C50

Journal of Organometallic Chemishy. 80 (1974) C5O-C52 @ Ekevier Sequoia S-A.. Lausanne - Printed in The Netherlands

Preliminary communication

ACTIVATION OF CARBON DISULZHIDE BY METAL CARBONYL ANIONS: FORMATION OF TRiTHTOCARBONATE COMPLEXES

JAMES HUNT, SELBY A.R. KNOX* and VALERiE OLtPHANT

Department of lnorganrc Chemistry, The Universrty. Bristol, BS8 ITS (Great Bntain)

(Received September 6th, 1974)

Summary

Trithiocarbcnate complexes are formed when metal carbonyl anions are treated consecutively wth carbon disulphide and a neutralistng agent such as methyl iodide or Re(CO)S Br.

Although activation of carbon disulphide by transition metal compleses is an area much studied of late (and recently reviewed [l] for the first time), no reports have appeared of attempts to directly exploit the electrophilic reactivity of carbon in the molecule. Nucleophiles SUC!I as cyanide ion do attack CS? at carbon [ 21, and it seemed likely that transition metal carbonyl anions might act simi.ia.rly. We describe here such reactions, which unexpectedly provide trithio- carbonate complexes.

Treatment of tetrahydrofuran solutions of the sodium salts of [M(CO), ]- (M = Mn, Re) with excess CSz for 1 h, followed by methylation with methyl iodide, gave (5-1070) tnthlocarbonate complexes M(C0)3SpC(SMe) (I; M = Mn, Re); for I (M = Re) m-p. 93”; v(C0) (hexane) 2109m, 2014s, 19999, 1963s cm-’ ; T 7.42s: m/e (111 - nCO)+ (n = O-3). Analogous products Fe(CO)(C,H,)S,C(SMe) [3] and Mo(CO)~(C~H~)S~C(SM~) [4] were obtained from [Fe(C0)2(CjHS)]- and [ Mo( CO),( Cj H5 ) ]- respectively.

The reaction of [Re(CO), ]- with CS2/MeI also gave small amounts of a yel- low crystalline complex (CO)AReS2CSRe(CO), (m.p. 135-140” (dec.); v(C0) (hexane) 2147w, 2103m, 2046s, 2005s, 1992s, 1955s cm-’ ; m/e (AZ - nCO)+ (n = O-9)). A trithiocarbonate-bridged structure II (M’ = MZ = Re) is strongly indicated by the carbonyl IR spectrum, which is composed of bands typical of both the (CO)dReSzC (2103m, 2005s, 1992s, 1955s cm-’ ) and (CO)sReS (2147w, 2046s, 1992s cm-‘) structural units, by comparison with the spectra of I (M = Re) and III respectively.

The apparent structural relationship of I (M = Re) and II (M’ = M’ = Re) led us to treat [Re( CO), ]- with CSI and Re(CO), Br consecutively in the hope of

c51

0 P

OC\ I /--+y oc,Ij\s,~C-sMe

:

(I)

I MZ

I E,

/=O ‘CO

0 C Co

0 l--O c _

\/ \/ ; occ?

OC-Fe- SAC\SMe OC-MM-S /K_ \ /I

s-Re-co

/\

Oc C A A

0 OC C C 0 0” 0

(III) (ix)

forming the dirhenium complex. That this reaction yielded II (M’ = M’ = Re) readily (45%) provides further support for the structural assignment. Only IR spectroscopic evidence was obtained for formation of (CO),MnS,CSMn(CO)j (II; M’ = M’ = Mn) by a similar route. Mixed metal analogues are obtained, however, if either [Mn(CO), ]- or [Re(CO), ]- isallowed to react with CS,, and is subse- quently treated with Re(CO),Br or Mn(CO)SBr. respectively. The major product (5%) in each case is II (M’ = Mn, M’ = Re), with minor formation of II (M’ = Re, M’ = Mn), suggesting that each reaction sequence involves a common mter- mediate. Most likely is (CO)5 ReSC(S)SMn(CO)j (IV) which would be expected to form II (M’ = Mn, M” = Re) preferentially on CO elimination.

Another example of this tendency towards trithiocarbonate formation has been presented in the very recent report [ 5] of the determination of the molecular structure of [(CO).,ReS,CSRe(CO)d lz, prepared from Re(CFa)(CO), and CS,. It is interesting that this complex can be envisaged as arising from dimerisation of (CO), ReS,CSRe(CO), , with sulphur bridge formation and CO elimination, though we have not yet established that this can occur. A complex (PPh,)(NO)NiSzCSNi(PPh3)2(NO), apparently related to II, has been prepared [6] from CS,‘- and Ni(I)(PPh,),(NO), but it was not possible for us to obtain II (,&I’ = M’ = Mn or Re) by a similar route.

The activation by metal carbonyl anions of other molecules (e.g. COz and RNCS) containing electrophilic carbon atoms, and the process by which trithio- carbonate complexes are formed from CS, in the reactlons described here, are under investigation. it is noteworthy to record in connection with the latter that addition of sulphur to the [Re(CO)s ]-/CSI/Mei reaction, prior to Mel addition, serves to promote formation (9%) of Re(CO),SC(S)(SMe) (III) { m.p. 83”; v(C0) (hexane) 214Ow, 2038s, 1991s cm-’ ; ‘i- 7.27s; m/e (AZ - nCO)+ (n = O-4)) over I (M = Re) (5%).

c52

References

1 LS. Butler and kE. Fenster. J. Organometal. Chem.. 66 (1974) 161. 2 G. 8Shr. Angew. Chem.. 70 (1958) 606. 3 ft. Bruce and G.R. Knox. J. OrganometaL Chem.. 6 (1966) 67. 4 R. Havlin and G.R. Knox. Z Nahu-forxb. B. 21 (1966) 1108. 5 G. ‘l7ueIe. G. Liehr and E. Lindner. J. Organomet.aL Cbem.. 70 (1974) 427 6 H. Brunner. 2. Naturforsch. B. 24 (1969) 275.