70-26,354

ROSS, Dominick Allan, 1940- REACTIONS OF SULFUR DIOXIDE WITH TRANSITION METAL UNSATURATED HYDROCARBON COMPLEXES.

The Ohio State University, Ph.D., 1970 Chemistry, inorganic

University Microfilms, A XEROX Company, Ann Arbor, Michigan REACTIONS OF SULFUR DIOXIDE WITH TRANSITION METAL ♦ UNSATURATED HYDROCARBON COMPLEXES

DISSERTATION

Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of The Ohio State University

By

Dominick Allan Ross, B.S.

******

The Ohio State University 1970

Approved by

Department of Chemistry ACMOWLEDGMENTS

Much credit for the completion of this dissertation must be given to my wife, Sharon. Without her constant encouragement, the task would have been much more difficult.

I would like to thank Dr. Andrew Wojcicki for his helpful guidance during the course of this research.

Finally, I am indebted to the National Science Foundation and the Petroleum Research Fund, administered by the American Chemical

Society, for financial support. VITA

November 16, 1940 Born - Binghamton, New York

1964 ...... B.S., The Ohio State University, Columbus, Ohio

1964-1966 .... Teaching Assistant, Department of Chemistry, The Ohio State University, Columbus, Ohio

1966-1969 ...... Research Assistant, Department of Chemistry, The Ohio State University, Columbus, Ohio

FIELDS OF STUDY

Major Field: Inorganic Chemistry. Dr. Andrew A. Wojcicki

iii CONTENTS

Page

ACKNOWLEDGMENTS o»*oe»ft0to»««o«»aODfte»»ee0eaooae«e«««o»e««oeee» XX

VITA oo.ooooo.eooao...... ooo.oottoooooo...... e.«oo..o.....oo XXX

TABLES . o o . o • o . . o o o o . . . . o o • a . . o •o • « o ..o o..•••« o...» VX

FIGURES ...... viii

INTRODUCTION I

EXPERIMENTAL saaaoaoaoasa.e.aaoo.aee.ees.se.oeooa.eooaaa.oeaeoo X6

St^rtXH^ 6rxclls eaaaeoeaeaaaaae.eaeeaao.ae.oooaeeee.oaeeoe X6 General Remarks on the Preparation of Allylic Sulfinato Complexes...... 26 Preparation of Allylic Sulfinate Complexes of Cyclopentadienyliron Dicarbonyl ...... 28 Preparation of Allylic Sulfinate Complexes of Cyclopentadienylmolybdenum Dicarbonyl ...... 38 Reactions of Cyclopentadienylmetal Dicarbonyl Complexes wxth Sulfur Dxoxxde o...... 43 Reactions of Boron Trifluoride with Sulfinate Complexes of Cyclopentadienyliron Monocarbonyl ...... a... 51

RESULTS AND DISCUSSION ...... ••....•..•.•».«.o.eo..o...«o 5^

Investigation of Allylic Sulfinato Complexes ...... 56 Preparatxon of the Complexes ...o...... 58 Physical Properties of Sulfinates .... 61 Infrared Studies ...... 6l Proton Magnetxc Resonance Studxes ...... «...«...... 67

Dxscussion of Mechanxsms ...... o . « . o ...... 113 Reactions of Cyclopentadienylmetal Dicarbonyl Complexes wxth Sulfur Dxoxxde ...... 120 Reactions of Boron Trifluoride with tr-C_HcFe(C0)„PR,.S(0)oCH , ...... 132 5 5 2 3 2 3

SUMMARY ...... a...... 142

APPENDIX A ...... o.ooooo...... o.«o«.«.*o....«*..e«....ol46

APPENDIX B ...... 152

iv CONTENTS'(Coatd.)

Page

APPENDIX C »C»000900®«000«#» 1^8

BIBLIOGRAPHY...... 163

v TABLES

Table Page

1® Infrared S-0 Stretching Frequencies of Compounds Containing ^SOp— ooo...... 0.09.0.0.00.00 ^

2. Infrared S-0 Stretching Frequencies of Substituted Sulfinatocarbonyl Complexes .... 6

3® SO^ Insertion Products of Allylic, Propargylic, and AlleniC Compounds .••o.».eooo.oeoooo..«eooo.oo.oooo® 10

4. Analytical and Molecular Weight Data for Allylic SulfmatO Complexes of Iron oooo.oooo.oo.ooob.ooo.ooo.o. 37

5® Analytical and Molecular Weight Data for Allylic Sulfinato Complexes of Molybdenum...... 44

So S-0 Stretching Frequencies of Allylic Sulfinato Complexes .. oo.' o • ® «•...»«. ®...«... ®. o. o. o o... . Sb

7® C-0 Stretching Frequencies of Allylic Sulfinato Complexes o®®...®..®®.®.®...... SS

8. Proton Magnetic Resonance Spectra of Allylic -CH-.C-H> Fe(CO)_R and 7^CH,CcH,1Fe(C0)oS0_R Complexes ...... ?..?...... 85

9® Proton Magnetic Resonance Spectra of Allylic rr-l,3-(C.Hc)„Cc.H,Fe(C0)_R and /r-l,3-(C.HJ_C_fL,Fe(C0)o- S02R Complexes ...... 89

10® Proton Magnetic Resonance Spectra of Allylic ?f'-(CH_)t-Cc.Fe(CO)_R and 7T-(CH,)[.C_Fe(C0)DS0-R Complexes ...... ?..?...... 96

11. Proton Magnetic Resonance Spectra of Allylic 7T-C H.-MoCCO) P(0C,H,_)xR and /^■Ct-H[-Mo(C0)_P(0CAHt.)xS0-R Complexes ...... ?.?...... 77... 112

12. Isomeric Distribution of Sulfinates from SO^ Insertion of Allylic Complexes of Iron ..... 117

13® Isomeric Distribution, of Sulfinates from S02 Insertion of Allylic Complexes of Molybdenum...... 119

vi TABLES (Contd.)

Table Page 1 * • 14. Proton Magnetic Resonance Spectra of Propargylic lf-C_H_Fe(CO)aR and 7f-C,-HI_Fe(C0 )o(S0 ,C,H_)..... ;...... 124 5 5 2 5 5 2245 15« B-F Stretching Frequencies of 1:1 Boron Trifluoride Complexes ...... 135

16. Infrared Spectra of tf’-C^H^FeCCO)P(n-ClfHg JjSC OjgCH-j and ^-C^5Fe(C0)P(n-CI|H9)3S(0)2CH3.BF3...... 136

17. Infrared Spectra of ^-CcHcFeCCOMcgHc^sCOjpCH, and >r-C5H5Fe(C0 )P(C6H p 3S(0 )2CH3 .BF^ ...... 137

vii FIGUHES

Figure

1. Ultraviolet irradiation apparatus ......

2. Pressure reaction vessel......

3. A comparison of the pmr spectra of: A. fl’-CH3C5H*iFe(C0)2CH2CH=C(CH3)H; B. ■rf-CH3C5Hi|.Fe(C0)2S02C(CH;5)HCH=CH ......

4. A comparison of the pmr spectra of: A. CICH2CH=C(CH3 )H;. B. TT-CjK^Fe (C 0) 2CH2CH=C ( CH3 )H; C. 7r-C^H^Fe ( CO ) 2S02C (CH3 )HCH=CH ......

5® A comparison of the pmr spectra of: A. »r-CH3C5H/fFe(C0)2CH2CH=C(CH3)2; B. A mixture containing 73% fr-CH3C5H/fFe(C0)2S02CH2CH=C(CH3)2 and Z3% »’-CH3C3H/tFe(C0)2S02C(CH3)2CH=GH2......

6 . A comparison of the pmr spectra of: A. 7r_c5H5Fe(C0)2S02CH2CH=C(CH3)2; B. A mixture containing 76% 1T-C cHcFe ( CO ) 2S02CH2CH=C (CH3 ) 2 and Zb% «r-C3H5Fe(C0 )2SG2C( CH3 )2CH=CH2; C. A mixture containing 6% ^-C5H5Fe(CO)2S02CH2GH=C(CH3 )2 and 9k% ^•-C5H5Fe(C0)2S02C(CH3)2CH=CH2 ......

7® A comparison of the pmr spectra of: A. ^•CH3C5HzfFe(C0)2CH2CH=C(C6H3)H; B. A mixture containing 83% Tr-CRjPcfiifie(CO)2S02CH2CH=C(CgHc )H and 13% 7r-CH3C3H2jFe(C0)2S02C(C6H5)HCH=CH2

8m A comparison of the pmr spectra of: A. /r-C5H5Fe(CO)2S02CH2CH=C(C6H5 )H; B. A mixture containing 80% »r-C5H5Fe(CO)2S02CH2CH=C(C6H5 )H and 20# if-CjHjFe ( CO ) 2S02C (C5H5 )HCH=CH2; C. A mixture containing 30$ IT-C3H3Fe(CO)2S02CH2CH=C(C6H5 )H and 70% 7f~C^H^Fe( CO ) 2S02C ( C6H5 )HCH=CH2 ...... FIGURES (Contd.)

Figure ' Page

9. A comparison of the pmr spectra of: A. ^-l,3-(C6H5 )2C5H3Fe(C0)2CH2CH=C(CH3)25 Bo A mixture containing 75% ,3-( C5H5 )2CcH3Fe (CO)2S02CH2CH =C( CH3 )2 and 2 % ^•-1,3-(C5H5 )2C5H3Fe(CO)2S02C(CH3 )2CH=CH2 .... 87

10. A comparison of the pmr spectra of: A. 77--( CH3 ) cCcFe ( CO ) 2CH2CH=C ( CH3 )H; B. rr- ( CH3 )^C3F e ( CO ) 2S02C (CH3 )HcH=CH ...... 90

11. A comparison of the pmr spectra of: A. rr- ( CH3 ) 5C3F e ( CO) 2CH2CH=C ( CH3 ) 2; B. >7"- ( CH3 ) 3C3Fe ( CO ) 2S 02CH2CH=C (CH3 ) 2; C. A mixture containing 60& 7r-(CH3 )5C5Fe(C0 )2S02CH2CH=C(CH3)2 and k0% 7f-(CH3 )5C3Fe(C0)2S02C(CH3 )2CH=CH2 ...... 92

12. A comparison of the pmr spectra of: A. /T-(CH3 )cC3Fe(CO)2CH2CH=C(CgHc )H; B. 7f- ( CH3 ) 5C3F e ( CO ) 2S02CH2CH =C (Cglhj )H ...... 9**

13. The isomers of a Tr-C^Hi-MoCCO^LR complex ..... 99

14. A comparison of the pmr spectra of: A. ( CO ) 2P( OC6H5 )3CH2CH=C (CH3 )H; B. A mixture containing 80& jt'-CcHcMoCC0)2P(OCgHc)3S02CH2CH=C(CH3 )H and 20# n'-C3H3Mo(C0)2P(0C6H3)3S02C(CH3)HCH=GH2...... 102 13. A comparison of the pmr spectra of: A. jr-CcH5Mo(C0)3CH2CH=C(CH3)H; B. jr-^^MoC CO^SO^C CH3 )HCH=CH ...... 10*f

16. A comparison of the pmr spectra of: A. JJS-C^HcMoC C0)2P( OCgHc )3CH2CH=C( CH3)2; B. »*-C3H5Mo(C0)2p(0CgH5)3S02CH2CH=ClCH3)2 ...... 108

17. A comparison of the pmr spectra of: A. /r-C^H^MoC C0)2P( OG6H5 )3CH2CH=C ( C6H5 )H; B. Tr-C^no(C0)2P(0C^E5)^S02Cli2p E = C ( G ^ ) H ...... 110

18 . A comparison of the pmr spectra of: A. tT-GcHcF e ( CO ) 2CH2CsCCH3 ; B. Tf-C^H^FeCC0)2(SO^ijH^ ...... 122 ix FIGURES (Contd.)

. Figure * Page

19. Infrared spectrum of Jf-C^H^FeCCO)P(n-Cz^Hg)3S02CH-z .BF-z in the regions 3500-1300 and 1300-^+50 c m ~ l ...... 138

20. Infrared spectrum of 7T-CcHcjFe(CO)£ -C=C(CH*)S(0)OCH2 ) in the regions 3500-1300 and 1300-300 c m ~ l ...... 154

x INTRODUCTION

Insertion reactions in organometallic chemistry have been studied extensively in the last ten years® They are important because: (l)

Their use often provides facile synthesis for organometallic compounds not accesible by alternative routes® (2) In identifying their role, many important processes, particularly catalytic processes, are better understood®

Lappert and Prokai (1) have recently reviewed insertion reactions of metal (M) complexes of the type X^M-R according to the nature of the inserting group® In general, they can be classified as 1,2-addition to an unsaturated substrate, 1,1-addition to an unsaturated substrate, and oxidative 1,1-addition to low coordination number compounds, tran­ sient species, or atoms® Examples of each class of reaction are given by equations (1), (2), and (3), respectively (2, 3» **»)•

+ (1)

+ 8 (2)

(C0H_),Si-H + :CC1_ » (C_H)SiCClH (3) O > *■ 2 3 3

1 Of particular interest to this investigation are insertion re­ actions of sulfur dioxide with complexes containing metal-carbon bonds®

Oxidative 1,1-addition reactions are not considered further since they do not apply to SO^® Sulfur dioxide can potentially participate in either 1,1- or 1,2-addition reactions as shown by equations (4) and

(5)9 respectively®

9 X M-R «• S0_ -> X M-S-R (k) n 2 n X

X M-R + S0_ S> X M-S-O-R or X M-O-S-R (5 ) n c- n A n 1

The problem of distinguishing between the products of 1,1- or 1,2-ad­ dition reactions may be resolved with the readily available techniques of infrared and nuclear magnetic resonance spectroscopy®

The S-0 stretching frequency ranges found for organic sulfones,

R-SCO^-R, sulfinates, R-S(0)-0-R, and sulfinic acids, R-S(0)-0-H, may serve as guidelines for distinguishing between the sulfur-bonded moiety,

M-SCO^-R, and the oxygen-bonded moieties, M-S(0)-0-R or M-0-S(0)-R®

For sulfones, the S-0 stretching frequencies are found in the ranges

13*t0-1290 and 1165-1120 cm-^ (5)® The S-0 stretches for R-S(0)-0-R occur at 1136-1120 and around 960 cm”'*' (6 )® For sulfinic acids, the

S-0 stretches are found in the regions 1090-990 and 87O-8IO cm"'*’ (5,6)®

Considering the large differences between sulfur-bonded and oxygen- bonded compounds in the S-0 stretching frequency region, infrared . spectroscopy should be quite helpful indetermining the mode of bonding of the MSO^R moiety® Table 1 reports absorptions in the infrared spectrum which have been assigned to S-0 stretches for a wide variety of -SO2" containing compounds0

An examination of the table reveals that, on the basis of their

S-0 stretching frequencies, the oxygen-bonded and sulfur-bonded sulfin­ ates form two non-overlapping groupso Compounds in Group I, i0e0 , 1-6, have S-0 stretching frequencies in the ranges 1103-998 and 965-836 cm «

Compounds 7-15 can be placed in Group II having 12^*0-1175 and 1095-1033 -1 cm ranges® There is limited crystallographic evidence which supports these assignments® Langs and Hare (17 ) in a preliminary communication report that for CuC^O)^ josCOjCgH^CH^-p^t compound 1 , x-ray data show that oxygen-bonding is present and only one oxygen is bonded to the metalo A full x-ray crystallographic study of jff-C^H^Fe( CO 2^*1 -

^S(0 )CgH^2 » compound 2, reveals the presence of C-S(0)-0-Sn units (l8 )®

The Fe2(C0 )gS(0)2 complex, compound 15, consists of two Fe(CO)^ groups bound together by bridging SO^ through the sulfur atom only (19)® Since two isomers of CgH^HgS02CgH^, differing markedly in their infrared spectra8 have been reported (9 )j it seems reasonable that linkage isomer­ ization has occuredo The infrared spectrum of C^II^HgS02CgH^ (Isomer II) in the S-0 stretching frequency region is closest to that of compounds

1 and 2 and it seems reasonable that the structure is CgH^HgOS(0 )C^H^o

Isomer I, compound 7, has much higher S-0 stretches and appears to be the S-sulfinate®

Of particular interest in the infrared spectra of Group II com­

pounds is that their S-0 stretching frequencies occur at lower ranges than those reported for R-S(.0)^-R compounds (vide surra)® It has been suggested that this results from metal-sulfur pi-interaction (15)®

The formation of a metal-sulfur pi bond would most likely be accomplished TABLE 1 4

INFRARED S-0 STRETCHING FREQUENCIES OF COMPOUNDS CONTAINING -SO.- • d.

Bibliog Compound S-0 Stretches, cm”^ Refer.

1 . CuC^O)^ [0S(O)C6HZtCH3 -p] 2 998 938 7

2. [c5H5Fe(C0 )2]2Sn|0S(0 )C6H5] 2 1103, 1088 869, 853 8

3 . C6H5CH2Hg0 S(0 )CH2C6H5 1055-1048 877-844 9

4. C.H_HgOS(0)C,Ht. 1048 836 9 (isomer II? 5

5a (CH,)oT10S(0)CH.. 1080 965 10 5 2 5 6 . (CgH^)^Sn0S(0 )C^H^ 979-954 933 11

7* O.Ht.HgS(0) C,H_ 1175 1048 9 (§somer If 5

8 . Hg[s(0 ) r] 1228-1192 1040-1037 12 (R=C6H5f CgfyCH^)

9 - [(C6H5 >3p]2ClPdS(0 )2C6H5 1213 1095, 1057 13

10. [(C.Ht-)zPL(C0)Cl_IrS(0)oR 1240, 1220 IO65 , 1055 14 (Ric^CH|-E)

11. C H Fe(CO) S(0) R 1205-1185 1052-1038 15 (&=3h , Cfi, C|H , CH2C6H5 ’ C6H4CV £) 12. Ct-Ht.Mo(C0)7,S(0)_R 1191-1171 1051-1038 16 (S=3h3 , e2^5 , c62c6h5 )

13. (C0)t.MnS(0)?R 1209-1189 1054-1033 11 (R=C§3 , C2H3> CH2C6H5 ) l4. (CO) ReS(O) R 1192-1185 1054-1033 11 (r=ch3 , ch2c6h5 )

15. Fe(C0)gS(0)2 1209 1048 19 by overlap between filled, non-bonding orbitals of the metal with

empty orbitals of the sulfur atom® If there is an appreciable

amount of metal-sulfur interaction, an increase of electron density

on the metal will result in an increase of metal-sulfur pi-bonding

with a concomitant decrease in sulfur-oxygen pi-bondingo The decrease

in sulfur-oxygen pi-bonding should give rise to lower S-0 stretching

frequencies in the infrared® The S-0 stretching frequencies for a

number of substituted metal carbonyl sulfinates are shown in Table 2®

The lower S-0 stretching frequencies found for these compounds than

for the corresponding unsubstituted sulfinates (see Table 1) is due

to an enhancement of metal-sulfur pi-bonding brought about by replace­

ment of a weak base and good pi-acceptor CO with a stronger base and

poorer acceptor amine, phosphine, or iodine (20)®

Additional support for the existence of metal-sulfur pi bonding

was obtained by comparing the anions CrCCOj^SCoJ^CgH^"" and V/(CO)^-

SCoJ^CgHj. with isoelectronic (CO^MnSCO^CgH^ in the S-0 stretching

frequency region (ll)® The S-0 stretches for the anions were approx­ imately 30-90 cm”^ lower than for (CO) <_MnS(O) 2^5^ s indicating an in­

creased amount of metal-sulfur pi-bonding brought about by a lower oxidation state of the metal® Preliminary crystallographic data on

(COjyfaCbipy^CO^CH^ (bipy = 2 ,2 *-bipyridine) confirms the presence of a sulfur-bonded SO^ moiety (22)® Thus the lower S-0 stretches found in this complex can be readily explained by the pi-bonding hypothesis®

Theoretically, proton magnetic resonance spectroscopy should also be helpful in determining the structure of the MSO2R moiety, es­ pecially when R is bonded to the metal through a methylene group® TABLE 2 6

INFRARED S-0 STRETCHING FREQUENCIES OF SUBSTITUTED SULFINATOCARBONYL COMPLEXES

Bibliog Compound S-0 Stretches3-, cnfV Refer®

1. C5H5Mo(C0)2P(C6H5 )3S(0)2CH5 1170 1042 16

2. C Ht.Fe(CO)PR^S(0)?CH, 1156-1152 1036-1025 21 (R=n-C^H9 , CgH^j *

3. (bipy)(C0)^MnS(0) R 1160-1148 1044-1034 20 (R=CH3 , C ^ , CH^H,.)

4. (o-phen)(C0)-.MnS(0) R 1175-1136 1037-1032 20 (R=CH3 , CH2CgH5) ‘

% (p-tol)2 (CO)3MnS(0 )2CH3 1102 1015 20

6 . (p-fan)2(CO)^MnS(0 )2CH3 1113 1025 20

7. (py)2(CO)3MnS(0 )2CH3 1125 1039 20

8 . [(n-C^H^N] [(CO^IMnStO^CHj 1138 1030 20

9. [(C6H5 )3p] (CO^MnStO^CHj 1145 1035 20

a Only the strong intensity absorptions are given®

Abbreviations: bipy = 2,2'-bipyridine; o-phen = 1,10-phen- anthroline; p-tol = p-toluidine; p-fan = p-fluoroaniline; py = pyridine® Assuming that there is no spin-spin coupling between the methylene protons and the R group, the methylene protons of structure I should appear as a simple singlet in the proton magnetic resonance spectrum

since they sire equivalent® For structures II and III, however, the methylene protons are non-equivalent and an AB -type spectra should re­

sult® Thus, the appearance of the methylene protons as sharp singlets

for jF-C5H5Fe(C0 )2S(0 )2CH2C6H5 (15), (CO^-InSCO^CH^H^ (ll), and

(CO)^ReS(0 )2CH2CgH^- (11) supports their assignment as being sulfur- bonded from infrared data (vide supra)®

Proton magnetic resonance spectroscopy alone, however, cannot be relied upon to differentiate.between 0- and S-bonded sulfinates®

Pollick, et al. have prepared a number of monosulfinates of the type

RHgS02R (R = CgHt-, C2Hj-, and CH^^H^) (9)„ The infrared spectrum of

C6H5CH2HgS02CH2C6H5 has S-0 bands at 1055-10^8 and 8??-8kk cm"1, con­ sistent with an oxygen-bonded S02 moiety (vide supra)• However, the

S02CH2CgHt- methylene protons appear as a sharp singlet in the proton magnetic resonance spectrum® There are several possible explanations for this observation® First, the SO2 moiety may be functioning as a bidentate ligand making the sulfur-methylene protons equivalent® This is shown in structure IV® 8

Secondly, a very rapid equilibrium, or, alternatively fast inversion

at the asymmetric sulfur, may be occuring which would make the two

methylene protons equivalent on the proton magnetic resonance time

scale (equation 7 )»

* 9 ? C6H5CH2Hg-0-S-C-C6H5 (?)

Thirdly, it has been suggested that CgH^CH^HgOSfmay undergo

a rapid but slight ionization which would account for the observed

magnetic equivalence of the sulfinate methylene protons (23 )«

C 6 H 5 CH 2 H g 0 S( 0 )CH 2 C 6 H 5 < _ 2 ---- + c6h5ch2so2~ (8 )

The third possibility is supported by the observation that the sulfinate

readily yields CgH^CH^HgX and CgHj-GE^SO^M when allowed to react with

MX (M = Na or K; X = Cl, Br) (9).

While we have only considered the various modes of attachment

of the SO^ moiety upon reaction of X^M-R complexes with sulfur dioxide,

various modes of attachment of the R group may result when R is an allylic, propargylic, or allenic moiety, equations (9 )» (10 ), and

(11), respectively* 9

X M-CH_CH=CR_ + S0o ~> X MSO_CH_CH=CR_ n <: c. d n <£ d

or (9)

X MS0oC(R)_CH=CH_ n d d d

X M-CH_C=CR + S0„ X MSO.CH-CsCR a d . d n 2 2

or (10)

X MS0dC(R)=C=CHo a c. d

X M-CH=C=CH~ + SO, X MS0_CH=C=CH_ n d n 2 2

or (11)

X MSO-CH.CsCH n 2 2

The results from the reactions of a number of allylic, propargylic,

and allenic compounds with SO2 are given in Table 3®

Upon examination of the table, it is apparent that for the crotyl,

-CH^CHs^CH^)!!, derivatives, rearrangement accompanies S02 insertion

regardless of the metal. The insertion products for the remaining

allylic compounds, however, show a strong dependency on the metal.

Thus 7T-G5H5Mo(C0)3CH2CH=C(CH^)2 (M = Mo,W) form sulfinates with no

rearranged allylic moieties. For (CO)cMCH_CH=C(CH,)_ (M = Mn,Re), 5 2 3 2 only the sulfinates containing the rearranged allylic group is isolated, while no rearrangement accompanies the S0_ insertion reaction of (C0)_ -

MnCH2CH=C(CgHj.)H. Interestingly, "ft-C^H^Fe(CO)2CH2CH=C(CH^ )2 and H (^ H 9 0 ) OgHOS HO^ (0 )S*(0 0 ) 3 4 h ? 0 # 0 8 • S2 H O = H O H ( H O ) 0 ( 0 )S (0 0 )®.I H O # 0 2 H ( S i 9 0 )0 = H 0 2 H 0 Z(0 0 )9 / h S 0

& H( ^H 9 0 )0 = H 0 2 H 0 2 (0 ) S ^ (0 0 ) O W ^ H ^ O h ( ^ h 9 o )o = h o ? h o ^ ( o o )°w ¥ o

H ( ^ H 9 0 )0 = H 0 ZH 0 Z(0 ) S « I ^ ( 0 0 ) H( % 9 0 )0 = H 0 2 H 0 « W ^ (0 0 )

E ( ^ H O ) 0 = H 0 ?H 0 ^ ( O ) S ^ ( 0 0 )9 S ^ h 5 o LZ H O = H O ( H O ) 0 (0 )S (0 0 ) 3 0 0 %Z S ( ^ H 0 )0 = H 0 SH 0 2 ( 0 0 )ss ¥ o

(ft ‘°W = w) £ 2 2 ( ^H O ) 0 = H 0 2 H 0 2 ( 0 )S ^ ( 0 0 )w S l S S ( ^ H 0 )0 = H 0 2 H 0 ^ ( O 0 )W ^ h S

£ ( e a ‘« h = H) 2 H 0 = H 0 2 ( ^ H 0 )0 2 ( 0 )swe ( 0 0 ) ( H 0 )0 = H O HOK(OO)

9 2 q S H 0 =H0 H ( ^ H D ) D ( 0 )S0 « S ^ H 0 ) H ( ^ H O ) 0 = H 0 SH 0 u S ^ (^ H O )

(£=u ‘OM = H ‘2 = g *e,j = w ) £ 2 SHO=HOH(^HO) 0 E(0 )SU(0 0 0 H( H 0)0= H 0 H O (00)W H 0

*lZ 2H 0= H 0H ( ^ H 0)0?(0) S « W ^ ( 00) H ( ^ H O ) 0= H 02H O « W ^ ( 00)

•J3J 9g -So-txqxg (s)qonpoo

scmnojwoo o m n v onv 7 ‘oi'nsHVdioad * oiT m v so ssoikkhm: n o ish ssn i o s

Compound Insertion Product(s)a Bibliog. Refer.

(C6H5 )5SnCH2CHCH (C.Hc)-,SnOS( 0)CH=C=CHob 26 0 3 3 ci (CH,),SnCH=C=CH- (CH,),Sn0S(0)CH_CHCHb 26 3 3 c. 3 3 c.

