Thiolates polynuclear complexes

Monomeric complexes have been formed with the bis(benzimidazolylmethyl) sulfide ligands to give tetrahedral N2S2 coordinated zinc in combination with thiolates.125 The benzimidazole ligand (9) shown has also been used to form polynuclear complexes with zinc and benzylthiolates.126... 

In conclusion, unlike heterogeneous processes with commercial HDS catalysts, single-site catalysts have been found to desulfurize thiophenes (T, BT, DBT) exclusively after these have been converted to saturated thiols or thiolates. No example of catalytic desulfurization of THT or DHBT by a single-site catalyst has ever been reported, although stoichiometric reactions assisted by both mononuclear and polynuclear complexes are known for THT and other cyclic thioethers [2 b, 32]. 

Keywords amino acids cadmium(II) peptides histidme cysteine thiolate ligands stability constants octahedral complexes polynuclear complexes... 

Some mixed valence polynuclear thiolate complexes such as [Ni4(SC3H7)8Br] and [Ni4(SC3H7)8I] have been prepared and characterized by single-crystal X-ray methods.203... 

Mononuclear tetrahedral complexes of Co", Zn" and Cd" are also formed with high molar ratios of arylthiolate whereas at lower thiolate concentrations polynuclear species can be obtained. The equilibria existing in acetonitrile solution containing Co", PhS and halide have been postulated as shown in Scheme l,114... 

Work on Ni-thiolate complexes has focused on the synthesis of mononuclear, S-bridged polynuclear, cluster, and cubane model complexes of relevance to active site in biological systems (see Section 8). Scheme 8 illustrates some of the thiolate complexes that have been prepared. 

In type IV, the thiolate sulfur atom coordinates to a metal atom and the thiocarbonyl sulfur coordinates to another metal atom. This type of coordination is seen in tetrathiooxalate complexes (see Sect.2.7) [21-30].This coordination style is also seen in polynuclear silver and copper complexes [31,32]. 

Metal thiolate complexes will reduce elemental sulfur or red selenium via the oxidative elimination of RSSR. In a similar manner, metal selenolate complexes ean be used to reduce elemental selenium. The resulting E ligands favor the formation of polynuclear cluster complexes, due to the greater tendency of E (vs. RE ) to form bridging interactions between metal centers. Originally developed in the synthesis of [Fe4Se4(SPh)4], this method has been well utilized in the synthesis of a number of iron thiolate/sulfide clusters, as well as their selenide counterparts (Equation (5)). More recently, sulfur- and selenium-containing lanthanide clusters (see Section 7.2.5.5) have been synthesized by the displacement of ER from Ln(ER)3 ... 

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