Advances in mixed ligand transition metal complexes: Chromone derivatives and N, O donor ligands – a comprehensive review

Mixed-ligand transition metal complexes have emerged as a significant area of research due to their tunable structural, electronic, and biological properties. This comprehensive review provides a detailed analysis of recent advances in the synthesis, characterization, and diverse applications of complexes formed by combining 3-formylchromone derivatives with auxiliary N, O-donor ligand 8-hydroxyquinoline. We systematically explore the coordination chemistry of chromone, a versatile pharmacophore, highlighting its role as a primary ligand. A critical examination of their biological properties, including antimicrobial, anticancer, and antioxidant activities, is presented. Furthermore, the review elucidates the key structure-activity relationships (SARs) that govern their efficacy. By compiling the current state of knowledge, this work aims to identify existing research gaps and propose future directions for the rational design of next-generation mixed-ligand complexes with tailored properties for advanced applications in medicine.