A topological analysis of the bonding interaction within the tri-nuclear heterometallic cluster [CoMoRu(µ3-S) (CO)8(Cp)COOCH3],(Cp= η5-C5H4)

Abstract

Abstract The tri-nuclear heterometallic tetrahedral cluster [CoMoRu(µ3-S)(CO)8(Cp)COOCH3], (Cp = η5-C5H4) in question was studied using the atoms in molecules quantum theory (QTAIM) to examine bonding interactions such as M-M, M-S, M-CO, and M-Cp. The electron density of bonding interactions within the cluster has its topological properties calculated based on this theory. Interestingly, the local topological parameters calculated for the Mo–Ru bond differ considerably from those of Mo-Co, and Ru-Co interactions, for which bond critical points and bond paths were not observed. Bridging sulfide ligands significantly impacted the electron density distribution of Mo…Co, and Ru…Co interactions more than Mo-Ru bond. The topological properties of the latter bond were characteristic of open-shell metal–metal interactions, with small positive values of ρb and ∇2ρb, and small negative values of Hb close to 0. The core part, [CoMoRu(µ3-S], was found to have a multicenter 4c–6e interaction. In this core, the three M-S bonds between the metal atoms and the sulfide ligand showed similar topological parameters that were typical of open-shell (covalent) interactions. A significant CO to M π-back donation was found by performing the Source Function and δ(M…OCO) delocalization index calculations.