Prepared in refluxing S02 unless noted otherwise.

^Experimental conditions not given. 12

;^-C^H^Fe(C0 )2CH2CH=C(CgH^)H react with SO^ to form a mixture of sul­

finates containing unrearranged and rearranged allylic groups©

The unusual behavior of transition metal allylic complexes to

form either unrearranged and/or rearranged sulfinates may be due to

two competing reaction mechanisms© The formation of unrearranged

allylic sulfinates may result from direct insertion of SO^ into the

metal-carbon bond (equation 12), while a cyclic concerted process in­

volving simultaneous interaction of SO^ with the metal and carbon(3 )

of the allyl chain has been suggested (2*f) for the formation of rear­

ranged allylic sulfinates (equation 13)®

m-ch2ch=crr' + so2 -— — > m-so2-ch2ch=crh* (12)

(1) (2) (3) H % M-CH2CH=CRR’ + S02 -> ,M.»^(1 ) O-Sl" ‘*C(2)-H 0 R / VH*

(3) (2)(1) ------> M-S02-CRR'CH=CH2 (13 )

If equations (12) and (13) are reasonable representations of the reaction mechanisms of allylic complexes with S02, increasing the rate of insertion of sulfur dioxide into the metal-carbon bond should favor the formation of unrearranged allylic sulfinates, while a decrease in the insertion rate of S02 into the metal-carbon bond should favor the formation of rearranged allylic sulfinates® 13

Recent investigations in these laboratories indicate that the rate of SO^ insertion into a metal-carbon bond is greatly accelerated as the electron density on the metal is increased (l6 „ 21). The

0 electron density on M for complexes of the type TT-C^H^MC CO)^CH-)CH=CRRa may be varied either by placing substituents on the cyclopentadienyl ring or by replacement of a carbonyl group with triphenylphosphiteo

Electron donating groups, e.g., CH^ 9 on the cyclopentadienyl ring are expected to increase the electron density on the metal, while electron withdrawing groups, e.g., on the cyclopentadienyl ring should decrease the electron density on the metal atom. Consequently, the amount of sulfinate containing the rearranged allyl moiety formed during the reactions of tT-CH C H , Fe( CO) _CH„CH=CR39 and ^-(CH_),_C_Fe- 3 3*+

■a’-CCgH^J^C^H^FeCCO^CH^CHsCRR' „ By replacing a carbonyl group with a better Lewis base such as P(OCgH^)^, the electron density on the metal will be directly increased. Thus, the amount of sulfinate containing the rearranged allylic moiety should be less for tt-C^H^Mo-

(C0 )2P(0C6H5 )3CH2CH=CRR' than for ff-C^^oCCO^CI^CH^RR'.

The proton magnetic resonance and infrared spectra of the product obtained from the reaction of (CgH^ J^SnCE^C^CH with SC>2 are consistent with the structure ( J^SnOSC 0)CH=C=CH2 (26). The reactions of

(COj^MnCH^HC-R and 1T-C Hyfo(COJ^CH^rC-R (R = H, CH^) are reported to yield sulfinates containing an allenyl(oxy)sulfinyl linkage M-

S(0)-0-C(R)=C=CH2 (26, 27)o More recently, Roustan and Charrier (66) Ik have examined the reactions of 7r-C_HcFe(C0 )oCH_C=C-R (R = CH_, C--Hc) 5 5 2 2 3 o ? and ■?7’-C^H^Mo(COj^CH^C^C-R (R = H, CH^, and C^H^) with SO^, and they

concluded that each of the SO^-containing products is best formulated as containing an allenyl-O-sulfinate moiety M-0-S(0 )-C(R)=C=CH2 (66)®

In order to explore further the reactions of transition metal 2-allcynyl complexes with S0_, the reactions of ^-CJH_Fe(CO)_CELC=C-CH, and 2 s 5 5 2 2 3 ■j7"-C^H^Mo(COj^PCOCgH,_ J^Cf^C^C-CH^ with sulfur dioxide will be reported®

While SOg insertion reactions for transition metal 2-alkynyl and

2-alkenyl complexes have been well documented (vide supra), no insertion reactions with complexes containing unsaturated carbon- carbon bonds adjacent to the metal have been reported® Therefore, the reactions of jr-C^H^Fe (CO) ^CH^CH^, ^-C^H,_Fe( 00)^0 hC-CH^ t and 7T-C^H^

Fe^Oj^CH-CsCH^ with SO^ will be investigated®

Graziani (21) has obtained chemical evidence that the amount of metal-sulfur pi-bonding is increased for metal carbonyl sulfinates by substituting a CO group with a phosphine ligand (vide supra)® The bonding of the Fe-S( 0)^-2 moiety can be represented by the resonance structures V, VI, and VII.

0 I Fe. S- R Fe R

V VI VII

By increasing the electron density on the iron atom, there will be an increased contribution from resonance structure V, and the basicity 15 of the oxygen atoms of SO^ will increase. This was demonstrated by the protonation of tr-C^H^Fe(C0 )P(n~C^Hg)^S(0 )2CH^ but not 77-C^H^Fe (C0 )2»

S(0 )2CH^ with hydrogen chloride (21),

TT-C^H^Fe(CO) P(n-CltH9 )5S(0)2CH3 + HC1 ------— >

r 9 [jT-C^H^FeCCO)P(n-C^Hg)3~$-CH3J Cl (Ik)

H

In order to determine if this reaction can be extended to other Lewis acids, the reactions of BF, with iT-Cc.HcFe(C0)PR,S(0)_CH, (R = C^H- and 5 5 5 5 2 3 6 5 n-C^Hg) will be investigated. EXPERIMENTAL

Starting materials

Metal carbonyls., The metal carbonyls used in this investigation were obtained from various sources® Iron pentacarbonyl was purchased from Alfa Inorganics, Inc. Cyclopentadienyliron dicarbonyl dimer,

{jr-C^H^Fe(00) ^ 2 * 311 d. cyclopentadienylmolybdenum tricarbonyl dimer,

Jtt-C^H^MoCCO^^* were purchased from Strem Chemicals Co. and Pressure

Chemical Co., respectively. These were used without further purifi­ cation.

Pentamethylcyclopentadienyliron dicarbonyl dimer, ^-(CH^)^C^-

FefCO^^* was prepared by the method of King and Bisnette (28) from iron pentacarbonyl and pentamethylcyclopentadiene. Pentaraethylcyclo- pentadiene is not commercially available and was prepared using the procedure of deVries (29) which contains the following five steps:

(a) Dry ethyl ether, 1300 ml., was placed into a 2-liter, 3-neck round bottom flask provided with a stirrer and reflux condenser. Lithium wire (8.4 g., 1.2 mole) cut into small pieces was added to the ether under nitrogen. 2-Bromo-2-butene (Columbia Organic Chemicals Co.)

(8l g., 0.6 mole), diluted with an equal volume of ether, was added to the flask over a one hour period. The ether refluxed spontaneously.

After the addition was complete, the reflux was continued for another hour. Tiglaldehyde (City Chemical Corporation) (50.4 g., 0.6 mole) was then added dropwise and the reflux continued for another hour. 16 17

After cooling to room temperature, the solution was hydrolyzed with

a saturated solution of ammonium chloride until no more heat developed*.

The aqueous layer was separated from the ether and extracted three times

with 100 ml® of ether0 The ether extracts were combined and dried over

magnesium sulfate® The ether was removed with rotary evaporator (25®,

20 mm®) leaving a yellow oil® The oil was distilled (55°, 1®0 mm®)

giving 45 go (0®31 mole, 50% yield) of 3,5-dimethyl-2 ,5-heptadiene-4-ol,

[CH.^CH=C(CH^)J2^H0H® (b) In a 5-liter, 3-neck round bottom flask were placed 45 g® (0®31 mole) of jCH^CH=C(GH^)J^CHOH, 2 liters of pentane and 450 g® of freshly prepared manganese dioxide® The mixture was

stirred for 3 days at room temperature® After filtration and solvent removal (25°* 20 mm®), an oil vras obtained® Distillation of the oil

(58°, 4 mm®) gave 35 go (0o24 mole, 77% yield) of di-2-butenyl ketone,

^H5CH=C(CH3 )]2C0. (c ) Ring closure of di-2-butenyl ketone was ac­ complished by dissolving 35 g® (0.24 mole) of the ketone in a mixture of 90% formic acid and 13®3 go of phosphoric acid® The mixture was heated to 80-90° for 4 hours, cooled, and poured into an excess ice- water solution. The brown, oily suspension that resulted was extracted with pentane® Removal of the pentane (25°, 20 mm®) and distillation

(60°, 3 mm®) of the residue gave 27 g® (0®21 mole, 87% yield) of

2,3,4,5-tetramethycyclopent-2-en-l-one. (d) The cyclic ketone obtained from step (c) was added dropwise to 0.42 mole of methyl lithium (Foote

Mineral Co. as a 1.6 M solution in ether). The mixture was refluxed for 1 hour before hydrolyzing with a saturated ammonium chloride solution®

The aqueous layer was separated from the ether and extracted with ether®

The combined extracts were dried over anhydrous magnesium sulfate® 18

Removal of solvent (25% 20 mm.) and distillation (70°, 5 mm.) of the

residue gave 211 g® (0.16 mole, 76^ yield) of 1 ,2 ,3 »**,5-pentamethylcyclo-

pent-2-en-l-ol® (e) Dehydration of l,2,3,%5-pentamethylcyclopent-2~

p en-l-ol was accomplished by adding a few crystals of iodine to the alco­

hol and gently heating the mixture for 2 hours at 65®° The dehydration

product was decanted from water and dried over anhydrous magnesium sul-

fateo The liquid was distilled (58°, 10 mm.) to give 20 g® (0®15 mole)

of 1,2,3,%5-pentamethylcyclopentadieneo The iron dimer, [V-(CH,)_C_- L 5 5 5 Fe(C0 )2J2, was prepared by charging a 1-liter, 3-neck round bottom flask

with 20 g® (0 o15 mole) of pentamethylcyclopentadiene, *f0 ml. (10®2^

mole) of iron pentacarbonyl, and 500 g® of 2,2,5-trimethylhexane® The

mixture was refluxed for kS hours under nitrogen® After cooling to

room temperature, the black residue was filtered off and washed with 1

liter of toluene® Solvent was removed from the combined washings and

filtrate in vacuo (25°, 0®1 mm®) to give 17 g® (10®03 mole, k3%) of

fr-(CH3 )5C5Fe(C0 )2]2®

Methylcyclopentadienyliron dicarbonyl dimer, jr-CH^C^H^FeCCO^^i

was prepared by slightly modifying the original procedure of Reynolds

and Wilkinson (30)® Commerical methylcyclopentadiene dimer (Aldrich

Chemical Company, Inc®) must be purified before use® Methylcyclo­

pentadiene monomer was taken off through a 20 cm. Vigreux column® The monomer was collected in a flask cooled to -20° in order to prevent dimerization® The monomeric methylcyclopentadiene was further purified by distillation through a 60 cm. Vigreux column® Pure methylcyclopent­ adiene monomer distills at 72-7^° and was allowed to diraerize by warming to room temperature® A 500 ml®, 3-neck round bottom flask was flushed 19 out with nitrogen and charged with bj> ml. (0.32 mole) of iron penta­ carbonyl and 166 g. (lo0*f mole) of methylcyclopentadiene dimer. The mixture was heated for 16 hours in an oil bath maintained at 150°.

The mixture was then allowed to cool to room temperature and dark , red-purple crystals separated. The crystals were filtered off and washed with liberal amounts of pentane to give 25 g® (b2% yield) of

|^-CH3C5H/fFe(CO)a]2„

1,3-Diphenylcyclopentadienyliron dicarbonyl dimer, j/r-1,3-

(CgH^)2^ 11^ 6(0 0 ) ^ 2 was prepared according to the method of Knox (31) from the reaction of 1 ,3-diphenylcyclopentadiene with excess of di-

for the synthesis was prepared as described by Drake and Adams (32).

Dry sodium ethoxide (prepared from 0 ob6 g.-atom of Na) was mixed with bOO ml. of dry benzene and *f8 g. (0.26 mole) of ethyl-3-benzoylpropionate

(Aldrich Chemical Company, Inc.). Acetophenone (Aldrich Chemical Com­ pany, Inc.) in an amount equal to 28 g. (0.28 mole) was then added and the flask stoppered. The mixture was allowed to stand for 2b hours at b0° before pouring into an excess ice-water mixture. The water layer was then removed and warmed to 60 °. Yellowish crystals soon formed and were removed by filtration. Recrystallization from benzene gave 18 g. (0.08 mole, 31% yield) of 1 ,3-diphenylcyclopentadiene.

1,3-Diphenylcyclopentadiene (bab g., 0.02 mole) was dissolved in benzene and treated with 7®2 g. (0.02 mole) of Fe2(C0 )^ for 16 hours under nitrogen at room temperature® The reaction mixture was then placed on a 5 x 15 cm. activated alumina column made up with benzene. Elution with benzene separated a brown band from a yellow-green band of unreacted 20

1,3-diphenylcyclopentadiene® The brown band was collected first, and the red-brown eluate was concentrated in vacuo (30°, 20 ram® )® The addition of pentane afforded 1®0 g. (10/a) of the red-brown crystalline ^-l,3-(C6H5)2C5H3Pe(00)2]2.

Cyclopentadienylmolybdenum triphenylphosphite dicarbonyl dimer,

JiT-C^H^MoCCO^PCOCgH,-)was prepared according to the method of

King and Pannell (33)° A mixture of 10 g® (20®*f mole) of IV-Cj-H-Mo-

(COjJgv 12®^ go (40 mmole) of triphenylphosphite (Aldrich Chemical

Company, Inc®) and AOO ml® of benzene was exposed for 20 hours to the ultraviolet irradiation from a Hanovia lamp (see Fig® l)® The purple precipitate was filtered off and washed with several liters of chloro­ form® After drying in vacuo (25®, 0®1 mm0), 12 g® (60% yield) of

^-C^H^Mo(C0 )2P(0CgH^)^j2 was obtained®

Ligands, solvents, other reagents, and chromatography supports®

Sulfur dioxide, obtained from Matheson, Inc®, was of anhydrous grade, but was further dried by passing through a column of calcium chloride®

Product purification was generally accomplished by column chrom­ atography® Neutral activated alumina was purchased from the Ventron

Corporation® It was found, however, that alumina deactivated with distilled water (6-10$) exhibited the most desirable adsorption prop­ erties® Florisil (60-100 mesh), from Fisher Scientific Company, was often used in chromatographies® It has the special advantage of per­ mitting the use of very polar solvents, eg®, acetone, which dehydrate deactivated alumina® Silica gel (100-200 mesh) was obtained from the

Davison Chemical Company® 21

The allylic halides were purchased from the following sources:

Cinnamyl chloride from K & K Laboratories; l-chloro-3-methyl-2-butene

(Practical) from Eastman Organic Chemicals; and crotyl chloride from

Aldrich Chemical Company, Inc®

Other ligands and reagents were purchased from a variety of sources as reagent grade chemicals and were used without further pur­ ification® 3“Bromopropyne, acryloyl chloride, and tri-n-butylphosphine were obtained from Aldrich Chemical Company, Inc® Triphenylphosphine was purchased from Matheson, Coleman and Bell, while Columbia Organic

Chemicals Company supplied iodomethane® Matheson, Inc® was the source of reagent grade boron trifluoride®

l-Chloro-2-butyne is not commerically available and was prepared by the method of Hatch and Chiola (3*+)® A mixture of 21 g® (0®3 mole) of 2-butyn-l-ol, purchased from Farchan Research Laboratories, and

5®5 g® (0.00? mole) of pyridine was added dropwise to l6®3 g® (0®12 mole) of phosphorus trichloride maintained at 0°. During the addition period the phosphorus trichloride was vigorously stirred with a magnetic stirrer® After all of the alcohol was added, the organic chloride was removed from the reaction mixture by distillation® The fraction distilling at 102-10*f° was collected® The distillate was washed with two 30 ml® portions of saturated aqueous potassium bicarbonate and then one 30 ml® portion of water. After drying over anhydrous magnesium sulfate, the product was redistilled to give 12 g. ik3% yield) of 1- chloro-2-butyne®

Tetrahydrofuran (THF) was purified by distillation over calcium hydride (Metal Hydrides Inc.) under nitrogen. With the exception of 22 technical grade pentane all solvents used in preparations and purifi­ cation steps were of reagent grade quality®

Solvents used for infrared spectra were spectroscopic grade from

Matheson9 Coleman and Bell® Nujol was dried over sodium wire® Stohler

Isotope Chemicals provided a source of 99°5% isotopic purity deutero- chloroform® Tetramethylsilane (IMS) was NHR grade and purchased from

Columbia Organic Chemicals Company®

Elemental analysis, physical measurements, and special apparatus®

Elemental analysis were performed by Pascher Mikroanalytisches

Laboratories, Bonn, Germany and Galbraith Laboratories, Inc®, Knoxville,

Tennessee®

Molecular weight determinations were done in chloroform solutions

(ca® 10' -2M) by Miss Margaret Jennings using a Mechrolab Osmometer-j501A«

Unless otherwise stated, all infrared spectral measurements were obtained on a Perkin-Elmer 337 spectrophotometer® Solution spectra were obtained by using a sealed sodium chloride solution cell (0®1 mm®) and a sodium chloride variable thickness solvent cell. Spectra of solid samples were taken as either potassium bromide pellets or Nujol mulls®

All melting points were measured in capillaries using a mineral oil bath and are uncorrected®

Proton nuclear magnetic resonance measurements were obtained using a Varian Associates A-60 or A-60A spectrometer® Unless stated otherwise, tetramethylsilane was used as an internal standard® All spectra were taken in deuterochloroform at room temperature® Equipment used for ultraviolet irradiations was purchased from the Hanovia Lamp Divison of Englehard Hanovia, Inc® (see Fig® l)®

The source of radiant energy was a h$0 watt high-pressure quartz mercury-vapor lamp, model 679A-36. Of the total energy radiated, approximately 30& is in the ultraviolet portion of the spectrum, 18% is in the visible, and the balance is in the infrared® The lamp is operated by a reactive type transformer, model 3^245-1, which supplies the extra voltage and current required to initiate the arc and the reduced power for operation® A double-walled, water cooled quartz immersion well, model 19^3^, holds the lamp in the center of the reaction vessel®

The pressure reaction vessel (Fig® 2) was an aerosol compatibility tube, 3 ounce capacity, with plastic shield and coupling, for use with one inch aerosol valves, purchased from Fischer & Porter Company.

Instead of using an aerosol valve, however, a needle valve, model 30^A from Hoke Incorporated, with an attached glass connecting adapter was used in its place. All connections were fitted with either rubber or teflon gaskets in order to insure proper seating. Water Outlet Water Inlet

Nitrogen Outlet Nitrogen Inlet

Reaction Vessel Immersion Well

Lamp

Sample Solution

Figure 1. Ultraviolet irradiation apparatus. Adapter

Needle Valve

. Plastic Shield

Liquid SO,

Figure 2. Pressure reaction vessel 26

General remarks on preparation of allylic sulfinate complexes

Because most of the steps used in the synthesis of the various allylic complexes were identical, some general procedures will be out­ lined before proceeding to an individual description of each allylic synthesis® Details of each individual preparation can be found in the following sections®

The sodium salts of the cyclopentadienyl iron and molybdenum carbonyls were prepared by reacting 1-3 mmoles of their dimers in 30-50 ml® of tetrahydrofuran (THF) with an excess of sodium amalgam (2®3 g° in 15 ml® of mercury to give a 1# amalgam)® The reactions were carried out in a 250 ml® 3-neck round bottom flask with a stopcock adapter fused to the bottom® A mechanical stirrer was used to stir the amalgam vigorously while keeping the system under nitrogen® The reductions were usually complete after 2 hours® The excess sodium amalgam was then removed by means of the stopcock adapter, and the reaction flask was then connected via the adapter to a standard 3-neck round bottom flask® The latter was equipped with a magnetic stirring bar and con­ tained a THF solution of the allyl halide® The sodium salt solution was added slowly via the stopcock adapter to the allyl halide solution®

The resulting mixture was stirred at room temperature under nitrogen for 1-9 hours. The THF and any unreacted allyl halide were removed in vacuo. After the mixture had been taken to dryness, the residue was extracted and filtered through 5 g» of Zeolite (used to aid filtration).

The filtrate was concentrated to 10-15 ml® with a stream of nitrogen and purified by column chromatography. The sigma-bonded allyls were used without further purification. Because of their instability, they

were not characterized by elemental analysis. However, their structures

were confirmed by infrared and proton magnetic resonance spectroscopy.

Due to the oily nature of the products, making solvent removal difficult,

the complete infrared spectra had little significance. The spectra

in the terminal carbonyl stretching frequency region, however, were un­

affected by solvent impurities and verified the presence of a sigma-

bonded allyl group. In general, solvent impurities did not affect

the proton magnetic resonance spectra and permitted an assignment of

the structure and point of attachment of the allyl moiety to the tran­

sition metal.

The sulfinato complexes of iron were purified by chromatography

on grade IV neutral alumina columns made up with chloroform. The molybdenum sulfinates were chromatographed with 1:1 chloroform-acetone

solvent mixtures on Florisil columns made up with chloroform. The

sulfinates were readily separated from small amounts of decomposition products and occasionally unreacted starting material. The decomposition products arose from the unstable starting materials and not the sul^

finates. This was demonstrated by the absence of decomposition upon chromatography of the pure sulfinates. The sulfinates were characterized by elemental analysis which also provided an indirect characterization of the starting allyl complexes. 28

Preparation of allylic sulfinate complexes of cyclopentadienyliron dicarbonyl

S- (l-Methyl-2-propenylsulf inato) (methylcyclopentadien.yl )iron

dicarbonyl, Tr-CK^C^El^’e(CO)^SO-^CE(CE^)CK=CR^„ The starting material,

tf^CH^Cc-H^FeC CO^CH^CH^HC CH^) , was prepared by the sodium amalgam

reduction of jV-CH- Cj-H^FeCCO^^ (1*00 g., 2.61 mmole) in 30 ml. of

THF. After removing excess amalgam, the sodium salt solution was added

to 0„k7 go (5®22 mmole) of crotylchloride in 10 ml. of THF. The mixture

was stirred for one hour at room temperature under nitrogen. Solvent

removal (25°, 0.1 mm.) was followed by extraction of the residue with

100 ml. of pentane. The extract was filtered through 5 g® of Zeolite

and the filtrate was concentrated to a volume of approximately 10 ml.

in a stream of nitrogen. The product was purified by chromatography

(2 x 20 cm. neutral grade IV alumina column made up with pentane).

Elution with pentane separated a yellow band of TT-CH^C^H^FeCCO^CH^-

CH=CH(CHj) from approximately an equal amount of purple jV-CH^C^H^Fe-

(CO)^^* yellow band was eluted first and collected under nitrogen.

An orange oil was obtained after removing the solvent in a stream of nitrogen.

Approximately 25 ml. of liquid sulfur dioxide was condensed onto

7T"CH^C^H^Fe(CO)^CI^CH^CHCCH^) and the mixture was allowed to reflux

for 6 hours using a Dry Ice condenser. After the reaction period was over, the excess SO2 was removed in a stream of nitrogen. The remaining red oil was purified by chromatography (2 x 20 cm. neutral grade IV alumina column made up with chloroform). Elution with chloroform removed a broad yellow band from a small band of decomposition material. 29

The yellow eluate vras concentrated to about 10 ml® with a rotary evap­

orator (30®, 20 mm®)® Slow addition of 100 ml® of pentane gave 0*48 g®

(30& yield based on ^/-CH^C^H^Fe(CO)2~|2) of yellow-orange crystals®

The sulfinate melted at 64-66®C0

Isomeric mixture of S-(3-methyl-2-butenylsulfinato) and S-(l„l°

dimethyl-2-propenylsulfinato)(methylcyclopentadienyl)iron dicarbonylB

v-CHy35H^Fe(C0)2S02CH2CH=£(CH3 )2 and /v-CH^H^FeC C0)2S02C( CH3 )2CH=CH2®

The starting material, v-CH^C^H^Fe(CO)2CH2CH=C(CH^)2, was prepared from

the reaction of Na p’-CH^C^H^Fe(GO)£J with l-chloro-3-methyl-2-butene®

A THF solution of Jr-CH^C^H^FeCC0)2J2, lo00 g® (2®6l mmole) in 50 ml®, was allowed to react with excess 1% sodium amalgam for 2 hours® The resulting sodium salt solution was slowly added to 0®55 g° (5°22 mmole) of l-chloro-3-methyl-2-butene in 10 ml® of THF® The mixture was stirred for three hours at room temperature under nitrogen® The solvent was removed from the reaction mixture (25°, 0®1 mm®), and the residue was extracted with 100 ml® of pentane® The extract was filtered through

Zeolite before chromatography (2 x 20 cm® neutral grade IV alumina column made up with pentane)® Elution with pentane separated a yellow band of product from an approximately equal amount of Jv-GH^C^H^Fe(CO)2J2

The yellow band was eluted first, and the eluate was taken to dryness in a stream of nitrogen®

The remaining orange oil was dissolved in 25 ml® of liquid S02®

After allowing the mixture to reflux for 6 hours, excess sulfur dioxide was removed in a stream of nitrogen® The remaining red oil was puri­ fied by chromatography (2 x 20 cm® neutral grade IV alumina column made up with chloroform)® Elution with chloroform separated a broad 30

yellow band from a small brown decomposition band that remained at the

top of the column.. The yellow eluate was concentrated to 10 ml® with a

rotary evaporator (30®, 20 mm®), and yellow-orange crystals were obtained

by the slow addition of 100 ml® of pentane® Yield: 0®67 go (^0^ based

on Jfl'-CH^C^H^FeCCO) ^ ^ ^ 0 mixture melted at 70-71 ®Co

Isomeric mixtures of S-( cinnam.ylsulfinato) and S-(l-phenyl-2-

propenylsulfinato)(methylcyclopentadienyl)iron dicarbonyl, iT-CH,C_H. ------2_Zjt Fe(C0 )2S02CH2CH=CH(C6H5) and 7T-CH^C^H^Fe(C0 )2S02C(C6H5 )HCH=CH2o

jt-CH^C ^.H^Fe (CO ) ^CH^CH =G ( ) H was obtained from the reaction of Na-

JifT-CH^C^H^Fe(CO)^] with cinnamyl chlorideo A THF solution of JV-CH^-

C^H^Fe(C0 )2J2 , 1«>00 go (2o6l mmole) in 50 mls, was reduced with excess

sodium amalgam0 The resulting sodium salt solution was then added to

. O08O go (5»22 mmole) of cinnamyl chloride in 10 ml0 of THF0 The mixture

was allowed to react for 2 hours under nitrogen® The solvent was then .

removed (25®, 0 ol mm®), and the residue was extracted with 100 ml® of

pentane and filtered® The filtrate was concentrated to ca. 10 ml® in

a stream of nitrogen and purified by chromatography (2 x 20 cm® neutral

grade IV alumina column made up with pentane)® Elution with pentane

separated the yellow product from a second band of jjy-CH^C^H^Fe(CO)2j2®

The JT-CH^C^H^FeCCOj^H^HsCCCgH^jH was eluted off the column first,

and an orange oil was obtained after removal of the solvent®

The orange oil was dissolved in 25 ml® of liquid sulfur dioxide

and the mixture was allowed to reflux for 6 hours with the aid of a

Dry Ice condenser® The excess SO2 was then removed in a stream of

nitrogen® The remaining red oil was purified by chromatography (2 x 20

cm® neutral grade IV alumina column made up with chloroform)0 Elution 31

with chloroform separated a yellow band from a small decomposition

band that remained at the top of the column® After concentrating the

eluate to ca» 10 ml® with a rotary evaporator (30®9 20 mm.), yellow- orange crystals were obtained by the slow addition of 100 ml® of pentane®

Yield: 0.58 g® (30$ based on J-jf-CHy^H^Fe( ) 2J2)® The melted at 125-127°C®

In another experiment, W-CH^C^H^Fe(C0 )2CH2CH=C(CgHj-)H was dissolved in 50 ml® of hexane, and gaseous SO2 was bubbled through the solution continuously for 48 hours at room temperature. The hexane and excess

SOg were removed and the residue was purified by chromatography (2 x 20 cm® neutral grade IV alumina column made up with chloroform)® Elution with chloroform separated a yellow band from a decomposition band that stuck to the top of the column. The yellow eluate was concentrated to about 10 ml. with a rotary evaporator and yellow-orange crystals were obtained by the addition of 100 ml. of pentane® An approximately equal amount of decomposition material remained at the top of the column®

Yield: 0.29 g. (15& based on JrT-CH^H^FetCO)^).

