Neutral carbene and vinylidene cyclopentadienyl ruthenium complexes with PPh2(2-MeC6H4)

The complex [RuCl(η 5 -C 5 H 5 ){PPh 2 (2-MeC 6 H 4 )} 2 ] ( 1 ), unlike the triphenylphosphine analog [RuCl(η 5 -C 5 H 5 )(PPh 3 ) 2 ], reacts under mild conditions with CO, N 2 CPh 2 and HCCPh to give the neutral carbonyl, carbene and vinylidene derivatives [RuCl(η 5 -C 5 H 5 )(L){PPh 2 (2-MeC 6 H 4 )}] (L=CO 2 , CPh 2 5 , CCHPh 6 ), respectively, via displacement of one phosphine ligand. The vinylidene complex 6 promptly reacts with benzylamine affording the aminocarbene [RuCl(η 5 -C 5 H 5 ){C(NHCH 2 Ph)CH 2 Ph}{PPh 2 (2-MeC 6 H 4 )}] ( 7 ). Moreover, the cyclometalated derivative [ Ru(η 5 -C 5 H 5 ){PPh 2 (2-C H 2 C 6 H 4 )}{PPh 2 (2-MeC 6 H 4 )}] ( 4 ) has been obtained from the methyl complex [RuMe(η 5 -C 5 H 5 ){PPh 2 (2-MeC 6 H 4 )} 2 ] ( 3 ) by intramolecular C–H bond cleavage and methane elimination. Complex 1 , whose X-ray structure analysis is also reported, has been found to catalyze alkyne coupling reactions.