Theoretical, spectroscopic and biological studies of some thiazepine derivatives / Salwa Abdelfattah Elramly ; Supervised Hussein Mohamed Ahmed Moustafa , Mohamed Elshakr , Huwaida Hassanin

Thesis (Ph.D.) - Cairo University - Faculty of Science - Department of Physical Chemistry

The electronic structure and NLO of 2, 4-di-aryl-1,5-benzothiazepine and some of its derivatives are investigated theoretically at the B3LYP/6- 311G**level of theory. The extent of delocalization and intramolecular charge transfer are estimated and discussed in terms of natural bond orbital analysis (NBO) and second order perturbation interactions between donor and acceptor MOs The calculated EHOMO and ELUMO energies of the studied compounds can be used to calculate the global properties; chemical hardness ({u019E}), softness (S) and electronegativity ({). The equilibrium geometries of the studied compounds are determined, and it was found that these geometries are non planar. The calculated nonlinear optical parameters (NLO); polarizability (Ü), anisotropy of the polarizibility (<Ü>) and first order hyperpolarizibility (Ý) of the studied compounds show promising optical properties. 3D-plots of the molecular electrostatic potential (MEP) for some selected molecules are investigated and analyzed showing the distribution of the electronic density. Electronic spectra of the studied compounds in 1, 2 dichloroethane as non-polar and Ethanol as polar solvents are investigated experimentally and theoretically using TD-DFT method at the B3LYP/6- 311G** level of the theory. The origin of the spectrum of the parent compound is found to be an additive one

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