Stoichiometric Reaction Chemistry of Cationic Ruthenium Silylene Complexes toward Polar and Nonpolar Organic Substrates

Reactions of the cationic ruthenium silylene complexes [Cp*((PPr3)-Pr-i)Ru(H)(2)(==SiRR')][B(C6F5)(4)] (R =Mes, R' = H, 1; R = R' = Ph, (2)) with alkenes, allcynes, ketones, and Lewis bases were explored. Addition of 1-hexene, 3,3-imethylbut-1-ene, styrene, and cyclopentene to 1 afforded the disubstituted silylene products [Cp*((PPr3)-Pr-i)Ru(H)(2)(= SiMesR)J[B(C6F5)(4)] (R = Hex, (3); R = CH(2)CH(2)(3)(t)u, (4); R CH,CH,Ph, (5); R = C5H9, (6)). Analogous reactions with 2-butyne and 3,3-dimethylbut-1-yne yielded the vinyl-substituted silylene complexes [Cp*((PPr3)-Pr-i)Ru(H)(2)(=Si(CR=CHR')Mes)][B(C6F)(4)] (R = R' = Me, 7; R = H, R' = Bu-t, 8). Complex 1 undergoes reactions with ketones to give the heteroatomsubstituted silylene complexes [Cp*((PPr3)-Pr-i)Ru(H)(2)(=Si(OCHPhR)Mes)][B(C6F)(4)] (R = Ph, 9; R = Me, 10). Interestingly, complexes 3-8 display a weak interaction between the hydride ligands and the silicon center, while 9 and 10 exhibit a relatively large interaction (as determined by (2)J(siH) values). The reaction of isocyanates with 1 resulted in the silyl complexes [Cp*((PPr3)-Pr-i)Ru(H)(2)(Si(Mes)[kappa(2)-O(CH)(NC6H4R)][B(C(6)Fs)(4)] (R = H, 11; R = CF3, 12), and an intermediate in this transformation is observed. Complex (2) was subjected to various Lewis bases to yield the base-stabilized silylene complexes [Cp*(P'Pr-3)Ru(H)(2)(SiPh2.L)][B(C6F)(4)] (L = DMAP, 13; L = Ph2CO, 14; L = PhCONH2, 15; L = NHMePh, 16, L = (BuSONH2)-Bu-t, 18), and the reaction of 1 with NHMePh gave [Cp*((PPr3)-Pr-i)Ru(H)(2)(SiHMes.NHMePh)][B(C6F)(4)].