FA20-R06-001Aqsa NisarDr. Mazhar Amjad GilaniLHR TP 78762026-02-262022-02-26https://repository.cuilahore.edu.pk/handle/123456789/2310Density functional theory (DFT) calculations have been performed for a series of supramolecular assemblies containing azobenzene (Azo-X where X=I, Br and H) and alkoxystilbazole subunits to evaluate their electronic, linear and nonlinear optical properties. These assemblies are derivatives of azobenzene, obtained by the substitution of electron-withdrawing and electron-donating groups onto the molecular skeleton. The interaction energies (Eint) of all the designed supramolecular complexes (IA-IF, IIA-IIF and IIIA-IIIF) range from -1.02 kcal/mol to -7.70 kcal/mol. Electronic properties of these hydrogen/halogen bond driven supramolecular assemblies such as, vertical ionization energies (VIE), HOMO-LUMO energy gap (GH-L), excitation energies, density of states (DOS) and natural bond orbital (NBO) analyses were also computed. The non-covalent interaction index (NCI) and quantum theory of atoms in molecules (QTAIM) analyses have also been performed to validate the nature of inter- and intra-molecular interactions in these complexes. A substantial enhancement in the first hyperpolarizability (βₒ) values of the designed supramolecular complexes has been observed driven by the charge transfer from the pyridyl moiety of alkoxystilbazole to Azo-X. The highest first hyperpolarizability (βₒ) value of 1.3×104 au is observed for supramolecular complex of p-nitro substituted azobenzene with alkoxystilbazole (ID complex). It was confirmed on a purely theoretical basis that both the type of noncovalent interactions present and the substituent group incorporated influence the nonlinear optical response (NLO) of the systems.enDepartment of ChemistryChemistryFA20Dr. Mazhar Amjad GilaniTheoretical ExplorationSupramolecular ArchitecturesNonlinear Optical (NLO) MaterialsThesis