First Examples of a Dithiolato Bridge in (η6-C6Me6)RuII−Cr0,II,III Complexes. Synthetic, Single-Crystal X-ray Diffraction, and Electrochemical Studies

The interactions of [(HMB)RuII{η3-tpdt)}] (1) [HMB = η6-C6Me6, tpdt = S(CH2CH2S-)2] with Cr(CO)6, [CpCr(CO)3]2, [CpCrCl2(SPyH)], and [Cp*Cr(CH3CN)4](PF6)2 (6) produced a series of thiolate-bridged Ru−Cr heterobimetallic complexes: viz., [{(HMB)Ru(μ-η2:η3-tpdt)}{Cr(CO)4}] (3), [{(HMB)Ru(μ-η2:η3-tpdt)}{CpCr(CO)2}][CpCr(CO)3] (4), [{(HMB)Ru(μ-η2:η3-tpdt)}{CpCrCl}](PF6) (5), and [{(HMB)Ru(μ-η2:η3-tpdt)}{Cp*Cr(MeCN)}](PF6)2 (8), in respective yields of 29%, 67%, 62%, and 79%. Complex 6 was synthesized from [Cp*CrBr2]2 and found to readily convert to [Cp*Cr{(CH3)2CO}3][Cp*Cr{(CH3)CO}2(MeCN)](PF6)4 (7) upon recrystallization from acetone. Each compound could be electrochemically oxidized and reduced in several one-electron or multiple-electron steps. The voltammetric responses were complicated and varied depending on the electrode surface and temperature. The single-crystal X-ray structures of 3−5, 7, and 8 have been determined.