A Review of Spectrophotometric Techniques for Evaluating Stability Constants of Metal–Ligand Complexes
Keywords:
Spectrophotometry, Stability constants, Metal–ligand complexes, UV–Visible spectroscopy, Coordination chemistry.Abstract
The determination of stability constants of metal–ligand complexes plays a fundamental role in coordination chemistry, environmental chemistry, pharmaceutical sciences, and analytical chemistry. Stability constants provide essential information about the strength of interaction between metal ions and ligands in solution, influencing reactivity, biological activity, and environmental behavior of metal species. Among various analytical methods available for studying metal–ligand interactions, spectrophotometric techniques have emerged as one of the most reliable, sensitive, and widely used approaches for evaluating stability constants. Spectrophotometry offers advantages such as simplicity, rapid analysis, cost-effectiveness, and the ability to monitor complex formation in solution under controlled experimental conditions. This review provides a comprehensive overview of spectrophotometric methods used for the determination of stability constants of metal–ligand complexes. The discussion includes the theoretical background of complex formation, the principles of UV–Visible spectrophotometry, experimental approaches, data analysis methods, and recent advancements in the field. Various spectrophotometric techniques such as continuous variation (Job’s method), molar ratio method, slope ratio method, and multiwavelength spectrophotometric analysis are examined in detail. The review also highlights applications of these methods in the study of transition metal complexes, Schiff base ligands, mixed ligand systems, and biological metal complexes. Additionally, the role of computational tools and modern software in interpreting spectrophotometric data is discussed. The advantages and limitations of spectrophotometric methods are critically evaluated with reference to recent research studies.
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