Aroylhydrazone-based transition metal complexes: Structural features, coordination diversity and catalytic applications

Aroylhydrazones are compounds characterized by a double bond between carbon and nitrogen atoms. They are notable in coordination chemistry for their versatile coordination modes and a wide range of applications. These compounds are synthesized by condensing hydrazides with aromatic aldehydes or ketones, forming stable imine linkages. Their coordination diversity comes from their ability to act as multidentate ligands, coordinating through nitrogen, oxygen, and sometimes sulfur atoms, resulting in various metal complexes with different geometries and properties. Factors like pH, solvent, and the nature of the metal ions influence this diversity. Aroylhydrazones are crucial in medicinal chemistry, material science, and catalysis, serving as antimicrobial agents, anti-inflammatory drugs, and sensors, and in developing organic-inorganic hybrid materials. In catalysis, they stabilize transition states and facilitate organic transformations, proving valuable in both industrial and synthetic organic chemistry. Aroylhydrazone-based complexes have shown efficiency in reactions such as oxidation, epoxidation, alkylation, and nitro-aldol condensation. Their structural versatility and catalytic efficiency make them valuable for developing new catalytic systems and materials. This review article provides an overview of the coordination diversity and significant catalytic applications of metal complexes derived from aroylhydrazone compounds.

Graphical abstract

Aroylhydrazones exhibit significant importance due to their versatile coordination diversity, enabling the formation of various metal complexes. These complexes demonstrate notable catalytic applications in organic transformations, highlighting their potential in industrial and pharmaceutical process. The multifaceted nature of aroylhydrazones underscores their value in advancing catalysis and coordination chemistry.