Molecular properties and electronic structure of phenazine ligand in binuclear molybdenum and manganese metal complexes: A density functional theory study

DFT calculations with full geometry optimization have been performed on the series of hypothetical and characterized binuclear compounds of general formula (L3M)2(C12N2H8) (M = Mo and Mn, L3 = (CO)3, (PH3)3 and Cp− and C12N2H8 = phenazine ligand). The various structures with syn and anti configurations have been investigated. The phenazine ligand can bind to the metals involving its C6 and C4N2 rings through η6–η4 and η6–η6 coordination modes giving rise to syn and anti structures, respectively, in agreement with the favored 34 electron count with closed-shell and open-shell configurations. This study has shown that the electronic communication between the metal centers depends on their oxidation state and the attached ligands. A more crowded attached ligand imposes an anti configuration despite its electron deficiency.

The coordination mode and the electronic communication between the metal centers of the studied binuclear complexes depend on the attached ligands. The C–C and C–N bond distances in the coordinated ring are elongated, indicative of π-back donation from the metal fragments to the phenazine π∗-MOs, inducing a loss of its aromaticity.Figure optionsDownload as PowerPoint slide