The hydrogenation of ethylene via photoproduced mrdinatively unsaturated iron carbonyls in the gas phase has ken investigated by measuring deuterium distribution in ethanes produced following photolysis of mixtures of Fe (CO) s, C2H4. and hydrogen (D2 or D2/H2) by monochromatic CW-UV light (ca. 250 nm). When mixtures of Fe (CO) s, C2H4, and D2 are photolyzed, only ethane-1, 2-d2 and ethane-1, l-d2 are produced. The ratio of ethane- ...