Isomeric mixture of S-(3-methyl-2-butenylsulfinato) and S-(l,l- dimethyl-2-propenylsulfinato)(1 ,3-diphenylcyclopentadienyl)iron dicarbonyl.

7T-1,3-( C6H5 )2C5H3Fe(C0)2S02CH2GH=C( CH3 )2 and ^-1,3-( )2C H Fe(C O ) ^

S02C(CH3 )2CH=CH2® The sodium salt of [ff-1,3-(C6H5 ^Cy^FetC0)2J2 was obtained from the reaction of the dimer (0.80 g., 1.22 mmole) with excess

1% sodium amalgam in 40 ml® of THF® After removing the excess amalgam, the sodium salt solution was added to 0®26 g® (2.44 mmole) of 1-chloro-

3-methyl-2-butene in 15 ml® of THF® The mixture was stirred for 2 hours under nitrogen at room temperature® After the reaction period was over, the solvent was removed in vacuo (25®, 0.1 mm®). The residue was 3 2 extracted with 100 ml® of pentane and filtered through about 5 g®

of Zeolite® The filtrate was concentrated to 15 ml® in a stream of

nitrogen and purified by chromatography (2 x 20 cm® neutral grade IV

alumina column made up with pentane)® Elution with pentane separated

a yellow band from unreacted dimer® The yellow band of-gr-1, 3-(c 6H5)2“

C^H^Fe(CO)^CH^CH=(CH^)^ was collected first, and an orange oil was

obtained after removing the solvent in a stream of nitrogen®

Approximately 25 ml® of liquid sulfur dioxide was condensed onto

the oil, and the mixture was allowed to reflux for 6 hours® After .

removing the excess SO^ in a stream of nitrogen, the residue was taken

up in 15 ml® of chloroform and purified by chromatography (2 x 20 cm®

neutral grade IV alumina column made up with chloroform)® Elution with

chloroform separated a yellow band from an immovable decomposition band®

The yellow eluate was concentrated with a rotary evaporator (30°, 20

mm.), and the bright yellow crystals were obtained upon the addition of

100 ml® of pentane® Yield: 0.80 g® (.70% based on jj*-l,3-(OgH^^C^-Hy

S-(l-methyl-2-propenylsulfinato)(pentamethylc.yclopentadienyl)-

iron dicarbonyl, ?r-(CHOcC_Fe(C0)-S0_C(CH,)HCH=CH_. Na r7r-(CH_)cCc- ______;______j ; 7______g- 2 3______2 L 3 5 5 FeCCO^] was obtained from the reaction of jTf-CCH^J^C^FeCCO)^^ (1*00 g

2®02 mmole) with excess sodium amalgam in 30 ml® of THF. After removing

the excess amalgam, the sodium salt solution was slowly added to O.36 g®

(beOk mmole) of crotyl chloride in 10 ml® of THF® The mixture was stirred for two hours under nitrogen at room temperature. Solvent re­ moval (25°, 0®1 mm®) was followed by extraction of the residue with 100 ml® of pentane® The volume of the filtrate was reduced to ca® 10 ml. in 33

a stream of nitrogen after filtering the extract through 5 g® of

Zeolite® The concentrated filtrate was placed on a 2 x 20 neutral

grade IV alumina column made up with pentane® Elution with pentane

separated a yellow band from an approximately equal amount of unreacted

^-(CH^J^C^FeC00) ^ 2° ® ie yellow band was collected first, and an

orange oil was obtained after removing the solvent in a stream of

nitrogen®

Approximately 25 ml® of liquid SO2 was condensed onto the oil

and the mixture was allowed to reflux for 6 hours® After the reaction

period was over, the excess SC^ was removed in a stream of nitrogen®

The residue was taken up in chloroform and purified by chromatography

(2 x 20 cm® neutral grade IV alumina column made up vrith chloroform)®

Elution with chloroform separated a yellow band that was collected under

nitrogen® The eluate was concentrated to 15 ml® with a rotary evapor­

ator, and the sulfinate was obtained as yellow crystals by the slow

addition of 100 ml® of pentane® Yield: 0®*t0 g® (27& based on

C^Fe(00)2^2 ^® The sulfinate melted at 117-119°®

S-(Cinnamylsulfinato)(pentamethylcyclopentadienyl)iron dicarbonyl

IT- (CH^)^C^Fe(CO) ^ 6 ^ 5 )H® The starting material, 7/-(CH^)^-

C^FeCCO^C^CHsCfCgH^H, was prepared in the usual manner by first

obtaining Na ^-(CH^j-CjJTeCCO^] from the reaction of ^-(CH^)^C^Fe-

(C0 )2]2 (1.00 g®, 2®02 mmole) with excess 1% sodium amalgam in 30 ml®

of THF® After removing the excess amalgam, the sodium salt solution

was slowly added to 0 ®6l g® (4®0*fr mmole) of cinnamyl chloride in 10

ml® of THF® The resulting mixture was stirred for k hours at room

temperature under nitrogen® Solvent removal (25°, 0®1 mm®) was followed

by extraction of the resulting residue with 100 ml. of pentane® The 3**- extract was filtered through 5 go of Zeolite and concentrated to ca»

10 mlo in a stream of nitrogen® The concentrated solution was then purified by column chromatography (2 x 20 cm® neutral grade IV alumina 0 column made up with pentane)® Elution with pentane separated a yellow band of Tf-CCH^J^C^FeCCO^CH^CH^CCgHj.)!! from an approximately equal amount of purple p-CCH^^C^FeCCO)^^® The yellow band was collected first9 and an orange oil remained after evaporation of the solvent in a stream of nitrogen®

The residue was dissolved in 25 ml® of liquid sulfur dioxide, and the mixture was allowed to reflux for 6 hours with the aid of a

Dry Ice condenser® A dark red oil remained after removing the excess

SO2 in a stream of nitrogen® The oil dissolved in 10 ml® of chloroform and purified by chromatography (2 x 20 cm® neutral grade IV alumina column made up with chloroform)® A yellow band of the sulfinate was obtained by elution with chloroform® The yellow eluate was concen­ trated to approximately 10 ml® with a rotary evaporator (30°, 20 mm®), and yellow crystals were obtained by adding 100 ml® of pentane to the concentrated eluate® The sulfinate melted at l63-l65°C. Yield: 0®^7 g®

(25# based on |jr-(CH3) C Fe(C0)2]2).

S-(3-Methyl-2-butenylsulfinato)(pentamethylcyclopentadienyl)- iron dicarbonyl, ^ - ( C H ^ ^ F e C C O ^ S C ^ C H ^ H ^ C H . ^ . A solution of

Na ^-(CH^^Cj-FeCCO^^ was obtained by treating ^ir-(CK^) ^C^eiCO)

(1®00 g., 2®02 mmole) in 30 ml® of THF with excess 1% sodium amalgam®

The excess sodium amalgam was removed, and the sodium salt solution was slowly added to 0®^2 g® (4®0^ mmole) of l-chloro-3-methyl-2-butene in 30 ml® of THF® The mixture was stirred for 2 hours under nitrogen at room temperature* The solvent was removed (25% 0,1 mm,) and the residue was extracted with 100 ml, of pentane® The extract was filtered through Zeolite, concentrated to 10 ml® in a stream of nitrogen', and purified by chromatography (2 x 20 cm, neutral grade IV alumina column made up with pentane)® Elution with pentane separated a yellow band of »r-(CH^^C^FeC C0)2CH2CH=C(CH3 )g from a purple band of unreacted

Jff-CCH^J^C^FeCCO^^* ® ie yeH ° w band was collected first * and nitrogen was used to remove solvent®

The orange residue was dissolved in 25 ml® of sulfur dioxide, and the mixture was allowed to reflux for 6 hours® After the reaction period was over, the excess SO2 was removed in a stream of nitrogen® The re­ maining red oil was purified by chromatography (2 x 20 cm® neutral grade IV alumina column made up with chloroform)® Elution with chloro­ form separated a yellow band of product from a small amount of decom- i position material that remained at the top of the column® The eluate was concentrated to about 10 ml. with a rotary evaporator and 0.50 g®

(30^ yield based on |^-(CH^)^C^Fe(CO)of yellow crystals were ob­ tained upon the addition of 100 ml. of pentane. The sulfinate melted at 135°®

Isomeric mixture of S-(3-methyl-2-butenylsulfinato) and S-(l,l- dlmethyl-2-propenylsulfinato)(pentameth.ylcyclopentadien.yl)iron dicarbonyl, 7T-( CH3 ^C^FeCC0 )2S02CH2CH=C(CH3 )£ and jf-tCH^C^FeCCO^SO^

C(CH3 )2CH=CH2. The starting material, V- (CH3 ^C^Fe(CO)2CH2CH=C(CH3 )2, was prepared as described above. The complex was dissolved in 50 ml. of hexane and gaseous S02 was bubbled through the solution continuously for 48 hours at room temperature. The hexane was then removed in vacuo (25®, 0.1 mm.) and the remaining red oil was purified by chromatography

(2 x 20 cm. neutral grade IV alumina column made up with chloroform)„

Elution with chloroform separated a yellow band from an equal amount of

p decomposition materialo The yellow eluate was concentrated to about 10 ml. with a rotary evaporator, and the sulfinate mixture was crystallized by the addition of 100 mlo of pentaneo Yield: 0®20 g0 (13% based on

1.00 g. of [jF-(CH3 )5C5Fe(C0 )2]2)o

A mixture of ;r-(CH_)cCcFe(C0)oS0_CHoCH=C(CH_.)_ and jr-(CH,),.CcFe(C0)o- 3 3 3 222 32 355 2 S02C(CH3 )2CH=CH2 was also prepared by reacting ^-(CH3 )3C3Fe(C0 )2CH2QH=C-

(CH3 )2 with liquid sulfur dioxide at approximately -50°o After isolating the starting material (vide supra), the complex was added to 50 ml. of liquid S02 maintained at ca. -50® with the aid of a Dry Ice-chlorobehzene constant temperature bath. After 6 hours the excess S02 was removed in vacuo (-50°, 0.1 mm.), and the remaining residue was purified by chroma­ tography (2 x 20 cm. neutral grade IV alumina column made up with benzene).

Elution with benzene readily removed a yellow band of unreacted isf-(CH_)e-Cir- 5 3 5 Fe(C0)2CH2CH=C(CH3 )2. The immovable band of sulfinates was obtained by eluting the column with chloroform. The chloroform eluate was concen­ trated with a rotary evaporator, and crystals were formed by adding 100 ml. of pentane to it. Yield: 0.25 g. (1 6% based on 1.00 g. of lyr-(CH,) c - L 5 5 Fe(C0)2]2).

The analytical and molecular weight data obtained for allylic sul- finato complexes of iron are given in Table TABLE 4

ANALYTICAL AND MOLECULAR WEIGHTa DATA FOR ALLYLIC SULFINATO COMPLEXES OF IRON

Compound*3 Calculated Found Analysis Molecular Analysis Molecular C H weight C H weight

GH^C^FeCCOjgSOgC^ 46.49 4.52 310 46.47 4.32 305

CHjC^FeC C0)2S02C5H9C 48.19 4.94 324 47.86 4.94 332

CHjC^FeCCO)^^* 54.88 4.30 372 54.03 4.33 377

*

(C6H5 )2C5H3Fe(C0)2S02C5H9C 62.37 4.76 462 61.90 4.82 476

(CH^^FeCCO^SO^H,, 52.A y 6.01 366 52.29 5-81 354

( CH^ )'-C'.Fe( C0)2S02C5H9 53-72 6.32 380 54.09 6.48 388

(CH3 )5C5Fe(C0)2S02C9H9 58.92 5-61 428 59-26 6.11 433

aOsmometry in chloroform (0.01-0.02M).

|. All compounds prepared in refluxing liquid S02.

°Isomeric mixture shown by nmr. 38

Preparation of allylic sulfinate complexes of cyclopentadienylmolybdenum dicarbonyl

Isomeric mixtures of S-(l-methyl-2-t>ropenylsulfinato) and S-

(crotylsulfinato)cyclopentadienylmolybdenum dicarbonyl triphenyl- phosphite, jr-^H^oCCO^tXJgH^SO^CCHjjHCHsCHg and sr-C^MoCCO^-

P(0G6H5 )3S0oCH2CH=C(CH3 )Ho The starting material, Jf-C^H^MoCCO)^

P(0CgH^)^CH2CH=C(CH^)H, was prepared from the reaction of Na [ps-C^Hj.-

Mo^O^PCOCgH^)^J with crotyl chloride® In a typical experiment, loO go of jW-C,-H£-Mo(CO)2P ( m^" was allowed to react with excess 1% sodium amalgam for 1*5 hours® After the reaction period was over, the excess amalgam was removed, and the sodium salt solution was added to 0«>95 go (10 mmole) of crotyl chloride in 15 .ml® of THF0 The mixture was allowed to react for 12 hours under nitrogen at room temper- atureo Solvent removal (40°, 20 mm.) was followed by extraction of the residue with 50 mlo of 2:1 pentane-dichloromethane0 The extract was filtered through 5 g® of Zeolite and purified by chromatography (2 x 20 cm® neutral grade IV alumina column made up with pentane)® Elution with a 2:1 pentane-dichloromethane mixture removed a broad yellow band® The

7f-C^H^Mo(C0)2P(0CgH^)^CH2CH=C(CH^)H was isolated as an orange oil after removing the solvent in a stream of nitrogen®

The oil was dissolved in 25 ml® of liquid sulfur dioxide, and the mixture was allowed to reflux for 6 hours® The excess S02 was allowed to boil off, and the residue was purified by chromatography (2 x 20 cm®

Florisil column made up with chloroform). Elution with chloroform fixes the sulfinates at the top of the column® The products were removed from a small amount of decomposition by elution with a 1:1 chloroform- 39 acetone mixture* The yellow eluate was concentrated to about 10 ml® with a rotary evaporator (30°, 20 mm,), and 0*70 g* (5 yield based on Jy^C^H^MoCCOj^PCOCgHj.)^.,) of bright yellow crystals were obtained by the addition of 100 ml® of pentane® The sulfinate mixture melted with decomposition at 118-120°®

In another experiment (CO) ^CH^CI^C ( CH^ )H was allowed to react with liquid SO^ maintained at ca* -50® with a chloro- benzene-Dry Ice constant temperature bath* After 8 hours the excess

SO2 was removed in vacuo (-50®, 0*1 mra*) and the remaining residue was purified by chromatography (2 x 20 cm* Florisil column made up with chloroform)* Elution with chloroform removed a faint yellow band from the major yellow band that remained at the top of the column* An infra­ red spectrum of the chloroform eluate in the C-0 stretching frequency region was identical with that of ^'-Cc.Hc:Mo(CO)_P(OC/rHc.),CH0CH=C(CH,)Ho 5 3 2 6 5 3 2 3 The remaining band was separated from decomposition material by eluting the column with a 1:1 chloroform-acetone mixture* The eluate was con­ centrated with a rotary evaporator and yellow crystals were obtained by adding pentane to the concentrated solution. Yield: 0*23 g» (23& based on 1.00 g. of Jrr-C^H,_Mo( CO)^P( OCgH^)^] 2 ^ *

Mixtures of rf-C_HcMo(C0)_P( 0CiH_)^S0_C(CH,)HCH=CH^ and tf-C_H_Mo- 3 5 2 6532 3 2 55 (CO^PC OCgHj- ) .^SO^CH^CH^CC CH^ )H were also obtained from the reactions of 7f-CcHt-Mo(C0)„P(0C£H(-),CH_CH=C(CH,)H with S0o saturated solutions 55 2 6 532 3 2 of dichloromethane or benzene. The starting material was prepared as described above and dissolved in approximately 20 ml. of solvent.

Sulfur dioxide was bubbled through the solution continuously at room temperature® The progress of the reactions were followed by infrared *K5

spectroscopy® The reaction in dichlororaethane appeared to be complete

in 1 hour® The dichloromethane was removed in vacuo (30°, 20 mm. )t

and the residue was purified by chromatography (2 x 20 cm® Florisil

column made up with chloroform)® Elution with chloroform fixed a broad

yellow band at the top of the column® The. band was removed by eluting

the column with a 1:1 acetone-chloroform mixture® The yellow eluate was concentrated in vacuo (30®, 20 mm®)9 and 0.60 g® of sulfinate yield based on 1®0 g® of jV-C^Hp-MoCCO^PtOCgH^^^) were obtained by the addition of pentane to the concentrated solution®

The reaction in benzene, was allowed to continue for 10 hours®

The products were isolated as described above® Yield: 0.48 g® (37$ based on 1®0 g® of Jff-C^H^Mo^Oj^PtOCgH^)J^)® Although the reaction times were substantially different for the two solvent systems, the ratios of rf-CcH_Mo(CO)-P(OC.H[-)2S00C(CH^)HCH=CH0 and aP-C_H_Mo(C0)_- 3 3 2 o 3 3 2 3 2 3 3 2 P( OC^H,.).^SO^CH^CH^(CH^)H contained in the reaction products were essentially unchanged as determined by proton nmr spectroscopy®

S-(3-Methyl-2-butenylsulfinato)cyclopentadienylmol.ybdenum di- carbonyl triphenylphosphite, TT-C^H^Mo(CO)^ P ( O C )^SO^CH^CH=C(CH^)£°

A solution of Na jir-C^H^MotCO^PtOCgHj-)^], prepared from the reaction of 1®0 g. (1 mmole) of ^-Cy^MotCO^PCOCgH^ ]2 and excess 1$ sodium amalgam in 50 ml® of THF, was slowly added to 1®0 g® (10 mmole) of 1- chloro-3-methyl-2-butene in 10 ml. of THF® The mixture was allowed to react for 12 hours under nitrogen at room temperature® The residue obtained after solvent removal (**0 % 20 mm.) was extracted with 50 ml® of a 1:1 pentane-dichloromethane mixture® The extract was filtered through about 5 g» of Zeolite, and the filtrate was concentrated to ca. 41

10 mlo in a stream of nitrogen,. The concentrated solution was then purified by chromatography (2 x 20 cm. neutral grade IV column made up with pentane). The starting material was obtained as a yellow oil » by elution with a 2:1 pentane-dichloromethane mixture and subsequent removal of the solvent from the yellow eluate in a stream of nitrogen®

Approximately 25 mlo of liquid sulfur dioxide was condensed onto the oil, and the mixture was allowed to reflux for 6 hours with the aid of a Dry Ice condenser® The excess SO^ was removed in a stream of nitrogen, and the remaining red oil was purified by column chroma­ tography (Florisil column made up with chloroform)® Elution with chloro­ form gave a broad yellow band that moved very slowly on the column,. The band was more readily obtained by eluting the column with a 1:1 chloro- form-acetone solvent mixtureo The eluate was collected and concentrated to ca. 10 mlo with a rotary evaporator (30°, 20 mm0)o The slow addition of pentane afforded 0.80 ge (60^ yield based on Jff-C^H^MoCCO^PCOCgH^^^) of crystalline ir-O^H^MoCCO^PCOCgH^SO^I^CH^CCH^. The sulfinate melted with decomposition at 116-117°C„

In an attempt to prepare an isomeric mixture

P(OCz-Hj.),S0oCH„CH=C(CHL)_ and ff-CcH1-Mo(CO)0P('OC^H-),S0_C(CH*)_CH=CH

«t-Cl_Hc.Mo(CO)DP(OC/-H_),CH0CH=C(CH ) was allowed to react with sulfur 5 5 2 6 5 5 2 3 2 dioxide (25 mlo) maintained at -50° with a chlorobenzene-Dry Ice constant temperature batho The mixture was allowed to react for 6 hours before removing the excess SO2 in vacuo (-50°, 0.1 mm.). The residue was taken up in about 10 ml. of chloroform and placed on a 2 x 20 cm. Florisil column made up with chloroform. Elution with chloroform removed a small yellow band from the slower moving major yellow band. An infrared 42 spectrum of the chloroform eluate indicated the presence of unreacted starting material* The sulfinate was easily removed by eluting the column with a 1:1 chloroform-acetone mixture* The eluate was con- centrated to 15 ml* with a rotary evaporator and 0,40 g* (30$ yield based on ^ ^ H ^ o C CO)£P( OCgH^ £) of Tf - C ^ MoCCO^PCOCgH^SO^

CHgCHsCCCH^)^ was obtained by the addition of pentane,

S-(Cinnamylsulfinato)cyclopentadienylmolybdenum dicarbonyl tri- phenylphosphite, r - C ^ M o ( C0)2P( OCgH^ )3S02CH2CH=C( CgH^)H. A THF solution of |^=-C^H^Mo(CO^PtOCgH^)^2’ s° in 50 ml, 9 was allowed to react with excess 1$ sodium amalgam. After 1,5 hours, the resulting solution of Na |V-C^H,_Mo(CO)^P(OGgH^)^J was slowly added to 1®53 g® (10 mmole) of cinnamyl chloride in 15 ml, of THF, The mixture was stirred for 8 hours under nitrogen at room temperature. After the reaction period was over, the solvent was removed in vacuo (40°, 20 mm,), and the residue was extracted with 50 ml, of a 2:1 pentane-dichloromethane solvent mixture. The extract was filtered through 5 g, of Zeolite, concentrated to 15 ml. in a stream of nitrogen, and then purified by column chromatography (2 x 20 cm. neutral grade IV alumina column made up with pentane). Elution with a 2:1 pentane-chloroform mixture removed a yellow band of •^CcHcMo (CO)_P(OC£H_)_CH_CH=C(C,;Hc )H. The excess 3 3 2 b 5 5 2 5 5 solvent was removed in a stream of nitrogen leaving a yellow oil.

The oil was dissolved in about 25 ml. of liquid and the mixture was allowed to reflux for 6 hours. A dark oil was obtained after removing the excess sulfur dioxide in a stream of nitrogen. The oil was dissolved in 15 ml. of chloroform and purified by chromatography (2 x 20 cm* Florisil column made up with chloroform)® The sulfinate

was removed from a small amount of decomposition material by eluting the

column with a 1:1 chloroform-acetone mixture® The yellow eluate was 0 concentrated to 10 ml® with a rotary evaporator, and yellow crystals

were obtained by the addition of 100 ml® of pentane to the concentrated

solution® Yield: 0®60 g® (42% based on jjT-C^H^Mo(CO)2P(OC^H^.)^]2^°

The sulfinate melted with decomposition at 130°®

The analytical and molecular weight data obtained for the allylic

sulfinato complexes are given in Table 5®

Reactions of cyclonentadienylmetal dicarbonyl complexes with sulfur dioxide

Attempted reactions of T^-C^H^FeCCO^CI^CsCCH^ with sulfur dioxide®

A solution of Na jff-C^FeCCOjJ , prepared from 1®0 g® (2®8 mmole) of

|ir-C H Fe(C0)J2 in 50 ml® of THF and excess 1% sodium amalgam, was

slowly added to 0®9 g® (10 mmole) of l-chloro-2-butyne in 15 ml® of

THF maintained at 0°® The mixture was stirred for 1 hour at 0° before

removing the solvent in -vacuo (25°» 0«1 mm®). The resulting residue

was extracted with pentane, filtered through Zeolite, and concentrated

to about 10 ml® in a stream of nitrogen. Purification was accomplished

by chromatography (2 x 20 cm. neutral grade IV alumina column made up

with pentane). Elution with pentane separated a yellow band from a

slow moving purple band of j^-C<_H<-Fe( ^°)2J20 ® ie ye^ ow band was re­

moved first and collected under nitrogen. Removal of the solvent in

a stream of nitrogen afforded 0®7 g. (50% yield) of yellow crystalline

TT-Cj-Hj-Fe(CO) 0 The complex melted at 46-48°® Anal®: Calculated

for: cu ? y / e: c» 57.39; H, 4.35. Found: C, 56.63; H, 4.29. TABLE 5

ANALYTICAL AND MOLECULAR WEIGHT3, DATA FOR ALLYLIC SULFINATO COMPLEXES OF MOLYBDENUM

Compound ^ Calculated Found Analysis Molecular Analysis Molecular C H weight C H weight

C5H5Mo(C0)2P(0C6H5 )3S02CifH7c 53.90 4.18 646 53.07 4.35 638

C^^MoCCO^PtOCgH^SO^Hg 54.50 4.4o 660 54.46 4.55 657 c5H5Mo(co)2P(oc6H5)3so2c9Hg 57-50 4.10 708 57.41 4.17 713

aOsmometry in chloroform (0.01-0.02M).

All compounds prepared in refluxing liquid S02. Q Isomeric mixture shovm by nmr. **5

A mixture of 0*5 g® (2*2 mmole) of 7f-CcHcFe(C0)oCH_C=CCEL and 5 5 2 2 5 15 ml* of liquid sulfur dioxide was allowed to reflux for 6 hours with

the aid of a Dry Ice condenser. After the reaction period was over, 0 the excess SC^ was removed in a stream of nitrogen. The resulting red-

orange residue was dissolved in 25 ml. of dichloromethane and filtered.

The filtrate was treated with 25 ml. of hexane, and the resulting so­

lution was concentrated in a stream of nitrogen to give 0.6 g. (91%)

of yellow-brown crystalline TT^C^Hj-FeCCO^CSC^C^Hj-), m.p. 136° (dec.)®

Anal* Calculated for C^H^QO^SFe: C, Mt.89; H, 3®**0; mol* wt*, 29**®

Found: C, kk„7k\ H, 3®53j mol® wt* (osometry, CHCl^ soln), 285®

The sulfinate was also prepared by allowing 0*3 g* (1*3 mmole)

of 7^CcH_Fe(C0)_CHoC=CCH_, to react with sulfur dioxide in 25 ml. of 5 5 2 2 3 pentane. A saturated SO^-pentane solution was maintained by bubbling

the gas through the solution continuously at room temperature® A yellow precipitate appeared within several minutes after the start of the reaction, and the reaction appeared to be essentially complete in

5 minutes. The precipitate was collected by filtration and washed with pentane to give 0*3 g® (80% yield) of tf-C^H^FeCCO^SO^C^H^.)* Th© structure of this complex will be discussed in the following section.

