Recent Advancements in the Synthesis and Biological Applications of Naphthaldehyde Derived Schiff base Ligands and Transition Metal Complexes

Naphthaldehyde derived Schiff base ligands have emerged as versatile platforms in coordination chemistry due to their extended π-conjugation, structural rigidity, and adaptable N O donor environments. In recent years, substantial growth has been achieved in the development of efficient and sustainable synthetic strategies. The recent advances have enabled rapid access to structurally diverse naphthaldehyde derived ligands and their transition metal complexes. This review summarizes post-2020 developments in the synthesis, coordination behavior, and characterization of naphthaldehyde-based Schiff bases and their transition metal complexes. These complexes generally adopt regular as well as distorted square planar, tetrahedral, and octahedral geometries. We put emphasis on modern spectroscopic, structural, thermal, and electrochemical techniques used to elucidate structure-property relationships. The applications of these complexes in biological activity are critically discussed.