HCIO^ when a strongly a c i d i c media i s required. In organic syntheses the SO3CF3 group i s a good leaving group, and in electrochemistry the weakly co-ordinat ing propert ies of the SO^CF^" ion make i t a good a l te rnat i ve to the perchlorate ion as a support e l e c t r o l y t e . That t r i f luoromethanesulfonic acid has been invest igated be-cause of i t s s i m i l a r i t y to other strong a c i d s , at l eas t in par t , i s 25 26 borne out by several authors who have used the propert ies of HSO^F ' , ?4 27 HC104 and H 2S0 4 to argue the f e a s a b i l i t y of HS0 3 CF 3 . However, even when the s i m i l a r i t y of HS0 3CF 3 to other strong acids i s the reason for i t s i n v e s t i g a t i o n , i t i s the unique c h a r a c t e r i s t i c s of the acid which are most important. For example, as a strong acid media instead of HC104, i t i s the ox idat ive s t a b i l i t y of HS0 3CF 3 which i s so va luable , while in t i t r a t i o n s in acet ic acid the non formation of gels with potassium hydrogen p^thal'ate i s important. Tr i f luoromethanesulfonic acid fumes on contact with a i r and reacts with moisture to form a stable monohydrate, HSC^CF-^^O which melts at 30°C. The formation of t h i s hydrate necessitates the use of a dry box to handle the a c i d . The formation of the monohydrate has on occasion proved u s e f u l . When water i s generated in a r e a c t i o n , the acid e f f e c t i v e l y removes the water from the reac t ion . For a l l 28 normal uses HS0 3CF 3 can be handled in the same manner as HS03F F i n a l l y , a word about the naming of HS0 3 CF 3 > The o r i g i n a l synthesis c a l l s the acid t r i f luoromethane-su l fon ic a c i d . From the point of view of inorganic nomenclature an argument can be made 14. for t r i f l u o r o m e t h y l s u l f u r i c a c i d . Various other permutations e x i s t in the l i t e r a t u r e . There is even a proposal that sa l t s of HSCLCF., Q J o V be ca l led " t r i f l a t s " for the sake of b rev i t y . In t h i s t h e s i s , however, the acid w i l l be ca l led t r i f luoromethanesulfonic acid and der ivat ives of i t t r i f luoromethanesulfonates. The main reason for t h i s decis ion is to avoid confusion and promote c l a r i t y . As for choosing the organic name over the inorganic name no real reason ex is ts but the terminology used is that most common in the l i t e r a t u r e . 15. Experimental A. Chemicals 1. Reagents Except for p e r o x y d i s u l f u r y l d i f l u o r i d e , RbCUSO^F)^] and cesium tr if luoromethanesulfonate a l l the reagents used in the synthesis of the various iodine tr if luoromethanesulfonates were e i ther ava i lab le commercially^or else were trifluoromethanesulfonates^ where the synthesis is the subject of t h i s t h e s i s , a. Commercial i ) Elemental iodine was supplied by the Fisher S c i e n t i f i c Com-pany (resublimed) and 99% pure. No further p u r i f i c a t i o n was undertaken. i i ) Elemental f l u o r i n e , 98% pure, used in the preparation of S20gF2 was obtained from A l l i e d Chemical Corporat ion, and passed through a sodium f l u o r i d e , NaF, metal trap to remove hydrogen f l u o r i d e , HF. No attempt was made to remove other impur i t ies commonly present in the s u c n a s ^2 o r ^2 s i n c e ^ e y do not enter into the reaction between S0*3 and F2. A high pressure Autoclave Engineering Valve and Crosby high pressure gauge regulated the flow of F 2 from the c y l i n d e r . i i i ) Elemental bromine, 99% pure, was supplied by B r i t i s h Drug House. I t was stored over P 20 5 and KBr and used without further p u r i f i c a t i o n . i v ) Elemental c h l o r i n e , 99.5% pure, was supplied by Matheson of Canada L t d . It was dr ied by passing the gas through two 96% H 2S0 4 traps and f i n a l l y through a P^O^ tube. No attempt was made to remove 0 9 or N 9 or other impur i t ies . 16. v) Sul fur t r i o x i d e was purchased from Baker and Adamson, A l l i e d Chemical Corporat ion, as "Sul fan" ( s t a b i l i z e d S0 3 ) and used without p u r i f i c a t i o n . v i ) Iodine pentoxide was obtained from Fisher S c i e n t i f i c Com-pany (pur i ty 99%). However, based on the in f rared spectrum of the coupound i t was HIgOg ?fe?7. and not 1^0^. I t was used as such without any attempt to pur i fy i t . . v i i ) Iodic A c i d , H I0 3 , was obtained from B r i t i s h Drug House at a pur i ty of 97.5%. Again i t was found to be Hl^Og -J-. I. It was used without p u r i f i c a t i o n . v i i i ) Potassium iod ide , 99% pure, was obtained from Fisher S c i e n t i f i c Company and used without further p u r i f i c a t i o n . i x ) Rubidium i o d i d e , 99% pure, was obtained from A l f a Inorganics L td . and used without fur ther p u r i f i c a t i o n . x) Cesium c h l o r i d e , 99.9% pure, was obtained from B r i t i s h Drug House and used without further p u r i f i c a t i o n . x i ) Tr i f luoromethanesulfonic a c i d , HSO^CF^, was obtained from the Minnesota Mining and Manufacturing Company as "Fluorochemical Ac id" and the pur i ty was not g iven. I t was p u r i f i e d by d i s t i l l a t i o n under reduced pressure. x i i ) F luorosu l fu r i c A c i d , HSO^F, ( technical grade) was supplied by A l l i e d Chemical Corp. and was p u r i f i e d by double d i s t i l l a t i o n under 2 d dry nitrogen at atmospheric pressure - ^ J . b. Prepared i ) P e r o x y d i s u l f u r y l d i f l u o r i d e , 6^2' w a s P r e P a r e a " i n 500 g. quant i t ies in a modified version of a general method reported by 17. * ' . Shreeve and Cady >'. A f te r having passed through a NaF t r a p , F^  was mixed with dry N 2 and S0 3 (sulfan) in a s i l v e r ( I I ) f luo r ide c a t a l y t i c furnace reactor F i g . 2 . The reaction temperature was 180°C and the $2®(f2 9 e n e r a t e d w a s condensed out at -78°C in dry ice t raps . Any unreacted S0 3 was removed by ext ract ion with Oleum, concentrated h^SO^ and l a t e r p u r i f i e d by f rac t iona l d i s t i l l a t i o n to y i e l d pure 19 S^Q^2 as indicated by F N.M.R. and inf rared spectroscopy. i i ) Rubidium t e t r a k i s - f l u o r o s u l f a t e i o d a t e ( I I I ) , Rb[ I (S0 3 F) 4 ] was synthesized from Rbl and S,,0gF2 in analogy to the reported syn-thesis of the potassium s a l t by Lust ig and Cady ( < f t ) . An excess of S 2 0gF 2 was d i s t i l l e d onto Rbl and a f t e r several hours the excess S 2 0gF 2 was removed leaving the Rb[ I (S0 3 F) 4 ] as a white s o l i d . No p u r i f i c a t i o n of the product was necessary. The react ion was fol lowed by weight. i i i ) Cesium tr i f luoromethanesulfonate, CsS0 3 CF 3 , was obtained fromCsCl and HS0 3 CF 3 . An excess of HS03CF was added to CsCl in a two part reactor and a f te r several hours the excess ac id was removed leaving the CsS0 3CF 3 behind. The react ion was followed by weight. i v ) Iodine t r i s f l u o r o s u l f a t e I ( S 0 3 F ) 3 was synthesized from I 2 and S 2 0gF 2 by the method of Roberts and Cady An excess of S 2 0gF 2 was d i s t i l l e d onto I 2 and the mixture was allowed to warm to room temperature. Heat was evolved and a greenish l i q u i d was formed. Eventual ly , a f te r leaving the reaction overnight, the l i q u i d became l i g h t yel low ind icat ing a complete reac t ion . The excess S 2 0gF 2 was removed in vacuo and the product used without further p u r i f i c a t i o n . The react ion was followed by weight. 18. 2. Products a. Iodine(I I I ) and Iodine(I) Tr i f luoromethanesulfonates. i ) Iodine t r is t r i f luoromethanesul fonate I ( S 0 3 C F 3 ) 3 I^  (0.958 g. 3.78 mmol.) was suspended in 29 g . of HS0 3CF 3 in a two part reactor . Then 2.453 g. (12.38 mmol.) of $2®6^2. w a s a c ' c ' e c ' by v a c u u m d i s t i l l a t i o n from a c a l i b r a t e d t r a p . The mixture was allowed to warm to room tem-perature and shaken manually from time to t ime. The colour was i n i t i a l l y brown and then changed to blue and blue green. Af te r 20-30 minutes the colour had changed to a l i g h t yel low and a p rec ip i ta te had begun to form. The v o l a t i l e products were removed in vacuo and 4.307 g. of I ( S 0 3 C F 3 ) 3 was obtained. i i ) An a l ternate route to I ( S 0 3 C F 3 ) 3 v ia I (S0 3 F.) 3 - 1 2 grams of HS03F was d i s t i l l e d onto 2.9654 g. of I ( S 0 3 F ) 3 in a two part reactor The reactor was evacuated and introduced into the dry box where approxi -mately 8 grams of HS0 3CF 3 was added. A yel low p r e c i p i t a t e was formed immediately. V o l a t i l e components were removed and 3.8279 g. of I ( S 0 3 C F 3 ) 3 were obtained. i i i ) Iodine(I) tr ifTuoromethanesulfonate, IS0 3 CF 3 ; in a t yp ica l preparation 0.982 g. (1.72 mmol.) of I ( S 0 3 C F 3 ) 3 and .460 g. (1.80 mmol.) of l£> both f i n e l y ground, were combined in a th ick walled pyrex glass tube. A f te r flame seal ing the react ion the tube containing one atmosphere of dry nitrogen was completely immersed in an o i l bath at 135 PC. Both reactants melted to a viscous dark brown l i q u i d . No appreciable quant i t ies of vapour could be detected v i s u a l l y . The temperature of the o i l bath was raised to 145°C and the react ion l e f t i n i t for one hour. A f te r cool ing slowly the product s o l i d i f i e d 19. to a black brown cake. Attempts to perform the reaction at higher temperatures resulted in decomposition with the formation of ^ and a c l e a r colour less l i q u i d . The reactor was broken open in the dry box and the contents transfered to a two part reactor . To ensure complete reac t ion , the powder was melted at 130°-135°C and then allowed to anneal s lowly . A l l v o l a t i l e s were removed by vacuum d i s t i l l a t i o n and the product was stored in the dry box. b. A l k a l i metal t e t r a k i s tr i f luoromethanesulfonate iodate( I I I ) s a l t s , i ) K [ I ( S 0 3 C F 3 ) 4 ] ; KI (0.239 g.) in a two part reactor was dissolved in 19 g. of HS0 3CF 3 and oxidized by .607 g. of S^OgF :2. The mixture was treated in the same way as described fo r I ( S 0 3 C F 3 ) 3 i n sect ion ( I IA2ai ) . White to s l i g h t l y ye l lowish c r ys ta l s began to form only a f t e r the volume of the l i q u i d had been considerably de-creased. A s o l i d (1.170 g.) i d e n t i f i e d as K [ I (S0 3 CF 3 ) 4 ] was obtained. i i ) R b [ I ( S 0 3 C F 3 ) 4 ] ; Rb[ I (S0 3 F) 4 ] (0.892 g.) was dissolved in 10 g. of HS0 3 CF 3 . A f te r removal of a l l the v o l a t i l e s 1.071 g . of Rb[ I (S0 3 CF 3 ) 4 ] was obtained as a white s o l i d . i i i ) C s [ I ( S 0 3 C F 2 ) 4 ] ; CsS0 3CF 3 (0.245 g.) was dissolved in 10.7 g . of HS0 3CF 3 and 0.472 g. of I ( S 0 3 C F 3 ) 3 was added. A c lear yel low s o l u -t ion formed from which Cs [ I (S0 3 CF 3 ) 4 ] c r y s t a l l i z e d out as a white s o l i d . c. Iodyl and Iodosyl tr i f luoromethanesulfonate I0 2 S0 3 CF 3 and I0S0 3CF 3 i ) Iodyl t r i f luoromethanesulfonate, I 0 2 S 0 3 C F 3 ; HI 30g (1.2211 g.) and 20 g . of HS0 3CF 3 were s t i r r e d together in a two part pyrex reactor with a magnetic s t i r r e r fo r two and a ha l f days. The s o l i d appeared to be cTiffetee&t but at no time was a l l s o l i d d i sso l ved . Upon removal 20. of a l l l i q u i d by f i l t r a t i o n the white s o l i d product was dr ied under vacuum. i i ) Iodosyl t r i f luoromethanesulfonate, I0S0 3 CF 3 ; H I 3 0 8 (.6017 g.) and I 2 (.3050 g.) were combined with 20 g. of HS0 3CF 3 i n a two part reactor containing a magnetic s t i r r e r . The mixture was s t i r r e d for one week and the l i q u i d removed by f i l t r a t i o n . The s o l i d product, which was contaminated with small amounts of iodine was washed with HS0^CF3. The yel low s o l i d I0S0 3 CF 3 was further dr ied in vacuo r e -moving the f i n a l traces of