Recent Advances in Physicochemical Properties and Applications of Schiff Bases and Heterocyclic Drug Systems

Abstract

Schiff bases and heterocyclic drug systems are becoming increasingly important in medicinal and materials chemistry because of their remarkable physicochemical and biological properties. Schiff bases containing azomethine (>C=N–) functionality possess excellent chelating ability, structural flexibility, electronic tunability, and broad-spectrum biological activity. Similarly, heterocyclic drug systems containing nitrogen, oxygen, or sulfur heteroatoms are of substantial pharmaceutical importance because of their therapeutic efficacy and molecular interaction behaviour. Recent years have seen increasing research interest in understanding the physicochemical behaviour of Schiff bases and heterocyclic drug molecules in different solvent systems using acoustical, refractometric, spectroscopic, and fluorescence techniques. Physicochemical investigations involving ultrasonic velocity, density, viscosity, refractive index, adiabatic compressibility, molar refraction, and polarizability provide valuable insights into intermolecular interactions, solvation effects, molecular aggregation, and structural organisation in solution systems. Such investigations are highly relevant to pharmaceutical formulation, molecular recognition, and sensor development. In addition to physicochemical characterisation, Schiff bases and their metal complexes exhibit diverse antimicrobial, antioxidant, anticancer, catalytic, and fluorescence-sensing applications. This review provides a concise overview of the physicochemical characteristics and diverse applications of Schiff bases and heterocyclic drug systems, thereby offering valuable insights for medicinal chemists, synthetic researchers, and pharmaceutical scientists involved in the development of advanced therapeutic and functional materials. In particular, the review summarises recent advances in the physicochemical properties and applications of Schiff bases and heterocyclic drug systems, with emphasis on acoustical studies, solvent effects, refractometric analysis, molecular interactions, biological applications, coordination chemistry, and fluorescence-sensing behaviour. Special attention has been devoted to recent developments in Schiff base-derived fluorescent chemosensors and physicochemical investigations of heterocyclic drugs in various solvent systems. Furthermore, the article highlights the importance of integrating physicochemical characterisation with biological and analytical applications for the development of advanced functional materials and pharmaceutical systems.