C−H Cleavage and Double Alkyl Additions to the Disulfido Ligand in Dicyanido-Bridged Ru₂S₂ Complexes

Novel dicyanido-bridged dicationic RuIIISSRuIII complexes [{Ru(P(OCH3)3)2}2(μ-S2)(μ-X)2{μ-m-C6H4(CH2CN)2}](CF3SO3)2 (4, X = Cl, Br) were synthesized by the abstraction of the two terminal halide ions of [{RuX(P(OCH3)3)2}2(μ-S2)(μ-X)2] (1, X = Cl, Br) followed by treatment with m-xylylenedicyanide. 4 reacted with 2,3-dimethylbutadiene to give the C4S2 ring-bridged complex [{Ru(P(OCH3)3)2}2{μ-SCH2C(CH3)C(CH3)CH2S}(μ-X)2{μ-m-C6H4(CH2CN)2}](CF3SO3)2 (6, X = Cl, Br). In addition, 4 reacted with 1-alkenes in CH3OH to give alkenyl disulfide complexes [{Ru(P(OCH3)3)2}2{μ-SS(CH2CCHR)}(μ-Cl)2{μ-m-C6H4(CH2CN)2}](CF3SO3) (7: R = CH2CH3, 9: R = CH2CH2CH3) and alkenyl methyl disulfide complexes [{Ru(P(OCH3)3)2}2{μ-S(CH3)S(CH2CHR)}(μ-Cl)2{μ-m-C6H4(CH2CN)2}](CF3SO3)2 (8: R = CH2CH3, 10: R = CH2CH2CH3) via the activation of an allylic C−H bond followed by the elimination of H+ or condensation with CH3OH. Additionally, the reaction of 4 with 3-penten-1-ol gave [{Ru(P(OCH3)3)2}2{μ-SS(CH2CCHCH2OH)}(μ-Cl)2{μ-m-C6H4(CH2CN)2}](CF3SO3) (11) via the elimination of H+ and [{Ru(P(OCH3)3)2}2(μ-SCH2CHCHCH2S)(μ-Cl)2{μ-m-C6H4(CH2CN)2}](CF3SO3)2 (12) via the intramolecular elimination of a H2O molecule. 12 was exclusively obtained from the reaction of 4 with 4-bromo-1-butene.