Structure-Optical, Linear and Nonlinear optical properties relationship in thiazolidine-amides

Five thiazolidine amides, including several substituents, were studied for their possible activity on nonlinear optical applications using quantum chemical calculations at multiple levels. Several properties including linear and nonlinear optical properties, HOMO and LUMO enrgies, energy gap, and reactivity parameters, have been calculated and analysed. High first hyperpolarizability βtot up to 1217.15 and 1546.58 a.u. were obtained for the thiazolidines with chlorine THA@Cl and two fluorines THA@FF , respectively, suggest strong nonlinearity. A direct correlation was achieved between the βtot and the energy gap Eg and between the βHRS and β//. The study shows that the frontier molecular surfaces play important role in the high qualitative interpretation of the chemical reactivity of these thiazolidines. Frontier molecular orbitals show that the HOMO density located over thiazolidine and phenyl rings, the LUMO isodensity is shifted towards the phenyl attached with electron acceptor groups. THA@Cl and THA@FF could be suggested as potential high-performance optoelectronic materials.