Attempted desulfonylation reactions of 7fr-C_Hl_Fe(C0)_(S0_C.,H_). ______5 5______2 2 5 Tf-C^H^FeCCO^SO^C^H^) (o*6 g., 2.0 mmole) was dissolved in 10 ml* of dichloromethane and chromatographed on a 2 x 20 cm. neutral grade IV alumina column made up with dichloromethane. The column was eluted with dichloromethane to give a broad yellow band* The yellow eluate was collected under nitrogen. After concentrating the eluate to about

10 ml. in a stream of nitrogen, pentane was added to the solution to k 6

give 0„3 go (50% yield) of unchanged ^“C^H^Fe(C0)2(SC^C^H,.) which was

collected by filtration.. The pentane filtrate was taken to dryness in a stream of nitrogen to give 0®2 gB (*f3% yield) of TT-C^K^c'etCO)^

p CH^CHCCH^o The products were identified by infrared and pmr spectre-

scopyo

A solution of 0o5 go of 7r-C^H^Fe(C0)2(S02C^H^) in 20 mlo of THF was introduced to a 100 ml. 3-neck flask, equipped with magnetic

stirrer, nitrogen inlet, and reflux condensero The solution was refluxed

for 12 hours under nitrogen® After cooling to room temperature, the

solution was filtered to remove a small amount of insoluble decompo­

sition materialo The filtrate was taken to dryness (30®, 20 mm.) to give Oo**- go (80$) of unchanged starting materialo Similar results were obtained by refluxing 0„5 g® of sf-G^H^Fe(CO)2( SO^^H^) in chloroform

for 12 hours® When 0®5 go of |P-C^H^Fe(C0)2(S02C^H^) was refluxed for

12 hours in chlorobenzene, 0.*f go of the decomposition product and 0.3 g« (6$) of unchanged starting material were obtained..

A solution of 0.5 g. of ir-C^H^Fe(G0)2(S02Ci+H^) in 50 ml® of benzene was subjected to ultraviolet irradiation for 6 hours under nitrogen. After the reaction period was over, 0.3 g« of an insoluble brown material was removed by filtration. The decomposition material showed no bands in the infrared corresponding to either C-0 or S-0 stretching frequencies® The filtrate was taken to dryness in vacuo

(30%, 20 mm®) to give 0.1 g. (20%) of unchanged starting material.

Attempted reaction of 7r-CKHcMo(C0)_P(0C,;Hc)_CH_CsC-CH- with ______5 z> 2 6 5 3 2_____ 3.____ sulfur dioxide® A solution of Na J^r-C^H^Mo(CO)2P( OGgH^ )^, prepared from 1.0 g® (1.0 mmole) of in 50 ml® of THF and excess sodium amalgam, was added to 0.54 g® (6.0 mmole) of

C1CH0C=C-CH, in 20 mlo of THF. The mixture was stirred for 4 hours 2 3 under nitrogen at room temperature. The solution was then filtered # through Zeolite, and the excess solvent was removed in vacuo (40®,

20 mm.). The residue was extracted with a 2:1 pentane-dichloromethane mixture and filtered. The filtrate was concentrated to ca. 25 ml. in a stream of nitrogen and cooled to -78° to effect precipitation.

Approximately 0.7 g° (60?6) of H -C^H^Mo( C0)2P( OGgH^^CH^CSC-CH^ was

obtained. The complex melts at 104-106®. Anal.: Calculated for:

C__H~c.Oc,PMo: C, 60.02; H, 4.55® Found: C, 59=74; H, 4.10. 2y 25 5 H-C5H5Mo(C0 )2P(0C6H5 )3CH2C=C-CH5 , 0.5 g. (0.86 mmole), was dis­

solved in 25 ml. of chloroform, and sulfur dioxide was bubbled through

the solution at room temperature for 10 minutes. Pentane was slowly added to the solution and a blue-green precipitate formed. The pre­

cipitate was collected by filtration but contained no distinguishing bands in its infrared spectrum. The filtrate was treated with ad­

ditional pentane to give 0.3 g® (55$) of a yellow crystalline material.

On the basis of the infrared and pmr spectra, the material appeared to have a similar structure as that proposed for rf-C_H_Fe(C0)_(S0_C.,H_) 5 5 2 d Lf 5 (see Discussion for further details); however, the instability of

?f“C,_Hj-Mo( C0 )2P( OCgHj. )^( S02C^H^) prevented the characterization of this compound by elemental analysis.

Allenylcyclopentadienyliron dicarbonyl, ff-C^H^Fe(CO)2CH=C =CH2 , with sulfur dioxide. The starting material, TT-C^H^Fe(CO)2CH=C =CH2 , was prepared from the synthetic procedure described by Jolly and Pettit

(55); however, they incorrectly identified the product as JT-C^H^Fe- 5 5 48

(CO^CH^CsCHo Recently it has been demonstrated that the product is in fact the allenyl derivative, e(CO)2CH=C =0^2 (36)®

Cyclopentadienyliron dimer, ^T-C^H^Fe(00)2^2 * mmo^-e^ was dissolved in 150 mlo of THF and the solution was added to excess

1% sodium amalgam tinder nitrogen*, After stirring the mixture for 2 hours, the excess amalgam was removed, and the THF solution of Na-

jjT-C^Ht-FeCCO^] was slowly added over a 1 hour period to 6«5 g® (5^® 6 mmole) of 3-bromopropyne in 50 mlo of THF maintained at 0®. The re­ sulting mixture was stirred for an additional hour at 0°o The solution was then taken to dryness (25®, 0«1 mmc) and the residue was extracted with 200 mlo of pentane and filtered through ca. 5 g® of Zeolitec The filtrate was evaporated in a stream of nitrogen leaving an orange oile

The oil was distilled in vacuo (80®, 0ol mm0) to give ^ 0 g, (33% yield) of ?f-CcHcFe(C0)_CH=C=CHoo 3 3 2 2 j-H,-Fe(CO)2CH=C=CH2 (loO go) was dissolved in 25 mlo of liquid sulfur dioxide and the mixture was allowed to reflux for 8 hours. After the reaction period was over, the SO2 was allowed to boil off in a stream of nitrogen. An infrared spectrum of the resulting oil indicated the presence of unreacted -Tf-G^H^FeCCO^CH^= 0 ^ o The starting material was quantitatively recovered,,

In another experiment, 1.0 g. of ?T-C^H^Fe(CO)2CH =C =CH2 and 50 ml® of liquid sulfur dioxide were introduced to the pressure apparatus shown in Figure 2. The system was cooled to -78° and degassed in vacuo (0.1 mm.) to remove oxygen. The mixture was allowed to react for 48 hours at room temperature. An insoluble decomposition product formed on the 49

sides of the reaction tube during the reaction period* The SO2 was

allowed to boil off, and the residue was treated with 25 ml* of chloro­

form* The extract was filtered and an infrared spectrum of the insoluble

p material collected on the filter contained no characteristic bands* An

infrared spectrum of the filtrate indicated the presence of ^-C^H^Fe-

(C0)2CH=C=CH2 only*

Sulfur dioxide was also allowed to react with 1*0 g* of jf-C^H^Fe-

(C0)2CH=C=CH2 in 25 ml* of chloroform* After bubbling the gas through

the solution for several hours at room temperature, extensive decom­

position began to take place* An infrared spectrum of the chloroform

solution, however, indicated the presence of starting material only*

1-Propynylcyclopentadienyliron dicarbonyl, 7T-C^H,-Fe(CO)2C-CCH^,

with sulfur dioxide* The propynyl derivative has been reported .by Jolly

and Pettit (35)= One gram (4*6 mmole) of ft-C^H^Fe(CO)2CH=C=CH2 (prepared as described above) was chromatographed on a 2 x 20 cm® silica gel

column made up with pentane* Elution with a 4:1 ether-pentane solvent mixture removed a broad orange band* The eluate was taken to dryness in a stream of nitrogen and 0*40 g. of yellov/ crystalline 7T-C_H_- 3 5 Fe(C0)_C=CCH, was obtained*

Approximately 50 ml. of liquid S02 and 0.*K) g. (1.85 mmole) of yr-C^H^Fe(CO)2C=CCH^ were placed in the pressure apparatus (see Fig. 2)*

The system was cooled to -78° and oxygen was removed in vacuo (0.1 mm.)*

The mixture was allowed to react for 24 hours at room temperature*

During the reaction period, a brown film of decomposition material formed on the sides of the reaction vessel. The sulfur dioxide was allowed to boil off in a stream of nitrogen after the reaction period was over. The residue was purified by chromatography on a 2 x 20 cm® 50 neutral grade IV alumina column made up with chloroform,, Elution with chloroform removed a yellow band from the brown decomposition material that remained at the top of the column® The eluate was taken to dryness in a stream of nitrogen, and an infrared spectrum of the residue indi­ cated the presence of unreacted starting materialo The starting material was recovered in ca® 50% yieldo

Vinylcyclopentadienyliron dicarbonyl, 7f-C^H^Fe(CO) , with sulfur dioxidea The starting material was prepared in the manner de­ scribed by King and Bisnette (37)® A solution of 5^®2 mmole of Na-

jjf-C^H^Fe(CO) J in 125 ml® of THF was prepared by reduction of

FeCCO)^]^ (10 go, 27=1 mmole) with excess 1% sodium amalgam0 After vigorously stirring the mixture for 3 hours, the sodium salt solution was added to 4®5 g® (5^*2 mmole) of acryloyl chloride in 15 mlo of THF maintained a -78 °® After warming to room temperature, the reaction mixture was transferred to the ultraviolet irradiation apparatus® The solution was irradiated for 12 hours under nitrogen before removing solvent with a rotary evaporator (30°, 20 nun.). The residue was ex­ tracted with two 50 ml. portions of pentane and filtered through Zeolite®

The filtrate was taken to dryness in a stream of nitrogen leaving an orange oilo The oil was distilled in vacuo (60°, Ool mm®) to give 0®3 g® (k%) of ^-C_H_Fe(C0)oCH=CH_. 5 5 2 2 The vinyl derivative (0®3 g«» 1®5 mmole) was dissolved in 25 ml® of sulfur dioxide, and the mixture was allowed to reflux for 2k hours with the aid of a Dry Ice condenser® After removing the SO^ in a stream of nitrogen, the residue was extracted with 10 ml® of chloroform and purified by chromatography (2 x 20 cm® column of neutral grade IV alumina made up with chloroform)® Elution with chloroform removed a yellow band 51

that was collected under nitrogen,, The eluate was taken to dryness

in a stream of nitrogen to give 0.2 g. of an orange oil. The oil was

identified as unreacted jF-C^H^FeCCO^CHsCHg from its infrared spectrum,,

*

Reactions of boron trifluoride with sulfinate complexes of cyclopentadienyliron monocarbonyl

Preparation of yf-C^H^Fe(C0)P(n-C^H^)^502GH^sBF^o The starting material, "jr-C^H^Fe(CO)P(n-C^Hg) ^SC^CH.^, was obtained by ultraviolet irradiation of tri-n-butylphosphine and 7l-CrHcFe(C0)~S0_CH,. First it 5 5 2 2 5 was necessary to prepare 1f-C^H^Fe(CO)^SC^CH^ from the reaction of ir-C_HcFe(CO)_CH_ with sulfur dioxide,, 5 5 2 5 1T-Cc-H^Fe(CO) was prepared according to the method of Piper and Wilkinson (58)0 A solution of NajTf-C^H^FeCCO)^], prepared from

3.5^ g» (0.01 mole) of ^T-C^H^Fe(C0)2]2 and excess sodium amalgam in

60 ml. of THF, was treated with 1.02 g. (0.02 mole) of iodomethane.

After stirring the resulting mixture for 6 hours at room temperature, the solvent was removed (30°, 20 mm.), and the residue was taken up in

50 ml. of pentane and filtered through about 5 g» of Zeolite. The volume of the filtrate was reduced to about 10 ml. in a stream of ni­ trogen and then chromatographed on a 2 x 20 cm. neutral grade IV column made up with pentane. Elution with pentane separated the yellow methyl compound from any unreacted dimer. The yellow eluate was collected under nitrogen which was also used to remove solvent. Yield: 2.95 g«

(76#).

One gram (5 mmole) of fT-C^H^Fe(CO) was dissolved in 25 ml. of liquid sulfur dioxide, and the mixture was allowed to reflux for k hours 52

v/ith the aid of a Dry Ice condenser. The excess sulfur dioxide was

removed in a stream of nitrogen leaving a dark red oil® The oil was

dissolved in 10 ml. of chloroform and chromatographed on 2 x 20 cm.

0 neutral grade IV alumina column made up with chloroform. The sulfinate

\i/as collected by eluting the column with chloroform. The yellow eluate

was concentrated with a rotary evaporator and the addition of pentane to

the concentrated solution afforded 1.30 g. (96%) of ^-C1_H[_Fe(C0)^S0_CH,o 5 2 2 3 This procedure was essentially the same as that reported by Bibler-(15).

The ultraviolet irradiation apparatus was charged with 1.0 g. (4

mmole) of -if-C^H^FeCCOj^SO^CH^, 1.2 g. (20% excess) of P(n-C^H^)^, and

125 ml. of benzene. The mixture was irradiated for 3 hours under ni­

trogen. The solution was then filtered to remove some decomposition

material. The filtrate was concentrated to 10 ml. with a rotary evapo­

rator and the addition of 100 ml. of pentane afforded 1.0 g. (50%) of

orange crystalline if-C^H^FeC CO)P(n-C^H^ J^SO^CH^. The infrared spectrum

of the product was identical with that obtained by Graziani (21) from the reaction of ?T“CKH_Fe(CO)P(n-C. H_)^CH, with S0_. P P ^933 2 The preparation of the boron trifluoride adduct of tf-C_H_Fe(C0)- P P P(n-C^Hg)^SO^CH^ was carried out on the vacuum line. The line was equipped with several distillation traps and a mercury U-tube manometer.

The traps had been previously calibrated for number of moles of gas introduced versus pressure. Approximately 25 ml. of toluene (distilled from calcium hydride) and 0.43 g» (l mmole) of -jf-C^H^Fe(CO)P(n-C^H^)^-

SO^CH^ were introduced to a 100 ml. 1-neck round bottom flask with a magnetic stirring bar and a stopcock adapter. The system was attached to the vacuum line by means of the adapter and freed from oxygen by degassing under vacuum (0®1 mm,), The mixture was cooled to 0® and

2,0 mmole of BF^ was added to the solution® The gas was consumed

immediately as evidenced by the attached manometer® The mixture was

allowed to react for 1 hour at 0® to insure complete reaction® Excess

BF^ and solvent were then vacuum distilled (0 ®, 0®01 mm®) leaving an

orange residue® The volatile materials were passed through a series

of three distillation traps® The first two traps were cooled to -78°

in order to remove toluene, while any excess BF^ was condensed in the

third trap which was cooled with liquid nitrogen® The BF^ was free of

toluene as determined by ir spectroscopy® A pressure-temperature-volume

measurement of the excess boron trifluoride showed that 0®9 mole of

BF_ was absorbed per mole of ff-CirHI_Fe( CO )P( n-C .H^ ),S0_CH,® The flask 5 5 5 y 5 2 5 containing the adduct was transferred to an inert atmosphere dry-box®

The residue was taken up in 10 ml® of dichloromethane and filtered®

Approximately 50 ml® of pentane was added to the filtrate to give 0,45

g. (80#) of orange crystalline tf-CT^FeC CO )P( n-C ,,H-) ^SO^CH^.BF,® Anal, 5 5 9 5 2 5 5 Calcd® for C^H^FeO^BF^: C, 48.88; H, 7®50. Found: C, 48.12; H, 7-35®

The adduct decomposed at 88-90®,

Preparation of ‘fl-C^H^Fe (C 0 ) P( C^-H^ ) ^SO^CH ®BF^® The starting material,

TT-C^Hj-Fe(CO)P( CgH^- J^SO^CH^, was obtained from the reaction of tf-C^H^-

Fe(CO)P(CgH^)^CH^ with sulfur dioxide.

Using the method of Treichel, et al® (39). ff-C^H^Fe(C0)P(C^H_)„- > 5 o 5 5 CH^ was prepared by irradiating a mixture of 7.0 g. (27 mmole) of tri- phenylphosphine, 5®0 g. (26 mmole) of -jf-C^H^Fe(CO)^CH^ (prepared as described above), and 100 ml® of petroleum ether (bp 30-60°) for 3 hours under nitrogen® The solvent was removed with a rotary evapor— ator (30®, 20 nun.), and the resulting red-orange residue was dissolved in a 1:1 benzene-chloroform mixture and chromatographed on a 2 x 20 cm® neutral grade IV alumina column® The major yellow band was collected using 1:1 benzene-chloroform as the eluent® Solvent was removed (40®,

20 mm®) and the solid residue was recrystallized from a pentane-dichloro­ methane mixture® Yield: 3°1 g« (28#)®

A mixture of 3.1 g. of rf-C^FeCCOjPCCgH^CI^ and 25 ml. of liquid sulfur dioxide were refluxed for 1 hour with the aid of a Dry Ice con­ denser® The excess SO^ was then removed in a stream of nitrogen9 and the residue was extracted with 20 ml® of chloroform® The extract was placed on a 2 x 20 cm® neutral grade IV alumina column made up with chloroform® Elution with chloroform removed an orange band of product®

The orange eluate was concentrated to 20 ml® in vacuo (30®, 20 mm®), and crystalline v/-C^H^Fe(CO)P(CgH^)^S02CH^ (3®3 g®, 90%) was obtained by slowly adding 100 ml® of pentane® The infrared spectrum was identical with that of an original sample prepared by Graziani (21)®

A 100 ml® 1-neck round bottom flask equipped with a magnetic stirrer and stopcock adapter was charged with 0.25 g® (0®5 mmole) of ff-C._H.-Fe- 5 5 (CO)P(CgH,.^SO^CH^ and 50 ml. of toluene (distilled from Ca^). The system was connected to the vacuum line and freed from oxygen by degas­ sing under vacuum (0®1 mm®). After cooling the mixture to 0®, 1.0 mmole of BF^ was added to the solution. The mixture was allowed to stir for 1 hour at 0® in order to insure complete reaction. The volatile compo- ents were distilled as described above, and it was found that 0®9 mmole of BF was absorbed per mmole of lT-CcHc-Fe(C0)P(C/:Hc.),S0-CH_o After trans- 5 5 5 05323 ferring the boron trifluoride adduct to a dry-box, the residue was

extracted with 10 ml. of chloroform, filtered, and 0.23 g« (85$) of

H -C^Hj-Fe( C0)P(C^Hj-)^SO^CH^.BF^ was obtained by treating the filtrate

with 50 ml* of pentane. The product decomposed at 98-100°C.

7f-C^H^Fe(CO)P ( )^S0^CE^.BF^ has a carbonyl stretching frequency

at 1966 cm ■*", while /T-C^H^Fe(C0 )P(CgH^)^S02CH^ has an absorption at

1950 cm After approximately 8 hours at room temperature under ni­

trogen, the infrared spectrum of /f-C_H_Fe(CO)P(C£Hc),SO_CH,.BF_ showed ? 5 o z> D c. ^ 3 a new band at 1950 cm”'*'. The complex was not characterized by elemental analysis because of its apparent instability with respect to dissociation. RESULTS AND DISCUSSION

Investigation of allylic sulfinato complexes

The insertion reaction of sulfur dioxide with transition raetal

complexes was recently extended to include sigma-bonded allyls of

rhenium (2*0 , manganese (2*0 , iron (25), molybdenum (25)» and tungsten

(25)® Of particular interest was the observation thatff-C^H^FetCO)^-

CH2CH=CRR' (R = H, R 1 = CgH^; R = R' = CH^) reacted with refluxing S02

to give mixtures of sulfinates containing unrearranged and rearranged

moieties (25)®

—in® 7r-C5H5Fe(CO)2CH2CH=C(CH3)2 + S02 — --- >

75% ir-C5H5Fe(C0)2S02CH2CH=C(CH3)2

(15)

25% if-C5H5Fe(C0)2S02C(CH3 )2CH=CH2

—TO® T^C3H3Fe(CO)2CH2CH=C(C6H5 )H + S02------— --- >

80% *r-C_HcFe(CO) S0 CH„CH=C( C,Hc)H P P d d d op + (16)

20% jr-C_HcFe(C0)oS0_C(C,Hc)HCH=CH- 5 5 2 2 o 5 c~

56 57

It was also found that the relative amounts of the sulfinates contain­

ing the rearranged allylic moieties could be increased by altering the

reaction conditions.. When insertion reactions were carried out in SO - *

amount of rearranged allylic isomer in the mixture of sulfinate products

was found to increase (40, 4l)» Since the amount of sulfinate contain­

ing the rearranged allylic group varies with the reaction conditions,

it was of interest to determine if substituents on the cyclopentadienyl

ring of fT-C^H^Fe(CO)^- would have an effect on the rearrangement ac­

companying SO2 insertion.. Consequently, the SO^ insertion reactions

of sigma-bonded allyls of jT-CH^C ^.H^Fe(CO) , s7-l ,3“( CgH,. J^C^H^FeCCO)^”,

and ff-CCH^J^C^FeCCO)^- were investigatedo

Tf-C^H^MoCCOj^CH^CHsCCCH^)!! reacts with refluxing liquid SO2 to

form tf-C^H^Mo(C0 )^S02C(CH^)HCH=CH2 (25); however, only the unrearranged

allylic sulfinates were observed for 7f-CcHcMo(C0)^CH_CH=C(CH,)_ and 5 5 5 2 5 2 7f-C_HcMo(C0),CH_CH=C(C,.Hc)H in refluxing sulfur dioxide (25)® The 5 5 5 2 0 5 yields of these reactions were unusually low (ca» 10$) (42) and the

possibility that the rearranged allylic sulfinates were formed but

decomposed before isolation cannot be ruled out® In order to expand

further the reactions of sigma-bonded allylic molybdenum complexes

with SO2, the reactions of allyls of ^r-C^H^MoCCO^PCOCgH^)^- with SO2

were examined.

The infrared spectra of the sulfinates examined in this study point to the formation of an M-S( O^-C bonding sequence in all cases®

In order to determine whether or not the sulfinates contained unrearranged or rearranged allylic groups, it was necessary to examine carefully the proton nmr spectra of the complexes..

Preparation of the complexes. A. Starting materials. The # sigma-bonded allylic complexes used to prepare the sulfinates were ob­ tained from the reactions of sodium salts of the transition metal cyclo- pentadienyl carbonyl anions with the appropiate allylic halides according to the following equations:

THF Jjf-CpFe (CO ) J g + ^ Na/Hg Na ^-CpFeCCOjJ

2 C1CH2CH=CRR9 (17)

V 2 -jf-CpFe (CO)2CH2CH=CRR *

+

2 NaCl

Cp = C H j C ^ , 1,3-(C6H5)2C5H3 , and ( C ^ ) ^

THF

2 Na |jf-C5H5Mo(C0)2P(0C6H3 )3]

2 C1CH2CH=CRR» (18)

2 ■fr-Cc;Hl-Mo( CO) _P( OC>-H_ )_CH»CH=CER' + 2 NaCl 5 5 2 6 5 3 2 The allylic complexes can be readily purified by column chrom­ atography® The major impurities are the starting metal carbonyl dimers®

The presence of unreacted dimers probably arises from oxidation of the 9 air sensitive carbonylate anions or decomposition of the allyl complexes themselves® The thermal and oxidative instability of the sigma-bonded allyls, as well as the difficulty of removing residual solvent from the oily products, discouraged attempts to obtain elemental analyseso The iron and molybdenum sigma-bonded allylic complexes, however, are analo­ gous to the allyls previously reported (33, 43, 44, 43)® Consequently, the infrared and proton magnetic resonance spectra seem adequate to characterize these complexes® The^values, relative intensities, and multiplicities taken from the spectra of the allylic complexes are given in Tables 8, 9» 10, and llo

B® Sulfinatese All of the reactions in refluxing liquid sulfur dioxide (-10°) were carried out by dissolving the sigma-bonded allylic complex in a large excess of SO^ and then refluxing the resulting mixture by means of a Dry-Ice condenser attached directly to the reaction flask*.

Upon completion of the reaction period, the excess S02 was allowed to boil off in a stream of nitrogen, and the resulting residue was purified by column chromatography®

The yields of the sulfinates prepared in refluxing SO2 varied from

25% for 7T-(CH5)5C5Fe(C0)2S02C9H9 to 70% for JT-l^-CCgH^C^FeCCO^SO^

C H . In general however,^ the molybdenum sulfinates were obtained in consistently higher yields (40-60&) than the corresponding iron deriva­ tives® This was probably due to the apparently greater stability of the starting allylic complexes of molybdenum® 6o

When ^-(CH,)cCKFe(C0)_CH-CH=C(CH,)o, 7f-C Hp.Mo(C0)_P(0C,HK) 5 5 5 2 2 5 2 5 5 2 © 5 5 CH2CH=C(CH5 )2, and Tr-C5H5Mo(CO)2P(OG6H5)3CH2CH=.-C(C6H5 )H were allowed to react with liquid sulfur dioxide at ca® -50°, the yields of the * sulfinates were approximately 50% lower than those obtained in re­ fluxing S02 (~10°)o The lower yields resulted from the failure of the insertion reactions to go to completion and to the formation of de­ composition materialso Although the temperature of the reaction mix­ ture was not monitored, an attempt was made to keep the cooling bath in a 10° range® Care was also taken to make certain that essentially all excess sulfur dioxide was removed before allowing the reaction flask to warm to room temperature,.

In addition to liquid sulfur dioxide, several reactions were carried out in organic solvents saturated with S02® In all of the reactions S02 saturation was maintained by slowly and continuously bubbling the gas thrpugh the reaction solution at room temperature®

The reactions of .if-CILC-H,,Fe(C0)oCH_CH=C(C£Hc)H and 7r-(CHL)_C_Fe(C0).,- 3 5 2 2 6 5 3 5 5 2 CH2CH=C(CH^)2 with SC>2 in hexane were allowed to continue for approx­ imately 48, hours® The hexane insoluble sulfinates precipitated out of solution as oils rather than crystals® The yields of the sulfinates were approximately 50% lower than those obtained in refluxing S0^o The lower yields were due to the presence of significantly larger amounts of decomposition materials®

The reactions of ir-C_HcMo(CO)_P(OC,Hc)^CH_CH=C(CH_)H with S0o 5 5 2 b 5 5 2 5 2 in chloroform or benzene were essentially complete in 1 and 10 hours, respectively® The yield of the sulfinates was slightly higher in chloro­ form (46%) than in benzene (37%)« This was probably due to the much 61 shorter reaction time in chloroform and, therefore, less decomposition of the starting materialo

Physical properties of sulfinates® The allylic sulfinato com” plexes of iron and molybdenum are stable -in air at room temperature, but for prolonged periods of storage, the compound should be refrigerated and kept under nitrogeno Qualitively it appears that the allylic sulfinates of jl^CH ^C^-H^Fe(CO)^“ are the least stable whereas the allylic sulfinates of ^-(CHz),-CKFe(CO)- and 75r-l,3-(C^Hc:)„CcH^Fe(C0)o- are the most stable derivatives® This observation is based only on the extent of darkening of the sulfinates after storage for several months under nitrogen with refrigeration® In general, the iron sulfinates melted sharply whereas the molybdenum sulfinates usually melted with decomp” osition®

All of the complexes were less stable in solution than in the solid state; however, characterization studies on solutions could be accomplished at ambient conditions if carried out in several hours®

The sulfinates were soluble in polar organic solvents such as acetone, chloroform, and dichloromethane; moderately soluble in benzene; and insoluble in hexane or pentane®

Infrared studies. The main application of infrared spectroscopy to the allylic sulfinates is in the assignment of the bonding of the

SO^ moiety. The mode of attachment of the allylic chain is readily determined by proton magnetic resonance spectroscopy®

The various probable modes of bonding of the SO^ group have been previously discussed (see Introduction). It was found that for a 62

number of compounds containing M-S( O^-R bonding sequences the S-0

stretching frequencies fell in the ranges 1240-1175 and 1095-1035 cm \

For compounds having M-0-S(0)-R linkages8 the S-0 stretches are found

in the ranges 1103-954 and 965-836 cm ^ (see Table 1).

