ACTIVATION OF CARBON-SULFUR AND CARBON-CHLORINE BONDS BY THE ELECTROPHILIC RUTHENIUM FRAGMENT RU(ETA-C5ME5)+

The 'Ru(eta-C5Me5)+' fragment generated by protonation of [{Ru(eta-C5Me5)(OMe)}2] by CF3SO3H, reacted with cyclohexene sulfide to give [Ru(eta-C5Me5)(eta6-C6H6)]+ 1 and H2S. With 1,4-dithiane no C-S bond activation was observed but instead the successive formation of [Ru(eta-C5Me5)(S2C4H8)(CF3SO3)] 2 and [Ru(S2C4H8)3]2+ 3, whereas with 1,3-dithiane two compounds resulting from the sequential activation of C-S bonds were isolated as CF3SO3- salts, namely [{Ru(eta-C5Me5)SMe)SCH2CH=CH2)}2]2+ 4 and [{Ru[C5Me4CH2S(CH2)3SMe]}2]2+ 5. The fragment also reacted with neat dichloromethane to give two trinuclear clusters: [{Ru(eta-C5Me5)}3(mu-Cl)3(mu3-CH)]+ 6 and [{Ru(C5Me5)}3(mu-Cl)2(mu-CO)(mu3-CH)]2+ 7 in 60 and 30% yield respectively. Its reaction with chlorocyclohexane, 1,2-dichlorocyclohexane and 1,2,3,4,5,6-hexachlorocyclohexane (lindane) yielded 1 and various amounts of H-2 and HCl. In the case of lindane the conversion was only 30% and yielded a 9:1 mixture of 1 and [Ru(eta-C5Me5)(eta6-C6H5Cl)]+ 9. Finally the reaction of C-Cl versus C-O bond activation was compared using 2-chlorocyclohexanone, 2-chlorocyclohexanol and 2,2,6,6-tetrachlorocyclohexanol. It was found that in all cases the C-Cl activation was easier. The first reaction yielded 1, the second the new trinuclear cluster [{Ru(C5Me5)}3(mu-Cl)2(mu-CO)(mu3-CCl)]2+ 11 similar to 7. The latter reaction depended upon the reaction conditions, but in tetrahydrofuran at 80-degrees-C, an 80% conversion was observed yielding a 1:7:<1 mixture of 1, [Ru(eta-C5Me5)(eta6-C6H5OH)]+ 10 and [Ru(eta-C5Me5)(eta6-CH5Cl)]+ 9 thus demonstrating a high selectivity for C-Cl activation in the presence of C-O bonds.