Nature of Intramolecular Metal–Metal Interactions in Supported Group 4–Group 9 and Group 6–Group 9 Heterobimetallic Complexes: A Combined Density Functional Theory and Topological Study

Abstract

Quantum chemical calculations have been carried out on a series of supported group 4–group 9 and group 6–group 9 heterobimetallic complexes designated by the general formulas [Cp₂M­(μ-E)₂M′(H)­(CO)­L] and [(CO)₄M­(μ-E)₂M′(H)­(CO)­L] where E = SH, SeH or PH₂ and L = PH₃, CO, NHC, or <i>a</i>NHC. An analysis of the optimized geometries of these molecules indicates the presence of an M···M′ interaction. The nature of this interaction is investigated by using Bader’s quantum theory of atoms in molecules (QTAIM), electron localization function (ELF), and source function (SF). The results of QTAIM analysis suggest a polar covalent interaction between the two disparate metal centers in these heterobimetallic complexes. ELF analysis identifies a bonding basin between the two metal centers, while SF analysis reveals that the metal–metal bonding is moderately delocalized. The strength of the M···M′ interaction is found to be stronger in group 4–group 9 heterobimetallic complexes compared to group 6–group 9 ones