l^. d. Dihalo iodine tr i f luoromethanesulfonate i ) IBr 2 S0 3 CF; IS0 3 CF 3 (1.2447 g.) was placed in an evacuated two part reactor connected with a glass T to a storage vessel of at room temperature. Bromine vapour was admitted to the evacuated 2 part reactor . A react ion between the B ^ and the IS0 3 CF 3 took place and was followed by weight. The f i n a l product IBr2S0 3 CF 3 (1.9305 g.) was c a r e f u l l y dr ied in vacuo to remove excess B r 2 . i i ) IC1 2 S0 3 CF 3 ; IS0 3 CF 3 (0.2897 g.) was placed in a one piece glass reactor and with the reactor at -196°C (cooled in l i q u i d n i t r o -gen) approximately 10 mis of chlor ine was added by vacuum t r a n s f e r . The react ion mixture was kept at -78°C in a dry ice t r ich loroethy lene s lush bath. P e r i o d i c a l l y the reactor was shaken to promote reac t ion . While the reactor was s t i l l at -78°C the excess ch lor ine was removed in vacuo. Upon warming to room temperature, the orange s o l i d obr tained l i q u i f i e d and turned yellow decomposing into ( I C 1 3 ) 2 . i i i ) I 3 S0 3 CF 3 ;at tempts to synthesize ^St^Cf^ were made in s t r i c t analogy to the successful synthesis of I 3 S O 3 F (34) and the 21. synthesis of ISO^CF^ described in th is study. Only incomplete uptake of I 2 could be accomplished at the high temperature M40°C needed to maintain the reactants in the molten s ta te . B. Apparatus 1. Vacuum Lines Standard high vacuum techniques were employed with a l l the com-pounds described because of the i r r e a c t i v i t y toward oxygen and water vapour. In order to achieve and maintain the vacuum necessary a Welch Duo-Seal pump Model 1400, was used, capable of maintaining a vacuum of .001 t o r r . The pump was connected to the l i n e through a l i q u i d nitrogen cold trap to prevent any v o l a t i l e mater ials from being drawn through the pump. a . Glass l i n e The main manifold of the glass l i n e was constructed of Pyrex tubing 600 mm. long and 20 mm. in diameter, sealed o f f at one end and connected to the cold trap and manometer by a Fischer and Porter 4 mm. glass and te f lon stopcock and a B19 ground glass cone and socket j o i n t . Four addit ional Fischer and Porter stopcocks served as i n l e t s to the manifold for attaching reactors and other apparatus v ia B10 ground glass cone and socket j o i n t s . Pressures in the manifold were measured with a mercury manometer which was attached to the main l i n e by a Kontes stopcock and a B10 cone and socket j o i n t . b. Monel Metal Line In the attempted preparation of Br (S0.XF~) - , where the reagent 22. BrF^ i s known to attack g l a s s , a monel metal l i n e was used. This l i n e i s a standard metal vacuum l i n e and has been previously described in the M.Sc. thesis of Larry Levchuck . . 2. Metal Fluorine Line For the preparation of $2®6^2 ^ w a s n e c e s s a r v to u s e a system su i tab le for flow react ions . The f l u o r i n e l i n e used consisted b a s i c a l l y of a skeleton of copper tubing and Whitey, Hoke, and Autoclave Engin-eering valves. The valves were supplied by Whitey Research Tool Co . , Oakland, C a l i f o r n i a ; Hoke I n c . , C r i s k i l l , New Jersey ; and Autoclave Engineering Inc . , E r i e , Pennsylvania respect i ve ly . F luor ine was i n -troduced through a NaF trap which could be regenerated by heating e l e c t r i c a l l y to remove any HF which became absorbed in i t . The f luo r ine could then be mixed with dry nitrogen or used undi luted and led d i r e c t l y into a c a t a l y t i c reactor furnace. Another i n l e t to the furnace permitted the addit ion of SO^ gas. This system i s shown schematical ly in f igure 2. 3 . Dry Atmosphere Box A l l manipulation of s o l i d a i r sens i t i ve mater ia ls and a l l addit ions of HSO-jCF^ were car r ied out in a Vacuum Atmosphere Cor-poration "Dri Lab" Model No. HE-43-2, f i l l e d with p u r i f i e d dry n i t r o -gen and equipped with "Dri Tra in" Model No. HE-93B. In order to make quant i tat ive addit ions in the dry box a Mett ler PI60 top loading balance was used. 4. Reactors a. Two Part Glass Reactor For the most part reactions were car r ied out in a two part To F lowmeter Copper Glass i i To F lowmeter ! 5 C O m l . Py rex F l a s k R e a c t o r (f) Whitey Va lve - 0 - Hoke 4 1 3 Va lve C r o s b y P r e s s u r e G u a g e Autoc lave Eng ineer ing Valves To F cylinder 2 Copper Glass r ^V7 B 3 4 B 3 4 B B 3 4 To S o d a - l ime Trap •Fluorolube Oil Tube C CO Fig. X Apparatus- for the Preparation of S 2 O s F2 24. pyrex glass reactor . The reaction f lask was a 50 ml . round bottom f lask with a B19 cone top. The reactor top consisted of a Teflon stem stopcock (Fischer and Por ter , or Kontes) j o in ing in l i n e a B19 socket, to be f i t t e d to the f l a s k , and a BIO cone, for attachment to the glass vacuum l i n e . b. One Part Glass Reactor. In the attempted synthesis of ICl^SO^CF^ a n c j - j n pur i f y ing / ISO^CFg a one part pyrex glass reactor was used. This consisted of a pyrex tube 20 mm diameter sealed at one end with a Teflon stop-cock at the other. In the attempt to prepare B r ( S 0 3 C F 3 ) 3 a s i m i l a r reactor u t i l i z i n g a quartz reactor and a graded quartz glass seal was used. c. Thick Walled Glass Tube Reactor In the preparation of IS0 3 CF 3 where I 2 and I ( S 0 3 C F 3 ) 3 are combined at 145°C high pressures were poss ib le . For t h i s react ion then a th ick -wa l led Pyrex tube of 20 mm outer diameter sealed at one end and with a cons t r i c t ion near the other end which had a B19 cone on i t was used. The two so l ids were introduced v ia glass funnels whose stems protruded beyond the c o n s t r i c t i o n . The reactor was f i t t e d v ia the B19 cone, with a P 2 0 5 drying tube to prevent the entrance of moisture when the tube was sealed with a flame in the a i r . d. Two part Monel reactor As mentioned above, when BrF 3 was used as a reagent glass apparatus had to be avoided. When large quant i t ies of BrF 3 were handled for long periods at elevated temperatures the quartz reactor described above was not su i tab le and a two part monel metal reactor was used. A su i table monel reactor consisted of a c y l i n d r i c a l metal pot of about 100 m. capacity which was connected with s i x bol ts to a l i d equipped with a Hoke valve (#431). A vacuum t i g h t seal was achieved with a te f lon r ing inserted into a groove between the pot and the l i d . This reactor could be attached d i r e c t l y to the metal l i n e using Swagelok connections. The two types of glass reactors described above are shown in f igure 3 and the metal reactor in f igure 4. 5 . Miscellaneous a. Vacuum F i l t r a t i o n Apparatus A pyrex dev ice , s i m i l a r to the one described by Shriver (35), designed to separate l i q u i d s from s o l i d s by f i l t r a t i o n under p a r t i a l vacuum was also used. The apparatus consisted of a 25 mm, outer diameter glass tube i n which a medium coarseness glass f r i t was set about one th i rd from the bottom. The top of the tube ended in a B19 socket for connecting a react ion f l a s k from a two part glass reactor and at the bottom was a B19 cone for attaching a 250 ml round bottom f lask with a B19 socket. Below the glass f r i t a side arm out le t connected to a 4mm bore greased stopcock and a BIO cone. . This allowed attachment to the glass vacuum manifold. The overa l l length of the apparatus without the f lasks i s 350 mm. b. Lubr icat ing grease A l l ground glass j o i n t s described in the preceding sections were lubr icated with a low v o l a t i l i t y grease designed to be iner t TEFLON STEM STOPlCCK B-IO G R O U N D GLASS CONE B-I9 GROUND GLASS . C O N N E C T I O N FIGURE 3 TWO-PART GLASS REACTOR TEFLON STEM STOPCOCK 8 - 1 0 GROUND GLASS CONE THIN or THICK WALL PYREX GLASS I ONE PIECE GLASS REACTOR CVJ 3 Hoke V a l v e ( N o 431) Monel Meta l Tube Lid a: n |i fl Eolts to Secure L i d to Bot tom Vessel | ^ . . Condenser Inlet B o t t o m Condenser Inlet Monel Metal React ion Vessel (150 ml ) F i g . 4\ Monel Metal 2 - P a r t Reaction Vesse l " ( Front V iew ) to f luoro acids and to maintain leakproof connections under vacuum. The grease was supplied by Hooker Chemical Company, Fai r lawn, New Jersey, as Fluorolube grease GR-90 d i s t r i b u t e d by Fisher S c i e n t i f i c Company, c . Analyses A l l elemental analyses were performed by A l f red Bernhardt Microanaly t ica l Laborator ies , Elbach, West Germany. C. Spectrophotometers 1. Infrared Spectrometer Infrared spectrographs were recorded using a Perkin Elmer Model 457 Grating Infrared Spectrophotometer in the range 4000-250 c m - 1 . Samples were genreal ly run neat between two s a l t windows. Due to the high r e a c t i v i t y of a l l samples there was no su i tab le mul l ing agent. Because of the high r e a c t i v i t y of the samples the windows were made from s i l v e r bromide, AgBr. Even these were sometimes attacked although only a f te r prolonged exposure. KP.S5 windows were severely attacked and both sodium chlor ide and s i l v e r chlor ide windows were of too l im i ted range t;o use. IB^SO^CF^ was unreactive towards Cesium iodide and these windows were used. A l l windows were supplied by Harshaw Chemicals. Gaseous samples were con tained in a monel c e l l f i t t e d with a Whitey IKS^ valve and AgCl windows. 2. Raman Spectrophotmeter The Raman spectra of the compounds were measured with a Cary 81 spectrophotometer using a Spectrophysics Model 125 He-Ne laser source with an exc i t ing l i n e at 6328 A. The pyrex sample tubes were f i l l e d in the drybox. The tubes were 5 mm outer diameter pyrex glass with an o p t i c a l l y f l a t end. The tube was about 120 mm long and a f te r f i l l i n g was sealed with a flame. 3. V i s i b l e and U l t r a v i o l e t Spectrophotometer U.V. v i s i b l e spectra were recorded on a Cary 14 spectrometer. The samples were contained in 1 mm path length quartz c e l l s f i t t e d with a i r t i g h t te f lon stoppers. The c e l l s were obtained from ISC Instruments L t d . A l l d i l u t i o n s and f i l l i n g of c e l l s were performed in the dry box. 30. Results and Discussion A. Introduction Compounds of p o s i t i v e l y polar ized halogens with strong oxyacids as pointed out in the introduct ion have been known for many years . The number of compounds obtainable from any one acid i s found to be pro-port ional to the strength of the a c i d . By f a r the largest number of compounds which have been synthesized are der ivat ives of f l u o r o s u l f u r i c ac id . There are three main reasons for th i s abundance: a . F luorosu l fu r i c i s one of the strongest oxyacids known. b. The peroxide of HSO^F, ^2^6^2' 1 S a s * r o n 9 ox id i z ing agent and very su i tab le as a synthet ic reagent. c. Halogen f luorosu l fa tes unl ike perchlorate are very thermally s t a b l e . A r e l a t i v e l y new a c i d , t r i f luoromethanesul fonic acid should be comparable in acid strength (or protonating a b i l i t y ) to HSO^F. There have been claims that i t i s the strongest ac id known. I t became i n t e r e s t i n g , therefore , to see what halogen t r i -f l uoromethanesulfonates might be synthesized. The most common type of ca t ion ic compound formed general ly by the largest number of oxy-acids are the i o d i n e l l l compounds. It seemed reasonable to attempt f i r s t the synthesis of iodine CUT) t r i s t r i fluoromethanesul fonate , I (S0 3 CF 3 )3 . B. Synthesis 1. Iodine(I I I ) t r i s t r i f luoromethanesu l fonate , I(SO^CF^)^. Iodine 33 t r i s f l u o r o s u l f a t e , the pattern compound for I(SO^CF^)^ was o r i g i n a l l y 31. prepared with the peroxide, S^OgF^, which can be regarded as a 37 pseudo halogen according to : I 2 + 3 (S0 3 F ) 2 — ^ 2 I ( S 0 3 F ) 