Search for heterobimetallic dihydrides from the reaction of H 2 with metal—metal bonds

Abstract

The arsenic-bridged bimetallic compounds (CO) 4 FeAs(CH 3) 2M (M = Mn(CO) 4, 1 ; M = Co(CO) 3, 2 ; M = Mo(C 5H 5)(CO) 2, 3) were investigated as possible CO and alkene hydrogenation catalysts. Heating these compounds under H 2 did not lead to any observable metal dihydride species but gave thermal decomposition. Thermal stabilities were found to be in the order 3 > 1 > 2. 1 and 3 reacted with CO at 45 °C and 110 °C, respectively, to give compounds 5 and 6 in which the metal/3-metal bond has been cleaved and CO added. Heating 1, 2, or 3 under CO and H 2 gave no observable CH 3OH or CH 4. Evidence that metal hydride species might be in equilibrium with 1, 2, or 3 was obtained from the observation that solutions of 1, 2, or 3 which are heated under H 2 catalyze the hydrogenation of 1-octene to n-octane and the isomerization of 1-octene to cis- and trans-2-octene.