Investigation of geometric, spectroscopic and optical properties of 4-acetylpyridine:4-aminobenzoic acid compound by using the density functional theory

In this study, theoretical calculations were performed on 4-acetylpyridine:4-aminobenzoic acid (APAB) compound using B3LYP/6-311++G(d,p) and HSEH1PBE/6-311++G(d,p) methods. Gaussian 09W and Gauss View 5 package programs were used for these theoretical calculations. Firstly, the ground state geometric structure, infrared vibration spectrum, ultraviolet-visible absorption spectrum, 1H and 13C-NMR chemical shift values of the APAB compound were calculated and compared with the results of experimental study. When the theoretical results were compared with the experimental ones. It was seen that there is a good agreement between them. In addition, HOMO and LUMO energies, electronegativity, ionization energy, chemical hardness and softness parameters were obtained. The dipole moment, the average polarizability, anisotropy of polarizability and the first order static hyperpolarizability values, reflecting the nonlinear optical (NLO) properties were calculated. The obtained theoretical results also demonstrated that APAB compound is a good NLO material. Finally, both experimental and theoretical band gap (Eg), refractive index, extinction coefficient and dielectric properties of the compound in the UV-Visible region were investigated. Keywords: 4-acetylpyridine:4-aminobenzoic acid, DFT, HSEH1PBE, B3LYP, 1H and 13C-NMR, IR, UV-Vis analysis.