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

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 ). N ature 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, -CONH 2 ) reduces the charge on selenium and enforces sp 2 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.