Acetylene Dithiolate Linking up the [Tp'W(CO)(CN)] Moiety with Ru~(II) or Pd~(II)

摘要

A series of heterodinuclear complexes with acetylene dithiolate (acdt~(2-)) as the bridging moiety were synthesised by a facile one-pot procedure that avoided use of the highly elusive acetylene dithiol. Generation of the W-Ru complex [Tp'W(CN)(CO)-(C_2S_2)Ru(η~5-C_5H_5)(PPh_3)] (Tp'=hydrotris(3,5-dimethylpyrazolyl)borate) and the W-Pd complexes [Tp'W(CN)(CO)-(C_2S_2)Pd(dppe)] and [Tp'W(CO)_2-(C_2S_2)Pd(dppe)][PF_6] (dppe=1,2-bis(diphenylphoshino) ethane), which exhibit a [W(η~2-k~2-C_2S_2)M] core (M=Ru, Pd), was accomplished by using a transitionmetal- assisted solvolytical removal of the Me3Si-ethyl thiol protecting groups. All intermediate species of the reaction have been fully characterised. The highly coloured W-Ru complex [Tp'W(CN)(CO)(C_2S_2)Ru(η~5-C_5H_5)- (PPh_3)] shows reversible redox chemistry, as does the prototype complex [Tp'W(CO)_2(C_2S_2)Ru(η~5-C_5H_5)(PPh_3)]- [PF_6]. Single crystal X-ray diffraction and IR, EPR and UV/Vis spectroscopic studies in conjunction with DFT calculations prove the high electronic delocalisation of states over the acdt~2- linker. Comparative studies revealed a higher donor strength and more pronounced dithiolate character of acdt~2- in [Tp'W(CN)(CO)(C_2S_2)Ru(η~5-C_5H_5)- (PPh_3)] relative to [Tp'W(CO)_2- (C_2S_2)Ru(η~5-C_5H_5)(PPh_3)]~+. In addition, the influence of the overall complex charge on the metric parameters was investigated by single-crystal X-ray diffraction studies with the W-Pd complexes [Tp'WL_2(C_2S_2)Pd(dppe)] (L= (CN~-)(CO) or (CO)_2). The central [W(C_2S_2)Pd] units exhibit high structural similarity, which indicates the extensive delocalisation of charge over both metals.