3 (8) in a simple and straightforward way. The S 2 0gF 2 in the react ion above has been wr i t ten as (S0 3 F ) 2 to i l l u s t r a t e more c l e a r l y i t s pseudohalogen character . Unfortunately and somewhat s u r p r i s i n g l y , the analogous 25 peroxide S 2 0g(CF 3 ) 2 had been found previously to be thermally unstable . Th us the analogous route to I ( S 0 3 C F 3 ) 3 did not appear to be f e a s i b l e . The fac t that HS n 3 CF 3 i s known to l i b e r a t e HCl from metal 17 23 chlor ides such as NaCl , dimethyl t i n d i ch lo r ide and t i tanium 25 te t rach lor ide suggested that the replacement of ch lor ine in IC1 3 mi ght be f e a s i b l e . As excess of HS0 3CF 3 was added to f resh ly prepared IC1^ but when the excess acid was removed a f te r 72 hours the dark red product was i d e n t i f i e d by i t s Raman spectrum as IC1. It appears that IC1 3 undergoes decomposition which i s not unexpected fo r t h i s compound and the method was unsuccessful . A s i m i l a r attempt involved the replacement of f l u o r o s u l f a t e with tr i f luoromethanesulfonate in I ( S 0 3 F ) 3 . I n i t i a l l y the simple reaction of I(SO^F)^ with excess HS0 3CF 3 was attempted as: HS0,CF, I ( S 0 3 F ) 3 + 3HS0 3CF 3 ^ — ^ I ( 5 0 3 C F 3 ) 3 + 3HS0 3F (9) I ( S 0 3 F ) 3 i s soluhble in HS03F and i t was hoped that i t would a lso be so lu -b le HS0 3 CF 3 . When the reaction was attempted the fo l lowing observations were made. The I(SO^F)^» a c lear viscous supercooled 32. l i q u i d at room temperature, turned into a yellow s o l i d material upon contact with HSO3CF3. However, upon removal of the excess acid in vacuo the weight of the s o l i d indicated less than complete re -placement of SO3F by SO3CF3. The gummy s t i cky appearance of the s o l i d also suggested an incomplete react ion producing a mixture of I(S0 3 F ) 3 and I(S0 3 C F 3 ) 3 . Two useful conclusions may be drawn from t h i s experiment. F i r s t , S0 3 F groups may be replaced by $0 3 CF 3 groups in the iodine t H compound and second, the r e s u l t i n g products, in contrast to I(S0 3 F ) 3 , may be i n s o l u b l e in the parent a c i d . However, i t appears that the formation of the s o l i d upon contact with HS0 3CF 3 occluded some of the very viscous I(SO^F}^ preventing a complete replacement r e a c t i o n . In order to prevent t h i s occlusion the synthesis of I(S0 3 F ) 3 in HS0 3CF 3 by method 2a!l (see experimental) was considered. HSO.CF-h + 6 H S 0 3 C F 3 + 3 S 2 ° 6 F 2 L " 1 ^ 2 I ( S 0 3 F ) 3 ( s o l v ) + 6 H S 0 3 C F 3 HS0 3CF 3 (10) ^ 2 I ( S 0 3 C F 3 ) 3 ( s ) + 6HS03F Af ter about 20-30 minutes at room temperature the colour of the so lu t ion undergoes changes from dark murky brown to pale c lear ye l low. The changes noted are : dark brown to dark blue green to pale ye l low. Some slowly decreasing amounts of s o l i d iodine are present in both the dark brown and dark blue green phases. When the so lut ion turns yel low a l l iodine has been consumed. The yel low s o l i d product which is formed appears e i ther during the green phase or a f te r the so lut ion turns ye l low. When the s o l i d formation occurs in the c learye l low so lut ion small needle l ike c rys ta ls 33. may be observed forming. If i n s u f f i c i e n t peroxide is used the f i n a l s o l i d material i s tinged with blue green. Whether the s o l i d forms before or a f te r the yel low phase appears seems to depend on whether the reaction mixture i s warmed to room temperature qu ick ly or s lowly . The f i n a l stage indicated by the colour change from blue green to ye l low, appears to be exothermic. The colour changes observed deserve some comment. Molecular iodine is only s l i g h t l y so lutb le in HSO^CF^ g iv ing r i s e to f a i n t l y purple so lu t ions . The presence of an ox id i z ing agent w i l l , however, produce brown coloured solut ions i n i t i a l l y and large amounts of iodine w i l l go into s o l u t i o n . The colour i s due to polyiodine cations such + + 38 as 1^ and I^  which have been previously i d e n t i f i e d in other strong protonic acids such as HSO^F and f^SO^. Further oxidat ion should produce the blue I 2 + c a t i o n . The green colour observed in t h i s react ion may be due to mixtures of blue I 2 with e i ther brown I3 (or 1^ ) or the yel low 1(19) species . Note the increase in the formal ox idat ion state of iodine from 0 through +1/5 and +1/3 to +1/2. The I 2 + cat ion i s only ex istent in very strong acids i . e . HSO^F or H ^ O y or in some superacid media i . e . HSO^F/SbF^. The f i n a l yel low colour i s due to the complete oxidat ion of iodine(O) to iodine(JH) and t h i s i s sub-stant iated by the f a i n t yel low tinge of the s o l i d product. While previously none of these polyiodine cations have been found in HSO^CF^ the colours observed here may serve as a f i r s t ind ica t ion that they do e x i s t . Further evidence obtained by recording the e lec t ron ic spectra i s required and w i l l be presented in a l a t e r chapter. 34. As a precaution in the synthesis described above a large excess of $ £ ( ^ 2 should be avoided. A mixture of $2(^2 and HSO^CF^ showed complete m i s c i b i l i t y and no apparent sign of react ion . However, a f te r about 30 minutes exothermic evolut ion of a v o l a t i l e compound, 25 l a t e r i d e n t i f i e d by inf rared spectroscopy as CF^SO^F was noted. This indicates the attack of the S-C bond in HSO^CF^ by S g O ^ . The success of the synthesis of I ( S 0 3 C F 3 ) 3 v ia the above route may be due to the fac t that oxidat ion of iodine takes precedence over the attack of the S-C bond in the so lvent . Any addi t ional side react ions , perhaps with the excess of $20gF2 normally used would resu l t in such rather v o l a t i l e by products as HSO^F, CF^SO^F and S 0 3 -None of these should in te r fe re with the i s o l a t i o n of the product. Another method for synthesiz ing I ( S 0 3 C F 3 ) 3 was subsequently developed. The o r i g i n a l method even though very successful i s some-what wasteful of HS0 3CF 3 ($150 a l i t e r ) since a large (10-20 fo ld ) excess i s required and separation from the HSO^F formed during the react ion would be extremely, d i f f i c u l t considering the s i m i l a r physical propert ies of the ac ids . We\therefore added a s l i g h t excess of HS0 3CF 3 to a so lu t ion of I ( S 0 3 F ) 3 in HS0 3F. I ( S 0 3 C F 3 ) 3 was formed immediately and could be i so la ted as in the f i r s t method. Iodine t r i s t r i f luoromethanesu l fonate , I ( S 0 3 C F 3 ) 3 i s a pale yel low s o l i d melting at +117-120°C and decomposing at approximately 170°C. This i s a rather noticeable departure from other i od ine (HJ : ) compounds of strong oxyacids. Iodine t r i sperch lo ra te decomposes 39 when warmed from -45°C to room temperature and iodine t r i s f l u o r o -35. su l fa te melts at +33.7°C and i s often found as a supercooled l i q u i d at room temperature. A s i m i l a r melting point i s found for iodine t r i s t r i f l u o r o a c e t a t e . In p a r t i c u l a r the d i f ference between I ( S 0 3 F ) 3 and I ( S 0 3 C F 3 ) 3 i s i n t r i g u i n g . The s o l u b i l i t y of I ( S 0 3 C F 3 ) 3 in both HS03F and HS0 3CF 3 i s s l i g h t and th is also i s qui te d i f f e r e n t from I ( S 0 3 F ) 3 which i s very soluble in the parent a c i d . Where I ( S 0 3 F ) 3 i s said to disproport ionate upon heating according t o : I ( S 0 3 F ) 3 - I S 0 3 F + I F 3 ( S 0 3 F ) 2 + 3S0 3 (11) thermal decomposition of I (S0 3 CF 3 ) , occurs at 170°C in vacuo and accompanied by p a r t i a l subl imat ion. Decomposition produces S0 3 and CF 3 S0 3 CF 3 as v o l a t i l e s and a small amount of yel low residue containing iodine in the +3 oxidat ion state and s u l f a t e . The observed propert ies of a high melt ing po in t , high thermal s t a b i l i t y and i n s o l u b i l i t y in the parent acid ind icate that I(SO^CF^)^ may be a polymer as has 33 been suggested for I ( S 0 3 F ) 3 . A l l the di f ferences mentioned above, however, ind icate a basic s t ructura l d i f ference between I ( S 0 3 F ) 3 and I ( S 0 3 C F 3 ) 3 > Hopefully the v ib ra t iona l spectrum w i l l al low further c l a r i f i c a t i o n of these d i f fe rences . Elemental analys is of I ( S 0 3 C F 3 ) 3 i s found in table 4. Subsequent to th i s synthesis of I ( S 0 3 C F 3 ) 3 a report has appeared 41 of the synthesis by: 60° I (0C0CF 3 ) 3 + 3 H S 0 3 C F 3 — 7 2 - 1 = r I ( S 0 3 C F 3 ) 3 + 3H0C0CF3 (12) 36. TABLE 4 Elemental analys is and Melt ing (decomposition) Points Compound 1% S% F% M.P. Ca lc 'd Found Calc 'd Found Calc 'd Found I (S0 3 CF 3 )3 22.10 22.21 16.76 16.79 29.78 29.64 119°C RbI (S0 3 CF 3 ) 4 15.69 15.92 15.86 16.07 28.19 28.07 208-212°C d. K K S 0 3 C F 3 ) 4 210-215°C d. Cs K S 0 3 C F 3 ) 4 190-200°C d. I S0 3 CF 3 45.98 46.16 11.62 11.57) 20.65 20.45 122°C I B r 2 S0 3 CF 3 29.12 29.46 * 13.08 13.39 72-75°C d. I0 2 S0 3 CF 3 41.20 41.40 10.41 10.26 18.51 18.28 315-230°C d. I0S0 3CF 3 43.46 43.20 10.98 11.15 19.52 19.26 235-240°C d. *For IBr 2 S0 3 CF 3 Br% was ca lcu lated rather than S%.calc . 36.67 found 36. 18 37. Elemental analys is of C and I ind icate the formation of I ( S 0 3 C F 3 ) 3 but the reported decomposition point (190°-192°C) i s not in agreement with our f ind ings . As no further evidence was given i t i s not possible to draw a conclusion at th i s t ime. . I ( S 0 3 C F 3 ) 2 + cat ion Like many iod ine( I I I ) d e r i v a t i v e s , e . g . IC1 3 and I (S0 3 F ) 3 the new compound, I(SG" 3CF 3) 3 may act as an S0 3CF 3~ ion donor towards strong Lewis acids and as an S0 3 CF 3 ~ ion acceptor towards compounds containing the S0 3 CF 3 group. Whereas the l a t t e r group i s well repre-sented, with a l k a l i metal s a l t s the most obvious case, no well proven Lewis acid of the type E (S0 3 CF 3 ) n was ava i lab le to us. 42 Recently Yeats and Aubke had found that SbFg and AsF g may abstract the S03F~ ion from f luorosu l fa tes such as CIC^SC^F, It seemed reasonable to attempt the S0 3 CF 3 ~ abstract ion with SbFg. However, the addit ion of SbF 5 to I ( S 0 3 C F 3 ) 3 caused an immediate colour change from yel low to deep b lue , i n d i c a t i n g the formation of the ion^ &n ion which i s per fec t l y stable in SbFg. This observation i s best explained by assuming a d i s p r o p o r t i o n a t e of I ( S 0 3 C F 3 ) 3 . As a resu l t of th i s f a i l u r e fur ther studies in t h i s system were not undertaken. As in the f luo rosu l fa te system where Sn(S0 3 F) 4 proved 43 to be an S0 3F acceptor more success may be expected from Sn(S0" 3 CF 3 ) 4 , however, t h i s compound was synthesized only a f t e r th i s study had been completed. . A l k a l i metal t e t r a k i s (tr i f luoromethanesulfonato) iodate( I I I ) M[I (S0 3 CF 3 ) 4 ] The synthes is .o f several compounds containing the [ I (S0 3 CF 3 ) 4 ]~ 38. anion was successfu l . This species should be s t a b i l i z e d best by the heavier a l k a l i metal ca t ions ; K , Rb and Cs . Accordingly K[I(SO^CF^)^], Rb [ I (S0 3 CF 3 ) 4 ] , and Cs[I(SO^CF^)^] were prepared, each by a d i f f e r e n t synthet ic route. The synthesis of K [ I (S0 3 CF 3 ) 4 ] was car r ied out according to methodJtifoi: in the experimental sec t ion : HSO.CF-KI + 2 S 2 0 g F 2 + 4HS03CF3 J J » K[I ( S O g C F ^ ] + 4HS03F (13) in a manner s i m i l a r to the o r ig ina l synthesis of I ( S 0 3 C F 3 ) 3 equation 10. Not unexpectedly the s a l t K [ I (S0 3 CF 3 ) 4 ] was quite soluable in HS03CF3 and could only be i so la ted by removal of the so lvent . No mixed s a l t s were found as shown by the v ib ra t iona l spectra . Whether the resu l t ing product was a mixture of KS0 3CF 3 and I ( S 0 3 C F 3 ) 3 w i l l depend upon an analys is of the spectra . However, the high melting point 210-215°C may serve as a prel iminary ind ica t ion of the pur i ty of the compound. Rb[ I (S0 3 CF 3 ) 4 ] was synthesized by the method 'i given in the experimental sect ion as: HSO-CF, Rb[ I (S0 3 F) 4 ] + 4HS03CF3 J J > Rb[ I (S0 3 CF 3 ) 4 ] + 4HS03F (14) Again a complete conversion from the f luo rosu l fa te to the t r i f l u o r o -methanesulfonate was obtained. F i n a l l y , the synthesis of Cs [ I (S0 3 CF 3 ) 4 ] was car r ied out according to the method given in sectioni$|)$iof the Experimental: HSO CF CsS0 3CF 3 + I ( S 0 3 C F 3 ) 3 Cs [ I (S0 3 CF 3 ) 4 ] (15) 39. A l l these methods are very straightforward and y i e l d high melting (190-215°C) pale yel low hygroscopic s o l i d s . The composition of Rb[ I (S0 3 CF 3 ) 4 ] was confirmed by an elemental analys is (given in table 4) and the cesium and potassium s a l t s were checked by comparing t h e i r in f rared spectra with that of the rubidium s a l t . Melt ing points for a l l three compounds are l i s t e d in table 4. 