LAUSR

Abstract In this study, three Schiff base derivatives of 1,3-bis[(E)-(4-dimethylaminobenzylidene)amino] propan-2-ol (BDP), 1,3-bis[(E)-(4-methoxybenzylidene)amino] propan-2-ol (BMP) and 1,3-Bis[(E)-(4-chlorobenzylidene)amino] propan-2-ol (BCP) were synthesized and resolved into their single crystal structures. Interestingly, the crystal structures of compound BDP and BMP preserved the asymmetric unit whereas compound BCP showed two symmetry independent units. Moreover, three derivatives retained the polymeric framework through hydrogen bonds(O H⋯N) between adjacent molecules in the solid state. Equilibrium structure and electronic properties including natural bond orbital (NBO), frontier molecular orbitals (FMO) and molecular electrostatic potential (MEP) were calculated using M06-2X/6-31G (d,p) level of theory. A good agreement was observed between density functional theory (DFT) optimized geometry and experimental SC-XRD structure.NBO calculation indicated that hyper conjugative interaction promotes the hydrogen bonds in all derivatives. The FT-IR, FT-Raman and UV-VIS spectroscopic analysis were carried out at B3LYP/6-31G (d,p) level of theory. The FT-IR, MPA and MEP also affirmed hydrogen bonds in the dimers, which supports the SC-XRD results. The stabilization energy for hydrogen bonds and delocalization of lone pair electron from N, O and Cl to π * orbital of benzene ring was enhanced in the following order BDP