SYNTHESIS AND STRUCTURAL CHARACTERIZATION OF THE MIXED-METAL SPECIES [CO2IR2(CO)10(ETA(4)-COD)] AND [COIR3(CO)10(ETA(4)-COD)] (COD = 1,5-CYCLOOCTADIENE)

The new mixed-metal clusters [Co2Ir2(CO)10(cod)] (4) and [CoIr3(CO)10(cod)] (5) (cod = 1,5-cyclooctadiene) have been obtained from [Co2(CO)8] (2) and [{IrCl(cod)}2](3). Alternatively, [Co2Ir2(CO)12] (1) reacts with cod to yield 4, which in the presence of CO reforms 1. Under the same conditions, however, 5 is inert. The solid state structures of 4 and 5 have been established by X-ray analyses, and the disorder shown by the two species is discussed. Compound 4 is monoclinic, space group P2(1)/c, a 8.891(2), b 10.746(3), c 22.648(8) angstrom, beta 95.16(3)-degrees, Z = 4, R = 0.048, R' = 0.050, for 2393 [I > 2sigma(I)] of 25% absorption corrected reflections; compound 5 is also monoclinic, space group P2(1)/m, a 8.5994(9), b 12.047(3), c 10.799(3) angstrom, beta 98.30(1)-degrees, Z = 2, R = 0.037, R' = 0.040, for 2071 [I > 2sigma(I)] of 2711 absorption corrected reflections.