4. Iodine monokistrif luoromethanesulfonate, IS0 3 CF 3 The only previously known iodine( I ) compounds of oxyacids are a poorly character ized yel low n i t r a t e ^ which i s r e p o r t e d t o be stable 45?*"^ only below room temperature, an iodine( I ) perchlorate 'was o r i g i n a l l y postulated as a react ion intermediate, but has never been iso lated in 39 *"1 34 substance, despite recent attempts and A Iodine(I ) f l uo rosu l fa te . The l a t t e r compound has been produced from the in te rac t ion of a s to ich iometr ic amount of and Sfl^^ and has been extensively in-? vest igated. The brown s o l i d product (m.p. 51.6°C) i s found to be extensively d issoc iated in strong protonic acids such as HS03F according t o : 5IS0 3F - 2 1 * + H S 0 3 F ) 3 + • 2S0 3 F" (16) 34 to give blue green solut ions . The observation of s i m i l a r colours in the formation of I ( S 0 3 C F 3 ) 3 by ox idat ion of I 2 in HS0 3CF 3 ind icate a s i m i l a r d i ssoc ia t ion in t h i s a c i d . The d i s s o c i a t i o n w i l l preclude the synthesis of IS0 3 CF 3 in HS0 3 CF 3 . In the i r study of the i o d i n e - f l u o r o s u l f a t e system, Chung and 40 Cady have produced the phase diagram for the iod ine -peroxyd isu l f -40. u r y l d i f l u o r i d e system (f igure 5 ) . I t was th is phase study which led to the choice of a synthet ic route to ISO^CF^. This phase diagram shows, f i r s t of a l l , that ISO^F i s a real compound. Secondly, no > \ £ o r species g iv ing r i s e to paramagnetism or the c h a r a c t e r i s t i c blue colour was found in the melt. Th i rd l y , the t rans i t i ons from I (S0 3 F ) 3 over ISO^F and ^SO^F to ^SO^F occur without a gap, which implies that any compound can be converted into any other by add i -t i on of I 2 or S£0gF2. Our method draws on the analogy to the f l u o r o -su l fate system. Although we do not have the corresponding peroxide, S20g(CF 3)2, as mentioned e a r l i e r , by combining and I^O^CF .^ in the correct mole r a t i o in the melt a l l the compounds r i che r in iodine than I ( S 0 3 C F 3 ) 3 such as IS0 3 CF 3 , I 3 S0 3 CF 3 and I 7 (S0 3 CF 3 ) should, i f they e x i s t , be formed. The synthesis of ISO^CF^ was'i successfu l l y car r ied out by the method given in the experimental sectionl'<$"according t o : 140°C h ( l ) + l{SW3(i) - 3 I S 0 3 C F 3 ( 1 7 ) The high reaction temperature was necessary to obtain both reactants in the molten s ta te . Higher temperatures (e .g . 170°C) resulted in thermal decomposition. I n i t i a l l y there was noticeable purple iodine vapour above the brown black melt. However, as the reaction proceeded t h i s vapour was consumed. Because the iodine and the iod ine( I I I ) tr i f luoromethanesulfonate were combined in s t o i c h i o -metric proportions elemental analys is i s not conclusive proof of a new compound. The analysis i s reported in table 4. The high 41. ' Figure 5 Melting point i°Cl o 42. melting point 122°C and more conclus ive ly the v ib ra t iona l spectrum do indicate that the compound i s IS0 3 CF 3 . Proof that the product i s indeed IS0 3 CF 3 rests on the analys is of the inf rared spectrum. IS0 3 CF 3 i s a dark brown hygroscopic s o l i d . I ts melting point i s 121-122°C and i t i s thermally stable to 170°C under atmospheric pressure. At i t s decomposition point the formation of I 2 > S 0 3 » and ( C F 3 ) 2 S 0 3 i s noted suggesting the decomposition reac t ion : . 2IS0 3 CF 3 - I 2 + S0 3 + ( C F 3 ) 2 S 0 3 (18) I t should be noted as evidence that ISO^CF^ i s a true compound and not a mixture, that no iodine vapour i s observed at the melt ing point or below, even under vacuum. The dark brown colour of ISO^CF^ i s in good agreement with the colour of IS0 3F and also IC1 and does not agree with the yel low colour found for iodine( I ) n i t r a t e . The melting point of IS0 3 CF 3 (+122°C) i s much higher than that of the f l u o r o s u l f a t e . This i s very s i m i l a r to the s i t u a t i o n for I(SO^CF^)^ a n c l I(SO^F)^• 5. Polyhalogen and Interhalogen t r i f luoromethanesulfonates IX 2 S0 3 CF 3 X=I,Br,Cl The phase diagram of the i o d i n e - p e r o x y d i s u l f u r y l d i f l u o r i d e system also indicates the existence of iodine r i ch f luorosu l fa tes of the composition ^SO^F and probably IySO-^F. Even though some decomposition 34 to I 2 and I S n 3 F seems to occur I^SO^F was i s o l a t e d and character ized but 1^SO^F which seemingly undergoes more extensive decomposition could not be i s o l a t e d . 43. In an attempt to extend the f luo rosu l fa te analogy to t r i -fluoromethanesulfonates attempts were made to synthesize I^SO^CF^ according t o : ~140°C l2U) + I S 0 3 C F 3 ( i ) ( 1 9 ) However, despite repeated attempts only incomplete uptake If of I^  from the gas phase occured. Unlike the s i m i l a r synthesis of ISOgCF^, the gas phase remained coloured during the reac t ion . A l l that was obtained upon removal of the v o l a t i l e s under vacuum was a b lack, tsnhomogeneous, t a r l i k e substance containing small amounts of c r y s t a l l i n e iod ine . The temperature needed for react ion necessitated by the high melting point of IS0 3 CF 3 i s probably higher than the decomposition temperature of the I 3 + group in a hypothetical I 3S0 3 C F 3 . One should keep in mind that the conversion of IS0 3 F (m.p. 50.2°C) to I3SO.JF may be performed at +65°C whereas in t h i s react ion the 140°C necessary i s already 70°C above the decomposition point of the I 3 + cat ion in I3SO.3F 3 4 . Two f l u o r o s u l f a t e s , s i m i l a r to I 3S0 3 F , that i s IBr 2S0 3 F and ICl^SO^jF ^ are both obtainable by s t ra igh t addit ion as: X 2 + IS0 3 F - I X 2 S 0 3 F where X = Cl or Br (20) An attempt was made to prepare the corresponding S0 3 CF 3 compounds by combining s o l i d IS0 3 CF 3 with the halogens at room temperature or s i i g h t l y below. 44. Chlorine gas was condensed onto ISO^CF^ at low temperatures, around 0°C, and was absorbed immediately. The resu l t ing orange sol id «"« warmed to room temperature where i t became l i q u i d and t h e ^ s o l i d i f i e d again to a yel low s o l i d . The Raman spectrum of the yel low s o l i d gave strong evidence for a mixture of ( I C 1 3 ) 2 ^ mixed with I ( S 0 3 C F 3 ) 3 , suggesting the fo l lowing rearrangement: 3IC1 2 S0 3 CF 3 - ( I C 1 3 ) 2 + I ( S 0 3 C F 3 ) 3 (21) A l l attempts to prevent th i s rearrangement and to i s o l a t e the o r i g i n a l orange compound at low temperatures were unsuccessful . Even in samples produced at low temperatures the Raman l ines due to ( IC1 3 ) 2 are found. Bromine vapour and IS0 3 CF 3 reacted to give a product which i s stable at room temperature. Bromine vapour was allowed to react with s o l i d IS0 3 CF 3 at 0°C. It would seem that the synthesis of IBr 2 S0 3 CF 3 i s possible because the react ion occurs at 0°C in the s o l i d s t a t e . A mel t , where rearrangements are achieved more teaalily i s never formed. In addit ion IBr 3 i s apparently nonexistent so that a mixture of IBr and B r 2 are the probable products of a rearrange-ment react ion . When l i q u i d bromine was allowed to react with s o l i d IS0 3 CF 3 at room temperature the product was a black s t i c k y s o l i d which was l i g h t e r than expected for I B r 2 S 0 3 C F 3 . The loss in weight could be due to loss of bromine in the rearrangement according t o : • 3IBr 2 S0 3 CF 3 *2IBr+2Br 2 + I ( S 0 3 C F 3 ) 3 (22) 45. IB^SO-jCF^ i s a dark red brown hygroscopic s o l i d which melts at 72-75°C with p a r t i a l decomposition. The s o l i d has a s l i g h t tendency to decompose and become " s t i c k y " i f i t i s not pure; i . e . i f formation of IBr^SO^CF^ is incomplete. The resu l ts of elemental analys is are shown in table 4 and the v ib ra t iona l spectra w i l l be discussed l a t e r . IBr^SO^CF^ i s one of a very l imi ted group of IBr 2 d e r i v a t i v e s . The only other examples known are IB^SC^F and I B ^ S b ^ i i IB^SO^F was synthesized in the manner mentioned above and IBr2Sb2F-|.| was obtained by react ing IB^SO^F with SbF^ according t o : IBr 2 S0 3 F + 3SbF5 • • I B ^ S b ^ + S b F ^ F (23) It appears that a dupl icat ion of the halogen-ISO^F addi t ion reactions i s successful only fo r IB^SO-jCF^. However, i t should be possible to form these compounds in s o l u t i o n , provided a su i tab le solvent can be found. HS0 3CF 3 was studied as a possible solvent and u l t r a v i o l e t and v i s i b l e spectra were taken on solut ions of halogen X 2 and ISO^CF^ and compared with spectra of the corresponding IX 2 S0 3 F compounds in HSO^F. ISO^CF^ alone in HSO^CF^ gave a spectrum a t t r ibu tab le to I 2 + . 48 The spectrum i s very s i m i l a r to that of IS0 3F in HS03F which has also been assigned to I 2 + and the posi t ions of the absorption maxima . . . 49 + are s i m i l a r to those found by Kemmit et a l . for solut ions of I 2 in SbFg. By comparing the ex t inc t ion c o e f f i c i e n t s in each of these 46. cases ,see table 5a, i t can be seen that although they vary considerably in magnitude, they are always in the same r e l a t i v e proport ions. The a b i l i t y of HS03CF3 to support I 2 + in so lu t ion i s thus demonstrated and the previous a t t r i b u t i o n of the blue-green colour formed during the synthesis of I ( S 0 3 C F 3 ) 3 as being due to I 2 + i s fur ther substant iated. The existence of I X 2 + (X = I, Br , or Cl ) in HS0 3CF 3 was pos-50 t u l a t e d , based on a study by Senior and Grover demonstrating the existence of these species in 100% s u l f u r i c ac id and t h e i r existence 39 in H S O ^ J F , Solutions of I 2 and ISO - jCF^; C l 2 and IS0 3 CF 3 ; as well as I B r 2 S 0 3 C f 3 were invest igated . The e lec t ron ic spectra of these s o l u -t ions are i d e n t i c a l to spectra of so lut ions of IX 2 S0 3 F + fi in HS03F which have been shown to have been due to the species IX 2 Having obtained the solvated cations as desired in so lu t ion the i s o l a t i o n of the compounds was attempted. The formation of I 3 S0 3 CF 3 was p a r t i c u l a r l y hopeful . However, no stable compound was i s o l a t e d . Upon removal of HS0 3CF 3 under vacuum a l l that remained were inhomogeneous tar l i k e mater ials while the v o l a t i l e products contained some molecular iod ine . 