On the prospects of polynuclear complexes with acetylenedithiolate bridging units.

The generation of polynuclear complexes with one, two, or four acetylenedithiolate bridging units via the isolation of eta2-alkyne complexes of acetylenedithiolate K[Tp'M(CO)(L)(C2S2)] (Tp'=hydrotris(3,5-dimethylpyrazolyl)borate, M=W, L=CO (K-3a), M=Mo, L=CNC6H3Me2 (K-3b)) is reported. The strong electronic cooperation of Ru and W in the heterobimetallic complexes [(eta5-C5H5)(PPh3)Ru(3a)] (4a) and [(eta5-C5H5)(Me2C6H3NC)Ru(3a)] (4b) has been elucidated by correlation of the NMR, IR, UV-vis, and EPR-spectroscopic properties of the redox couples 4a/4a+ and 4b/4b+ with results from density functional calculations. Treatment of M(II) (M=Ni, Pd, Pt) with K-3a and K-3b afforded the homoleptic bis complexes [M(3a)2] (M=Ni (5a), Pd (5b), Pt (5c)), and [M(3b)2] (M=Pd (6a) and Pt (6b)), in which the metalla-acetylendithiolates exclusively serve as S,S'-chelate ligands.

Acetylenedithiolate: alkyne complex formation renders it a dithiolate chelate ligand.

The isostructural complexes [{Tp'W(CO)(2)(eta(2)-C(2)S(2))}(2)M] (M = Ni, Pd, Pt) show that the eta(2)-C,C'-alkyne complexes of acetylenedithiolate at [Tp'W(CO)(2)](+) can generally act as dithiolate chelate ligands, leading to dithiolene type complexes.

Molybdenum and tungsten eta2-alkyne-1-thio complexes acting as sulfur donors in homoleptic Werner type complexes with nickel(II) and palladium(II).

Facile access to the eta2-alkyne-1-thio complexes [Tp'M(CO)2{eta2-(BnS)CC(S)}] (Tp' = hydrotris(3,5-dimethylpyrazolyl)borate; Bn = benzyl; M = Mo, W) by reductive removal of one benzyl group in the corresponding bis(benzylthio)acetylene complexes, [Tp'M(CO)2{eta2-(BnS)CC(SBn)}](PF6), has been thoroughly investigated. Experimental evidence of the intermediates, [Tp'M(CO)2{eta2-(BnS)CC(SBn)}] (M = Mo, W), and the fate of the cleaved benzyl group by isolation of the byproduct, [Tp'W(CO){C(O)Bn}{eta2-(BnS)CC(SBn)}], is provided. Neutral eta2-alkyne-1-thio complexes [Tp'M(CO)2{eta2-(BnS)CC(S)}] bearing a free terminal sulfur atom have been established as monodentate ligands L in homoleptic pentanuclear [M'L4]2+ complexes with nickel(II) and palladium(II).

A neutral tungsten-eta2-alkyne-1-thio ligand forming a homoleptic Werner type complex with Cu(I).

The 1-thio-eta2-alkyne-complex [Tp'(CO)2W(BnSCCS)][Tp'= hydrotris(3,5-dimethylpyrazolyl)borate; Bn = benzyl], which was obtained by reductive removal of the benzyl group at the alkyne complex [Tp'(CO)2W(BnSCCSBn)]PF(6), has been established as a ligand in a combined organometallic/Werner type heterobimetallic complex with Cu(I).