FORMATION OF CARBON HYDROGEN AND OXYGEN HYDROGEN-BONDS AT IRIDIUM CENTERS - ADDITION OF H-2 AND HCL TO TRANS-RIR(CO)L2 (R = ME, OME, L = PPH3, P(PARA-TOLYL)3)

Reaction of trans-RIr(CO)L2 with HX (R = Me, L = P(p-tolyl)3, X = H, Cl; R = OMe, L = PPh3, X = H; R = OMe, L = P(p-tolyl)3, X = Cl results in RH and HIr(X)2(CO)L2. Low-temperature NMR spectra (1H and31P) show that these reactions occur through oxidative-addition, reductive-elimination sequences. A normal deuterium isotope effect is observed (KH/KD = 1.4). Formation of the carbon (sp3)–hydrogen bond occurs more readily than formation of the carbon (sp2)–hydrogen bond or the oxygen–hydrogen bond. The nature of the hydrogen source (HX; X = H, Cl) does not significantly affect CH4 formation but is significant for CH3OH formation. Considering the geometric and product differences, however, the three types of bonds are formed with remarkably similar barriers. © 1990, American Chemical Society. All rights reserved.