Dehydroisomerization of 1-pentene on the diruthenium disulfido complex

In situ generated [{Ru(P(OCH3)3)2(CH3CN)3}2(μ-S2)]4+ (2), produced by abstracting the chloride atoms from [{Ru(P(OCH3)3)2Cl}2(μ-Cl)2(μ-S2)] (1) with Ag+ salts, reacts with 1-pentene in CH3CN to afford [{Ru(P(OCH3)3)2(CH3CN)3}2{μ-SCH2CHdouble bond; length as m-dashC(CH3)CH2S}]4+ (4) via dehydroisomerization of 1-pentene, and [{Ru(P(OCH3)3)2(CH3CN)3}2(μ-SCH2CH2CH(CH2CH3)S)]4+ (3), which is the reaction product from the reaction of the isolated 2 with 1-pentene.The elimination of two hydrogen atoms was confirmed by GC–MS analysis of the pentanes produced via disproportionation of two molecules of 1-pentene.In contrast, the reaction of in situ generated 2 with 1-hexene gave the cyclization product [{Ru(P(OCH3)3)2(CH3CN)3}2(μ-SCH2CH2CH(CH2CH2CH3)S)]4+ (5) and a trace amount of the side product [{Ru(P(OCH3)3)2(CH3CN)3}2(μ-SSCH2CHdouble bond; length as m-dashCHCH2CH2CH3)]3+ (6) via elimination of H+ from the intermediate.Similarly, [{Ru(P(OCH3)3)2(CH3CN)3}2{μ-SCH2CH2CH(CH(CH3)2)S}]4+ (7) and [{Ru(P(OCH3)3)2(CH3CN)3}2{μ- SSCH2CHdouble bond; length as m-dashCH(CH(CH3)2)S}]3+ (8) were obtained from the reaction of in situ generated 2 with 4-methyl-1-pentene.