The absorption assigned to the S-0 stretching frequencies of the

allylic sulfinates prepared in this investigation are reported in

Table 6. The strong intensity asymmetric and symmetric S-0 stretches

fall in the ranges 1182-1170 and 1047-1035 cm"’*', respectively.. It is apparent that all of these complexes may be considered to have M-SCO^-R modes of bonding. Upon examination of Table 6 , it is evident that the

S-0 stretching frequencies are essentially invariant to changes of sub­ stituents and metals. This suggests that the amount of sulfur-oxygen pi-bonding is essentially the same for all the sulfinates.

The C-0 stretching frequencies are expected to be sensitive to changes in the electron density on the metal. A shift to higher energies for carbonyl stretching frequencies has been interpreted as being the result of a decrease in the electron density on the metal which permits less metal-carbon pi-bonding and thereby more triple bond character in the C-0 linkage (46). Conversely, an increase in the electron density on the metal should result in lower C-0 stretching frequencies. The carbonyl stretching frequencies for the starting allylic complexes and their sulfinates are given in Table 7® The carbonyl stretching bands of the sulfinato complexes appear at frequencies 26-50 cm”'*' higher than those of the starting materials. The higher C-0 stretches result from a decrease in electron density on the metal brought about by the replacement of the poor electron-withdrawing allylic group with a better 63 electron-withdrawing sulfinato group* Similar shifts have been observed for 77-CcHcFe(CO) , 3^Cc.H(:.MoCC0),R, ^-CcHcFe(CO)„SO„R, and 37-0^310(00),- 5.5 2 3 3 3 5 5 2 2 v 3 5 5 SO^R where R is an alkyl (15) or allylic (47) group*

The infrared spectra of fT-CH^C,_H^Fe(CO)^- and 77-1 , 3-( ^6^5 ^2<’V*3"’

Fe(C0)2- derivatives (Table 7) are not significantly different than those reported for the allylic sulfinates of jf-C^H^FetCO)^” (47)* For the allylic sulfinates of 77—(CH^)^G^Fe(CO)^-, however, the C-0 stretches are approximately 27-39 cm**^ lower than those reported for the corre­ sponding allylic sulfinates of -^-Ci-H^FeCCO^- (47)* Apparently the electron density on the metal atom has been significantly increased by placing five methyl groups on the cyclopentadienyl ring*

Similarily, the carbonyl stretching frequencies of the allylic sulfinates of 7?-C H31o(C0)2P(0CgH^)^- are expected to be lower than the C-0 stretches of the corresponding allylic sulfinates of Jf-C^H^-

Mo(CO)^-. The carbonyl stretching frequencies of the allylic sul­ finates are given in Table 7» and they occur in the 1995-1917 cm""**- range* Downs (47) has reported that the C-0 absorptions for the corresponding allylic sulfinates of 7?=»C^H^Mo(C0)^- fall in the range

2058-1969 cm 1* The lower C-0. stretches for the substituted sulfinates can be attributed to the replacement of the good pi-acceptor CO with a poorer pi-acceptor P(OCgH^)^, resulting in an increase in electron density on the metal* 7 *2Hp=gO^(SHQ)0?OS?(00)sA^02(5H90)“C‘l-^- %GZ P®® ( HO) 0=H0 HO OS ( 00 )3i H 0 ( H O ) -£ ‘ TrU %<*L atduiBS sti^

c c Q ■?■? ■? °?Hp=H0H(S90)0?OSS(O 0 )9 .iS S - KO-Jt P®® H( H 0 )0=HD HO OS (00 )8I T O HOil %$% ©idures STmo

_ ? ? ? 4, c c •?ho=ho2(^h o )dho s ?(o o )®1i • H 0 HO"/l fSSZ pu® ( HO)0=H0 HO OS (00 )9i V o HO’it %L ®I^ures stiu;

jspxnons = qs iSucu:is = s »^££-j3uii3; upiaa^ ‘^euad

(S)Oi?OI (9)0811 H ( S 90) 0=HoS oS s S S 9 00 )

(S )^ O I ( 9 ) ^ 1 1 S(So)0=HoSoSs^(S900)d?(00)°wSS

(9)£*T0T (9)2811 9h( S o )o=hdS o?osS S 9oo )a? (oo) °w S S

(HS)o£OT (9)0*701 (9)0811 H (S90 )0=HoSoSs2’(00)9dS^(So)

(^ s)0 2 0 I (H®)O^TT (9)CH70I (9)0811 2 ( S o ) 0=HOSH02OSE( 0 0 ) » .lS 5 ( S o )

(^9)0911 (S)^O T ( 9 ) ^ 1 1 2H0=H0H( S o ) 02 ( 0 0 )sdS^( S o )

(9)0*701 ( 9 ) ^ 1 1 p2 ( S o ) D=H0SH02OS2 (O0 ) a . l S S 2 ( S 90 )

(®)££0T (9)0811 0H( S 90 ) 0=HOSHoS>SS ( 00 ) s A S S o

(M9)0ZII (9)0*701 (9)0811 qS( S o ) 0=H oSo?OS ? (00 )9 A S S o

(M 9 )^ 0 I (H 9)09II ( 9 ) ^ 0 1 ( 9 ) ^ 1 1 So=HOH( S o )o S s ? (00 J Q d S S S o

oxj^auiuiXg oxaq.stcmi^sv punodiaoj) rao & jWajc^s O-S I" *

saxaridwoo oiVNiaans o rim v ao saioMaritoa OMiHoiaaas o-s

9 aiaviE

<79 TABLE 6 (Contd*)

eThis sample 8o£ ’Sr-C_Ht-Mo(CO) _P(OC.H,- )-,SO_CH_CH=C(CH, )H and W - C ^ M o ( CO >2P(OC6H5 )|S02C ( CH^THCHsCH^. 5 66

TABLE 7

C-0 STRETCHING FREQUENCIES OF ALLYLIC AND ALLYLIC SULFINATO COMPLEXES

-3 Compound C-0 Stretch, cm

CH^Cj-H^Fe ( C0)2CH2CH=C ( CH^ )Ha 2011(vs) 196l(vs)

CH^C^H^Fe(CO)2S02C(CH^)HCH=CH2b 2060(vs) 2000(vs)

CH^C^H^Fe(C0)2CH2CH=C(CHj >2& 2011(vs) 1960(vs)

CH^H^FeC CO )2S02CH2CH=C( CH3 >2b 9 C 2059(vs) 1998(vs)

CH,C_H. Fe(CO)0CH0CH=C(C.H_ )Ha 2010(vs) 1955(vs) 3 5 ^ 2 2 6 5 CH^H^Fet C0)2S02CH2CH=C( CgH^ )Hb 5 d 2060(vs) 1998(vs)

( C ^ ) ^H ^ F e ( C0)2CH2CH=C ( 2010(vs) 196l(vs)

(C6H5 )2C5H3Fe(CO)2S02CH2CH=C(CH3 )2b 9 e 2059(vs) 1998(vs)

(CH,)cCcFe(CO)0CH_CH=C(CH,)Ha 1988Cvs) 1938(vs) 5 5 5 d d 3 (CH,)cC_Fe(CO),SO_C(CH,)HCH=CH b 2031(vs) 1976(vs) ; 3 5 d d 5 d (CH,),CJe(CO)0CH„CH=C(CH,) a 1993(vs) 19^(vs) 5 3 3 d d 5 d ( CH, ) ,C_Fe( CO ) -SO -CH „CH=C ( CH, ) b 2030(vs) 1975(v s ) 5 5 3 d d d $ d. (CH3 )3C3Fe(CO)2CH2CH=C( CgH^H* 2000(vs) 1950(vs)

(CH3 ) CF e (CO)2S02CH2CH=C(CgH^)Hb 203l(vs) 1976(vs)

C H^foCCO)2P(OC6H3 )3CH2CH=C(CH3 )Hf 1950(vs) 188o(vs)

C-EM CO) „P( OC.Hc ),S0_CHoCH=C( CH, )Hb ,s 1995(m-s) 1918(vs) 5 5 2 6 5 3 2 2 3 c^h^oC co) 2p( oc6h5 )3ch2ch=c ( ch3 )2f 1955(vs) 1877(vs)

C3H3Mo(C0)2P(0C6H3 )3S02CH2CH=C(CH3 )2b 1993(m-s) 1917(vs)

C_HcMo(CO)_P(OC^H c),CH_CH=C(C^H_)Hf 1955(vs) 1878(vs) 5 5 2 6 5 3 2 6 5 C_HcMo( CO) -P( OC^H ) SOCH_CH=C( OjH- )Hb 199Mra-s) 1918(vs) 5 5 2 65322 6 5 67

TABLE 7 (Contdo)

^entane solution, Perkin Elmer-337®

Chloroform solution, Beckman IR-9® # °This sample 75# 7T-CH C H F e ( CO) pS0 CHpCH=C(CH, )p and 25% $=-CH,- CcHi5 ^ Fe(C0)oS0_C(CH,)oCH=CH»o 2 2 3 2 2 ^ ^ * * dThis sample 85# ?T-CH,C H. Fe(CO) SOpCH CH=C(C.H£-)H and 15# Tf-CH,- C5H^Fe(C0 )2S02C(C6H5 )HCH=CH2? 2 2 2 0 3 5

eThis sample 75# rf-l^-CC.Hc) C H,Fe(CO) SO CH CH=C(CH,)_ and 25# 7T-l,3-(C6H5 )2C5H3Fe(C0 )2S02C(c8^ 26HiCH2. ^ ^ 2 3 2 f Dichloromethane solution, Perkin Elmer-337®

eThis sample 80# 7f-C H Mo(CO) P(OC.H ) SOpCH CH=C(CH,)H and 20# tr-c jhlmo( co) „p( oc^hc ),so0c( 8h, )HCH=CH_o 5 ^ d * * 55205523 2 Abbreviations: vs * very strong; s = strong; m = mediums,

Proton magnetic resonance studies.. The modes of attachment of

substituted allyl groups to 7T-CH^C^H^Fe(CO)2~ ,?f-l,3-(CgH^)2C^H^Fe-

(C0)2-, *jr-(CH3)5C5Fe(CO)2-, and TT-C^MoCCO^PCOCgH^- have been determined with the aid of proton magnetic resonance spectroscopy..

Complexes containing the parent allyl group, -CH2CH=CH2, were not investigated since the sulfinate, ie„, >7'-(CH^)^C^Fe(CO)S02CH2CH=CH2, would have the same structure whether rearrangement did or did not

O C C U T o

The pmr spectra of allylic and allylic sulfinato complexes of

^"-CH^C^H^Fe(CO)2~ are reproduced in Fig. 3, 5, and 7, and the chemical shifts and other pertinent data obtained from the spectra are given in Table 8. In order to be able to assign correctly the resonances due to the CH^C^H^ group, the pmr spectrum of the starting dimer,

j7f-CH^C^H^Fe(CO)2^j2, was examined. The spectrum shows singlets at 68

T’5«it8 andT7®95 assigned to the and CH^ protons, respectively,.

The chemical shift of the methyl absorption is not expected to change

significantly upon formation of the various allylic derivatives,, A

characteristic feature of the pmr spectra of allylic complexes of

Tf-CH^C^H^FeCCO^- was the appearance of the protons as a broad

singleto For the sulfinates, however, the cyclopentadienyl absorptions

are present as two complex multiplets» Theoretically, there are "two

kinds" of hydrogen on the ring and two resonances should be obr-

servedo The broadness of the C^H^ absorption in the spectra of the

parent allylic complexes suggests that the resolution may not be suf­

ficient to observe the two expected peaks0 In order to make certain

that the two complex absorptions observed in the spectra of the

sulfinate derivatives was not due to the presence of isomers resulting

from rearranged and unrearranged allylic moieties, the pmr spectrum of

TT-CHy^H^FeCCO^SC^CH^ was examinedo The spectrum shows two complex

cyclopentadienyl resonances at £’4*99 and2T4083, and it is concluded

that the presence of two multiplets in the cyclopentadienyl resonance

region of the pmr spectra of allylic sulfinates of ^-CHy^H^FeCCoW­

are due to the nonequivalent hydrogens of the ringo

The pmr spectrum of ff-CH^Cj-H^Fe(CO)^CH^CH =C(CH^ )H is shown in

Fig0 3 (spectrum A)„ The spectrum is characterized by the presence

of doublets at'C7®93 andTSc^o Due to the cyclopentadienyl methyl

resonance at /£8«> 13$ it was not possible to determine the relative

intensities of the two doublets,, The assignment of the peaks can

be made by examining the pmr spectra of CICH^CH^C CH^ )H and

Fe(CO)^CH^CH^C(CH^ )H shown in Fig„ ba The spectrum of crotyl chloride Fig. 3«— A comparison of the pmr spectra of:

A. ir-CH3C5HlfFe(CO)2CH2CH=C(CH;5)H

B. 7T-CH3C5HitFe(C0)2S02C(CH5 )HCH=CH2

69 IMS

TMS

la Fig. 4.— A comparison of the pmr spectra of: a . c i c h 2c h =c (c h 3 )h

B. 7r-C_HcFe(C0)oCH_CH=C(CH,)H - 5 ? 2 2 p C. 7T-C JIRFe( CO) _S0„C(CH,)HCH=CHo (49) P P 2 2 p 2

71 72

TMS

(A)

V .CH5 Fe — C — C *= C \ I H TMS t^H

(B)

TMS

(C)

8.2 10 2.9 L. ao 7.0 6.0 5.0 4.0 3.0 20 1.0 0 PPM (8) 73

shows doublets at ca.%6.0 and ^8® 4® The lower field doublet arises

from the methylene protons being split by the adjacent vinyl proton®

Upon formation of •jT“C^H^Fe(C0)^CH2CH=C(CH^)H9 the methylene doublet

shifts to a much higher field as a result of diamagnetic shielding by

the transition metal atom® Interestingly, two cyclopentadienyl reso­

nances are observed and they are assigned to cis and trans crotyl

isomers (U8). It is apparent that except for the cyclopentadienyl

methyl resonance, the spectra of7T-C_HcFe(CO)_CHJ3H=C(CH,)H and 3 3 2 2 3 -ff-CH^C^H^Fe(CO)^CH^CH =C(CH^ )H are essentially identical in the region

'£'7-10 and they have crotyl groups with similar ’ modes of attachment®

For SO^ insertion without rearrangement of the crotyl moiety, the methylene protons should appear as a doublet with a relative intensity of 2®0 in the pmr spectrum® What is observed, however, is a complex multiplet atlT6o66“6ol6 with a relative intensity of 1®0 (spectrum B of Fig® 3)« This strongly supports the rearranged structure,iT-CH^-

C^H^FeCCO^SO^CCCH^HCHsC^, the raethine proton being split by both the methyl and vinyl protons® A similar spectrum was obtained by

Downs (^9) for 7T-C5H5Fe(C0)2S02C(CH:5)HCH=CH2 (spectrum C of Fig® k)a

The pmr spectrum of ^-CH^C^H^Fe(CO)2CH2CH=C(CH^)2 is shown in Fig® .

5 (spectrum A)® The presence of a triplet C ) and a doublet

(£7«8*0 in the vinyl and methylene regions of the spectrum, respect­ ively, militates against the tt-CH^C H^Fe(C0)2C(CH^)2CH=CH2 structure.

The relative amounts of each isomer in a mixture containing 7T-CH^C^H^-

Fe(C0)2S02CH2CH=C(CH5)2 and ff-CH^H^Fe(CO)2SC>2C( CH^ )2CH=CH2 can be determined on the basis of the difference in chemical shifts of the methyl protons of the allyl chain. This can be clearly demonstrated Fig. 5»— A comparison of the pmr spectra of:

A. 7r-CH3C5H4Fe(CO)2CH2CH=C(CH5 )2

B. A mixture containing 7 % tf-CHLC-H. Fe(CO) pCH_CH=C(CH, ) _ and .25^ ^-0^0^^6(00)25020(0^)2^=^2. d * d

74 0CP8 75 Fig. 6.— A comparison of the pmr spectra of:

A. TT^Cj-H-Fe (CO ) _SO_CH„CH=C ( CH_ ) _ 5 5 2 2 2 5 2 B. A mixture containing 76% Fe(CO) SO CH CH=C(CH,)p and 2k% IT-C_H.Fe(C0)oS0aC(CHj)'CH=CH_7 ^ 5 5 2 2 5 2 2 C. A mixture containing 6% tT-C H Fe(CO) SO CH CH=C(CH,)p and 9k% TT-CcHcFe(C0)oS0_C(CH3oCH=CH^ (50)7 * 5 5 2 2 5 2 2

76 77

Fe-S-C-C«C

T M S I

(A)

7 6 %

TMS

(B) 1.0 3.15

F 0 CH> H /III Fe — S— C— C«*C

TMS 6% \ (C) JU ' 1 0 16.2 i — I— L_ .-I. 7.0 6.0 5.0 4.0 3.0 2.0 0 PPM(8) 78

by comparing the pmr spectrum of 100% |f-C HcFe(CO)_S0_CH„CH=C(CH_,)_ 2 2 2 2 2 J 2 with the spectra of mixtures containing 24% and 94% If-C^H^Fe^O^SC^-

CCCH^^CH^H^ (Fig® 6)o The spectrum of the unrearranged isomer shows

# singlets at'J,8®22 and TSol? (49), while the rearranged isomer shows a

singlet at ^8065 (48)® Since the resonances do not overlap, they provide

a convenient means for semi-quantitatively determining the percentages of

each isomer in the sulfinate mixture,, The pmr spectrum of a mixture of

if-CHyy^Fe( C0)2S02CH2CH=C( CH3 )2 and fT-CH^H^Fe( C0 )2S02C( CH^ )2CH=CH2

obtained from the reaction of ff-CH^C^E^Fe(CO)2CH2CH=C(OH^ )2 with refluxing

liquid sulfur dioxide is shown in Fig® 5 (spectrum B)0 The singlets at

^ 8o23 and ^ 8019 are assigned to if-CH^C^H^Fe(CO)2S02CH2CH=C(CH^)2, while

the singlet at£8,69 is due to Tf-CH^C H^FetCO^SO^CH^ )2CH=CH2® By

expansion and integration of the spectrum, the mixture was shown to con­

tain 75% tr-CH3C5HifFe(C0 )2S02CH2CH=C(CH3 )2 and 25% tt-CH^H^CO^SC^C-

(CH3 )2CH=CH2« The relative percentages were further supported by the

appearance of the methylene protons of ?7'-CH^CcHi1Fe(C0)„S0_CH-CH=C(CH,)_ 2 2 ^ 2 2 2 5 2 with a relative intensity of 1®5»

The pmr spectrum of ff-CH^C^H^Fe(CO)2CH2CH=C(C^H^ )H is given in

Fig® 7 (spectrum A)® The appearance of the methylene protons as a

doublet with a relative intensity of 2®0 supports the assigned structure,,

The criteria used to determine the relative amounts of each isomer in

a mixture of sulfinates containing the rearranged and unrearranged

cinnamyl moiety are demonstrated in Fig® 8® The pmr spectrum of

7T-C5H5Fe(C0)2S02CH2CH=C(C6H5 )H shows a doublet at ^6®08 (J = 6®5 cps)

and a singlet at^ 4.85 (48)® For 77- C ^ F e (CO)2S02C(CgH^HCI^CI^, the

methine doublet is observed atE^5«45 (J = 8®5 cps) and the cyclo- 79 pentadienyl resonance is shifted to#5*11 (*t8 )» The percentage of each isomer in the mixture can be determined by either comparing the areas under the cyclopentadienyl resonances or by a comparison of the relative areas of the methine to methylene doublets® The spectrum of the products obtained from the reaction of ^-CHy^H^FeCCO^CH^CHsC*-

(CgHj_)H with refluxing liquid sulfur dioxide is shown in Fig® 7 (spec­ trum B)o The doublet at 6®15 (J = 6 cps) is undoubtedly due to the methylene protons of /T'-CH^G^H^Fe(CO)2S02CH2CH=C(^^5 )H° The relative intensity of the doublet is 1«>7 rather than 2®0 and suggests that the sample does not consist of 100$ unrearranged isomer® The criteria used to distinguish between TT-C^H^Fe( CO)^SO^CH^CH =C( CgH,_ )H and ^-C^H^Fe(CO)2-

S02C(CgH^)HCH=CH2 are of little help in this case® The methine doublet of W-CH5C5H/fFe(C0)2S02C(C6H5 )HCH=CH2 is probably obscured by the C ^ absorptions9 and the cyclopentadienyl resonances are too broad and complex to be of any help® A careful examination of the spectrum in the cyclopentadienyl methyl region reveals an intense peak at ^ 8®07 and a much less intense absorption attT8®08® It is particularly in­ viting to assign the resonances at'£8®07 a n d ^ 8®08 to the unrearranged and rearranged isomers, respectively® On the basis of the relative intensity of the methylene protons as 1®7 » it would appear that the mixture contains 85$ Tf-CH^C^Fe(CO)2S02CH2CH=C( CgH^ )H and 15$ rZ-CH^-

C^H^Fe(C0)2S02C(CgH^)HCH=CH2« If the above assignment of the spectrum is correct, an increase in the amount of TT-CHy^H^FeCCO^SO^CCgH^)-

HCH=CH2 in the mixture should result in an increase in the intensity of the peak at "C'8o08 with a simultaneous decrease in the relative in­ tensities of the peaks at ^8®07 and 2T6®15® Downs (25) has reported 80 that the reaction of rf-C^H^Fe(C0 )^CH^CH=C(C )H with refluxing liquid

SO^ gives a mixture containing 80# jr-Cj.Hj.Fe (CO) ^O^CH^CH =C (CgH,- )H and

20# ;rf-C^H^Fe(C0 )2S02C(CgH^)HCH=CH2; however, when the reaction was

0 carried out in SO^-saturated hexane solution, the resulting mixture contained 30# jT-C^Fe(CO)^SO^CH^CH =C(CgH^)H and 70# 1T-C^FeCCO^SO^

C(CgH^)HCH=CH2* The similarity in the results obtained from the re­ actions of tT-C^Hj-Fe (C0)2~ and jr-CH^H^Fe(CO)2CH2CH=C(CgH^ )H with re- fluxing S02 suggests that in S02«saturated hexane solution the amounts of unrearranged and rearranged isomers should likewise be the same* The pmr spectrum of the products obtained from the reaction of j^-CH^C^H^-

Fe(C0 )2CH2CH=C(CgH^)H with S02 in hexane solution shows an intense ab­ sorption at Z 8.08, a weak absorption at 2^8*07, and a doublet att'6.15 with a relative intensity of 0*5* On the basis of the. relative intensity of the methylene doublet, the mixture is believed to contain 25# tf'-OH,-

C5HifFe(C0)2S02CH2CH=C(C6H5 )H and 75# TT-CH^C^FeCC0)2S02C( )HCH=CH2*

While it was still not possible to observe the methine doublet of jr-CH*-

C^H^Fe(CO)2S02C(CgH^)HCH=CH2, it would appear that the above assignments are correct* Fig. ?•--A comparison of the pmr spectra of:

A. 7r-CH3C5H^Fe(C0)2CH2CH=C(C6H5 )H

B. A mixture containing 85% tf-CH C H.Fe(CO)?SO CHpGH=C(C/,HI-)H and 15% JT-CH^C H^Fe( CO)2S02C( JHCH=CH|. 5

81 TMS Fig. 8.— A comparison of the pmr spectra of:

A. ‘jT’-Cg.HLFe ( CO ) _S0_CHoCH=C ( C^H- )H y y 2 2 2 o ? B. A mixture containing 80% ^-CRHqFe( CO) _SO?CH_CH=C( C^H,- )H and 20# ^-Cc.HcFe(CO)„SO_C(C,Hc?HCH=CH^. b ^ 3 y d. 2 o 5 2 C. A mixture containing 30% >r-C HsFe(C0) SO CH CH=C(CAH,_)H and ?035-»r-C5H5Fe(C0)2S02C(Cg3 ?HCH=CH| (51)7 5

83 8^

TMS /IIIC°0 H H Fe —S— C-C*=?C,

(A)

COo H H /III ^ c6h5 Fe —S-C-C* 80% #- 'Co 01 LH

/C° o c6 h 5 Fe — S— C -C « 2 0 % Cg A A A TMS

/>— f _JL JL

TMS Fe —S— C— C**= C, 30%

Fe-S-C-C«=C

8.0 . 0 PPM(8) 85 TABLE 8

PROTON MAGNETIC RESONANCE SPECTRA OF ALLYLIC 7PCH,C_H.Fe(CO) R AND Tf-CHyyijFetC0)2S02R COMPLEXESa ^ 5

-R and -S02R Chemical ShiftRelo Area Aseign.

-CH_CH=C(CH,)H 8.42(d) (J=6cps) =c (c h l ) 8.13(s ) 8.0 7.93(d) (J=?cps) S t - 5 5.58(a) 4.cf 5.13-3.89(a) 2 . 0 S J j L

-S02C(CH3 )HCH=CH2 8,66(d) (J=7cps) 3.0 -C-CH 7.92(s) 3.0 6.66-6.l6(m) 1.0 -^H°5 5.17(m) 4.83(m) [C5H4] 5.25-3.70(m) H -CH=CH2 -CH2CH=C(CH5 )2 8,38(s) =c(ch_)5 8.12(e) . Jll.oj CH,-C? 2 7.84(d) (J=9cps) - c l 5 5.46(e) 4.0 c^Hr 4.52(t) (J=10cps) 1.0

-S02CH2CH=C(CH3 )2 8.69(e) -(CH,),,- 8.23(e) 9.0 [•=c(cy2| and 8.19(e) -so2c(ch3 )2ch=ch21 7.92(e) 6.32(d) (J=9cpe) 1»5 £ 2 5.23(m) 5.05(m) 5.14-4.36(m) H -CH=; -CH=CH„

-ch2ch=c(c6h5 )h 8.18(e) 3.0 7.77(d) (J=8cps) 2.0 5.58(e) 4.0 4.00-3.l4(m) - § & ch- 2.83(m) M °6H5 -so2ch2ch=c(c6h5)h 8.08(e) p.°] [CH3-05j 8.07(e) and 6.15(d) (J=6cpe) 1.7 -CH_- 5.02(m) T't.oi M r | -S0oC(C,Hc)HCH=CHoC 2 6 5 2 86

TABLE 8 (Contde)

~R and -SO^R Chemical Shift Rel* Area Assign* #

*fo98(m) i__ i |2«,6j -CH=CH-? -CH=CH 2„70(m) 5* 1 °6H5

In CDCl, with Si(CH,)^ as internal standard., Multiplicities and J values are for first order splittings only* s = singlet; d <=doublet; m = complex raultiplet; t = triplet

bThis sample 75% 7T-CH C^H.Fe(CO) SO CH?CH=C(CH ) and 25% ff-CH,-

C^H^Fe(CO)2S02C(CH^)2CH=CH^o? ^ ** '

°This sample &5% ir-CH^C^H, Fe(CO) _SO_CH?C H = C ( C ) H and 15% tf-CH,- C^H^Fe (CO) ^ > 0 ^ (CgHj. )HCH=C!L,? H ^ ^ b 5 *

y The pmr spectra of rf-1,3-(G^H^)^H ^ F e (CO)2CH2CH=G(CH^>2and

a mixture containing 75% jr-1 »3-(GrHc)o0cH,Fe(CO)_S0oCH_CH=C ( CH_,) „ O j d ? $ d d d j d and 2.5% if-l . S - C C g H ^ C ^ F e C C O ^ S O ^ C C H ^ C H a G I ^ are given in Fig„ 9.

