Tetranuclear dioxomolybdenum (VI) cluster anion, hydrogen bond interaction with 1,2-di(4-pyridyl)ethylene

Abstract

Tetranuclear dioxomolybdenum cluster complex (TMC) [C12H11N2+]2[Mo4O10(OCH3)62−]·CH3OH has been synthesized by the reaction of MoO2(acac)2 with 1,2-di(4-pyridyl)ethylene. The cluster core is composed of four molybdenum atoms arranged in the rhombus shape bridged by two oxo ligands, one bridging O, and three methanol molecules. The TMC [C12H11N2+]2[Mo4O10(OCH3)62−]·CH3OH is comprised of two moieties of pyridyl cation [C12H11N2+]2 (1,2-di(4-pyridyl)ethylene) and cluster anion [Mo4O10(OCH3)62−]. The cluster is stabilized by two intermolecular interactions (hydrogen bond and π–π stacking interactions). The 1D chain is formed as a result of the hydrogen interaction between (1, 2-di(4-pyridyl)ethylene) and [Mo4O10(OCH3)62−]. Thermogravimetric analysis clearly indicated the thermal stability of the cluster. Electrochemical measurement showed two irreversible reduction processes at scan rates (−1 to −2 V) and an irreversible one-electron oxidation at +0.79 V. Optical absorption measurement shows that the fundamental absorption edge obeys Tauc’s relation for the allowed non-direct transition. Optical band gap (Eg) values equal 2.4 eV.