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

The complex [RuCl(eta (5)-C5H5){PPh2(2-MeC6H4)}(2)] (1), unlike the triphenylphosphine analog [RuCl(eta (5)-C5H5)(PPh3)(2)], reacts under mild conditions with CO, N2CPh, and HC=CPh to give the neutral carbonyl, carbene and vinylidene derivatives [RuCl(eta (5)-C5H5)(L){PPh2(2-MeC6H4)}] (L = CO 2, CPh2 5, C=CHPh 6), respectively, via displacement of one phosphine ligand. The vinylidene complex 6 promptly reacts with benzylamine affording the aminocarbene [RuCl(eta (5)-C5H5) {=C(NHCH2Ph)CH2Ph} {PPh2(2-MeC6H4)}] (7). Moreover, the cyclometalated derivative [Ru(eta (5)-C5H5){PPh2(2-CH2C6H4)}{PPh2(2-MeC6H4)}] (4) has been obtained from the methyl complex [RuMe(eta (5)-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. (C) 2001 Elsevier Science B.V. All rights reserved.