Comparative Experimental and DFT Studies of Selenium and Tellurium Derivatives of N,N,N’,N’‐Tetraisopropyl Pyridine‐2,6‐dicarboxamide and Their Antioxidant Properties

In this research, we introduce the synthesis, evaluation of antioxidant properties, and comparative molecular analysis of two organochalcogen compounds: N,N,N’,N’‐Tetraisopropyl‐3‐(methylselenyl)pyridine‐2,6‐dicarboxamide and N,N,N’,N’‐Tetraisopropyl‐3‐(methyltelluryl)pyridine‐2,6‐dicarboxamide. The antioxidant capabilities of both derivatives were evaluated through standard in vitro assay, DPPH radical scavenging technique. The compound containing tellurium exhibited superior antioxidant performance in comparison to its selenium counterpart, which can be attributed to variations in chalcogenide electronegativity and bonding properties. In order to gain a deeper understanding of their electronic structures and reactivity, density functional theory (DFT) studies have been reported in order to investigate the structural changes, electronic structure study, thermodynamic, and vibrational properties of the compounds. Formation energies have been calculated for both compounds to investigate about their stability. Frontier molecular orbital (FMO) analysis reveals the changes in electronic structure as both compounds have different HOMO‐LUMO gaps. Analysis of FMOs indicated that the tellurium compound has a smaller HOMO‐LUMO energy gap, which supports its enhanced antioxidant effectiveness. These results not only underscore the subtle yet significant influence of chalcogen substitution on biological activity and molecular stability but also lay a theoretical groundwork for the development of more potent antioxidant agents based on pyridine‐dicarboxamide frameworks.