ORGANOMETAL COMPOUNDS OF IRIDIUM AND RHOD IUM .31. HETEROBIMETALLIC DINUCLEAR COMPLEXES BY ADDITION OF CP(CO)(3)MH (M=MO, W) TO IR(CH3)(CO)(PPH(3))(2)

Treatment of Ir(CH3)(CO)(PPh(3)), with molybdenum or tungsten hydrides Cp(CO)(3)MH results in elimination of both CH4 and CO to give heterob imetallic products of composition Cp(CO)M(mu-CO)(2)Ir(PPh(3))(2) (1: M = Mo; 2: M = W). Degradation of these complexes in solution occurs by CO transfer and oxidative P-C addition, affording the phosphido-bridg ed derivatives CP(CO)(2)M(mu-Ph(2)P)Ir(C6H5)(CO)(2)(PPh(3)) (3: M = Mo ; 4: M = W) as the ultimately stable compounds. The structures of 1 an d 2, determined by X-ray crystallography, comprise Cp(CO)(3)M groups a ttached to the Ir(PPh(3))(2) moiety by short metal-metal bonds (Mo-Ir 2.579(1), W-Ir 2.583(1)Angstrom) and two asymmetric CO bridges.