Synthesis, Properties, and Applications of Aminoquinoline-Derived Schiff Bases and Their Metal Complexes

Aminoquinoline derivatives, renowned for their versatile biological activities, are crucial scaffolds in medicinal and material chemistry. These compounds are integral to developing antimalarial, antibacterial, anticancer, and immunomodulatory agents, with prominent examples including chloroquine, neratinib, and imiquimod. Furthermore, aminoquinoline moieties serve as precursors for Schiff bases and their corresponding metal complexes, which exhibit properties such as selective fluorescence sensing, catalytic activity, and enhanced therapeutic potential. This review covers recent advances in synthesizing aminoquinoline-based Schiff bases and their metal complexes, focusing on their structural diversity, coordination chemistry, and reaction mechanisms. It highlights their significant roles in fluorescence-based detection of metal ions (e.g., Fe3+, Al3+, Hg2+) and their application in anticancer, antimicrobial, and antitubercular therapies. The complexation of Schiff base ligands with metal ions often enhances their pharmacological profiles, leading to superior activity compared to the free ligands. By discussing synthetic methodologies, characterization techniques, and bioactivity evaluations, this review provides a comprehensive overview of the potential of aminoquinoline derivatives in drug development and sensor technology, paving the way for innovative applications in therapeutics and diagnostics.