GENERATION AND REACTIVITY OF UNSATURATED IRIDIUM AND RHODIUM DIMETHYL COMPLEXES

Protonation (HBF4·OEt2) of MMe3P3(M = Rh, Ir; P = PMe2Ph) in CH2Cl2gives CH4and cis,mer- MMe2P3BF4, characterized as a fluxional (methyl site exchange) molecular η1-BF4species by 1H,31P,19F, and11B NMR studies and (for M = Ir) X-ray diffraction. Crystal data for IrMe2P3BF4·C6H6(-100 °C): a = 16.708 (6) Å, b = 9.332 (2) Å, c = 23.214 (8) Å, ß = 110.05 (2)°, with Z = 4 in space group P21/c. Ethylene replaces BF4 -to give (at 25 °C) [IrMe2(C2H4)P3]BF4and (at 50 °C) [Ir(C2H4)2P3]BF4and C2H6. Carbon monoxide replaces BF4to give first [IrMe2(CO)P3]BF4and then IrMe[C(O)Me](CO)P3 +. Ethylene reacts (25 °C) with RhMe2P3BF4to immediately give ethane and [RhP4]BF4. Carbon monoxide replaces BF4 -to give first RhMe2(CO)P3 +and then acetone and [RhP4]BF4. Ethylene also promotes acetone elimination from RhMe2(CO)P3 +, to again generate RhP4 +. All of the above are characterized by multinuclear NMR and vibrational spectroscopy and, for [IrMe2(C2H4)P3BF4, X-ray diffraction. Crystal data (-155 °C): a = 13.373 (4) Å, b = 12.242 (3) Å, c = 18.139 (b) Å, with Z = 4 in space group P21cn. © 1990, American Chemical Society. All rights reserved.