Investigation of structure-property correlation in 2, 2′-dipyridyl diselenide based derivatives

Abstract

Structure-property correlation in 2, 2′-dipyridyl diselenide derivatives has been investigated using four test cases 2, 2′-dipyridyl diselenide (1), 2, 2′-disleno bis(3-pyridinol) (2), 2, 2′-diseleno bis(3-carboxypyridine) (3) and 2, 2′-diselenobis(3-nicotinamide) (4). Nature of substituent at C-3 position of pyridyl ring has been found to be a key factor in controlling the molecular structure, its packing capacity and thermal stability of molecular assembly. Strong electron withdrawing group (viz. -COOH, -CONH₂) reduces the charge on selenium and enforces sp² hybridization induced planar molecular configuration. Bent molecules 1 and 2 favors denser crystallographic packing in comparison to planar molecule 3 and 4. Thermal investigation reveal that temperature range for thermal decomposition to elemental selenium for 4 and 2 is 210-460°C and 150-275°C respectively indicating higher thermal stability of former. The higher thermal stability of 4 has been attributed to secondary intermolecular interactions with the entrapped solvent molecule in the molecular lattice, which is not the case for 2. Thus C-3 position of pyridyl ring of dipyridyl diselenide derivatives can be adopted as one of the focus points for the future drug designing process.