ACTIVATION OF 2-PROPYN-1-OL DERIVATIVES BY INDENYLRUTHENIUM(II) AND INDENYLOSMIUM(II) COMPLEXES - X-RAY CRYSTAL-STRUCTURES OF THE ALLENYLIDENE COMPLEXES 2))(ETA(5)-C9H7)(PPH(3))(2)][PF6]CENTER-DOT-CH2CL2 (M=RU, OS) AND EHMO CALCULATIONS

The allenylidene complexes [M(=C=C=CR(2))(eta(5)-C9H7)L(2)][PF6] (M = Ru, L = PPh(3), L(2) = 1,2-bis(diphenylphosphino)ethane (dppe), bis(di phenylphosphino)methane (dppm), R(2) = 2 Ph (1a-c), C12H8 (2,2'-biphen yldiyl) (2a-c); M = Os, L = PPh(3), R(2) = 2Ph (3), C12H8 (4)) have be en prepared by reaction of the complexes [MCl(eta(5)-C9H7)L(2)] with H C=CC(OH)R(2) and NaPF6 in refluxing methanol. The crystal structures o f [M(=C=C=CPh(2))(eta(5)-C9H7)(PPh(3))(2)][PF6]- C2Cl2 (M = Ru (1a), O s (3)) were determined by X-ray diffraction methods. In the structures the M=C=C=C chains are nearly linear (M-C(1)-C(2) = 168.5-(5)degrees (1a) and 169.3(4)degrees (3); C(1)-C(2)-C(3) = 168.2(7)degrees (1a) an d 168.0(5)degrees (3)) with M=C(1) distances of 1.878(5) Angstrom (1a) and 1.895(4) Angstrom (3). The indenyl ligand is eta(5)-bonded to the metal with the benzo ring orientated ''cis'' with respect to the alle nylidene group. Extended Huckel molecular orbital calculations have be en used to rationalize the preferred ''cis'' orientation. The reaction of [RuCl(eta(5)-C9H7)L(2)] (L = PPh(3), L(2) = dppe, dppm) with HC=CC Me(OH)Ph and NaPF6 in refluxing methanol leads to the formation of the allenylidene complexes [Ru-{=C=C=C(Me)ph}(eta(5)-C9H7)L(2)][PF6] (6a- c) along with the vinylvinylidene isomers [Ru-{=C=C(H)C(Ph)=CH2}(eta(5 )-C9H7)L(2)][PF6] (L = PPh(3) (5a), L(2) = dppe (5b), dppm(5c)). Only complex 6a could be isolated by chromatography (SiO2) from these mixtu res along with complex 7a obtained from the deprotonation of the vinyl vinylidene complex 5a. The treatment of these reaction mixtures with p otassium carbonate yields the neutral sigma-enynyl derivatives [Ru{C=C C(Ph)=CH2}(eta(5)-C9H7)L(2)] (7a-c). The monosubstituted allenylidene complex [Ru{=C=C=C(H)Ph}(eta(5)-C9H7)(PPh(3))(2)][PF6] (9) has been pr epared by the reaction of [RuCl(eta(5)-C9H7)(PPh(3))(2)] with HC=CCH(O H)R and NaPF6 in methanol. Under similar reaction conditions [RuCl(eta (5)-C9H7)L(2)] reacts with HC=CCH(OH)R and NaPF6 to afford the alkenyl methoxycarbene derivatives [Ru{=C(OMe)C(H)=CH(R)}(eta(5)-C9H7)L(2)][PF 6] (L(2) = dppe, R = Ph (11b); L(2) = dppm, R = Ph (11c), H (13)). [Ru Cl(eta(5)-C9H7)(PPh(3))(2)] also reacts with HC=CC(OH)H-2 to give the hydroxyvinylidene complex [Ru{=C=CH(CH2OH)}(eta(5)-C9H7(PPh(3))(2)][PF 6] (12), which is stable toward the dehydration process.