6. Iodine-Oxygen Trif luoromethanesulfonates Some of the e a r l i e s t known compounds of p o s i t i v e l y po lar ized 13 iodine are the iodine oxygen der ivat ives of oxyacids . Two types of compound are encountered, the 10 -der i va t i ves , named in analogy to NO compounds, iodosyl compounds and the I 0 2 der ivat ives labe l led iodyl compounds. The former ones were also regarded as "bas ic" s a l t s of t r i v a l e n t oxyacid der ivat ives suggesting, at l eas t fo rmal l y , the 46a. Ext inct ion ylunax. (my) for I S n 3 C F 3 sample IS0 3 CF 3 in HS0 3CF 3 IS0 3F in HS03F I 2 in oleum I 2 in IF 5 I 0 in SbF c Table 5a Coef f i c ien ts for it, 638 465 400 Einax. (per 1^) 2368 836 815 2186 580 630 1850 460 490 884 326 301 1410 462 504 47.. existence of a base I (0H) 3 , incomplete s a l t formation, and dehydration: I (0H) 3 + HY -IOY + 2H20 (24) It became in te res t ing to extend t h i s study to SO^CF^ der ivat ives of these two types. Iodyl tr i f luoromethanesulfaonate I0 2 S0 3 CF 3 51 Iodyl s a l t s are known for some oxyacids inc luding HSO^F Again where the S0 3F compound had been obtained v i a : I 2 0 5 + S 2 0 6 F 2 *• 2I0 2 S0 3 F (25) Because of the u n a v a i l a b i l i t y of the peroxide an a l ternate route had to be devised. The synthesis of I0 2 S0 3 CF 3 was car r ied out as described in s e c t i o n - ^ ' : of the experimental as : H I 3 0 g + 3HS03CF3 - 3 I 0 2 S 0 3 C F 3 + 2H20 (26) The s t a r t i n g m a t e r i a l , HI 3 0g, was at f i r s t thought to be iodine pentoxide, I 2 ^5 ' a n c * i n ^ a c t 1 S s o ^ a s s u c n - However, when the pur i ty was checked by in f rared spectroscopy i t was found to be almost e n t i r e l y HI 3 0g. This fac t i s extensively discussed by Selte 29 and Kjekshus who found most commercial samples of l 2 0 g and HI0 3 were contaminated with HI 3 0g, or in the case of even with HIO^. Because both the s t a r t i n g material and the product are white so l ids i t was d i f f i c u l t to judge whether a react ion was complete or not. Therefore, s t i r r i n g for more than 72 hours was found necessary to en-sure complete react ion . 48. IC^SO-JCF-J i s a white hygroscopic sol id which decomposes between 310-320°C with purple iodine vapour re leased. The high melting point i s not unexpected for an iodyl compound. Elemental analys is given in table 4 indicates that the compound is indeed IO^SO^CF^. The i n f r a r e d , and more conc lus ive ly , the Raman spectrum confirms th is and w i l l be discussed l a t e r . The p r i n c i p l e reason why conversion i s so read i l y accomplished can be seen in the fac t that HSO^CF may act as a dehydrating agent. The water which i s formed during the synthesis immediately reacts with the HSOgCF-j, present in a large excess, to form the stable mono-27 hydrate . In a d d i t i o n , un l ike the S-F bond in most f luorosu l fa tes the S-C bond in Su^CF-j compound appears to be res i s tan t to hydro ly t ic at tack. b. Iodosyl t r i f luoromethanesulfonate, I0S0 3 CF 3 A modif icat ion of the synthesis of iodyl compounds suggested 52 by Masson and Argument afforded a route to the iodosyl t r i f l u o r o -methanesulfonate. The synthesis of I0S0 3 CF 3 was car r ied out using HI 30g and I 2 in HS0 3CF 3 according to the method described in sect ion ~ZCf' of the experimental v i a : HSCLCF. HIgOg + I 2 + 5HS03CF3 ^ - ^ 5 I 0 S 0 3 C F 3 + 3H20 (27) I0S0 3CF 3 i s a yel low hygroscopic s o l i d which decomposes between 235 and 240°C. The product was i d e n t i f i e d by elemental analys is ( table 4) as I0S0 3 CF 3 . V ibrat ional analys is discussed l a t e r confirmed t h i s . 49. An unsuccessful attempt was made to synthesize IOSO^CF^ by contro l led hydrolysis of I ( S 0 3 C F 3 ) 3 in suspension in HSO^CF^ according t o : HSCLCF. I ( S 0 3 C F 3 ) 3 + H 20 — i * . I0S0 3CF 3 + 2HS0 3CF 3 (28) However, the addit ion of t race amounts of water to I ( S 0 3 C F 3 ) 3 r esu l t s r instantaneously in the occurence of the f a m i l i a r blue-green colour of I 2 + . This indicates a d i s p r o p o r t i o n a t e or redox react ion rather than a straightforward s o l v o l y s i s . For any previously synthesized iodine tr i f luoromethane-sulfonate a f luo rosu l fa te analogue was known. However, in the case of I0S0 3 CF 3 , no such analogue had been prepared. The formation of 34 I0S0 3F had been mentioned only b r i e f l y in the l i t e r a t u r e as a pro-duct of the hydrolys is of I ( S 0 3 F ) 3 according t o : I ( S 0 3 F ) 3 + H20 - I 0 S 0 3 F + 2HS03F (29) The react ion i s accompanied by a blue colour ( I 2 + ) suggesting a d i s p r o p o r t i o n a t e reac t ion . The s o l i d product, however, was found to contain substant ia l amounts of pentavalent iod ine , suggesting the claim of I0S0 3F may be erroneous. I t i s d i f f i c u l t to assess the c la im as no analys is i s reported. 53 Subsequent to th is work I0S0 3F was prepared by a method analogous to that used for I0S0 3 CF 3 . Attempts "to form I0S0 3 CH 3 , I0C0 2CF 3 and ( I 0 ) 2 P 0 2 F 2 f a i l e d . During the synthesis of I0S0 3 CF 3 the f a m i l i a r colour change sequence from brown to blue green to 50. yel low was observed. A s i m i l a r change was observed for the formation of the f l u o r o s u l f a t e . In the three unsuccessful cases the solut ions were at a l l times f a i n t l y tinged with red , ind ica t ing iodine i n the 0 oxidat ion s t a t e . This would, seem to suggest that a possible pre-requ is i te for the formation of iodosyl compounds by th is method is the c a p a b i l i t y of the acid to s t a b i l i z e I 3 + (or I^+) and as i n t e r -mediates in the oxidat ion of 1(0) to I ( I I I ) . The acids HP0 2 F 2 , HSOgCHg and HC0 2CF 3 are weaker protonic acids than e i ther h^SO^, h^SeO^, HSOgCFg and HSOgF, incapable of s t a b i l i z i n g even the leas t e l e c t r o p h i l i c of the poly iodine cations I 3 + . This point could be confirmed by experiment. Addit ion of I3SO3F to e i ther HP0 2 F 2 or 55 HC02CFg resulted in the instantaneous formation of molecular iodine . 7. Bromine t r is t r i f luoromethanesul fonate A f te r the f i e l d of iodine tr i f luoromethanesulfonates had been extensively invest igated attempts were made to form other halogen tr i f luoromethanesulfonates. Observing table 3 in the introduct ion i t can be seen that for the f luo rosu l fa te group the fo l lowing com-pounds e x i s t . BrtSOgFjg, BrSOgF and BrSOgF^" .We therefore attempted the synthesis of Br(S0gCF,j)g as an entry into th i s area. Complexation hopeful ly would lead to B r(S0 3 C F 3 ) 4 ~ and reduction to BrSO^CF^. The f i r s t attempt to form the B r(S0 3 C F 3 ) 3 was to fo l low the synthesis of I(S0 3 C F 3 ) 3 using B r 2 in place of L,. Unfortunately the resu l ts were inconclusive and alarming. Upon warming, the mixture of S 20gF 2, B r 2 , and HS0 3CF 3 detonated shatter ing the react ion vessel 51. and thus deterr ing any fur ther attempts v ia th i s route. The addit ion of HS0 3CF 3 to B r ( S 0 3 F ) 3 gave a red-brown so lu t ion which at f i r s t looked promising. However removal of the solvent did not y i e l d the expected product. A brown v o l a t i l e m a t e r i a l , comparable in v o l a t i l i t y to HS0 3CF 3 was obtained and i t was impossible to e f fec t a complete separation of the two. An al ternate route was sought by the react ion of BrF 3 and HS0 3CF 3 as fo l lows : BrF 3 + 3HS0 3CF 3 *- Br(SG" 3CF 3) 3 + 3HF (30) The reaction was car r ied out on a monel metal vacuum l i n e in a quartz reactor . Upon warming the c lear l i q u i d formed detonated with no v i s i b l e sign of decomposition. At th i s point the invest igat ion was abandoned. Attempts to solvolyse BrF 3 in HS0 3CF 3 in a monel reactor again only y ie lded v o l a t i l e mater ia ls and no separation was attempted. Cat ionic bromine oxygen compounds are also more unstable than the corresponding iodine compounds. Naumann et a l . have prepared the compound KI0 2 (0C0CF 3 ) 2 by react ing KI0 3 with (CF 3C0) 20 but attempts to prepare th i s bromine analogue resul ted only in an m explos ion. H.A. Car ter 's attempts to prepare Bromine-oxygen compounds of f l u o r o s u l f u r i c acid also met with f a i l u r e . There s t i l l may be a p o s s i b i l i t y of forming some bromine t r i f luoromethanesulfonates^ however, the f i e l d should not prove to be as extensive as that of iodine tr i f luoromethanesulfonates. C. V ibrat ional Spectroscopy 1. General Introduction The main in te res t in the v ib ra t iona l spectra of iodine t r i -fluoromethanesulfonates is centered on the SO^CF^ group, and even more narrowly on the S-0 v ib ra t iona l modes, because bonding of the SO^CF^ group to iodine or any other central atom w i l l most l i k e l y occur through the oxygen of the SO3 group. In a general way the SO^CF^ group can be considered as SO^X with X = CF^. An SO^X group can be e i ther i o n i c , i . e . i n compounds of the type M^SO^X where = K or N0+ or covalent ly bonded. In a l l of the c a t i o n i c halogen com-pounds, the SO-jX w i l l probably be covalent due to the r e l a t i v e l y large e lec t ronegat i v i t y of iod ine . The highest symmetry for the SOgX" ion i s Cy. I f the ion i s bonded covalent ly through one oxygen, monodentate.or two oxygen, *\ bidentate^then the symmetry w i l l be reduced to C . What t h i s w i l l mean in terms of the v ib ra t iona l freauencies i s summarized in the cor re la t ion diagram o f SO^X in f igure 6. When the SO^X group has C^v symmetry there are 6 normal v i -brat ional modes. These are three A-j modes, one symmetric SO^ s t r e t c h , one SX st retch and one SO^ bend, and three degenerate E modes, one asymmetric SO^ s t r e t c h , one asymmetric SO^ bend and one rocking mode. I f the SO^X group acts as a monodentate or bidentate l igand then the reduction of symmetry to C resu l ts in the s p l i t t i n g s of the degenerate E modes and a l l 9 fundamental v ibrat ions are observed. FiyreL Correlation Diagram for the S 0 3 X group-symmetry: 1 type a) : vibration'-for K S Q F a ) s o 3 * ~ •' tonic C in cm 3 V A , <( l . R ) ( 7 8 6 ) type b) and c) - oso x 2 b ) covalen\-monodentate C s c) *soX T-bidentate ' v i V 3 v5 ' " E A, . . E ' t A, E S r o c k v S O s :.» v S O , a 3 * s s o » s s o , a 3 ( J . R ) ' ( 4 0 9 . ) ( I. R ) ( I . R ) ( l . R ) ( l . R ) ,(1082) ( I287) i. ( 5 6 6 ) .. ( 5 9 2 ) ( l . R ) ( l . R ) T r ^ 2 A* A' A" .A" • H j ? • ^ 6 ^ 9 A' A u A' A' A" Cl .R) ( l . R ) Cl.R.) Cl.R) ( l . R ) A = . n o n d e g e n e r a t e :1 = , i n f r a r e d a c t i v e a = a n t i s y m m e t r i c E = d o u b l y d e g e n e r a t e .R = , R a m a n ' a c t i v e s = s y m m e t r i c us 54. In the SO^ st retching region there i s a change from two st retch ing modes to three. The E mode i s s p l i t into an A' and A" mode. In the bending region a s i m i l a r s p l i t t i n g i s observed. The rocking mode i s also s p l i t in the same manner. To complete the c i r c l e , i f the SOgX group i s t r i d e n t a t e , i . e . each oxygen i s bonded^then the symmetry i s once more C^v. This i s the general case for SO^X. The p a r t i c u l a r case of SO^CF-j i s somewhat more complicated. Assuming the CF 3 group, which i $ t h e anion maintains the C^v symmetry, can be considered to have l o c a l i z e d C^ v symmetry in the covalent s i t u a t i o n where the SO^ symmetry i s reduced^then there are another 5 fundamentals to be expected. And, i f the symmetry of the CF^ group i s reduced there woul be another three bands in a d d i t i o n . This i s shown in the co r re la t ion diagram fo r S0 3 CF 3 shown in f igure 7>. As has been mentioned e a r l i e r , v ib ra t iona l studies of the SO^CF anion, inc luding normal coordinate analyses and valence force f i e l d 20 21 ca lcu la t ions have been reported by two groups ' . These two studies do not agree on the assignment of the spectra . The major d i f f i c u l t y in assigning the bands i s that the S0 3 and CF 3 s t retching v ibrat ions are of ident i ca l symmetries fo r the ion (E and A-|) and unfortunately occur in the same region of the spectrum. Considerable mixing of the frequencies occurs resu l t ing in a very complex spectrum. For the 21 purpose of t h i s d iscussion the assignment of Burger et a l . i s used. The reason for th i s i s that the S0 3 and CF 3 bands are assigned by comparing the bands observed with bands assigned previously for other FIGURE 7 Normal Vibrat ions of SO^CF^ groups with C^ v Symmetry Descript ion A 2 v CF 3 v, v ? & C F 2 . 