The ruthenium-ruthenium bonding in bridged ligand system: QTAIM study of [Ru3(μ3-κ2-MeimCh) (μ-CO) (CO)9] complex

Abstract

The nature of the Ru-Ru, Ru-C and Ru-CO interactions in the di-bridged triruthenium carbonyl cluster [Ru3(μ3-κ2-MeImCH)(μ-CO)(CO)9] have been explored theoretically the topological analysis of the electron density using Quantum Theory of Atoms-in-Molecules (QTAIM) approach. The topological properties of the electron density involved in the metal-metal and metal-ligand bonds as well as the bond delocalization indices δ(A, B), have been computed, are highly agree with the previous results for organometallic systems studies. The analyses of the core of bridged triruthenium cluster, Ru3C2 part, reveal the existence of an Ru(1)-Ru(3) and Ru(2)-Ru(3) bond critical points associated with a bond paths running between those atoms. However, neither Ru(1)-Ru(2) critical point nor bond path are observed. The delocalization indices calculated for Ru-Ru indicate the significant indirect Ru(1)…Ru(2) interaction mediated through presence of the carbonyl and alkylidyne bridging ligands. An interaction of 5c-8e type is proposed to exist over their fifth-membered, Ru3C2 core part. The electron density ρ(r) and Laplacian ∇2ρ(r) parameters computed for the Ru-C(NHC) were indicative of significant pure σ bond character for this interaction. In addition, the analysis of the data of the topological properties involved in the N-heterocyclic carbines ligand bonds reveals the existence hindered π-electron delocalization over the ring with appearance some feature of double bond for the bonds that linked the carbine C atom and the two neighboring N atoms.