Exploring the Coordination Chemistry and Biological Applications of Compartmental Complexes of Thiosemicarbazones: Synthesis, Characterization, and Functional Insights

Abstract: Compartmental complexes of thiosemicarbazones, a class of versatile ligands derived from thiosemicarbazide and aldehydes or ketones, have garnered significant attention in coordination chemistry due to their ability to form stable chelates with a wide range of metal ions, and their structural flexibility, arising from the presence of both sulfur and nitrogen donor atoms, enables them to adopt diverse coordination modes that facilitate the formation of mono-, bi-, and polynuclear complexes with well-defined geometries, which are not only of theoretical interest but also hold substantial potential in biological and pharmaceutical applications, as these complexes exhibit promising antimicrobial, antitumor, and antioxidant properties attributed to their ability to interact with biomolecules and induce oxidative stress in cells, while their electronic and steric properties, influenced by the nature of the substituents on the thiosemicarbazone backbone and the coordination environment of the central metal ion, can be fine-tuned to optimize their reactivity and selectivity, thereby broadening their applicability in catalysis, material science, and therapeutic design, and recent advancements in analytical techniques, such as single-crystal X-ray diffraction, UV-Vis spectroscopy, cyclic voltammetry, and electron paramagnetic resonance, have provided deeper insights into the structural, electronic, and redox properties of these complexes, allowing for a better understanding of their coordination behavior and mechanistic pathways in biological systems, while the exploration of compartmental ligands designed with pre-organized donor sets further enhances the specificity and efficiency of metal binding, offering new opportunities to design multifunctional complexes with targeted activity, yet challenges remain in elucidating the exact mechanisms of action, particularly in biological environments where factors like solubility, stability, and interaction with cellular components play critical roles, highlighting the need for comprehensive studies that integrate experimental and computational approaches to unravel the full potential of thiosemicarbazone-based compartmental complexes, which hold promise not only as bioactive agents but also as templates for developing next-generation materials and catalysts with enhanced performance and sustainability.