The chemical shifts and other data obtained from the spectra are

reported in Table 9» The relative percentages of each isomer were

determined by comparing the area under the singlets at 'E’8»3^ and

X 8.28 arising from the unrearranged isomer to the area under the

singlet at "K8.67 which is assigned to the rearranged isomer* The

percentages determined in this manner were further supported by the

appearance of the methylene doublet at T6.^6 with relative intensity

of 1,5 Fig. 9«— A comparison of the pmr spectra of:

A. -jr-l»3-(C6H5 )2C5H3Fe(C0)2CH2CH=C(CH3 )2

B. A mixture containing 73% C H Fe(CO) SO CH_CH=C(CH_) and 25% TT-1,3-( CgH^ )^ H ^ F e ( CO)2S02C( CH^ )'CH=CH2? ^ ^

87 (A) TMS

*

(B)

TMS

oo oo ~ ~ ~ I" T ml li 89

TABLE 9

PROTON MAGNETIC RESONANCE SPECTRA OF ALLYLIC 7f-l,3-(C,H ) C H_Fe(CO) R AND y-1,3-( C^-H,- ) J3_H_Fe( CO) -SO-R COMPLEXES'* 5 * 41 o ) c J ; d d

-R and -S02R Chemical Shift Relo Area Assign.

-CHdCH=C(CH-.)_ 8.57(m) 6.0 =C(CH,)_ 2 3 2 7.90(d) (J=9cps) £.0. -CH,-3 2 5.05(d) (J=2cps) 4.78(t) (J=1.5cps) k.O 151 4.83(m) - -CH= 3.15-2.65(m) 10.0 (C6H5}2 -S0oCH,CH=C(CH,)_ 8 67 s -CfCH-);,- 2 2 3 2 . ( ) 1.5 8 . 3 M s ) [^.51 l=C(GEpf\ and 8.28(s ) I 1 I 3 2J I. 6.zf6(d) (J=8cps) 1.5 -CBL- -S02C(CH3 )2CH=CH2 *f.88-3®72(m) k.o c-i i \ =CH_ 2.57-l«90(m) 10.0

aIn CDC1, with Si(CH,)^ as internal standard. Multiplicities and J values are for first order settings only, s = singlet; d = doublet; ra = complex multiplet; t = triplet.

bThis sample 75% Tr-1,3-(C.H[_)?CI-H Fe(CO) SO CH CH=C(CH ) and 25# flr-l,3-(C6H5 )2C5H5Fe(C0)2S0°C?CH352CH=CH2.^ ^ 5 *

The pmr spectra of allylic and allylic sulfinato complexes of iT-CCH^^C^FeCCO)^ are reproduced in Fig. 10, 11, 12 and the chemical

shifts and other data obtained from the spectra are given in Table 10.

The procedure used to . determine the modes of attachment of the allylic

groups are identical with those used for the derivatives of fT-CH^C^H^-

Fe(C0)2~ (vide supra). Fig. 10.— A comparison of the pmr spectra of:

A. /T-(CH5)5C5Fe(CO)2CH2CH=C(CH3)H

B. tf-(CH3 )5C5Fe(C0)2S02C(CH3 )HCH=CH2

90 91

1 I I 0

Fig. 11.— A comparison of the pmr spectra of:

A. TT- (CH, ) j-Cj-Fe (CO ) _CH_CH=C ( CH_ ) _ ; ) 5 2 2 5 2 B. 7r-(CH3 )5C5Fe(CO)2S02CH2CH=C(CH3 )2

C. A mixture containing 60& /r-(CH ) C Fe(CO) S0oCH_CH=C(CH,)_ and bCfc w-(CH,)t.Cc.Fe(C0)-S0_C(CH,)^CH=dHo. d d 2 * d 5 5 5 22522

92 93

TMS

TMS (B)

TMS

. 40% Fig. 12.— A comparison of the pmr spectra of:

A. lT-( CH, ) CcFe ( CO ) _CH _CH=C ( CrH_ )H 5 5 ? 2 2 o 5 B. TT- ( CH, ) j-Cj-Fe ( CO ) _SO_CH_CH=C ( C/-HL )H 3 5 5 2 2 2 6 5

9^ 95 «Tll

CO

J

< m 96

TABLE 10

PROTON MAGNETIC RESONANCE SPECTRA OF ALLYLIC 1T-(CH,) C^Fe(CO) R AND ir-(CH,)cC_Fe(CO)_SO-R COMPLEXES3, ^ 5 5 ' * 5 5 5 d 2

-R and S02R Chemical Shift.% Relo Area Assign®

-CH_CH=C(CH,)H 8.45(d) (J=6cps) =C-CH, 2 5 8.2j5(s) Jao.oj (CH-)? -CHp- 5 .22-4.05(m) 2.0 -CH=CH-

-S0oC(CH_)HCH=CH« 8.62(d) (J=7cps) 3.0 -d(CH,)- d 5 d 8.05(a) 15.0 (CH,)| 6.75-6.03(m) 1.0 -QH- 5 4.66-3.28(m) 2.9 -c h =c h 2

-CH2CH=C(CH3 )2 8.55(d) (J=9cps) 8.43(a) 23.0 5 s . ) 2 8.28(a) 4.50(t) (J=10cps) ' 1.0 a *

-S02CH2CH=C(CH3 )2 8.25(a) =C(CH3)2 8.2l(s) 21.0 8.08(s) (CH,),- 6.42(d) (J=8cps) ' 2.0 * -CHp- 4.56(t) (J=10cps) 1 . 0 -CH=

-S02CH2CH=C(CH3 )2 8.68(a) -C(CH,)_ 8.25(a) =c (ch|)| 8.21(s) and 21.0 8.09(a) (ch3 )5 -s o 2c (ch3 )2c h =c h 2c 8»o8(s) 6.42(d) (J=8cpa) 1.2 -CH - 4.98-4.35(m) 1.8 -CHS; -CH=CHp ■CH2CH=C(C6H3 )H 8.26(a) M (CH,)/ 8.13(d) (J=8cps) -CHp- 4.00-3.25(m) 1.9 -CHiCH- 2.84(m) 5.0 C6H5 97

TABLE 10 (Contd. )

-R and -SO^R Chemical Shift ^ Rel. Area Assign. 0

-SO-CH _CH=C ( Cz-Hr- )H 8.07(s) 15o0 (CH_)_ 2 2 o p 6.05(d) (J=7cps) 2.0 -CH|-5 3.72-2.90(m) 2.0 -CH=CH- 2.50(m) 5.0 °6H5

aIn CDC1, with Si(CH^)^ as internal standard. Multiplicities and J values are for the first order splittings only, s = singlet; d = doublet; m = complex multiplet; t = triplet.

-CH*- protons obscured by (CH,)c and =C-CH_. . c. 5 p P cThis sample M «"-(CH,) C Fe(CO) SO CH?CH=C(CH,)p and W ir-(CH,)cCc.Fe(C0)_S0oC(CH_)*eH2cHo. ^ ^ ^ P ^ 3 5 5 2 2 3 2 2

The pmr spectrum of 7T-(CH^)^C^Fe(C0)^CH^CH =C(CH^)H (spectrum A

of Fig. 10) deserves special comment. The spectrum contains only

one doublet at X 8 A 3 (J = 6 cps). For ff-CH^H^FeCCO^CRgCHKKC&^H,,

the spectrum shows a methylene doublet atX 7«93 (J = 7 cps) and the

crotyl methyl resonance appears as a doublet at'T8.^2 (J = 6 cps)

(spectrum A of Fig. 3)» On the basis of the chemical shift and

coupling constant, it seems reasonable that the doublet in the spectrum

of fl’-tCH^^C^FetCO^G^CHsCtCH^H can be assigned to the crotyl methyl group. Upon integration of the spectrum, however, the peaks at 2T8.*f5-

8.23 show a relative intensity of 20.0 indicating the presence of the methylene protons. It must be concluded, therefore, that the methylene proton resonance is hidden by the resonance due to (CH^)^ and =C(CH^)0 The spectrum of the sulfinate obtained from the reaction

of ff-( CH^ )^C^Fe(CCO^Cl^CH^C CH.^)h and refluxing liquid SO^, is shown

in Fig. 10 (spectrum B)0 The appearance of a complex multiplet at # T 6o75-6o03 with a relative intensity of 1.0 supports the structure

lT-(CH,)_CcFe(C0)oS0_C(CH_)HCH=CH_o ; ? 5 2 2 3 2 The pmr spectrum of ff~{ CH^ ^C^Fe(CO)2CH2CH=C(CH^ )2 is reproduced

in spectrum A of Fig. 11. The low field component of the methylene

doublet overlaps with the singlet arising from the methyl protons

on the allyl chain. The spectrum of the sulfinate obtained from the

reaction of ir-(CE^)^C^Fe(CO)^CELjCHsCCCHj)with refluxing liquid SO^

is shown in spectrum B. The presence of singlets at £8.21 and'£'8.25

and the absence of any resonances at higher field corresponds to the

presence of only *r-(CHjcC_Fe(C0)_S0oCH„CH=C(CHj.,. When TT-CCH-.),.- 3 P P 2 2 2 3 2 3 P G^Fe(CO)^CE^CR=G(CH^ )2 was allowed to react with SO^ in hexane solution,

a solid having spectrum C of Fig. 11 was obtained. The singlet at

£8.68 confirms the presence of fr-(CH_)_Fe(C0)_S0oC(CH,)„CH=CHo in this 3 P 2 2 3 £ 2 mixture.

The pmr spectra of 7T-(CH^)^C^Fe(CO^CH^CH =C(C^H^ )H and fT-(CH^)^-

C^Fe(CO)^SO^CE^CE=C(C^E^)E are shown in Fig. 12. The appearance of

the methylene doublet of the sulfinate with a relative intensity of

2.0 supports the presence of only the unrearranged cinnamyl isomer.

The pmr spectra of the allylic and allylic sulfinato complexes

of Tr-C^H^Mo^O^PCOCgH^)^- are shown in Fig. l*f, 16, and 17, and the

chemical shifts obtained from the spectra are given in Table 11. The

spectra of the molybdenum complexes are analogous to those obtained

for the corresponding derivatives of iron (vide supra); however,

there are additional factors present in the molybdenum system that may give rise to more complicated spectra.. For example, the presence of the triphenylphosphite ligand may give rise to additional splitting in the spectra since the phosphorus atom has a nuclear spin of )6® Also complexes of the type tt-C^H^Mo(CO)^LR can exist in two isomeric forms

(see Fig® 13)® In addition to the cis and trans isomers of rr-C-ELMo-

(CO^LR two more isomers may result from the cis and trans isomers of -CI^CHsCClOH. In order to avoid confusion in the discussion of

7T-Cj-H^Mo(CO) ( OCgH,-)^-CH^CH=C (R ) H complexes, cis and trans will only refer to the spatial distribution of the ligands about the Mo atom (Fig*

13)® The stereochemical descriptors E and Z will be used to designate the isomers of the allyl chain® "Z" is derived from the German "zusammen"

CL L CO 0

trans cis

Fig® 13— The isomers of a '/^•C^H^MoCCO)^LR complex® meaning "together" and "E" comes from the German "entegen" meaning

"opposite"® The isomers and their corresponding descriptors are

shown below®

9 H R -q-cw? H H H R

E Z

It has been shown that the cis and trans isomers of TT-C.-H.-MoCCO)-' 3 3 2 P(OCgH^)^R (R = CH^, CH^CgHj.) can be readily distinguished from each

other using proton magnetic resonance spectroscopy® It was concluded

that the appearance of the cyclopentadienyl resonance as a doublet

with Jp/vl«3 cps confirms the presence of the trans isomer (52)®

The pmr spectrum of TT-C^H^MoCCOj^PCOC^H^J^CH^CH^CCH^jH is shown

in Fig. l*f (spectrum A)• The presence of two doublets in the ratio

of 2:3 atT^7»78 and£8.35* respectively, supports the assigned

structure. An unusual feature of the spectrum is the presence of two doublets and two singlets in the cyclopentadienyl resonance region

(T 5-5*5)® The doublets have J = 1.5 cps and it is concluded that they arise from trans-7T-Cf-H^Mo(C0)^P(0C/-Hr.),CH^CH=C(CH^)H. The singlets at — ------33 2 0332 3 lower field are assigned to cis-TT-C^MoC CO)£P( OCgH^) CH2CH=C( GH^)H

The presence of cis and trans isomers, however, can only account for the appearance of one singlet and one doublet. The two additional resonances are probably due to the E and Z isomer of the crotyl moiety. 101

The possibility that E and Z isomers will give rise to two cyclo­

pentadienyl resonances receives support from the pmr spectrum of

Tf-C^H^Mo(CO=C(CH^)H (Fig® 15)® The presence of two cyclopenta­

dienyl absorptions in the latter spectrum can only be due to isomers

of the crotyl group. The pmr spectrum of the products obtained from

the reaction of tf-C^H^MoCCOj^PCOCgH^^CH^CHsCCCH^)!! with refluxing

liquid SO2 is shown in spectrum B of Fig, 14. The percentages of

ff-C5H5Mo(C0)2P(0C6H5)5S02CH2CH=C(CH3 )H and TT-C^MoCCO^PCOCgH^SO^

C(CH3)HCH=CH2 in the product mixture was based on the relative intensi­

ties of the doublets at ^8.77 and'£'’8,33° First, it was necessary to

assign correctly these absorptions to the corresponding isomers® The

crotyl methyl resonance of #-CcHcMo(CO)„P(OC-:HI-),CH_CH=C(CH-z)H appears 3 3 2 0 3 5 & 3 as a doublet atX 8,35 (Table 11), For S02 insertion without rearrange­

ment of the crotyl moiety, the chemical shift of the methyl resonance

should remain essentially the same since the S02 moiety is well removed

from the methyl group® The doublet a t £8.33 is almost identical with

the chemical shift found for the crotyl methyl resonance of the starting

material, while the doublet at £8.77 represents a chemical shift of

0.42£ units to higher field. Similar shifts to higher fields are also

observed for the crotyl methyl resonances of ff-CH^C^H^Fe(CO)2S02C(CH^)-

HCH=CH_ (Table 8) and !T-(CH,)_C_Fe(C0)„S0oC(CH*)HCH=CHo (Table 10). d. 3 3 5 . 2 2 3 t 201

c £?H0=H0H(^H0)0?0 S ^ H 900)d3(00)°jA^0-^ %02 H( HO)0=H0 HO OS ( H 00 )d (00 )°W H 0"U* #08 Suxutc^uoo a m q x j m v •9

H( ^HO ) 0=H0?H0^ ( ^H900 )dS ( 00 ) ow^O-i/ •V

: jo Baq.osds atud aift jo uosxxedu/oo y— ®-f7x •^Td 103

CM

o x—6

:°o (££) ?HO=HOH(^HO)0?OS^(00)otfifpQ-Jl *9

H(^H0)D=H02H0^(00)oW5H^0“Ji “V

;jo ea:pads otud aift jo uosxaisdtaoo y— -{Tl! *sTd ac — o — x TMS No'0 5-00

Downs (5*0 has suggested that the doublet at if8.25 (J = 5 cps) in the pmr spectrum of ■jf~C^H^Mo( GO J^SO^GC CH^ )HCH=CH2 may be due to the presence of a small amount of jr-C_HcMo(C0)_S0_CH_CH=C(CH,)He On the 3 5 3 2 2 5 basis of the chemical shift and coupling constant of the crotyl methyl resonance (^8033; J = 5 cps) of Tr - C ^ M o CCO^PCOC^H^SO^I^C H^CH^Hj it appears that this assignment is correct® The cyclopentadienyl resonance region (^5®0-*+®5) of the spectrum of vf-C^H^MoCCO^PCOCgHj-)^-

SO^C^H^ (spectrum B of Fig® 14) requires additional comment® The spectrum shows doublets at2^*f®83 and Z k a 75 with J = 1 cps® The magnitude of the coupling constants suggest that they arise from spin- spin coupling with the phosphorus atom of the triphenylphosphite ligand® The assignment of the two doublets, however, is difficult to determine® It is possible that the two resonances are due to the rearranged and unrearranged crotyl sulfiziates® If this is the case, the relative intensities of the two peaks should be 4:1 (vide supra)®

Since the resonances overlap, however, it is not possible to determine accurately their relative intensities. Another possibility for the presence of two cyclopentadienyl resonances may be the presence of

E and Z isomers of the crotyl moiety of 1T-C^H^Mo(CO)£?(

CH2CH=C(CH^)H® We have already seen that E and Z isomers of the crotyl moieties of jr-Ct.H_Mo(CO)_P(OC.Hc),CH_CH=C(CH2)H and 7T-CJI_Mo(C0),CH.,- 3 3 2 5532 3 55 3 2 CH=C(CH^)H give rise to two cyclopentadienyl resonances (vide supra)®

At the present time it is not possible to assign these resonances to their corresponding isomers®

The pmr spectra of 7T-CcHI.Mo(CO)0P(OCrH_)_CH-CH=C(CH,)0 and 5 5 2 6532 32 107

77--C5H5Mo (C0)2P(0C6H5 )5S02CH2CH=C(CH3)2 are shown in Fig. 16. The appearance of the methylene protons with a relative intensity of 2.0

supports the assigned structures. The splitting of the cyclopenta-

dienyl resonance of 7f-CJ04o(CO)2P(OC6H5)3S02CH2CH=C(CH5 )2 into a

doublet is more clearly evident by expanding the spectrum in this region.

The pmr spectrum of the sulfinate arising from S02 insertion of IT-C5H5Mo (CO)2P(OC6H5)5CH2CH=C(C6H5 )H (Fig. 17) demonstrated that only the unrearranged isomer is formed. 801

S(^H0)0=H0SH0S0S^(^H900)dS(00)oW^He0-it *S

2( ^H0 ) 0=H0?H0^ ( ^H900 )dS(00)oW^0-^ #V

:jo Baq.oads .iuid aqq jo xxostjBdtaoo y— *91 ’^Td H H I I

r u ch»

(A)

W ( O H H "Mo-S-C-C.C' 0 * 3 A < U CH3 TMS

i

I X =P -wi Fig. 17.— A comparison of the pmr spectra of:

A. JT-C-Hj-Mo ( CO ) _P( OC^Hj.) ,CH_ C H = C ( C ,-H,- )H P P 2 b p p 2 b p B. jr-C_HcMo( CO) 0P( OC.Hc )_S0oCHoCH=C( C.Hc )H p p 2 b p ; 2 2 b p

I

110 ■ITT M W V S" on 112

TABLE 11

PROTON MAGNETIC RESONANCE SPECTRA OF ALLYLIC 7f-C[_Ht-Mo(CO)?P(OC.H(-),R AND «f-C_Hc.Mo(CO)-Jrvw,n_/^-1P(OC.rHI_),SO_R _ x COMPLEXES b 5 5 5 5 2 6 5 5 2.

-R and -SOgR Cheoiical Shift Rel. Area Assign.

-CH„CH=C(CH,)H 8.35(d) (J=6cps) 3-0 -CH, 2 5 7.78(d) (J=7cps) uev -ch: 5.45(d) (J'=1.5cps) r 5.38(d) (J*=1.5cps) 5.32(e) 7.0 C5H5 5.22(e )

5.03-^.38(m) . -CH=CH 2.45(m) 14.8 p(°c6H5 )3 -S02CH2CH=C(CH3 )H 8.77(d) (J=7cps) [3.0] 8.33(d) (J=5cps) -C-CH and 5.99-6.49(ra) 1.8

-so2c(ch3 )hch=ch21 4.83(d) (J'=lcps) 4.75(d) (J'=lcps) 4.78-4.20(01) 6.4 -CH=CH-; -CH=CHp 2.65(m) 16.0 p(oc6h|)3

• • -CH2CH=C(CH3 )2 8.47(e ) 8.40(e ) 8.34(e ) 6.0 8.27(e ) 7.73(d) (J=9; J'=2cps) 2.0 -CH_- 5 .37(d) (J'=1.2cps) 5.20(s) [5.J 4.34(t) (J=9cps) 1.0 2 .4 5 (01) 15-0 p(006h5 )3

-S02CH2CH=C(CH3 )2 8.37(s ) [6.0] [(CII3)2] 8.28(b ) 6.50(d) (J=8cps) 2.0 -CH - 4.84(d) (J'=lcps) p.9] c,_Hf 4.82-4.48(0i) 2.66(01) 15.0 P(OCgH_) 5 3 113

TABLE 11(Contdo)

-R and -SC^R Chemical Shift ,*£ Rel* Area Assign*

-c h 2c h =c (c 6h5 )h 7.57(d) (J =9; J"=2cps) 2*0 -CH - 5®37(d) (J'=l*5cps) [ ^ f j 5®23(s) [51 3.28-2.70(m) 2*1 -CH=CH- 2.^5(m) 20*0 P(0C,H-),; -S0_CHoCH=C ( C/-H_ )H 6.26(d) (J=6; J'=l*5cps) 2*0 -0H-- 2 2 6 5 4.85(d) (J'=1.2cps) 5*0 3.78-3»27(m) 2*1 -§S§CH- 2*72(m) 19*6

aIn CDCl, with Si(CH^)^ as internal standard* J = proton-proton coupling; J = phosphorus-proton coupling; s = singlet; d = doublet; m = complex multiplet; t = triplet

bThis sample 80# 1T-C H Mo(CO) P(OC.H,.),SO CHpCH=C(CH,)H and 20# 1T-C.-Ht-Mo(C0KP(0C£Hc),S0oC(dH-)HCH=CH_ * 5 d * 0 0 -2 b 5 5 2 O 2

Discussion of mechanisms* Downs (55) has discussed three possible

reaction mechanisms in order to explain the results from the reactions

of allylic complexes of ■ff-C^H^FeCCOjg- , Tr-C^H^MoCCO)^-, and *P-C^H^W-

(CO)^- with sulfur dioxide* While the reactions were not carried out

under conditions which permitted determination of kinetic parameters,

the mechanisms were suggested in order to determine whether or not the

results from the syntheses were consistent with them*

In Mechanism I an ionic dissociation was postulated (56). Upon

recombination of the ions, the product contains SO^ inserted between

the metal-carbon bond. In the reaction between TT-C^^Fe^O^CH^CHsCRR' and S02, for example, the following process could occur® n k

’Jf-C r-H,-Fe ( CO ) -CH -CH =CRR' + SO_ -> Jjr-cyy’eCco)^ “(+) 5 5 d d d

H + +(-) (19a)

[fft-C5H5Fe(CO)2]"(+) + S02 ---- — > ^T-C^FeC C0)2S02]”(

(19b)

[CH2CHCRR']^f-C5H5Fe(C0)2S02] (19c)

tf-C_Hc.Fe(C0)oS0_CRR'CH=CH_ and/or ^-CcHcFe(CO)-SO_CH_CH=CRR» 5 5 2 2 2 5 5 2 2 2

In Mechanism II a two step reaction was considered and involves

SC>2 insertion followed by rearrangement (57)* The reaction of SC>2

with H-C^H^FeCCO^CH^HsCRR1 will be used as an example®

9 TC-C-H-Fe(CO) CH_CH=CRR' + SO--- > 7T-CcHcFe ( CO ) ^-S-0-CHnGH=CRR' 5 5 2 2 2 5 5 d 2 i

if-C_H_Fe(CO)_-S-0-CH_CH=CRR• -> tT-C_Hc.Fe(CO)--S-CRR'CH=CH, 5 5 2 2 5 5 2 t 0

and/or (20b)

IT-C_HcFe(CO)_-S-CH_CH=CRR' 5 5 2 t 2 115

Mechanism III involved a concerted cyclic process in competition

with a direct insertion reaction (58)» The formation of ■^-CcHcFe(C0)o-

S02CRR,CH=CH2 can be visualized as proceeding in the following manner:

CO / CO ff-CcHcFe(C0)oCHoGH=CHR» + SO------> f/-CcHcFe C 5 5 2 2 2 5 5 ^ > C H - 0 s h j 2 o ' CH &*// RR'C

7f-CcH_Fe(CO) SO-CER’CHsCEL (21) ? 5 2 2 2

It was concluded that of the three mechanisms discussed the

cyclic concerted process in competition with direct SO2 insertion

reaction was most consistent with the synthetic results (59)® On

the basis of this conclusion an increase in the rate of the direct

insertion reaction should result in preferential formation of unre­

arranged allylic sulfinates. Conversely, a decrease in the rate of

direct SO2 insertion should favor insertion of SC^ with rearrange­

ment of the allyl.

For the allylic derivatives of iron the rate of direct SO^ in­

sertion is expected to increase with electron-donating groups, eg.,

CH^, on the cyclopentadienyl ring, while the addition of electron- withdrawing groups on the ring, eg., CgH^, should result in a decrease in the rate of direct SO^ insertion into the iron-carbon sigma bond.

