Synthesis of the first non-carbonyl cisoid fulvalene complexes with an Ru–Ru bond bridged by thiolate ligands

The addition of PPh3 to a solution which was produced by the oxidation of [(eta5-Cp)Ru(mu2-eta6:eta6-C10H8)Ru(5-Cp)]2+ (BF4–)2(1) with p-benzoquinone and BF3·OEt2(abbreviated as p-Bq/BF3) in CH2Cl2–CH3CN and subsequent Znreduction gave the transoid Ru–Fv complex (Fv = fulvalene) formulated as [(CH3CN)2(PPh3)Ru(mu2-5:5-C10H8)Ru (PPh3)(CH3CN)2]2+(BF4–)2(2a) in high yield as stable yellow crystals. Treatment of 2a with excess aryl thiols (ArSH; Ar = C6H5, p-CH3C6H4 and p-ClC6H4), their thiolates and aryl dithiols (1,2-benzenedithiol or 3,4toluenedithiol) or their dithiolates at room temperature afforded the Ru–Fv complexes bridged by thiolate ligands formulated as [(PPh3)Ru(mu2-5:5-C10H8)(mu2-SAr)2Ru(PPh3)]2+(BF4–)2(3a–c), (ArS)Ru(mu2-5:5-C10H8)(mu2SAr)2Ru(SAr) (4a–c) and [(PPh3)Ru(mu2-5:5-C10H8)(mu2-S2C6H3R)Ru(PPh3)]2+(BF4–)2(5a; R = H, 5b; R = CH3), in high yield, respectively. Treatment of 2a with excess tert-butylthiolate produced the complex [(PPh3)Ru(mu2-5:5C10H8)(mu2-StBu)2Ru]2+(BF4–)(StBu–)(6a). In contrast with complexes 2–5, a coordinatively unsaturated Ru atom was found in 6a, which is probably formed owing to the bulkiness of the tBuS– ligand. X-Ray analysis of complexes 3–6 showed the presence of an RuIII–RuIII single bond.