Thiolato-complexes

Scheme 18 Synthesis of group 5 metal disulfido complexes from the metal thiolato complexes...

The thiolato complex 97 that was postulated as the active catalytic species in the reaction was prepared from 96 and the thiol in the presence of NEtj. Certain analogues of 97 (NHC = Mes, SIMes, IPr, SIPr R = Ph) have also been independently synthesised, isolated and fully characterised. A plausible mechanism for the hydrothiolation involves insertion of the alkyne into the Ni-SR bond forming the (non-isolable) p-thioalkenyl complex, from which the product can be released via alkanolysis of the Ni-C bond by the thiol and regeneration of the active catalyst 97 [84]. 

Nickel complexes of this group are of interest in biomimetic work. By means of ligand (320) the complete reaction cycle of acteyl CoA synthase could be executed (Scheme 2). Ligand (320) can also be synthesized by a template reaction. Upon reduction of the Ni11 complex (321) with Na/Hg, the ligand backbone is cleaved, resulting in a thermally stable trinuclear Ni11 alkyl thiolato complex (322). 

Another type of binuclear thiolato complex is derived from certain tridentate dithiols, as illustrated in Fig. 13b [92]. Oxo-free species, which are exceptions,... 

Another type of mixed ligand technetium or rhenium complexes in the above sense contains two or more monodentate ligands (Fig. 26b). The six-coordinated polypyridyl-thiolato complexes of rhenium(V) [ReO(terpy)(SR)2] + [186] are an example. Further representatives are a variety of mixed-ligand complexes, combining tetramethylthiourea with dimethyldithiocarbamate [TcO(tu)2-((CH3)2NCSS)]2+ [194],... 

Unlike C—S insertion, the conversion of metallathiacycles to thiolato complexes via M—C bond cleavage, followed eventually by the formation of free thiols, is a quite rare reaction occurring both stoichiometrically and catalytically. Stoichiometric reactions proceed via either protono-lysis208,209,223 or hydrogenation of metallathiacycles.221 224 225 226-228 Selected examples are illustrated in Scheme 37 for (103),208 (102),221,224,225 and (104).223... 

Related sulfur-containing derivatives are formed from the reaction of 49 with 2-methyl-2-propanethiol, cyclo-hexanethiol, and 2-propanethiol in toluene at ambient temperature. The resulting tetrameric cyclopentadienyl thiolato complexes [(if-Cp)Mg(/.t3-SR) ]4 (R = Bu, CgFIn, Pr1) are colorless crystalline solids. Treatment of... 

Fig. 22. Remarkable activation-by-ligand-oxidation pathways for the reaction of ruthenium-arenes with thiolates. (a) Reaction of [Ru (r 6-bip)(en)(OH2)]+ with GSH (b) direct synthesis of ruthenium-arene sulfenato complexes (c) the air-stable thiolato complexes are oxidized in the presence of the antioxidant GSH.

Scheme 12. Synthesis of the thiolato complex [Zn(hdthpza)(SCH2Ph)l (13) (41).

The first osmium(IV) thiolato complex, [Os(salen)(SPh)2] (132), was prepared by the reduction of [0s(0)2(salen)] with thiophenol in CH2Cl2. The complex has a distorted octahedral structure, and both phenyl groups tilt away from the methylene bridge of the salen ligand, which is in the gauche confirmation. The mean Os—S distance is 2.32 A, which is shorter than that (2.415 A) in [Os2(Et2dtc)6](PF6)2 (Et2dtc = A,A-diethyldithiocarbamate). 

A. Levina, L. Zhang, and P. A. Lay, Formation and reactivity of chromium (V). Thiolato complexes A model for the intracellular reactions of carcinogenic chromium(VI) with biological thiols, /. Am. Chem. Soc., 132 (2010) 8720-8731. 

Ir(III) and Rh(III) peroxo complexes, species 3, may be obtained by reaction of 2 or O2 with Ir(I) and Rh(I) thiolato complexes (equation 5). An analogous reaction was observed also with a dimeric Rh(I) species and singlet oxygen that produces (equation 6). 

An alternative synthetic route to platinum(II) thiolates is by the oxidative addition of the S—S bond to platinum(O). When the sulfur atom has phenyl or electron-withdrawing substituents such as CF3, this reaction is a useful one to synthesize the thiolato platinum(II) complexes (equation 503).1703-1705 Simple alkyl disulfides such as Me2S2 and Et2S2 do not form stable dithiolato complexes of platinum(II) by S—S addition to Pt(PPh3)3, but if chelation can occur, chelate-assisted oxidative addition can induce S—S cleavage (equation 504).30 An unusual cyclic thiolato complex is obtained by the decarbonylative cleavage of a C—S bond (equation 505).1707... 

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