8 6 FCS v CS v * v 2 3 9 v S0 3 v 4 10 6 S0 2 11 6 C-S-0 5 12 * tors ion C-S vc This band i s inact ive in both in f rared and Raman. 56. compounds containing only S0 3 and CF 3 groups. A l s o , the assignments 54 are in accord with trends observed in other sulfonates . The assignment of spectra fo r covalent , e i ther mono, b i , or t r identate groups should not be quite as d i f f i c u l t as the ion ic case, because the loca l symmetry for the S n 3 part of the molecule i s reduced, e l iminat ing extensive mixing. Complications may a r i se when there i s more than one type of SO^CF^ group present. This resu l ts in more bands, which often co inc ide . This leads to rather unresolved broad band contours. When attempting an assignment of the compounds syn-thesized in th i s thesis considerable help can be derived from the fac t that examples of each coordination type fo r the SO^CF^ group may be found in the l i t e r a t u r e . Monodentate SO^CF^ groups are found in ( C F ^ S O g whose in f rared spectrum has been reported by Noft le and Cady 3 in FXeS0 3CF 3 3 0 and in (CH 3) 3GeS0 3CF 3 . Bidentate br idging CA S0 3 CF 3 i s found for organotin(IV) der ivat ives (CH 3 ) 3 SnS0 3 CF 3 and (CH 3 ) 2 Sn(S0 3 CF 3 ) 2 ^ where s t ructura l proposals are based on ^ S n Mossbauer spectra and the X-ray d i f f r a c t i o n study of the analogous t i n compound (CH 3 ) 2 Sn(S0 3 F) 2 5 7 . A t r identate group has been pro-2? posed for the compound.TiCI 3S0 3CF 3 . I t may a lso be noted that the spectrum of any of these S0 3 CF 3 compounds i s quite s i m i l a r to the spectra of the analogous S0 3F compound. The S0 3 frequencies for the S0 3 CF 3 compounds are s l i g h t l y lower than for the corresponding f l u o r o s u l f a t e s . This is in accord with the e lec t ronegat i v i t y arguments and also the underlying bonding concept, that of d^-pir in te ract ion based on the model discussed by 57. Cruickshank . This trend is i l l u s t r a t e d in table 5 where a comparison of (C 2 H 5 ) 2 Sn(S0 3 F ) 2 and (C 2 H 5 ) 2 Sn(S0 3 CF 3 ) 2 i s made. As may be seen from the examples quoted above a d i f f e r e n t i a t i o n between monodentate and bidentate br idging S03X groups i s possible even through the symmetry of both i s C_. In the SO- s t retch ing region s J 0 0 there i s a d e f i n i t e d i f fe rence . In the monodentate case, i . e . S * X 0 where 0 i s the bonding oxygen, there are three s t retch ing modes. S02- as (A") S0 2sym(A') and S0*(A') . The pos i t ion of the l a s t mentioned band i s dependent on the nature of the group "E" to which O 0 - E the 0* i s bonded. On the other hand in the bidentate case, S * X * 0 - E where again 0 indicates the bonding oxygens there are 3 d i f f e r e n t S-0 s t retching bands. These are v S 0 ( A ' ) , VSO* as (A") and ^S0*sym (A 1) Here the pos i t ion of VSO i s independent of the moiety to which the S03X i s bonded and the pos i t ion of the other two modes i s dependent on the nature of E. By comparing spect ra , the shif fc l of one SO st retching mode on ly , indicates a monodentate S03X group while the s h i f t i n g of two modes i s a good ind ica t ion of a bidentate S03X group. The p a r t i c u l a r case of the S0 3 CF 3 group w i l l be considered l a t e r in the assignment of CF 3 S0 3 CF 3 > In summary, these are the ways in which the v ib ra t iona l spectra of S0 3 CF 3 - I compounds w i l l be studied. Assignments of the spectra w i l l be made with reference to the study of the anion by 21 Burger et a l . and the published spectra of covalent S0 3 CF 3 groups. The decis ion of whether or not the compound contains i o n i c S0 3 CF 3 groups w i l l be made on the basis of the number of SO., modes present. 58. TABLE 5 A comparison of SO^X inf rared v ib ra t iona l frequencies in ( C 2 H 5 ) 2 Sn(S0 3 F) 2 and CC 2 H 5 ) 2 Sn(S0 3 CF 3 ) 2 2 3 (C 2H 5) Sn(S0 3F) (C 2 H 5 ) 2 Sn (S0 3 CF 3 ) 2 Assignment -1 cm * i n tens i t y - 1 cm i n t e n s i t y 1360 vs , b 1340 vs , b S0 3 s t retch (A") 1170 vs , b 1138 s , b S0 3 s t retch (A 1 ) 1070 s 1036 vs S0 3 s t retch (A') 612 m, sh 632 s S0 3 bend (A") 585 s , sh 581 m S0 3 bend (A 1 ) 575 s 512 s S03X; bend (A 1) 416 ms 356 m S03X rock 355 m 320 ms S0 3S tors ion Term meanings: vs - very strong s - strong m • - medium w - weak vw - very weak b - broad sh - shoulder 59. Whether a compound contains monodentate, b identate, or both mono-and bidentate SO^CF^ groups w i l l be decided by comparing the spectra with spectra of compounds known to contain mono- or bidentate SO^CF^ groups. These and other features of the spectra w i l l be discussed in conjunction with the analogous f luo rosu l fa te compounds. F i n a l l y , because of the complex symmetry of the SO^CF^ group i t should be noted, from a purely p rac t i ca l point of view that a l l v ib ra t iona l modes should be both Raman and Infrared a c t i v e . 2 M[ I (S0 3 CF 3 ) 4 ] The v ib ra t iona l frequencies observed for Rb[I(SG*3CF3)4] are l i s t e d , along with estimated i n t e n s i t i e s i n table 6 as wel l as 56 the S0 3 CF 3 v ibrat ions found fo r (CH 3 ) 3 GeS0 3 CF 3 . It i s in te res t ing that because of the unreactiveness of the S0 3 CF 3 compound the in f rared spectrum was obtained below the s i l v e r hal ide region in contrast to the s i t u a t i o n fo r I-SO^F compounds. The assignment of the spectra 21 i s based mainly on the assignment by Burger et a l . . The small s p l i t t i n g of the absorption bands fo r the [ I (S0 3 CF 3 ) 4 ]~ ion which are p a r t i c u l a r l y obvious in the Raman spectrum in the S-0 and C-F s t retch ing range ^ { i r a t t r ibuted to s o l i d state s p l i t t i n g caused probably by weak coupling of the ind iv idual S0 3 CF 3 groups. Precedent f o r such s p l i t t i n g s are found in a number of f l u o r o s u l f a t e - 59 anions, i . e . [I(SO^F)^] . Many features observed in the spectrum of Rb [ I (S0 3 CF 3 ) 4 ] , such as the very broad in f rared absorption bands and the discrepancies in pos i t ion between the in f rared and Raman Table 6 GO. Vibrational Frequencies for Rb [KOSC^CF.^] and (CH 3) 3 Ge OS0 2CF 3 Rb[I(OS0 2CF 3) 4' (CH 3) 3GeOS0 2CF 3 Raman fern "^1 Infrared \cm ^ ] Infrared [cm Approximate description 1376 mw 1368 w 1365 vs,b 1365 s v S0 o as 2 1251 m 1234 mw 1242 s sh 1241 v CF_ as 3 1214 w 1210 vs.b 1205 vb v S0„ sym 2 1170 ms 1150 s,b 1164 s v CF. as 3 1074 vw ~1080 vwjsh impurity of I(0S0 2CF 3> 974 vw 854 865 s.sh 830 vs, b 984 vs,b vS-OX 777 vs 770 s 768 m vCS 652 ms 642 w 632 s,b 634 s 6S02 620 ms 615 m,sh 620 m,sh S0 2 rocking 598 vs 590 m 590 s 6 CF„ sym 3 576 578 w 572 ms 6S02X 6 CF. * as 3 536 s 528 s 515 515 sh 510 435 ms v 10 as 408 w 394 s vIO sym in phase 383 ms vIO sym out of phase 346 ras 352 vs pso 2 322 s 315 ms | 6CS 264 ms 253 w PCF 3 61. bands are a lso present for FXeSO^CF^, ind icat ing a strong s t ructura l s i m i l a r i t y . There are , nevertheless, some differences in the proposed assignments. The three sulfur-oxygen v ibrat ions expected fo r a monodentate SO^CFg group are found at 1365, 1210 and 850 cnf^. This i s in r e l a t i v e l y good agreement with corresponding bands fo r (CH^GeSOgCFg except for the 850 cnf^ band which i s assigned to S-OX and i s d e f i n i t e l y affected by the e lec t ronegat i v i t y of the group X. The comparable bands fo r FXeS0 3CF 3 are at 1390, 1200, and 840 cm - 1 55 respect ive ly . The C-F s t retch ing modes are found at 1251, 1234, and 1 1 7 0 . c m - 1 , a region s i m i l a r to that for the SO^CF^ i o n . This indicates that the CFg group is l i t t l e affected by the bonding through oxygen. The loca l symmetry fo r the CF 3 moiety remains C 3 v and i s not reduced. The number and pos i t ion of the st retching modes i s i n every way con-s i s t e n t with a monodentate SO^CF^ group. In the region of the bending modes good agreement between the f indings for Rb[ I (S0 3 CF 3 ) 4 ] and both (CH 3 ) 3 GeS0 3 CF 3 and FXeS0 3CF 3 i s found. The in f rared and Raman spectra are well resolved and consistent _ i i n th i s region. The only exception occurs around 400 cm . Bands of f a i r l y high in tens i t y which occur at 394 and 383 cm"^ in the Raman spectrum are absent in the in f rared spectrum while a band at 435 cm"^ only appears in the in f rared spectrum. The two Raman bands are assigned as the symmetric in phase and out of phase 1-0 s t retch ing modes. The 435 cnf^ band i s assigned as the asymmetric 1-0 s t retch ing 62. mode. This mutual exclusion i s what i s expected for a square planar 60 conf igurat ion around iod ine . Several precedents have been reported where the asymmetric s t retch ing band occurs at a higher wave number than the two symmetric bands. However, t h i s i s not found for ICl^ The posi t ions observed for the [ I (S0 3 CF 3 ) 4 ]~ ion are s l i g h t l y lower than those observed for the [ I (S0 3 F ) 4 ] " ion . The extremely low 1-0 - 39 st retching modes found for [ I (C10 4 ) 4 ] are unusual but may perhaps be due to a very weak 1-0 bond. This i s indicated by the low thermal 39 s t a b i l i t y (up to room temperature) of Cs [ I (C10 4 ) 4 ] compared with the thermal s t a b i l i t y of the [ I ( S 0 3 F ) 4 ] " and [ I (S0 3 CF 3 ) 4 ]~ ions which 39 can be as high as 200°C. This trend i s also found for I (C10 4 ) 3 , s table up to -45°C and I ( S 0 3 C F 3 ) 3 which begins to decompose only above 170°C. The iodine oxygen deformation modes which should occur below 200 cm"1 were not observed. The spectra of K[I (S0 3 CF^) 4 ] and Cs [ I (S0 3 CF 3 ) 4 ] presented an almost i d e n t i c a l p i c t u r e . Only very minor discrepancies were observed. 3. I ( S 0 3 C F 3 ) 3 The assignment of the spectrum of I ( S 0 3 C F 3 ) 3 presents a more complex problem than was encountered for I(SO^CF^)^ -. This i s seen by the increased number of bands observed in the S-0 and C-F s t r e t c h -ing region from 1450-700 c m - 1 . There are ten bands assignable as fundamentals in the spectrum of I (S0 3 CF 3 ) 4 ~ while there are 14 bands for I ( S 0 3 C F 3 ) 3 . The d i f f i c u l t y in assigning these bands i s increased by the fac t that many of them are extremely broad in the inf rared spectrum. In a d d i t i o n , accidental coincidence of bands, sensitivity 1 x 5 0 0 64. p a r t i c u l a r l y in the 1280-1150 cm - 1 region may present addit ional complications. Because of th i s complexity only approximate ass ign -ments of the S-0 and C-F s t retching modes dinz possible and some ambiguity i s unavoidable. The complexit ies observed are most l i k e l y due to SO^CFg groups of d i f f e r e n t f u n c t i o n a l i t y . The in f rared and Raman spectra are l i s t e d in table 7. Bands occuring at 1420, 1210 and 830 cm are assigned as S-0 s t retch ing modes for a monodentate SO^CF^ group. This ass ign -ment i s based mainly on the s i m i l a r i t y of these bands to the cor res -ponding bands for USO^CF^)^ . The s h i f t to s l i g h t l y higher wave-numbers for vS0 2 i s a lso observed i n the corresponding f l u o r o s u l f a t e compounds and may r e f l e c t the e lec t ron ic d i f fe rences between a neutral species and an anion. The bands at -1320, 1120, and 980 cm"1 on the other hand are remarkably s i m i l a r to sulfur-oxygen s t retch ing bands fo r a bidentate br idging SO^CF^ group as found in both (CH 3 ) 3 Sn S0 3 CF 3 5 4 and (CH 3 ) 2 Sn(S0 3 CF 3 ) 2 1 8 . The remaining three bands in t h i s region at 1240, a n d ^ f ^ - c m " 1 are assigned to CF s t retch ing modes. It might be expected that these bands should occur at d i f -ferent wavenumbers for d i f f e r e n t S0 3 CF 3 groups. However, i t seems reasonable to assume that the CF 3 groups are not affected much by the environment of the S0 3 moiety. A l l of these bands occur as shoulders in the inf rared spectrum (see table 7) and any s p l i t t i n g may be e i ther too small to be observed or obscured by the adjacent broad S0 3 bands. Table 7 65. Vibrational Spectrum of I(0S0 2CF 3) 3 Raman IR Approximate Raman IR Approximate r -1, I n t ' -1 I n t * 1 I n t - i Int. l c m J f c m 1 description [cm ] [cm X ] description 1435 m,sh 1420 s,b v S0„(t) 619 vs 625 s,b 1427 ms a s 2 1321 m 1324 ms vSO(br) 1240 ms 1235 m,sh vCF 3 1208 mw 1210 vs, b v S0 o(t) sym 2 568 vw 580 ms.sh 549 s 542 w,sh 513 w 515 s '1160 w.sh 1165 w,sh vCF 3 w 1120 s 1130 s,b vSO(br) 452 414 w 415 w 1084 s 1090 s,sh vCF 3 361 993 mw 980 ms vSO(br) 818 vs 830 vs,b vSO 793 w 780 vs 780 s,b vSC 768 w 729 vw 730 s,b " 640 w 393 s 390 s 358 s 362 s 327 s 318 s 275 s 269 s \ 66. As was explained for Rb[ I (S0 3 CF 3 ) 4 ] a square planar conf igura -t ion of oxygen around iodine i s to be expected. However, in the case of I ( S 0 3 C F 3 ) 3 i t i s not possible to make a d e f i n i t e assignment of the 1-0 s t retch ing bands based on a square planar arrangement. Almost a l l the bands observed in the region from 430-380 cm - 1 are in f rared and Raman a c t i v e . This may be due to a d i s t o r t i o n of the square planar arrangement of oxygen caused by the presence of two non-equivalent S0 3 CF 3 groups. 