Alkylindium(I) vs carbon monoxide bridges in binuclear iron carbonyl complexes: A theoretical study

Polynuclear iron carbonyl complexes have been prepared only recently, in, w hich bridging carbonyl ligands were replaced by isolobal monoalkylindium gr oups. A theoretical analysis of the compounds (CO)(3)Fe-(mu -CO)(3-x)(mu -I nCH3)(x)Fe(CO)(3) (x = 0, 1, 2, 3) shows the specific influence of a stepwi se substitution of CO by Rln-(I) fragments on their electronic, structural, and bonding properties. This influence is determined by the order of the a donor [Rln(I) much greater than CO(bridge)] and pi acceptor [RIn-(I) < CO( bridge) <much less than> CO(terminal)] capabilities of these ligands.