The results obtained from the reactions of SO^ with substituted and unsubstituted cyclopentadienyliron dicarbonyl allylic complexes are shown in Table 12. 116

A cursory examination of the table reveals that all of the

crotyl

rearranged crotyl moiety regardless of the substituents on the cyclo™

pentadienyl ringo The percentage of sulfinate containing the rearranged

allylic moiety in the sulfinate mixtures of ff-CH^C^H^Fe(CO)2CH2CH=C(ch^) 2,

|r«ls3~(C6H5)2C5H3Fe(C0)2CH2CH=C(CH3 )2 and r-CH^HjFe(CO)

(CgH^)H was essentially unchanged from that observed for the corres­

ponding derivatives of Tf-C^H^Fe ( C 0 ) 2~ « Although the percentages are

not identical, they fall within the experimental error®

The failure to observe a change in the reaction products by placing

either one methyl group or two phenyl groups on the cyclopentadienyl

ring is not unexpected since infrared evidence (vide supra) indicates

that the extent of substitution is not great enough to alter the

electron density on the iron atom® Infrared spectroscopy does indicate * that the electron density on the iron atom of 7T-(CH,)^C^Fe(CO)_- deriva- 3 5 5 2 tives is significantly increased (vide supra)® On this basis the re­

actions of 7T-(CH,)j-C,-Fe(CO)0CH0CH=C(CH_)0 and jr-(CHjcCcFe(C0)_CHo- 5 5 5 2 2 3 2 3 5 5 2 2 CH=C(C6H5 )H with S02 are expected to give products containing smaller

amounts of the rearranged allylic moiety® In fact, the reactions yield

7f-( CH^ )j-C^Fe(C0)2S02CH2CH=C( CH^ )£ and 7T-( ^C^Fe (CO)2S02CH2CH =C(CgH^H

exclusively. The reaction of rf-(CH,)_CcFe(CO)_CH»CH=C(CH,)_ with SO. 3 5 5 2 2 3 2 2 in hexane solution yielded a mixture of 60% 7?^(CH:z)i:.C_Fe(C0)»S0„CH^- 5 5 5 2 2 2 CH=C(CH5 )2 and kO% CH^^C^Fe(CO)2S02C(CH^)2CH=CH2; however, under

similar conditions the TT^-CJfl derivative formed 7% ?f-CcH1.Fe(C0)oS0oCH-- 5 5 5 5 2 2 2 CH=C(CH3 )2 and 93% Tf-C^Fe(CO)£C(CH^)2CH=CH2 (6o). It is evident that the five methyl groups have inhibited the rearrangement of the 3-methyl-

2-butenyl and cinnamyl groups® 11,7

TABLE 12

ISOMERIC DISTRIBUTION OF SULFINATES FROM SO INSERTION OF ALLYLIC COMPLEXES OF IRON*®0

9 8 R H R CcHc X Fe(CQ)SO_- -C-CH=CH„ -C-CH=C 5 5-n n 2 2 R 2 H R

X = coc; R = CH 100° % 0 % n = 0° R* = H , R = CH, 28-24°, 60° , 93°,e 72-76°, 4oc,d, 7°’® R' = CH£ R = C ^ 23-18°, 70°,e 77-82°, 30°*e R« = H

X = CH, R = CH, 100 O n = 1 3 R' = H R = CH, 25 75 R' = CH, -e o_ __e R = CM 15 , 75 85 , 25 R* = H6 5

X = CH; R = CH 100 n = 5 R' = H R = CH, 0, 40e, 10d 100 , 60e, 90d R' = CH^ R = cC J L 0 100 R'. = hH'6 5

X = C,Hc; R = CH, 25 75 n = 2 R' = CH3

£1 All reactions were carried out in refluxing liquid sulfur dioxide unless otherwise stated*

The pmr of the sigma bonded starting material showed only the primary form, M-CH^-CH^RR', 118

TABLE 12 (ContcL)

CThis data taken from reference (60)o

^Prepared in liquid sulfur dioxide at ca0 -50®o

Prepared in SC^-saturated hexane solution at 27®°

The substitution of a carbonyl group by triphenylphosphite in fT-Cg.H^Mo(CO)jR (R = allylic group) is expected to increase the rate

of direct S02 insertion since the weak base CO is replaced with the

stronger base P(0C^H^)^o The results obtained from the reactions of f f-C^MoCCO^R and Tf-C^Mo(CO)£P(OCgH^) R (R = allylic group) are

summarized in Table 13° Since no rearrangement was observed by Downs

(25) in the reactions of jT-C^MoC CO^Ci^CE^CCCH^)£ and jr-C^H^MoCCO)^-

CH2CH=C(C6H5)H with SO^ it is not surprising that the corresponding

'triphenylphosphite substituted derivatives also insert SO2 without rearrangement of the 3-methyl-2-butenyl and cinnamyl groups« Since the reaction of jf-C^H^Mo(C0)^CH2CH=C(CH^)H with refluxing sulfur dioxide gives a mixture containing 10-15& yT-C^H^Mo(C0)^S02CH2CH=C(CH^)H and 90-

85^ 7T-C5H5Mo(C0);5S02C(CH;5)HCH=CH2 (25), the triphenylphosphite deriva- 1 tive is expected to insert S02 with preferential formation of TK-C^H^Mo-

(CO)£P( OC6H5)3S02CH2CH=C(CH^)H0 The reaction of TT-C^MoCCO^PCOCgH^-

CH2CH=C(CH^)H with refluxing S02 gives a sulfinate mixture containing 80$ fT-C-H-Mo( CO) 0P( 0C/-HL )-,S0_CH CH=C( CH, )H and 20& Tf-C-H.-MoC CO ) _P( 0C.Hc ),- 3 3 2 05522 3 5 5 2 o53 S02C(CH^)HCH=CH2« As was observed in the reactions of the allylic de­ rivatives of iron with S02$ the rearranged product can be formed in higher yields in liquid SO2 at ca» -50°®

It must be stressed that the data summarized in Tables 12 and 13 119

TABLE 13

ISOMERIC DISTRIBUTION OF SULFINATES FROM, SOp INSERTION OF ALLYLIC COMPLEXES OF MOLYBDENUM3' 9 d

R H R C H Mo(CO)_ X SOv- -C-CH=CH_ -C-CH=C 5 5 '3-n n 2 R 9 H R 9

n = 0° R = CH 85-90° % 15-10° % R 9 = H R = CH, 0° 100° R 9 = CK' R = cAr. 0° 100° R' =" H„6 5

X . p (005h > , R = CH 20 , 40 80 , 60 n = l R 9 = H * R of 100f R 9 R 0 100 R 9 = H6 5

aAll reactions were carried out in refluxing liquid sulfur dioxide unless otherwise stated. b The pmr spectra of the sigma bonded starting material showed only the primary form, M-CH^-CHsCRR9.

°This data taken from reference (25).

Similar results were obt.ained in SO»-saturated benzene and chloroform at 27 °« 0 Prepared in liquid sulfur dioxide at ca. -50®.

f Similar results were obtained in liquid SO^ at ca. -50°. 120

were not obtained from kinetic studies and must be used with con­

siderable caution in any discussion of mechanisms,, The synthetic

data, however, are consistent with two competing reaction mechanisms:

direct insertion without rearrangement of the allylic moiety and a

cyclic concerted process involving rearrangement of the allylic group.

It must be pointed out that unless a mixture of sulfinates was obtained

from the reactions of ff-C^Fe(CO)2CH2CH=CRR* or Tf-C^^MoCCO^CT^-

CH=CRR' with refluxing SO^, substitution had no effect on the nature

of the allylic linkage in the reaction products,, For example, the reactions of tf-C^Fe(CO)2CH2CH=C(CH^)H (25) and rf-(CH^C^FeC CO) 2~

CH2CH=C(CH5)H with refluxing SO2 yielded only jr-C^Fe(COj^SO^CCCH^)H-

CH=CH2 and J7-( CH^ )^^^Fe( CO) JHCH-CH^, respectively. This implies that the direct insertion mechanism is of little importance in these reactions.

Reactions of cyclopentadienylmetal dicarbonyl complexes with sulfur dioxide

Starting materials. The details for the preparation of

Fe(C0)oCH_CHC-CH,, «lC_HcFe(CO).,C=C-CH-, tT-C1.HcFe(CO)„CH=CH_, 1T-C_H_- 22 y 55 2 5 5 5 2 2 5 5 Fe(CO)„CH=C=CH , and tr-C_HcMo(CO)~P(OCrH^CH_Cs£-CH_ are described 2 2’ 55 2 6532 3 in the Experimental® Since U -C^H^Fe(C0 )^C=C-CH^, jr-C^H^Fe(CO)2CH=CH2, and if-C^H^Fe(CO)^CH=C=CH^ were, previously reported in the literature, they were readily characterized by their infrared spectra. The prepa­ ration oftf^CcHcFe(CO)_CH0C=C-CH, and ^-CcHcMo(CO)„P( 0C,Hc),CH0C3C-CH,, 5 5 22 3 3 3 2 b 552 5 however, were not previously reported; it was necessary to assign the structure of these complexes with the aid of proton magnetic resonance and infrared spectroscopy. 121

Na [f-Cyi5Fe(C0)2]readily reacts with CICH^hG-CH^ to form a

complex analyzing for C^H^FeCCO^C^H,.. The presence of carbonyl

bands at 2025 and 1975 cm "*■ is consistent with an organic group sigma-

bonded to the iron of the e(CO)2~ moiety. The two most probable

structures of the organic chain are: l) an acetylenic structure,

Fe-CH^C^C-CH^; or 2) the rearranged allenic form, Fe-C(CH3 )=C=CH2.

For organic acetylenes and allenes, Bellamy (6l) reports that the C=C

and C=C=C absorptions occur at 2260-2100 cm”'*' and ca. 1950 cm”"*",

respectively. Unfortunately, the infrared spectrum of rr-C^H^Fe(CO)^-

contains no bands that can be assigned to either C=C or C=C=C.

This is in contrast with the infrared spectra of (OC) JinCELC=C-CH_ 5 2 5 and rf-C^cMoiCO)which have very weak intensity bands in the range 2216-2206 cm”'*' (62).

The pmr spectrum of ^C^H^FeC0 0 ) ^ 0 is reproduced in Fig. 18

(spectrum A), and the chemical shifts and other data obtained from the spectrum are given in Table 1*4-. Due to the complex nature of the

C^Hj- resonance, the splitting pattern was not analyzed. It is possible, however, to differentiate between the allenic and acetylenic structures on the basis of the chemical shifts of the CEL, resonances. The pmr spectra of lf-C5H5Fe(C0)2CH=C=CH2 (36) and (CH3 )3SnCH=C=CH2 (26) show that the =CH2 protons absorb atT*6.03 and'T5»80, respectively. The methylene protons of the acetylenic structure are expected to appear at higher X values since the -CEL- protons of 3^CcELFe(C0)_CELCH=CRR' 2 5 5 2 d occur in the region X 7°72-8.37 (^8). The presence of resonances as® signed to the moiety in the regionT 8.40-8.00 militates against the allenic structure. Fig. 18.— A comparison of the pmr spectra of

A. Tf-C-ELFe ( CO) 0CH_CSC-CH, > j d d p B. if-C^Fe ( C0)2( S02C4H5 )

122 CO

x - o - x oo oo

I : i . CO 1 2 k

TABLE l*f

PROTON MAGNETIC RESONANCE SPECTRA OF PROPARGYLIC ^-C H^FeCCOj-R AND jT-C^FeCCO)^ SO ^ ^ ) a 5 5

-R and -S(0)0R Chemical Shift,T Relo Area Assign®

-CH«C=C-CH, 5«2k(&) 5.0 C H £ P 8.*t0-8.00(m) 5.0 -CK-; -CH,

7.60(t) (J=2cps) 3.0 -CH_ (x) *f.8o(s) 7.0 4.8l, (Jbx=2cps) (Jab=l*fcps) k*k5 (Jax=2cps) (Jab=l*fcps) H(a)

aIn CDC1-, with Si(CH,)^ as internal standard, s = singlet; m = complex multiplet; t = triplet.

^AB part of an ABX pattern, analyzed according to the method described by Jackman (64).

Roustan and Cardiot (63) have very recently reported the prepa­

ration of tf-CcHcFe(CO)_CH_C=C-CH_. The C=C absorption is reported P P 2d 5 to be clearly discernible in the Raman spectrum at 2210 cm“\ A

comparison of the pmr spectrum reported in the literature (63) with

that obtained in this investigation indicates that the complexes are

identical.

The product obtained from the reaction of Na JtT-C^H^Mo(CO)2P-

(OCgH^Jwith C1CH2C=C-CH5 analyzed for C-H^Mo( C 0 ) £P ( OC ) ^C ^ „

The presence of two carbonyl bands at 1961 and 1883 cm is con­

sistent with the organic group sigma-bonded to the -fl’-C^H^MoCCO^P"

(OC^H^)^- moiety. Unlike the iron derivative, however, a weak intensi­ ty band is present at 2200 cm and indicates-the presence of a C=C 1 2 3 bond (vide supra)® The pmr spectrum of J^-C^H^MoCCO^PCOCgH^J^C^H^ is also consistent with the presence of a -Ct^CsC-CHj moiety® The spectrum contained a complex multiplet centered at ''£8®00 (relative intensity of 5) that can be assigned to the butynyl protons® The cyclo~ pentadienyl group gives rise to a singlet and doublet at^^088 and 99

(J = 1®5 cps), respectively, that can be assigned to the cis and trans isomers of the molybdenum derivative (vide supra)® On the basis of the relative intensities of the cyclopentadienyl resonances, the ratio of cis to trans isomers is determined to be 1:2® The triphenylphosphite group gives rise to a multiplet centered at £ 2*50 with a relative in» tensity of 15® The pmr and infrared data are entirely consistent with the structure ^-C_Hc.Mo( CO) _P( 0C,Hc ),CH0C£C-CH,.« 3 3 d o 3 3 2 3 Attempted reactions with sulfur dioxide® Only tt-C ^.H^Fe(CO)2^ 2"

C=C-CHL and 3T-C_Hc.Mo(C0 )_P(0C^Hc.)~CH_C=C-CH_ were found to react with 3 3 3 2 0332 3 sulfur dioxide of the five compounds investigated® The instability of the product obtained from the reaction of the molybdenum derivative with SO^, however, prevented its complete characterization®

A monomeric compound analyzing for C^H^Fe(CO)^(SO^C^H^) was obtained in approximately 90% yield after allowing the starting material to react with refluxing sulfur dioxide or with SO^in pentane solution®

The formation of stable 1:1 adducts of transition metal 2-alkynyl complexes with sulfur dioxide have been reported previously (65, 27* 66)®

From the infrared and proton magnetic resonance spectra, sin allenyl

(oxy)sulfinyl linkage-- Mn-S(0)-0-CH=C=CH_--was postulated for (0C)_- 2 3 MntSO^C^Rj) (65)® Similar structures were proposed for the products of analogous reactions of (OC) MnCH0C=C-CH_ and 7f-C HcMo(CO)-.CH0C=C-R 126

(R = H, CHj) with sulfur dioxide (27)® More recently, Roustan and

Charrier (66) have examined the reactions of lF-CcHcFe(C0_)CH.J3=C-R 5 5 2 2 (R = CH_, C,Hc) and'tf-CcHcMo(CO)_CH_CHC-R (R = H, CH- and C.Hc) with 3 . b 5 5 5 5 2 5 o p SO^o The authors concluded that each of the SO^-containing products is best formulated as containing an allenyl-O-sulfinate moiety-— M-

0-S(0)-C(R)=C=CH2 (66)o In order to clarify this ambiguity, the structure of ff-C^H,_Fe(CO ) 2( S02C^H^) was studied in details

The infrared spectrum of 1?-G^H^Fe(CO)2( SC^C^H^- ) contains two strong intensity bands at 1100 and 903 cra""^ in the S-0 stretching frequency region.. The complete ir spectrum is reproduced in Appendix

Bo The values of the S-0 stretching band's are consistent with those observed for the other S02~containing derivatives of transition metal

2-alkynyl complexes (65,27,66)® The product of the reaction between

(CgH^^SnC^CsCH and SO2 shows S-0 stretching bands in the region 990-

950 cm~^ and is best formulated as (CrHc),Sn-0-S(0)-CH=C=CH_ (26)® The o 5 3 2 proton magnetic resonance spectrum of rT-C^H^Fe(CO)2( S02^ 11) is shown in spectrum B of Fig® 18, and the pertinent data obtained from it are given in Table 14. The C^H^ group gives rise to an ABX^ pattern with

Jax = Jbx. Although the four quartets of the AB portion of the spec­ trum overlap with the cyclopentadienyl signal, it is possible to analyze them, and the results are given in Table 14® The features of the spec­ trum are remarkably similar to those previously reported for (OC)^Mn-

(SOgCj^) and tT-C^Mo(C0)^(SOgC^) withT7.80-7.95 (CH^), 4.87-4.94 and 4®48-4.57 (CH2 ), and Jab = 14®5-15 ops and Jax = Jbx = 2 cps (27).

The product obtained from the reaction of 7T-CcH.-.Mo(C0) JP( OC^H-),- 5 5 2 o 5 3 C^CsC-CH^ with SO2 was very unstable with respect to decomposition 127

and could not be characterized by elemental analysis® Its infrared

spectrum, however, indicated the presence of two bands at 1100 and

900 cm”^ that can be assigned to S-0 stretching frequencies® These

values are almost identical with those observed for. ^-C_H._Fe(C0)_(S0_- 3 3 2 2 ) (vide supra)® Although the pmr spectrum of the molybdenura-SO^

derivative was poorly resolved due to the presence of paramagnetic

decomposition materials, the spectral pattern was similar to an AJBX^-

type® In addition to the presence of triphenylphosphite (f 2®^1) and

cyclopentadienyl CE4®85) resonances, a quartet and complex multiplet were observed at *£-4® 00-5® 00 and £70 67, respectively® The chemical

shifts are analagous with those observed for the iron derivative (Table

14).

From the spectral resemblances of 7T-CtHI±Fe(C0)_(S0-C. IL.) and P ? 2 2 7f-C^H^Mo(CO^PCOCgH^^CSO^C^H,-) with other SO^-containing derivatives of transition metal 2-alkynyl complexes (65,27,66), it is apparent that the same type of structure is present for all of the S0_C,H_R (R = H 2 5 2 and CH^) moieties® The appearance of ABX^-type spectra can be ration­ alized by the presence of an asymmetric sulfur atom resulting in mag­ netic nonequivalence of the CH^ protons® If insertion occurs without rearrangement of the butynyl chain, either TT-C <_H^.Fe(CO)^-S(0)-O-CH^-

C=C-CH_ or tT-Cj-H^Fe(CO) -0-S(0)-CH_C=C-CH^ can be formed; for insertion 5 5 5 2 2 3 with rearrangement of the butynyl chain to an allenic structure, either

7T-C(-Hj-Fe( CO)_-S( 0)-0-C( CH, ) =C =CHD or 7r-CcHcFe(CO)_-0-S( 0)-C(CH, ) =C=CH0 0 Z> 2 3 2 5 5 2 3 2 can result® The problem of distinguishing between Fe-S(0)-0- and Fe-0-

S(0)- is hampered by the fact that both structures are expected to give similar spectra® For example, Thompson (67) reports X values of 5®75 and 6®60 for the oxygen- and sulfur-bonded mehtylene protons, respec- 128

tively, for CH2^HCH20S(0)CH2CH=CH2® It should be possible, how­

ever, to distinguish between the allenic and butynyl structures on the

basis of their different chemical shifts and coupling constants® These

differences can be illustrated by considering the pmr spectra of (CgH^)^-

Sn0S(0)CH2(a)CHC-H(b) and (C6H5 )5Sn0S(0)CH(c)=C=CH2(d) (68)® For the

propynyl sulfinate, the CH2 protons appear at%.7®58 (Jab = 3 cps) and

the unique proton, H(b), is present at£7®88 (Jab = 3 cps)® In the

spectrum of the allenic sulfinate H(c) appears at 2? 4® 43 (Jed = 6®5)

and the CH2 protons are found at7T5®l8 (Jed = 6.5 cps)® The magnitudes

of the coupling constants are in agreement with those commonly found for

acetylenes and alienes (36)® Therefore, if jf-C_HI_Fe(CO)_(SO-C.1H1-) 5 5 2 2 3 contains the butynyl structure, the CH2 protons should appear at ca®

T^7o6 with Jax = Jbx 3 cps; for the allenic structure, the CH2 protons

are expected to be present at ca. T5 with Jax = Jbx 6.5 cps®

The analysis of the pmr spectrum of 7f-C^H^Fe(C0)2(SC^C^H,-) reveals

that the chemical shifts of the CH2 protons are £4.8l and ”2*4®45 with

Jax = Jbx = 2cps. The lowvalues are more compatible with those

found for allenic =CH2 protons, while the small Jax and Jbx coupling

constants suggest the acetylenic structure (vide supra). In order to

elucidate the structure of /T-C^H^Fe(C0)2(S02C^H^) an x-ray diffraction

study was carried out (69)® The structure is different than those

previously proposed and is shown below® While the reaction of ff-CcHcFe(C0)oCH_C=CCH, with S0_ was not 5 5 2 2 3 2 studied under conditions which allowed thje determination of kinetic parameters, it is desirable to postulate several reaction mechanisms that might account for the formation of this unusual derivative. Of course any such proposals must be consistent with the following: l) the reaction proceeds rapidly in the nonpolar solvent pentane; 2) no evidence exists for the presence of species other than 7r-Cc.H_Fe(CQ)_- p -? 2 CH-C=CCH, before reaction with SO_s 3) the sulfur atom of SO- is 2 3 2 2 attached to the methyl substituted carbon atom. On the basis of the first observation, an ionic process can be ruled out. While many mechanisms can be proposed, the following are straightforward and con­ sistent with the synthetic results. Mechanism I

r»

F e ~ C H - > f0\2 H 0 - S jJ% c \ CH,

Mechanism II 131

Initial interaction of the incoming SC^ molecule with the electron- rich butynyl moiety is proposed in both mechanisms* In Mechanism I, insertion takes place with the formation of an allenic sulfinate intermediate containing an Fe-O-S-C linkage* The formation of such an intermediate receives support from the observation by Kitching, et al* that (CgHj-J^SnCKLpCsCH reacts with S0„, to form (CgH^)^Sn-O-S(O)-

CH=C=CH2 (26)® Although the O-sulfinate is the thermodynamic stable product for tin, all previous reactions of ^-G^K^FeCCO)^^ with SC^ result in the formation of S-sulfinate derivatives (vide supra)*

Thus, while the O-sulfinate intermediate may be the kinetically con­ trolled product, further rearrangement to a more stable structure is expected® This rearrangement would have to be very fast since there is no experimental evidence for the existence of such an intermediate*

The reaction path illustrated in Mechanism II involves a concerted path similar to that proposed in the reactions of transition metal allyls with SO2 (vide supra)® Due to the linearity of the butynyl chain, how­ ever, the sulfur dioxide molecule cannot interact with the iron atom and ring formation occurs with a simutaneous attack by iron on the butynyl chain® Mechanisms involving intermediates containing iron- sulfur bonds are not considered likely since it is believed that they would be stable with respect to rearrangement® For example, Thomasson

(70) has found that TT-C^H^Fe (C 0 ) ( 0 ) =C-CH^, prepared from the reaction of Na Jb^Ht-FetCO^SO^] with CICH^C^C-CH^, is stable with respect to rearrangement under thermal and photolytic conditions®

Recently there has been some interest in desulfonylation reactions

of metal complexes containing SO^ (16, 71)® Deacon and Felder (71) have 132

reported the only reversible insertion reactions of metal alkyl (aryl)

derivatives with SO^ and (CgH^^Hg and (jv-C^H^CH^The observation

that 7T-C^H^Mo( CO^SC^CH^CgH^ loses SO^ under photolytic conditions repre­

sents the first example of a transition metal sulfinate that undergoes

both SC>2 insertion and desulfonylation (l6)o Tt-G^E^Fe(CO)

is found to undergo partial reconversion to yf-C^H^Fe(GO)^CH^CSU-CH^ in

approximately h3% yield upon chromatography on alumina® The relative

ease of desulfonylation upon chromatography is unusual as this is a

common purification technique for complexes of the type Jf-C^H,_Fe(CO^-

SCOj^R® All attempts to desulfonylate 3T-C^H^Fe(CO)^ ( ) under

thermal or photolytic conditions resulted in the recovery of unchanged

sulfinate and decomposition material®

All attempts to insert SQ_ into lT-CcHcFe(CO)_CH=C=CH_, yr-CJEL-Fe- 2 5 5 2 2 5 5 (C0)2CH=CH2, and Tf-C^H^FeCCO^CsC-CH^ were unsuccessful® The reactions

yielded unreacted starting materials and decomposition products® Since

SO^ insertion has only been reported for transition metal complexes

containing metal-carbon sigma bonds, the failure of the above complexes

to insert SO^ may be due to the ability of the unsaturated carbon atoms

to participate in back-bonding with the iron atom® Thus, in addition

to the iron-carbon sigma bond, bonding between filled iron d-orbitals

and empty antibonding orbitals on the carbon atoms may take place®

Although the extent of this double bond character is not certain, it

may be sufficiently strong to prevent SO^ insertion®

Reactions of boron trifluoride with TT-C^FeC C0)PR3S( 0)2CH^ “

It has been noted that upon substitution with better Lewis bases 133

(poorer pi-acceptors) the S-0 stretching frequencies of metal Carbonyl sulfinates are shifted to lower wavenumbers (see Introduction)® The lowering may arise by donation of electrons from the metal via pi bonding to the SO^ group resulting in a reduction of the S=0 character and, therefore, an increase of electron density on the sulfinate oxygen atoms®

In order to test this hypothesis of sulfur-oxygen pi bonding, Graziani

(21) investigated the reactions of'|7-Ct.HcFe(C0)«S(0)_CH:z and 7T-C_H.-Fe- 3 3 2 2 3 5 3 (CO)P(n-C^Hg)^S(0)^011^ with hydrogen chloride® In agreement with the hypothesis, only the tributylphosphine derivative could be protonated®

The site of protonation was readily determined with the aid of infrared spectroscopy® The infrared spectrum of 7T-C^H^Fe(C0)P(n-C^H^)^S(0)^CH^ *■1 shows a carbonyl band at 19^6 cm and S-0 asymmetric and symmetric bands at 1156 and 1036 cm~\ respectively® After reacting with hydrogen chloride, the CO band shifts to 1962 cm"’^" and the S-0 stretches are lowered to 1116 and 985 cm”^ (21)® The spectrum of TT’-C^H^Fe(CO)-

P(n-C^H^)^S(O)2CH . HC1 also contains a new band at 3601 cnf^ which is assigned to the OH stretching frequency (21)® The observed shift of the S-0 stretching frequencies is consistent with one of the SO^ oxygen atoms being protonated® The shifting of the CO stretching frequency to a higher value upon protonation is in accord with an increase of positive charge on the metal® A similar shift was observed for the terminal CO stretching frequency of Tf-Cj.H^Fe(C0)P(CgH^)^C(0)CH^ upon protonation of the ketonic group (72)®

7T-C5H5Fe(C0)P(n-C/fH9)5S(0)2CH5 .and 7f - C ^ F e t C O M C g H ^ S t O ^ C E j combine with boron trifluoride in a 1:1 ratio in toluene solutions®

Analysis of the 7r-C,-HcFe(C0)P(n-C.,H_.),S(0)oCH,-BF_ adduct further . 3 3 ^ 9 3 2 3 3 supports the formulation of these complexes as 1:1 adducts® 134

The presence of coordinated boron trifluoride can also be readily determined by infrared spectroscopy.. Coordinated BF^ is expected to exhibit broad asymmetric and symmetric B-F stretches in the infrared spectrum® The position of these stretches for several 1:1 BF^ adducts are given in Table 15° It is apparent that the B-F stretches fall in the S-0 stretching frequency region and it will not be possible to assign the bands in this region unambiguously® For example, in the infrared spectrum of ( C H ^ ^ O ^ o B F ^ it was not possible to distinguish between the asymmetric B-F and symmetric S-0 stretches in the region

1150-1020 cm (73)<> The bands observed in the infrared spectra of

7f-C5H5Fe(C0 )P(C6H5 )5S(0 )2CH3 , Tf-C^H^Fe( CO ) P( n- C ^ ) ?S ( 0 )2CH^, and their corresponding boron trifluoride adducts are given in Tables 16 and 17®

The complete ir spectrum of JM3cHcFe(C0)P(n-C.Hri),S(0)_CH-joBF_ is re- 5 5 ^93 255 produced in Fig® 19®

The infrared spectrum of /T-CcHcFe(CO)P(n-C.,EL).,S(0)_CH, (see 3 3 ^ 9 3 2 5 Table 16) is characterized by a carbonyl band at 1946 cm“^ and S-0 asymmetric and symmetric stretches at 1156 and 1036 cm”\ respect­ ively® Upon formation of 7r-C_HcFe(C0 )P(n-C.1H_),S(0)_CH,®BF,, the CO 3 3 **93 2 3 3 stretch is shifted to 1964 cm”^ and four broad bands appear in the spectrum at 1130» 1005, 995» and 890 cm”^® The shifting of the CO band to a value 18 cm”'*' higher upon coordination with boron tri­ fluoride is consistent with the formation of a sulfinate-oxygen to

BFj bond® A similar shift was observed in the infrared spectrum of

TT-C^H^Fe(CO)P(n-C^H^)^S(0)2CH^ after reaction with hydrogen chloride

(vide supra)® It is difficult to assign unambiguously the four broad bands to either B-F or S-0 stretches® The infrared spectrum of tT-C^H^-

Fe(C0)P(n-C^Hg)^S(0)2CH^«HCl contains S-0 asymmetric and symmetric bands 135

TABLE 13

B-F STRETCHING FREQUENCIES OF 1:1 BORON TRIFLUORIDE COMPLEXES

B-F Stretches, cm ^ Bibliog. Complex Asymmetric Symmetric Refer*

Cl_.PO.BF, 1062, 1030 955, 9^5, 936 7b 5 5 (c 2h5 )2o .bf 3 1065, 1025 900, 876 7b c^h 5n .bf3 1165, 1125 912, 893 7b

(CH2 )ZfS(0)2.BF3 1150-1021 771 73

(C-H-Jjffl-.BF- 1100-1000 75 (M5=5W?M§) 3

TABLE 16

INFRARED SPECTRA OF rt'-C^H_Fe(CO)P(n-CiHQ)_S( 0)_CEL AND -fT-Cj-Hj-Fe ( CO )P( n-C. H_ )_S(0) _CH_ • BF, * * 55 *<-93 2 3 3

tT-C^H^F e (CO ) P( n-C^Hg ) ^S (0)2CH3 ^-C_H_Fe(C0)P(n-C. HQ)-,S(0)0CHX.BF_ 5 5 ^ 9 3 2 3 3

19^ (s) 196^ (s) 1295 (w) 1305 (w) 1215 (vw) 1210 (w) 1156 (s) 1165 (sh) 1085 (w) 1130 (s, br) 1070 (sh) 1090 (w) 1036 (s) 1065 (w) 1020 (sh) 1005 (s, br) 965 (w) 995 (s, br) 935 (m) 9^5 (vw) 910 (w) 890 (s, br) 885 (w) 850 (m) 850 (in) 770 (vw) 830 (m) 715 (s) 770 (w) 605 (vw) 700 (s) 575 (m) 605 (w) 555 (sh) 580 (m) 550 (s) 555 (s) 520 (s) 525 (s)

^ujol mull, Perkin-Elmer-337» The absorptions in common with or masked by those of Nujol are not included.

