Investigation of torsional barriers and nonlinear optical (NLO) properties of phenyltriazines

In this study, electronic and nonlinear optical properties of six phenyltriazine isomers were calculated. The calculated properties are electronic energy, HOMO–LUMO energies, static polarizability α, anisotropy of polarizability Δα, and first static hyperpolarizability β at equilibrium geometry and their torsional dependence. The torsional barriers and potential energy curves were calculated at HF/6-31++G(d,p) and B3LYP/6-31++G(d,p) methods. The number of ortho hydrogen atoms mainly determines the torsional barriers of these molecules, while the meta hydrogen atoms have a small influence on the equilibrium torsional angles and barriers. Nonlinear optical properties (NLO)-dihedral angle θ correlations of phenyltriazine isomers were calculated at the B3LYP/6-31++(d,p) level. Polarizabilities of phenyltriazines decrease with shifting the nitrogen atoms to the para position. On the contrary, hyperpolarizabilities of phenyltriazines increase with shifting the nitrogen atoms to the ortho position.