Green mechanochemistry meets catalysis: molybdenum–hydrazone complexes for mild oxidation reactions

Title : Green mechanochemistry meets catalysis: molybdenum–hydrazone complexes for mild oxidation reactions

Abstract:

Hydrazides, carbohydrazides, and their related analogs are versatile building blocks in heterocyclic and coordination chemistry, with potential applications in catalysis, materials science, and molecular sensing. Among them, 2-thiophenecarboxylic hydrazone ligands remain relatively underexplored, despite evidence that their metal complexes can exhibit catalytic and electronic functionality. Traditional syntheses of such complexes often rely on solvent-intensive methods, which pose environmental and sustainability concerns.

Mechanochemistry provides a green alternative, using mechanical energy to drive reactions under solvent-free or minimal-solvent conditions. Techniques such as neat grinding and liquid-assisted grinding (LAG) enable rapid and efficient preparation of ligands and metal complexes while reducing chemical waste, energy consumption, and environmental impact.

In this work, we report the mechanochemical synthesis of novel molybdenum complexes based on 2-thiophenecarboxylic hydrazone ligands. Their catalytic potential was evaluated in the oxidation of benzyl alcohol, chosen as a benchmark reaction for sustainable oxidation chemistry. Reactions were carried out under mild, environmentally friendly conditions, demonstrating that mechanochemically prepared complexes can enable selective and efficient oxidation using benign oxidants.

In addition to catalysis, the electronic properties of the Mo-hydrazone complexes were investigated, revealing promising semiconducting behavior. The dual focus on catalytic activity and electronic performance underscores the multifunctionality of these materials and illustrates how green synthetic strategies can yield compounds with broad applicability.

Overall, this study highlights how mechanochemical synthesis can integrate green chemistry principles with functional performance, offering a sustainable route to metal-hydrazone complexes for oxidation catalysis and materials applications. These findings pave the way for environmentally responsible design of multifunctional coordination compounds, bridging catalysis and electronic materials in a single, sustainable platform.

Biography:

Dr. Jana Pisk is an Associate Professor of Chemistry at the University of Zagreb, Faculty of Science, where she has been a member of the Department of Chemistry since 2007. She earned her Ph.D. in 2012 and has conducted extended research in catalysis at the Laboratoire de Chimie de Coordination in Toulouse, France. Her scientific work centers on the coordination chemistry of molybdenum and vanadium compounds, with a strong focus on their catalytic applications in oxidation processes. Dr. Pisk has authored more than fifty publications and is actively engaged in advancing sustainable catalytic methodologies and functional inorganic materials.