Bifunctional molybdenum and vanadium materials: semiconductor properties for advanced electronics and catalytic efficiency in linalool oxidation†

Polynuclear and mononuclear molybdenum(VI) complexes, coordinated with water or methanol, were synthesized using acyl-hydrazone ligands, derived from the reactions of 2-hydroxy-3-methoxybenzaldehyde with formic – (H₂L¹) or acetic acid hydrazide (H₂L²). Characterization of the complexes was conducted utilizing advanced spectroscopic techniques and elemental analysis. Crystal and molecular structures of ligand H₂L², and complexes [MoO₂(L¹)(H₂O)], [MoO₂(L²)(MeOH)], together with (Hpy)₂Mo₈O₂₆ were determined by single crystal X-ray diffraction. The thermogravimetry provided insights into the thermal stability and decomposition patterns of the complexes. In situ solid-state impedance spectroscopy was employed, revealing correlations between the electrical properties and the thermal and structural transformations of Mo complexes. This multifaceted approach enabled a profound understanding of the interplay between structure, thermal behaviour, and electrical characteristics. The polynuclear complex [MoO₂(L¹)]_n exhibited remarkable conductivity, achieving values up to 10⁻⁸ (Ω cm)⁻¹ at room temperature. This performance, compared to previously reported vanadium-based analogues, highlights its considerable potential for integration into electronic device manufacturing. Additionally, the catalytic efficiency of these newly synthesized molybdenum complexes was evaluated in linalool oxidation, alongside previously reported vanadium compounds, further demonstrating their promising applications in catalysis.