SYNTHESIS AND REACTIVITY OF RU(ETA(5)-C(5)ME(5))(ETA(4)-CYCLOPENTADIENONE) COMPLEXES - X-RAY STRUCTURES OF RU(ETA(5)-C(5)ME(5))(ETA(4)-C5H(4)O)BR, RU(ETA(5)-C(5)ME(5))(ETA(4)-C5H3O-2-BR)BR, AND [RU(ETA(5)-C(5)ME(5))(ETA(4)-C5H2O-2-ME,5-PCY3)BR]CF3SO3

Ru(eta(5)-C(5)Me(5))(eta(4)-C5H4O)BT (1a) and RU(eta(5)-C(5)Me(5))(eta(4)-C5H3O-2-Me)Br (1b) are synthesized via the synthetic intermediates RU(eta(5)-C(5)Me(5))(eta(3)-C5H5O)Br-2 and RU(eta(5)-C(5)Me(5))(eta(3)-C5H4O-2-Me)Br-2. Complex 1a crystallizes in the space group Pnma (No. 62), with a 11.080(2) Angstrom, b = 10.557(2) Angstrom, c 12.225(2) Angstrom, V = 1430.0(5) Angstrom(3), and Z = 4. The structure was refined to R = 0.021 and R(w) = 0.023. Complexes 1a and 1b react with Br-2 to afford the bromo substituted eta(3)-cyclopentenoyl Ru(TV) complexes 2a and 2b. Bromine attack occurs exclusively a to the ketonic functional group and anti to the coordinated ruthenium. On addition of excess triflic acid, 2a is shown to undergo facile conversion to [RU(eta(5)-C(5)Me(5))(eta(5)-C5H3OH-2Br)Br]CF3SO3 (4). Deprotonation of4 with excess H2O gives RU(eta(5)-C(5)Me(5))(eta(4)-C5H3O-2-Br)Br (5) in 98% yield. Complex 5 has been found to crystallize in space group P2(1)/c (No. 14), with a = 9.606(2) Angstrom, b = 13.421(4) Angstrom, c = 12.946(4) Angstrom, beta = 111.46(1)degrees, V = 1553.3(7) Angstrom(3), and Z = 4. The structure was refined to R = 0.027 and R(w) = 0.026. Cationic complexes [RU(eta(5)-C(5)Me(5))(eta(4)-C5H4O)(CH(3)cN)](+) (7a), [RU(eta(5)-C(5)Me(5))(eta(4)-C5H3O-2-Me)(CH3CN)](+) (7b), and [Ru(eta(5)-C(5)Me(5))(eta(4)-C5H3O-2-PCY3)(CH3CN)](2+) (10) are prepared by the action of AgCF3SO3 on 1a, 1b, and [RU(eta(5)-C(5)Me(5))(eta(4)-C5H3O-2-PCy(3))Br](+) (9a(1)), respectively. Complex 7a reacts readily with nucleophiles (Nuc = PCy(3) and PPhMe(2)) to form regioselectively [RU(eta(5)-C(5)Me(5))(eta(5)-C5H3-OH-2-Nuc)](+) (8a(1), 8a(2)). PPh(3) did not react with 7a. Complexes 8a(1) and 8a(2) undergo facile oxidation with Br-2 to give 9a(1) and [RU(eta(5)-C(5)Me(5))(eta(4)-C5H3O-2-PPhMe(2))Br](+) (9a(2)), respectively. In analogous fashion, [RU(eta(5)-C(5)Me(5))(eta(4)-C5H2O-2-Me, 5-PCy(3))Br](+) (9b) is obtained on treatment of 7b with PCy(3) and subsequent oxidation with Br-2. A single crystal structural study has been carried out for this complex. The space group is P2(1)/c (No. 14), with a = 12.226(2) Angstrom, b = 16.304(3) Angstrom, c = 18.803(3) Angstrom, beta = 93.75(1)degrees, V = 3740(1) Angstrom(3), and Z = 4. The structure was refined to R = 0.036 and R(w) = 0.037.