Molecular structure, quantum chemical and spectroscopic properties of 2,6–dibromonaphthalene by density functional theory calculations

Abstract

In this work, the quantum chemical calculations were performed by means of the Gaussian09 packet program, using DFT in gas phase at the B3LYP level, with cc-pVDZ, cc-pVTZ, 6-31G(d,p) and 6-311G(d,p) basis sets. The most stable conformation of the 2,6–dibromonaphthalene (2,6–DBrN) molecule in free state was determined by the Spartan'14 program. The vibrational frequencies have been calculated at the same level of theory. These frequencies were calculated and scaled, and then values have been compared with the experimental Infrared and Raman spectra. The vibrational modes were determined based on TED analysis on the basis of 6-311G(d,p) using the SQM program. Theoretical 13C–NMR and 1H–NMR chemical shifts of the 2,6–DBrN molecule were calculated in DMSO and were compared the experimental values. NBO analysis study of 2,6–DBrN was performed to investigate charge transfer as well as to analyzed intra- and interactions. The HOMO and LUMO energy levels of the 2,6–DBrN molecule were determined. Besides, molecular electrostatic potential (MEP) maps of the studied molecule were made using the DFT method. Since the apparent absorption maxima of the molecules correspond to the electron transitions between the boundary orbitals corresponding to the HOMO–LUMO energies, these transitions were analyzed by UV/Visible spectroscopy.