Molecular orbital calculations on [HRu<SUB>3</SUB>(CO)<SUB>9</SUB>(PhNCO)]<SUP>-</SUP> and related clusters

Molecular orbital calculations (EHMO) have been performed on five ruthenium carbonyl clusters considered to be involved in the reductive carbonylation of nitrobenzene. The bonding in the isocyanate cluster, [HRu3(CO)9(HNCO)]-, is shown to arise mainly from the interaction between the LUMO of HNCO and HOMO of the [HRu3(CO)9]- fragment. The relative stabilities of this cluster, two of its isomers and the CO-eliminated cluster [HRu3(CO)9(HN)]-, are also commented upon. The calculated results are in accordance with empirical kinetic data