ETHYLENE HYDROGENATION BY THE HYDRIDE ALKOXIDE SPECIES IR(H)2(OCH2CF3)(PTBU2PH)2 - ETHYLENE-INDUCED REDUCTIVE ELIMINATION OF ALCOHOL FROM IR(III)

Ir(H)2(ORf)P2 (P = PtBu2Ph, R(f) = CH2CF3) reacts with ethylene at 25- degrees-C to give R(f)OH, ethane and Ir(P approximately C)P(C2H4) (2) then Ir(P approximately C)(C2H4)2 (1) and Ir(P approximately C)H(OR(f) )P (3) (p approximately C = eta2-C6H4PtBu2). It is shown that 2 and 1 are in equilibrium by P and C2H4 addition/dissociation. Compound 3 is a product ''late'' in the reaction sequence, and results from H-OR(f) oxidative addition to 2. Since 3 reacts with ethylene to give 2, 2 and 3 are in thermal equilibrium. Compound 3 reacts readily with H-2 to g ive IrH5P2 and R(f)OH. The reason why OR(f) and ethylene ligands seem to be mutually incompatible is discussed.