4. IS0 3 CF 3 For t h i s very dark red brown compound no Raman spectrum was obtained, despite repeated attempts on several d i f f e r e n t samples. The inf rared spectrum i s very complex. The spectrum i s l i s t e d in table 8. Although the spectrum i s very complex and d i f f i c u l t to assign i t i s d i f f e r e n t fo^the spectra for I ( S 0 3 C F 3 ) 3 , ( I ( S 0 3 C F 3 ) 4 ] " or S 0 3 C F 3 " . IS0 3 CF 3 i s , therefore , a unique compound rather than merely a mixture of -I and I ( S 0 3 C F 3 ) 3 . Unusual i on ic formulations such as I 3 + [ I ( S 0 3 C F 3 ) 4 ] ~ or I + (S0 3 CF 3 ) are also highly u n l i k e l y . The m o s t l i k e l y structure i s a polymer with polydentate S0 3 CF 3 groups. Any assignment of the inf rared spectrum i s d i f f i c u l t and a more deta i led descr ipt ion of the structure would only guesswork. The I in ISO^CF should be p o s i t i v e l y polar ized and extensive anion-cat ion in te rac t ion could r e s u l t . The x - ray d i f f r a c t i o n study on the two modif icat ions of IC1 may serve as an i l l u s t r a t i o n for complications which may be expected in such a case. TABLE 8 V ibrat ional Spectrum of ISO^CF inf rared , cm * 1340 w, sh 1210 vs 1135 j . b 1025 m 930 m 770 ms 684 m, sh 624 ms , b 585 m, sh 555 sh 518 ms 455 vw 371 m, sh 358 vs 338 m, sh 312 ms * For explanation of terms see Table 5 68. 5. IBr.,SO,CF The spectra of IBr^SO^CF^, l i s t e d in table 9 w i l l be considered + as derived from IBr 2 and SO^CF^ with allowance for some cat ion-anion i n t e r a c t i o n . This treatment i s based on studies of analogous f l u o r o -6 — su l fa te compounds . In considering the SO^CFg" anion spectra the 21 + assignments of Burger et al w i l l be used, while the IBr 2 cat ion spectrum w i l l be compared with the spectra of other compounds conta in -ing the I B r 2 + ca t ion . In contrast to the interhalogen f luorosu l fa tes^ which were found to react with most conventional l .R . window materials I B ^ S O - J C F - J gave well resolved in f rared spectra with both AgBr and KRS-5 windows and spectra were recorded down to 200 c m " 1 . More anion bands were observed for IB^SO-jCF^ than were observed by Burger for AgSO^CFg. This most l i k e l y i s due to the removal of the degeneracies of the E modes of the S0 3 and CF 3 v i b r a t i o n s . In p a r t i c u l a r anion-cat ion in te rac t ion would resu l t in the s p l i t t i n g of the S0 3 modes, and th is i s the most l i k e l y source of addi t ional bands. The I B r 2 + c a t i o n , unl ike the Ag + c a t i o n , i s not spher ical and some symmetry lowering due to t h i s asymmetry may s p l i t the CF 3 modes as w e l l . The only major changes f romthe assignment made by Burger i s fo r the CF 3 s t retching frequencies. Burger assigns the band at 1237 cm~^  as ano- A mode and the band at 1167 as an E mode. Spectra for IBr 2 S0 3 CF 3 ind icate that the band at 1237 i s s p l i t and thus the A and E modes should be interchanged. Burger bases his assignments on comparisons made with other CF 3 containing compounds. In every other case the A 69. TABLE 9 Infrared Spectra of IBr 2 S0 3 CF 3 and AgS0 3CF 3 21 IBr 2 S0 3 CF 3 S 0 3 C F 3 ~ i n A g s 0 3 C f : Approximate descr ipt ion *a 1400, vw, sh comb, band 1280 vs , b 1270 vs , b S-0 st retch 1220 s , sh 1237 s CF s t retch 1205 vs CF st retch 1165 s , sh 1167 s CF st retch 1025 s (1026m)b) 1043 vs S-0 st retch 935 vw comb. 770 ms (770w)b) 760 m C-F st retch 650 m, sh 0-SO bend 625 vs 647 s C SO bend 580 ms 582 m FCF bend 565 W, sh 579 sh Comb, band 525 s 525 0S0 bend 515 s 515. 0S0 bend 360 vw, sh Comb, band 345 s (354) b ) 351 m C-S-0 bend 315 ms 320 m F-C-F bend 258 s (260s) b ) SD . . . v ' h \ IBr 0 s t retch 248 s (253vs ) D ; d 215 m 217 s F-C-S bend a. For explanation of terms see table 5, b. Raman Spectrum 70. mode occurs at a lower wavenumber than the E mode. SO^CF^" i s the only case where the E mode is lower. I t would seem reasonable, therefore , in view of the s p l i t t i n g observed for IB^SOgCF^ to interchange the two assignments. The CFg st retching bands occur at 1220, 1205 and 1165. The SO^ st retch ing modes which are expected to be s p l i t more than the CF^ bands occur at 1280 and 1025. The band at 1280 which is assigned to the E mode for SO^ i s very broad and some s p l i t t i n g is' ind icated . That the SO^ bands are broader than the CF^ bands has been observed 22 for other SOgCF^ compounds . The bending modes occur much as would be expected for an SO^CF^" ion . The only d i f ference is that the SO^ E mode i s s p l i t . The SO^ bending v ib rat ions occur at 650, 525 and 515 c m " 1 , while the CF 3 bending v ibrat ions occur at 580 and 315 c m " 1 . A l l the other bands between 1400 and 300 cm - 1 can be assigned to SO^CF^" v ibrat ions except f o r three bands at 1400, 935 and 565 c m " 1 . These bands are very weak and are assigned as combination bands of the SO^CF^" i o n . The remaining two bands at 258 and 246 cm - 1 are assigned as IBr^ s t re tch ing v i b r a -t i o n s . As can be seen from table 10 bands in th i s region agree quite well with the bands assigned for IB^SO^F. Unlike the case for IB^SOgF, however, the I B ^ st retching modes appear to be s p l i t into a symmetrical and an asymmetrical band. Both are Raman a c t i v e , as would be expected for a bent IBr^ group. When discussing the i r f ind ing for IB^SO^F, where only one IBr st retch was observed in the Raman spectrum, Wilson et a l . invoked accidental degeneracy for the 71 TABLE 10 Vibrat ional frequencies for I B r 2 + in IB^SO^CF^ and IBr^SO^F^ Compound v lBr 2 asym. v i B r 2 sym <5IBr2 IBr 2 S0 3 CR 3 258 cm"1 248 cm - 1 IBr 2 S0 3 F 256 cm"1 256 cm" 1 ' 127 cm"1 72. two st retching modes (a s i t u a t i o n which had been previously found for + 63 Br^ ) rather than a l i n e a r cat ion where only one band would be Raman ac t i ve . The resu l ts for IBr^SO^CF^ c l e a r l y point to a bent t r i atomic cat ion as would be expected using a simple valence electron pa i r repulsion treatment. The only remaining band at 215 cm i s assigned to an S-C-F bending mode. 6. I0 2 S0 3 CF 3 Iodyl tr i f luoromethanesulfonate i s a very good Raman scat terer and a well resolved Raman spectrum was obtained. The inf rared spec-trum obtained on a f i n e l y powdered sample held between two s i l v e r bromide plates was a lso wel l resolved. In assigning the spectra two main features were considered. For the S0 3 CF 3 group, at tent ion was focussed on the S-0 and C-F s t retch ing region while for the I 0 2 moiety a comparison with other iodyl s a l t s was made. The band frequencies of I02SG"3CF3 and the assignments are l i s t e d in table 11-For the SO^CF^ group, the presence of three S-0 s t re tch ing modes at 1326, 1221 and 941 ind icate that the S0 3 CF 3 group i s in te rac t ing with the I 0 2 and is not jus t a simple S0 3CF 3~ i o n . The pos i t ion of the bands i s compatible with e i ther a monodentate or b i -dentate br idging group, but the fac t that only 3 bands occur would suggest that only one type of S0 3 CF 3 group i s invo lved. The CF 3 st retching frequencies are at 1225 and 1125 c m " 1 . The lack of s p l i t t i n g of the E mode suggests that they re ta in a loca l C3V symmetry. Again the other bands have been assigned by comparison 73. S0 3 s t r , TABLE 11 Vibrat ional frequencies fo r I0 2 S0 3 CF 3 and I0 2 S0 3 F Approximate I0 2 S0 3 F I0 2 S0 3 CF 3 Descr ipt ion -1 -1 -1 Raman Cm Raman Cm IR Cm Int . 1424 vw 1335 1326 msa" 1332 s S0 3 s t r 1233 m 1225 s , sh CF 3 sym s t r . 1195 1221 mw 1210 s S0 3 s t r . 1170 1125 s 1125 s CF 3 as . s t r . 1070 1055 w, sh 1030 975 w 965 m, sh 1010 941 s 938 s 900 878 849 ms 860 vs I 0 2 as. s t r . 865 823 vs 830 vs I0 2 sym. s t r . 843 S-F s t r . 774 ms 780 m S-C s t r . 678 s 680 w, sh 660 645 m 642 s 615 628 w 630 s , sh 589 ms 600 s , sh 578 m 585 s , sh 542 s 540 s 522 ms 520 m, sh 459 ;428 395 s 415 367 w, sh 360 ms , 345 s 340 m, sh 328 ms 320 w, sh 310 311m continued. TABLE 11, continued I0 2 S0 3 F I0 2 S0 3 CF 3 290 m 258 ms 235 vs 217 mw 190 vs 163 m 115 w, sh a. For explanation of terms see table 74. 21 to the assignment of Burger et a l . on the SO^CF^ ion . The band at 780 cm 1 which i s c h a r a c t e r i s t i c of the SO^CF^ group i s present and i s not s p l i t . This i s further evidence for only one type of S0 3 CF 3 group. The iodine oxygen st retch ing v ibrat ions occur in ^SO-^F at 878 and 865 cm"1 in the Raman Spectrum. In the corresponding IOgSO-^ CF-j these same bands are at 823 and 849 c m " 1 . A l l ind icat ions are that the 10^ group in the S0 3F compound i s s i m i l a r to the same group in the S0 3 CF 3 compound. Structural proposals for ^SO-^F and several fid other I0£ compound are given by Carter and Aubke . Based on v i b r a -t iona l spectra and so lut ion studies they suggest that d iscreet I 0 2 + groups are associated by br idging anions. The s t re tch ing frequencies which occur between 800 and 950 cm - 1 are i n d i c a t i v e of an iodine oxygen - l fi5 mult ip le bond e . g . 10 for I0F 5 i s 927 cm . The resu l ts for IOgSO^Fg agree with these s t ruc tura l proposals. In conc lus ion , assoc iat ion over 1 - 0 — I bridges i s probably very s l i g h t judging from the pos i t ion of - The obvious polymeric nature of the material must, therefore , be due to anion br idging between d iscreet 10^ groups. The pos i t ion of the t h i r d S-0 st retching mode at 940 cm"1 i s somewhat lower than for the same band in (CH 3 ) 3 SnS0 3 CF 3 where a bidentate bridging group i s present. The r e l a t i v e l y low pos i t ion of t h i s band in IO^SO^CF^ seems to indicate preferent ia l bonding to one 10^ group (a) rather than ideal Figure 9 75. Infrared Spectra of (10) S0 3CF 3 and (I02) S O 3 C F 3 from 1 5 0 0 - 2 5 0 cm"1 ( I 0 2 ) S 0 3 C F 3 76. bridging (b), (a) 0 2 I ,102 (b) 0 2 I , 10, o — s — o ' 0 ^ . — 0 /\ A 0 CF 3 0 CF 3 The large number of bands in the spectra are presumably due to extensive coupling of v ib rat iona l modes and a more deta i led assignment of the spectra i s not poss ib le . 