Comparative study of DFT/B3LYP, B3PW91, and HSEH1PBE methods applied to molecular structures and spectroscopic and electronic properties of flufenpyr and amipizone

The optimized molecular structures, conformational analyses, vibrational (IR) frequencies and their assignments, maximum electronic absorption wavelengths (gas phase and in ethanol solvent), H-1 and C-13 NMR chemical shift values (gas phase and in CDCl3 solvent), HOMO-LUMO analysis, molecular electrostatic potential surfaces, and nonlinear optical properties of flufenpyr (C14H9ClF4N2O4) and amipizone (C14H16ClN3O) compounds that have many biological activities have been calculated using the DFT/B3LYP, B3PW91, and HSEH1PBE methods with the 6-311G(d, p) basis set in the ground state. A comparison among the results calculated at the mentioned levels indicates that the HSEH1PBE calculations give usually greater values compared with the others in terms of vibrational frequencies, the maximum electronic absorption wavelengths, and HOMO-LUMO energy gaps of the title compounds.