Stacking of dicarbonylacetylacetonatorhodium(I) molecules

Abstract

Density functional theory calculations was used to understand the stabilisation of intermolecular rhodium-rhodium interactions as observed in [Rh(acac)(CO)2] crystals. Quantum theory of atoms in molecules calculations confirm that bonding paths, consistent with weak bonds stronger than hydrogen bonds, between the rhodium centres in different [Rh(acac)(CO)2] molecules, exist. The linear array of [Rh(acac)(CO)2] molecules were further stabilised by intermolecular hydrogen bonds. The weak interaction between the rhodium centres were further confirmed by natural bond orbital (NBO) calculations that showed donor-acceptor interaction between the a filled and an empty NBO on the rhodium atoms in adjacent [Rh(acac)(CO)2] molecules. A visualisation of the molecular orbitals of linear units of [Rh(acac)(CO)2] molecules showed σ bonding and anti-bonding interactions between the dz2, as well as between the pz orbitals, on rhodium of different [Rh(acac)(CO)2] molecules.