Abbreviations: vw = very weak; w = weak; m = medium; s = strong sh = shoulder; br = broad. 137

TABLE 17

INFRARED SPECTRA OF «f-C_Hl.Fe(CO)P(C,Ht.)-S(0);)CH-if-CcH_Fe(C AND fT-C-H.-Fe«s v( v/uCO )P( 3/-Hc ) )yb „S ( \ 0 /) 2Wn3"_CH,.BF, * *

TT-C^FeC CO)P( CgH^ ^SC 0)2CH3 1f-C^H^Fe( C0)P( CgH^ )?S( O^CH^.BE^

1950 (s) 1966 (s) 1300 (w) 1165 (sh) 1287 (w) 1155 (sh) 1180 (w) 1125 (s, br) 1155 is) 1090 (m) 1088 (m) 1065 (w) 1030 (s) 1010 (s, br) 1000 Cw) 995 (s, br) 970 (w) 895 (s, br) 940 (m) 857 (m) 887 (m) 760 (sh) 845 (m) 745 (m) 835 (m) 720 (m) 762 (m) 695 (s) 750 (m) 615 (vw) 740 (m) 600 (w) 710 (s) 570 (m) 695 (s) 555 (s) 600 (w) 530 (s) 577 (m) 520 (s) 555 (m) 530 (m) 510 (m)

^ujol mull, Perkin-Elmer-337« The absorptions in common with or masked by those of Nujol are not included.

Abbreviations: vw = very weak; w = weak; ra = medium; s = strong; sh = shoulder; br = broad. Fig. 19.— Infrared spectrum of ^■-Cc.H[-Fe(CO)P(n=-C.HQ),S05CH,.BF, in the regions 3500-1300 cm” and 1380-^50 cm” . * ^ ^

138 2000 1500 139

FREQUENCY (CM-1)

l4l at 1116 and 985 cm”\ respectively. The close similarity between the

CO stretching frequencies of the hydrogen chloride and boron trifluoride adducts (vide supra) suggests that the S-0 bands should also occur at approximately similar values.. The presence of B-F stretches in the same region, however, makes it impossible to assign the bands in this region unambiguously® Similarily, the infrared spectrum of tf-CJHLFe- 5 5 (COjPCCgHjOySCO^CH^ (see Table 17) shows a CO band at 1950 cm”'*’ and asymmetric and symmetric S-0 stretches at 1155 and 1030 cm”^ , respect­ ively. Upon formation of Tf-C_HcFe(C0)P(C£Hc),S(0)_CH_.BF,, the CO 55 053 2 3 x band shifts to 1966 cm”^ and four broad bands appear at 1125» 1010,

995» and 895 cm \ While it is not possible to differentiate between the B-F and S-0 stretches in the infrared spectra of the above complexes, the spectra and quantitative data are in complete agreement with the formation of 1:1 adducts containing S-O-BF^ bonds. SUMMARY

Earlier studies in these laboratories have shown that sigma-

bonded allylic derivatives of transition metals react with sulfur

dioxide to form products resulting from 1 ,1-insertion of SO^ into

the metal-allyl sigma bond* The insertion reactions were often

accompanied by simultaneous rearrangement of the allyl chain* The

ratios of unrearranged and rearranged allylic sulfinates in the

reaction products were found to be affected by the metal, the sub­

stituents on the allyl chain, and the reaction conditions® In the

continuing study of the parameters affecting allylic rearrangement

accompanying SO^ insertion, the reactions of SO^ with allylic complexes

of TS-CHyy^FeCCO^-, ?r-l,3- ( ) ^Cj-H^Fe (CO)2>, rf-( CHyy^FeCCO^-

and Tf-CyiyioCCO^PCOCyy)^- were examined® Thus, an attempt has been

made qualitatively to access the effects of substituents on groups

not directly involved in the insertion process.

The amount of allylic rearrangement accompanying S02 insertion

was found to be insensitive to the substitution of one methyl or two

phenyl groups on the cyclopentadienyl ring of 7r-C^H^Fe(C0 )2CH2CH=CRR'•

The only product observed from the reaction of yJ^CH^C^H^Fe(CO ) 2**

CE^CHsCCCH^H in refluxing sulfur dioxide was J^-CHyjyiyreCCO^SOg-

C(CH-.)IICH=CH_® The reactions of jr-CH,CcH,1Fe(CO)_CH_CH=C(CH_)_ and 3 2 3 3 4 2 2 j> 2 if-CiycyijFe(CO)2CH2CH=C( ) H in refluxing SO^ yielded mixtures

containing the rearranged and unrearranged isomers in ratios of 1:4

and 3!l7» respectively. The ratio of 7f'-CH^C^ElF e (CO)2S02C(

142 143

CH=CH2 to /f-CH3C ^ F e ( C 0 ) 2S02CH2CH=C(CH3 )2 was increased to 3:1 by allowing the reaction to proceed in S02~saturated hexane at room

temperature., A 1:3 mixture of the geometric isomers

C^FeCC0)2S02C(CII3)2CH=CH2 and CgH^)^ R ^ F e (CO)2S02CH2CH =C(CH3 >2 was obtained from the reaction of #"-1, 3 - ( ) G H^FeCGO)„CH_CH=C(CH-)_ b ) c ? ; 2 2 3 2 in refluxing S02® The ratios of unrearranged and rearranged allylic

sulfinates of the above mono- and disubstituted cyclopentadienyl iron derivatives were very similar to those previously obtained from the reactions of tt-Q HcFe(C0)oCHoCH=CRR' with S0_. 5 5 2 2 2 The substitution of five methyl groups on the cyclopentadienyl ring of ^ C cHcFe(CO)_CH_CH=CRR' had a dramatic effect on the insertion 5 5 2 2 products when the allylic group was 3-methyl-2-butenyl or cinnamyl.

The reactions of 7f-(CHjcCcFe(C0)oCH«CH=C(CH,)_ and ;*-(CKL)cC_Fe(C0)o- 355 22 32 335 2 CH2CH=C(CgH3)H in refluxing S02 yielded the unrearranged allylic sulfinates exclusively. This was in contrast with the previously observed results that the corresponding allylic complexes of

Fe(C0)2~ yielded mixtures of unrearranged and rearranged allylic sulfinates in refluxing S02® Mixtures of rearranged and unrearranged sulfinates in the ratios of 2:3 and 1 :9 * however, were obtained by allowing the 3-methyl-2-butenyl complex to react with SO2 at -50° or in S02~saturated hexane solution at room temperature, respectively.

As was observed for the jf-CJI,- complex, the reaction of ^■(CH_)_C_Fe- 5 5 3 5 5 (C0)2CH2CH=C(CH3 )H with refluxing SO2 yielded only the rearranged isomer.

The reactions of jf-CcHc.Mo( CO) _P( 0C ,HC )-.CH_CH=C( CIR ) „ and Tf-C-H-- . 53 2 o552 32 55 Mo (CO)2P(OC6H3 )3CH2CH=C(C6H3 )H in refluxing S02 or S02 cooled to

-50° yielded only the unrearranged sulfinates. Similar results had 144

been observed in the reactions of the corresponding allylic derivatives

of The effect of the triphenylphosphite group on

the allylic rearrangement was observed in the reaction of

(CO^PCOCgH^JyjI^CHsCCCH^jH with sulfur dioxide® The nature of the

insertion products was influenced by the reaction conditions as well®

In refluxing S O a mixture consisting of ?f-C^H^Mo(C0 )2P(0CgH^)^S02'”

C(CHjHCH=CH_ and yr-C He:Mo(CO)«P(OC,H_)_.SO_CH„CH=C(CH,)H in the ratio 5 2 5 5 2 6 5 3 2 2 5 1:4 was obtained® The relative amount of the rearranged sulfinate

was increased to 2:3 by allowing the reaction to proceed at -50® in

liquid SO^o Surprisingly, the relative amount of the rearranged

isomer formed in SC^-saturabed benzene or dichloromethane was identical with that formed in refluxing SO^® It is apparent that the triphenyl­ phosphite group inhibits the formation of the rearranged product since

the reaction mixture obtained from rr-C^H^lo( C O (CH^)H in refluxing SC>2 contained the rearranged and unrearranged geometric isomers in the ratio 9 si®

While the above reactions were not carried out under kinetic condi­ tions, the effects of substituents on the inserted products were con­ sistent with a proposal that two competing mechanisms account for the

formation of unrearranged and rearranged allylic sulfinates® A cyclic concerted process involving interaction of SO^ with both the metal atom and the double bond of the allyl chain accounts for the formation of rearranged allylic sulfinates, and a direct insertion of SC^, analo­ gous to that observed in alkyl and aryl derivatives, accounts for the formation of unrearranged allylic sulfinates® The more favorable for­ mation of the unrearranged allylic sulfinates upon substitution with 3A5 electron-donating groups gave evidence that the direct insertion mechanism was enhanced by an increase of electron density on the metal atom.

Several reactions of 7M3_H,-Fe(CO)_R, where R is an unsaturated 0 0 2 organic chain, with SO2 were also investigated. Contrary to previous reports that transition metal 2-alkynyl complexes react with SO^ to form rearranged allenic sulfinates, the reactions of SO^ with

Fe(C0 )2CH2CSCCH5 and jf-C^H^MoCCO)2P(OCgl^ ^CiyjsCCH yielded IT-C ^ -

Fe(C0)_-6=C(CH,)S(0)0CH, and rT-GJlJ\o(CO)0P(OC^H-),-C=C(CHX)S(0)OCH_. 2 5 2 0 O 2655 3 2 The iron derivative underwent partial reconversion to the starting starting material upon column chromatography. The reactions of tf-Ct.Hc.Fe(C0)oC=CCH_, ff'-CcHcFe(C0)oCH=CH„ and ^•CcHcFe(C0)oCH=C=CH_ 0 0 2 5 0 0 2 2 0 0 2 2 with S02 yielded unreacted starting materials and decomposition pro­ ducts. The failure of S02 to insert into the iron-carbon bond of these derivatives was attributed to backbonding between the iron d-orbitals and antibonding orbitals of the unsaturated organic chain, resulting in a strengthening of the iron-carbon bond.

The reactions of ?r-C(.HI-Fe(C0)PR^S(0)_CH^ (R = C,Hc and n-C.H,J 0 0 0 c. o o 0 ** 9 with boron trifluoride were investigated. The basicity of the oxygen atoms of the S02 moieties were demonstrated by the formation of 1:1

BF,-sulfinate adducts. O APPENDIX A

Tabulated Infrared Absorption Frequencies of Allyl Sulfinato Complexesa

^letal carbonyl stretches are listed in Table 7« Unless other­ wise noted, all absorptions were recorded in potassium bromide pellets using a Perkin-Elmer 337 Spectrophotometer. Abbreviations: s = strong vs = very strong; m = medium; w = weak; vw = very weak; br - broa

if -CHyy^Fe ( CO )2S02C( CH^ )HCH=CH2

3083 (m) 965 (w) 3072 (w) 930 (sh) 3025 (w) 920 (m) 1625 (w) 890 (vw) 1475 (m) 860 (w) 1440 (m) 830 (vw) 1405 (w) 720 (w) 1360 (w) 690 (vw) 1335 (vw) 625 (s) 1240 (vw) 605 (s) 1215 (m) 580 (s) 1175 (s) 550 (s) 1155 (sh) 510 (m) 1045 (s, br) 475 (w) 1025 (sh) 440 (vw) 1000 (w)

a tf-CH^H^Fe ( CO ) 2S02CH2CH=C( CH^ ) 2

3120 (vw) 1110 (w) 3085 (sh) 1070 (w) 3072 (ra) 1040 (vs) 2965 (w) 985 (w) 2933 (w) 925 (w) 2911 (sh) 900 (ra) 2850 (w) 880 (m) 1655 (w) 860 (w) 1625 (vw) 8*10 (w) 1472 (m) 775 (w) 1450 (w) 710 (m) 1400 (w) 620 (s) 1365 (w) 610 (s) 1245 (w) 575 (s) 1230 (sh) 555 (s) 1225 (m) 500 (m) 1180 (vs) 480 (w) 1170 (sh) 450 (w) 1140 (m) 430 (w) 1125 (m)

fixture of ca. 80# tf-CH C H. Fe(C0)5S0_CH_CH=C(CH,)o and ca. 20% 7r-CH3C5H2fFe(C0T2S02C(CH3 )^CH=CH2 ^ * d * * 1T-CH C ^ F e C C0)2S02CH2CH=C(CgH^H

3105 w) 985 (m) 3075 m) 925 (vw) 3033 sh) 930 (vw) 2960 vw) 910 (vw) 2922 w) 900 (m) 2895 w) 875 (m) 2850 sh) 845 (m) 1595 w ) 805 (w) 1485 w) 800 (w) 1472 w) 750 (s) 1445 ra) 700 (s) 14D0 w) 630 (w) 1383 vw) 620 (m) 1372 w) 610 (s) 1300 vw) 575 (sh) 1280 vw) 560 (s) 1240 vw) 525 (m) 1230 vw) 510 (m) 1210 m) 505 (m) 1180 vs) 490 (w) 1150 m) 460 (m) 1140 m) 445 (w) 1075 ra) 1035 vs)

tf-(CH_)rC_Fe(C0)_S0_C(CH,)HCH=CKL 5 3 5 2 2 3 2 2960 (w) 1075 (w) 2922 (w) 1045 (s, br) 2850 (vw) 1000 (w) 1625 (vw) 938 (w) 1485 (w) 925 (w) 1450 (w) 860 (vw) 1422 (w) 625 (m) l4ll (w) 590 (s) 1375 (ra) 555 Cm) 1311 (vw) 540 (vw) 1260 (vw) 510 (w) 1210 (m) 485 (vw) 1175 (s) 1160 (sh)

fixture of ca. 85% TT-CH C H.Fe(CO) SO CH?CH=C(CaH,.)H and 7r-CH5C5HifFe(C0)2S02C(C6H5)HCHiCH2. 5 149

7f-( GH3 J^C^Fe ( CO ) 2S02CH2CH=C( C H ^

3033 (w) 1075 (w) 2911 (m) 10*»0 (s) 2850 (w) 1020 (sh) 1665 (vw) 955 (vw) 1472 (ra) 890 (w) 1439 (m) 850 (w) 1411 (w) 770 (m) 1383 (n) 710 (m) 1365 (ra) 610 (m) 1350 (w) 580 (m) 1333 (vw) 56O (m) 1225 (w) 5to (vw) 1200 (m) 525 (w) 1180 (s) 515 (m) 1170 (sh) 510 (sh) 1125 (w) 475 (m) 1110 (w) 430 (ra)

77-( CH- ) _CcFe ( CO) oS0_CHoCH=C( C.Hc )H 3 5 5 2 2 2 6 5 3061 (vw) 1080 (m) 3022 (vw) 1070 (w) 3000 (vw) 1040 (s) 2950 (sh) 1030 (sh) 2922 (m) 990 (m) 2850 (w) 900 (w) 1483 (w) 760 (m) 1465 (w) 705 (s) 1450 (m) 685 (m) 1415 (w) 615 (m) 1389 (w) 605 (w) 1380 (w) 575 (m) 1370 (m) 555 (ra) 1280 (vw) 540 (w) 1200 (m) 525 (m) II80 (s) 510 (w) 490 (vw) 1130 (w) 470 (m)

4*K) ( w ) 150

Tf-l, 3-( CgH^ ) ^H ^ F e C CO ) ?S02CH2CH=C ( CH^ >2&

3100 (sh) 1015 (sh) 3055 (m) 1000 (vw) 2900 (w) 920 (sh) 2850 (sh) 910 (m) 1650 (w) 900 (m) 1572 (vw) 890 (m) l46l (m) 855 (w) 1439 (m) 830 (vw) 1425 (w) 760 (m) 1361 (w) 685 (s) 1300 (vw) 660 (m) 1265 (vw) 605 (m) 1215 (w) 570 (s) 1175 (vs) 550 (m) 1130 (m) 510 (ra) 1075 (w) 500 (m) 1040 (vs) 470 (vw)

i T - C ^ K o i C0)2P( OC6H3 ) so2ch2ch=c(ch3 )2

3110 (w) 935 (s) 3075 (w) 920 (s) 2965 (vw) 890 (s) 2900 (w) 845 (m) 1590 (m) 835 (m) 1485 (s) 775 (s) 1450 (w) 765 (s) 1422 (w) 735 (ra) 1415 (vw) 720 (ra) 1315 (vw) 715 (sh) 1215 (ra) 690 (m) 1195 (s) 660 (w) 1177 (s) 610 (m) 1168 (s) 590 (vw) 1130 (w) 575 (w) 1075 (w) 565 (ra) 1065 (m) 550 (s) 1047 (s) 505 (s) 1025 (m) 495 (s) 1020 (sh) 485 (m) 1010 (w) 440 (m)

fixture of ca. 73% rF*l,3-(C.H ) C H Fe(CO) SO CH CH=C(CH ) and ca. 25% ff- 151 77-C5H5Mo(C0)2P(OC6H5 )3S02CH2CH=C(CH^)Ha

3100 (w) 965 (w) 3065 (w) 935 (sh) 2900 (vw) 920 (s, br) 1 5 7 7 (m) 905 (sh) 1^72 (s) 900 (s) lhkk (w) 825 (ra, br) 1^35 (w) 775 (sh) 1415 (w ) 765 (s) lk05 (w) 735 (w) 1388 (vw) 720 (m) 1215 (m) 695 (m) 1190 (s) 655 (w) 1182 (s) 615 (w) 1165 (s) 590 (m) 1075 (w) 580 (w) 1065 (w) 560 (w) 10^5 (s) 550 (m) 1025 (m) 515 (s) 1020 (sh) k85 (s) 1005 (vw)

TT - C ^ M o ( CO ) 2P( OC6H5 )3S02CH2CH=C ( CgH(. )H

3050 (w) 96O (w) 1590 (m) 920 (s) 1^90 (s) 900 (m) 1^50 (w) 825 (w) 1 ^ 5 (w) 770 (s, br) 1^30 (vw) 720 (w) 1^15 (vw) 695 (m) 1210 (ra) 615 (w) 1190 (sh) 600 (w) 1180 (s) 58O (w) 1160 (m) 3^5 (m) 1075 (w) 500 (m, br) 10^f0 (s) 490 (sh) 1025 (m) 1005 (vw)

^Mixture of ca. B0% 1T-C H Mo(CO)pP(0C.H ) SO CH:)CH=C(CH,)H and ca. 20% rr-Ct-H[.Mo(CO)_P(OC.H JLS0„C(CH!t)HCH=CH. d d * 3 5 2 b > 3 2 5 2 APPENDIX B

Tabulated Infrared Absorption Frequencies of 2-Butynyl Complexes and Their SO^-Containing Derivatives3,

Unless othervd.se noted, all absorptions were recorded in potassium bromide pellets with a Perkin-Elmer 337 Spectrophotometer. 7T-C^H^Fe(C0)2c h 2cscch3

2910 (ra) 1000 (vw) 2.8kk (w) 8k5 (w) 2025 (vs) 835 (w) 1975 (vs) 825 (w) 1^22 (w) 720 (vw) 1^05 (w) 630 (ra) 1365 (w) 600 (w) 1260 (vw) 585 (m, 1055 (vw) 565 (sh) 1050 (vw) 1015 (vw)

Tr-C{.HcFe(C0)D(-C=C(CH, )s(o)odn2) 3 5 2 3 3112 (w) 1025 (w) 3088 (w) 1000 (w) 2922 (vw) 970 (w) 2855 (vw) 903 (s) (m) 2039 (TS)h CO8553 1983 (vs)b (w) 1600 (m) 750 (s) Ikkk (w) 700 (s) 1^33 (m) 670 (w) 1^15 (m) 630 (s) 1365 (w) 605 (m) 1265 (vw) 590 (s) 1130 (m) 575 (ra) 1100 (s, br) 560 (s) 1060 (sh) 500 (w)

f*Hexane solution. Chloroform solution. Fig. 20— Infrared spectrum of tr-Cj-H^FeC ^0)p( -0=0(011., )S(0)0CH_) in the regions 3500-1300 and 1300-500 cm^l.

15^ } r \

CHC13

SOLUTION

I— — ______1______1 j___ 3500 3000 2500 1500

FREQUENCY (CM’1) 900 frequency tr-C^H^MoC C0)2P( OCgH^ )-,CH_C=CCH, 3 d 5 3077 (w) 930 (s) 2915 (w) 915 (s) 2200 (vw) 890 (s) 1961 (s)_ 812 (m) 1883 (vs) 765 (s, br) 1590 (m) 730 (w) 1485 (m) 718 (w) 1210 (m) 690 (m) 1195 (s, br) 620 (w) 1165 (m) 595 (m) 1075 (w) 568 (m) 1030 (m) 530 (w) 1010 (w) 500 (s)

TT-C^H^Mo ( CO ) 2? (OC6H5 )3( -C=C(CH3 )S( 0 )0CH2>

3050 (w) 915 (s, br) 2900 (w) 900 (s, br) 1977 (s)a 820 (m) 1900 (vs)a 770 (s) 1588 (m) 745 (w) 1488 (s) 715 (w) 1220 (m) 690 (m) 1190 (s) 665 (w) 1165 (m, br) 615 (w) 1100 (m) 600 (w) 1070 (w) 555 (m) 1028 (w) 500 (s) 1005 (w)

Chloroform solution APPENDIX C

Additional Reactions of Transition Metal Complexes with SOg

158 159

Preparation of 7£-C^H,-Fe(CO^SC^CHgOCH^

The starting material, TT-C^H^Fe(CO)^CH^OCH^, was prepared using the procedure of Green, et ale (77)® A solution of Na ^-C^H^FeCCOjgJ in 50 nil® of THF was obtained from the reaction of 7®08 g. (0®02 mole) of [jr~C(-H^Fe( 00)^2 excess 1% sodium amalgam® The sodium salt solution was slowly transferred to a well stirred solution of CIC^OCH^

(3®22 go, 0.0^ mole) in 15 ml® of THF maintained at 0°® The resulting mixture v/as allowed to stir for 1 hour at 0° under nitrogen® The solvent was then removed in vacuo (25°, 0.1 mm0) and the residue was extracted with 100 ml0 of pentane® The extract was filtered through ca. 5 g® of Zeolite and concentrated to 10 mlo in a stream of nitrogeno

The concentrated solution was purified by chromatography (2 x 20 cnu neutral grade IV alumina column made up with pentane)® Elution with a 9:1 pentane-ether mixture separated a yellow band of 7T-CcH,-Fe(C0)_- 5 5 2 CH^OGH^ from a purple band of unreacted JV-C^Hj-FeCCO^J^® The yellow band was removed first and collected under a stream of nitrogen® After evaporating the solvent in a stream of nitrogen, the remaining yellow- brown oil v/as distilled in vacuo (*f0°, 0®1 mm.) to give 6.22 g® (7090 of P-C HcFe(C0)_CH n0CH_,. 5 5 2 2 3 Approximately 25 nil® of liquid sulfur dioxide was condensed onto

6.22 g. (0®03 mole) of rr-C^E ,-Fe (CO)^CH^OCH^ and the mixture was allowed to reflux for 2b hours with the aid of a Dry-Ice condenser® After the reaction period was over, the excess S0^ was removed in a stream of nitrogen. The residue v/as taken up in 15 ml. of chloroform, and the extract was chromatographed on a 5 x 20 cm. neutral grade IV alumina column made up with chloroform. Elution with chloroform separated a broad yellow band from a yellow-orange band. The yellow band was l6o

collected first, and after removal of the solvent in a stream of nit­

rogen, 2.1 g. of unreacted j7'-C_HcFe(C0)_CH_0CH_ was recovered. The 3 3 2 2 3 second band was collected by further elution with chloroform. The

yellow-orange eluate was concentrated in vacuo (30°, 20 mm.), and

yellow-brown crystals of CO^SO^CI^OCH^ were obtained by add­

ing pentane. Yield: 3®7 g. (50^). Anal. Calcd. for C^H^Ot-SFe: C,

37.85; H, 3.52. Found: G, 38.01; H, 3-56. m. pt. 81-83°.

The pmr spectrum of jf-C^H^Fe( COj^SO^CH^OCH^ was obtained in CDCl^

with TMS as an internal standard. Three singlets were observed at

T4.78 (C^H^), T5.83 (CH^) and 2*6.27 (CH^). The bands observed in the

infrared spectrum are listed below; unless otherwise indicated, the

data were obtained as KBr pellets.

7T-CcHcFe( CO) _S0_CBL0CH,, 3 5 2 2 2 3 . 3100 (w) 950 (w) 2940 (w) 915 (m) 2055 (vs)a 865 (w) 2000 (vs)a 840 (w) 1425 (w) 730 (w) 1410 (w) 615 (m) 1295 (w) 580 (s) 1265 (w) 530 (m) 1200 (s) 500 (m) II85 (s) 470 (m) 1110 (m-s) 450 (w) 1070 (m) 420 (w) 1045 (s) 1025 (m)

& Chloroform solution. 161

Attempted reaction of 7T-C^H^Fe( CO^OpCCF^

The starting material was obtained from the reaction of AgC^CCF^

and It-C^H^FeCCO^I as described by King and Kapoor (78)® ^C^H^Fe-

(00 )2! was prepared using the procedure of King (79)® After filling

with nitrogen, a 250 ml® flask was charged with 20 g® (0®06 mole) of

jiT-C^H^Fe(00)2^2 65 ml® of chloroform followed by 20 g. (0®08 mole)

of iodine® A condenser was attached to the flask, and the mixture

was allowed to reflux for 0®5 hours® After cooling to room temperature,

the reaction mixture was washed in a 1-liter separatory funnel with

a solution of **0 g® of sodium thiosulfate 5-bydrate in 500 ml® of water®

The solvent was then removed in a water-aspirator vacuum® The remain­

ing black residue was washed with three 25 ml® portions of pentane on

a filter to give 28®7 g® (83#) of ^~C[_H-Fe(C0)_I. 5 5 2 A mixture of /f^C^H^FeCCO^I (l®53 g® 9 5 mmole) and Ag02CCF^

(I«l6 got 7®25 mmole) was stirred for 5 hours at room temperature in

50 ml® of dichloromethane under nitrogen® After the reaction period

was over, the mixture was filtered and the filtrate was taken to dry­ ness in vacuo (25°, 20 mm.)® The remaining red solid was purified by vacuum sublimation (80°, 0.1 mm®) to give 1.30 g. (8l$) of red- brown / - C H cFe(CO)„0_CCF,. 5 5 2 2 3 A mixture of 1®30 g® (4mmole) of 7f-CcHcFe(C0)„0,,CCF,, and ca® 50 5 5 2 2 3 — ml. of liquid SO^ was placed in the pressure reaction vessel® The system was cooled to -78° and freed from oxygen by degassing under vacuum (0.1 mm.)® The mixture was then warmed to room temperature and allowed to react for 24 hours. After the reaction period was over, the reaction vessel was opened, and the excess sulfur dioxide was re­ moved in a stream of nitrogen. The residue was taken up in 20 ml® of 162

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