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

The complex [RuCl(η5-C5H5){PPh2(2-MeC6H4)}2] (1), unlike the triphenylphosphine analog [RuCl(η5-C5H5)(PPh3)2], reacts under mild conditions with CO, N2CPh2 and HCCPh to give the neutral carbonyl, carbene and vinylidene derivatives [RuCl(η5-C5H5)(L){PPh2(2-MeC6H4)}] (L=CO 2, CPh25, CCHPh 6), respectively, via displacement of one phosphine ligand. The vinylidene complex 6 promptly reacts with benzylamine affording the aminocarbene [RuCl(η5-C5H5){C(NHCH2Ph)CH2Ph}{PPh2(2-MeC6H4)}] (7). Moreover, the cyclometalated derivative [H2C6H4)}{PPh2(2-MeC6H4)}] (4) has been obtained from the methyl complex [RuMe(η5-C5H5){PPh2(2-MeC6H4)}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.