Insertion of acetylene and nitriles into a Ru-C bond of a dicationic triruthenium complex having a mu(3)-eta(3)-C-3 ring: Formation of six-membered ruthenacycles on a triruthenium core

摘要

A triruthenium complex having a mu(3)-ruthenacyclohexadienyl moiety, [(Cp*Ru)(2){Cp*RU(mu(3)-eta(2):eta(2)-CHCMe=CH-CH=CH-)}(mu(3)-CH)](+) (9), was synthesized by the reaction of an equilibrating mixture of dicationic complexes having a mu(3)-eta(3)-C-3 ring, [(Cp*Ru)(3)(mu(3)-eta(3)-C3H2Me)(mu(3)-CH)(mu-H)](2+) (2a and 2b), with acetylene. The protonation of 9 resulting in the formation of a dicationic mu(3)-ruthenacyclohexadienyl complex, [(Cp*Ru)(2){Cp*RU(mu(3)-eta(2):eta(2)-CH-CMe=CHCH=CH-)}(mu(3)-CH)(mu-H)](2+).(10), strongly indicates that the hydrido ligand of 2 was removed as a proton after the six-membered metallacycle was formed by the insertion of an acetylene molecule into a Ru-C bond. The thermolysis of 9 resulted in an isomerization of the metallacycle moiety via the formation of a mu(3)-cyclopentadienyl intermediate and quantitatively afforded a mu(3)-4-methylruthenacyclohexadienyl complex, [(Cp*Ru)(2){Cp*RU(mu(3)-eta(2):eta(2)-CHCHCMe=CH-CH=CH-)}(mu(3)-CH)](+) (13). Nitriles also inserted into a Ru-C bond of 2 and afforded a series of dicationic 2-azaruthenacyclohexadienyl complexes, [(Cp*Ru)(2){Cp*RU(mu(3)-eta(2):eta(2)-NH=CR-CHCMeCH-)}(mu(3)-CH)](2+) (18a: R = Me, 18b: R = Et, 18c: R = Ph).