Binuclear dioxomolybdenum(VI) complexes of some tridentate ONS donor ligand containing [MoO2]2+ as the acceptor center: Synthesis, crystal structure, supramolecular architectures via hydrogen bonds, π-π stacking and DFT calculations

A series of linear diimine and diamine-bridged binuclear dioxomolybdenum(VI) complexes having general formula [(MoO2L)2(B-B)] [where, B-B is a bridging linear N,N′-bidentate spacer 4,4′ bipyridine, 1,2 bis (4-pyridyl) ethene and 1,2 bis (4-pyridyl) ethane] with the tridentate binegative Schiff base ligands obtained by the condensation of salicylaldehyde/2-hydroxyacetophenone with S-benzyl/S-methyl dithiocarbazate have been synthesized. Elemental analysis, various spectroscopic (IR, UV–Vis, 1H NMR) measurements and electrochemical studies have been used for characterization of these complexes. The complexes 2, 2a, 9 and 10 were structurally characterized by single crystal X-ray crystallography which reveal that in these complexes the overall coordination geometry around the Mo(VI) center can be described as distorted octahedral. Complexes 2, 2a, 9 and 10 give rise to interesting supramolecular architectures via hydrogen bonding and π-π stacking interactions. In addition, extensive hydrogen bonding interactions in complex 10 lead to the formation of cavities. DFT calculations on the ligand and complexes 2, 2a, 9 and 10 were also carried out.