Vinylidene, acetylide, and carbene complexes from reactions of 2,5-dithiahex-3-yne (MeSC.tplbond.CSMe) with Cp(PMe3)2Ru+

Abstract

The alkyne MeSC{triple bond}CSMe initially displaces Cl{sup {minus}} in Cp(PMe{sub 3}){sub 2}RuCl at room temperature in MeOH to form the sulfur-bound alkyne complex {l brace}Cp(PMe{sub 3}){sub 2}Ru(S(Me)C{triple bond}CSMe){r brace}PF{sub 6} (1). When it is warmed 1 rearranges to the vinylidene complex (Cp(PMe{sub 3}){sub 2}Ru{double bond}C{double bond}C(SMe){sub 2})PF{sub 6} (2). Complex 2 is reduced by Na(HBEt{sub 3}) or Na/Hg to give the thioacetylide Cp(PMe{sub 3}){sub 2}Ru-C{triple bond}CSMe (5) and MeSSMe. The vinylidene complexes (Cp(PMe{sub 3}){sub 2}Ru{double bond}C{double bond}C(R)(SMe)){sup +} (6, R = H; 7, R = Me) are formed by electrophilic addition to the {beta}-carbon of the thioacetylide 5. Addition of CuCl to 5 forms Cp(PMe{sub 3}){sub 2}Ru(C{triple bond}CSMe)(CuCl) (8), in which the copper is {pi}-bound through the C{triple bond}C group. Reaction of 6 with methanol and ethanol yields the alkoxycarbene complexes (Cp(PMe{sub 3}){sub 2}Ru{double bond}C(OR)(CH{sub 2}SMe))BF{sub 4} (11a, R = Me; 11b, R = Et). Deprotonation of 11a with NaOMe yields the vinyl complex Cp(PMe{sub 3}){sub 2}Ru(C(OMe){double bond}C(H)SMe) (12). Addition of (Me{sub 3}O)BF{sub 4} to complexes 6 and 7 yields the first examples of sulfoniovinylidene dicationic complexes (Cp(PMe{sub 3}){sub 2}Ru{double bond}C{double bond}C(R)(SMe{sub 2}))(BF{sub 4}){sub 2} (9, R = H; 10, R = Me). Complexes 7 and 10 undergo one- andmore » two-electron reductions, respectively, to give the acetylide Cp(PMe{sub 3}){sub 2}Ru-C{triple bond}CMe (14) and MeSSMe (for 7) or SMe{sub 2} (for 10). Complexes 6 and 9 are readily deprotonated to give 5 and the sulfonioacetylide (Cp(PMe{sub 3}){sub 2}Ru-C{triple bond}CSMe{sub 2})BF{sub 4} (13), respectively. Mechanisms of the reactions and structural features of the vinylidenes are discussed.« less