7. I0S0 3 CF 3 We'll 1 resolved in f rared and Raman spectra were obtained fo r I0S0 3 CF 3 . The v ib ra t iona l frequencies and the proposed assignments are given in table 12. The discussion of the assignments w i l l again center on the S0 3 CF 3 group and the 10 st retch ing frequencies. The S0 3 CF 3 group i s not merely an anion with C3V symmetry. The s p l i t t i n g of the E mode S-0 st retching frequency indicates a lowering of symmetry by associat ion through the oxygen. The S-0 st retching bands at 1390, 1210 and 970 cm - 1 are assigned to an unsymmetrical bidentate br idging S0 3 CF 3 group. (See the discussion fo r IOgSOgCF^) The CF 3 s t retch ing frequencies, found at 1242 and 1133 c m - 1 , ind icate the loca l symmetry of the GF3 group remains C 3 v . The lower frequency bending and deformation region below 1000 cm 1 has a large number of bands ind icat ing an extensive degree of v i -brat ional coupling between d i f f e r e n t v ib ra t iona l modes. This allows only an approximate descr ipt ion of the bands. The attempted ass ign -77. cm 1 1395 1284 1242 1214 1133 1040 1025 969 883 865 779 662 634 624 587 560 535 529 453 380 360 355 329 316 290 248 155 a. For TABLE 12 V ibrat ional Frequencies for IOSO^CF^ Raman Infared in tens i t y c m - 1 i n tens i t y Approximate Descr ipt ion 1420 vw w a 1390 ms S0 3 s t retch ing ms 1280 ms m, sh 1240 ms sym.CF3 s t retching ms 1210 s S0 3 s t retching s 1140 vs as .CF 3 s t re tch ing w, sh s 1018 s ,b S0 3 s t retch ing ms 970 m vs 885 s 10 s t retch vw 860 s s 777 ms S-C s t retch 670 m, sh s 655 m, sh s 640 s ms 625 m, sh s 585 m, sh w 550 s w, sh s 528 s vs 455 w,b 418 mw ms 375 m, sh m > 350 m, sh m m 320 w, sh m ms vw explanation of terms see table 5 78. ment i s given in table 12. Notice that once again the c h a r a c t e r i s t i c band at 777 cm"1 i s present as a s ing le band ind ica t ing the presence of only one type of SO^CF^ group. Structural proposals for iodosyl compounds have been based mainly on a polymer of ( I 0 ) " + units surrounded by anions. The main thrust of th i s proposal comes from the rather low 1-0 s t retch ing frequencies found fo r most iodosyl s a l t s . As mentioned before in the case of IG^SOgCFg an iodine oxygen double bond would resu l t in a st retching frequency between 800 and 900 cm - 1 while as has been shown for several iodosyl compounds the 1-0 s t retch ing frequencies occur somewhat lower, around 600 cnf . Dasent and Waddington proposed the chain polymer for ( I 0 ) 2 S 0 4 and ( I0 ) 2 Se0 4 on th i s bas?s as well as for I 2 0 4 - Subsequent to the preparation of IOSO^C^ the iodosyl CO f luo rosu l fa te I0S0 3F was also prepared . I t was found to conform to th is general d e s c r i p t i o n . That i s , the st retching frequencies were much lower than 800 cm - 1 and a chain polymer of I 0 + units i s proposed. For IOSO^CFg, however, there are no su i tab le v ibrat ions in the region from 550-600 cm"1 which could be assigned as 1-0 st retching bands. Two bands at 860 and 885 cm"1 are assigned as vIO. The s p l i t t i n g into two bands i s due to s o l i d state e f f e c t s . The compound I0F 3 which has been shown by an x - ray d i f f r a c t i o n s t u d y 6 7 to contain a short 10 bond has 1-0 at 883 cm"1 6 4 . In I0F c 6 5 the 1-0 s t r e t c h -ing frequency i s found at 927 c m " 1 . Several d i f f e r e n t 1-0 st retching frequencies which have been found are shown in table 13. The 79. Table 13 1-0 st retching frequencies in several compounds Compound V I 0 cm" proposed structure ( I 0 ) 2 S 0 4 6 6 j ^ 2 , chain polymer ( I 0 ) 2 S e 0 4 6 6 chain polymer IOSOgF53 650 chain polymer I0S0 3CF 3 ° ° Q d iscrete 10 groups 64 I0F 3 907 d iscrete 10 groups 64 I OF,- 927 d iscrete 10 groups 80. s ingu la r l y high VIO fo r IOSO^CF^ would seem to ind icate the presence of d iscreet 10 units in IOSO^CF^ as opposed to polymeric 10 structures for other iodosyl compounds. In comparing th is f ind ing to the s i tua t ion for IOSO^F i t must be concluded that any extensive 1 - 0 — I associat ion i s absent fo r the IOSOgCF^. It should be kept in mind that a l l previous 10 s a l t s ; ( I 0 ) 2 S 0 4 , ( I0 ) 2 Se0 4 and (I0)S0 3F- have r e l a t i v e l y small anions. The larger anion in IOSO^CF^ may prevent the formation of 1 - 0 — I bridges in the compound. A s i m i l a r s i t u a t i o n would be expected for IOSO^CHg or IOCO^jCFg. However, as mentioned previously a l l attempts to obtain these compounds have been unsuccessful to t h i s po int . In conclusion for the v ib ra t iona l spectra of a l l the I-SO^CF^ compounds studied im th is work there i s a complete analogy to the spectra of the corresponding f luorosu l fa tes except for the rather unique case of the iodosyl compounds. 8. CF^SOgCF^ jrif1uoromethy1 tr i f luoromethanesulfonate 25 This compound had already been reported by Noft le and Cady who also l i s t in f rared frequencies in the NaCl region. In t h i s work the thermal decomposition of I(S0gCF 3)g was found to y i e l d CF^SOgCFg as a v o l a t i l e product. The v ib ra t iona l spectrum of CF 3 S0 3 CF 3 i s in terest ing in that i t may be expected to provide an example of a monodentate covalent tr i f luoromethanesulfonate group. Only l i m i t e d information on v ib ra t iona l spectra of t h i s monodentate group are 25 ava i lab le . The spectrum should i l l u s t r a t e several arguments which have been invoked previously regarding the di f ferences in f u n c t i o n a l i t y 81. Table 14 V ibrat ional Spectra of CF^SO^CF^ This work Reference no. 25 Assignment Raman cm 1 in f rared cm - 1 in f rared cm - 1 1470 * w 1460 w 1462 s 1461 s 1370 w 1350 w 1272 s 1270 s ,sh 1253 w,sh 1262 vs 1258 s 1228 vw 1232 vs 1230 s 1154 s 1150 w,sh 1130 m,sh 1135 vs 1134 s 1074 954 w 950 s 954 s '868 vw 805 m 770 vs 785 m 786 m 760 w 766 m 745 w 715 w 610 vw 620 m,sh 585 m 595 m 580 m,sh 547 m 528 w -490 w,sh 397 w 349 ms 325 m 305 m 281 s not assigned S0 2 asym. s t retch not assigned not assigned 502 sym. st retch CF3-O asym. s t retch CF3-S asym. s t retch CF3-O sym. s t retch CF3-S sym. s t retch 503 impurity S-0* s t retch not assigned S-C st retch CF3-S bend not assigned not assigned not assigned SO3 asym. bend CF3 deformation CF3 deformation SO3 deformation 82. of the SO-jCFg group. The inf rared and raman spectra of CF^SO^CF^ obtained by thermally decomposing I (SO^CF.^ (irJ-reported i n table 14. along with the inf rared bands reported by Noft le and Cady. The main in te res t in the v ib rat iona l assignment of SO^CF^ groups of d i f f e r e n t f u n c t i o n a l i t i e s i s in the unambiguous i d e n t i f i -cat ion of the S-0 s t retch ing frequencies. The observed posi t ions should be comparable to those for the f luorosu l fa te group. The CF^ posi t ions are only of secondary in terest as the group may be expected to re ta in l oca l C^V symmetry regardless of the symmetry of the f u n c t i o n a l i t y with only small s p l i t t i n g s of the degenerate E modes. In summarizing the monodentate, b identate, and ion ic SO^CF^ and SO^F cases the ranges expected for S-0 are shown in table'"15. along with the assignment for CF^SO^CF^. The presence of two d i f f e r e n t CF^ groups in one molecule is detectable in the st retching region only . Overlap and superposit ion of bands obscure the deformation region. The SOg st retching frequencies are c lear and the assignment i s c l e a r in the region from 830-1500 c m - 1 . For the ion ic SOgX group (X being CF 3 of F ) , the symmetry of the S0 3 moiety i s C 3v and there are only two S 0 3 s t re tch ing modes, a degenerate E mode and an A1 mode. These occur at 1260 and 1050 cm"1 respect ive ly . For a monodentate SO^CFg group the symmetry is lowered to C,- and the E mode i s no longer degenerate. The two bands obtained from the s p l i t t i n g of the E mode can be considered as an S0 2 asymmetric s t retch between 1470 and 1370 cm - 1 and an S0^ symmetric st retch between 1180 and 1270 c m - 1 . The A' mode can now be thought of as an SO st retch where the 0 indicates the oxygen through which bonding 1 83. Table 15 S-0 st retching frequencies in i o n i c , monodentate, and bidentate S0 3F and S0 3 CF 3 groups. GROUP Ranges for vS-0 cm -1 i on ic S0 3F S0 3 CF 3 monodentate S0 3F S0 3 CF 3 bidentate S0 3F S0 3 CF 3 E mode 1280 1260 VSO2 asymmetric 1400-1500 1370-1470 * V S0 2 asymmetric 1300-1380 A-j mode 1080 1050 VSO2 symmetric 1200-1250 1180-1270 >*S02 symmetric 1145-1220 VSO 980-850 950-830 V SO 1000-1060 CF 3 S0 3 CF 3 1461 1270 950 84. occurs. This band i s considerably lowered and occurs between 830 cm 1 and 950 c m - 1 . F i n a l l y , for the bidentate S0 3 CF 3 group the symmetry i s also C and the E mode i s s p l i t . The two bands derived from the E s r * * mode can be considered as SO ^ s t re tches , here 0 referes to the two oxygens through which bonding occurs. The bands are considerably lowered compared to the unsp l i t E mode of the i o n . The asymmetric band occurs between 1300 and 1380 cm"1 and the symmetric between 1145 and 1220 c m - 1 . The A1 mode, an S-0 stretch^occurs between 1000 and 1060 cm - 1a-J'f not changed too much from the ion ic p o s i t i o n . Note that a t r identate S0 3 CF 3 group would again have C*3v symmetry and have two S-0 s t retch ing modes. These modes should occur considerably lower than they would for an ion ic S0 3 CF 3 group. Comparing the SO v ibrat iona l band assignments fo r CF 3 S0 3 CF 3 with the scheme out l ined above and summarized in table if we can see that i t f a l l s neatly with in the monodentate group with a l l bands at the upper l i m i t s . This treatment is only feas ib le for s t retch ing v i b r a -t ions i . e . above 550 cm - 1 as below 550 cm - 1 the number of bands i s too great to allow unambiguous assignment. 85. IV General Conclusions It was shown e a r l i e r that the number of pos i t i ve halogen compounds ava i lab le obtainable from any oxyacid depends somewhat upon the strength of the a c i d . Tr i f luoromethanesulfonic ac id has been found to be a very strong a c i d , comparable to f l u o r o s u l f u r i c a c i d . A reasonably large number of I-SO^CF^ compounds have been obtained. These d i s p l a y , with one exception, IOSO^CF^, s t ructura l s i m i l a r i t i e s to the analogous f l u o r o s u l f a t e s . The structures proposed for these compounds, both SO^CF^ and SO^F, have been based, fo r the most part on the analyses of t h e i r v ib rat iona l spectra. The complexity of the spectra for SO^CF^ com-pounds i s due to the near coincidence of the S -0 and C-F s t retch ing region. However, much information which i s unobtainable for the f l u o r o -su l fates because of the i r r e a c t i v i t y with inf rared c e l l window material was obtained for the tr i f luoromethanesulfonates which are r e l a t i v e l y unreact ive. F i n a l l y , here are a few suggestions for fur ther study in t h i s area. 1. The s o l v o l y s i s of BrF^ in HSO^CF^ might be studied further with a view to obtaining B r ( S 0 3 C F 3 ) 3 . However* the detonations r e -corded for other attempts to form B r ( S 0 3 C F 3 ) 3 suggest extreme caut ion . 2. The so l vo l ys i s of C1F in HS0 3CF 3 may y i e l d C1S0 3 CF 3 . C1N03 i s known while BrN0 3 i s not. 3. The so l vo l ys i s of BrS0 3F in HS0 3CF 3 may y i e l d BrS0 3 CF 3 . The s o l v o l y s i s of 1(1) compounds r e s u l t i n the formation of iodine cat ions I 3 + and along with There might be more success with bromine(I) compounds. 86. 4. The in teract ion of CsS0 3CF 3 with BrS0 3F may lead to formation of BrS0 3 CF 3 . 5. The in teract ion of I ( S 0 3 C F 3 ) 3 with Sn(S0 3 CF 3 ) 4 might y i e l d [ I ( S O - j C F ^ ^ Sn(S0 3 CF 3 )g. Attempts to form the I (S0 3 CF 3 )2 + cat ion using SbFg were unsuccessful . This method using the j u s t recently ava i lab le compound Sn(S0" 3CF 3) 4 as a Lewis ac id and S0 3 CF 3 ~ ;ion acceptor looks promising. 6. 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