Structure, Frontier Molecular Orbitals, MEP, Charge Analysis, and NLO Study of 2,4-, 2,5-, and 2,6-Dimethylanilines Using DFT

This study includes the evaluation of most stable structure, frontier molecular orbitals, molecular electrostatic potential (MEP), and nonlinear optical (NLO) parameters of 2,4-dimethylaniline (2,4DMA), 2,5-dimethylaniline (2,5DMA), and 2,6-dimethylaniline (2,6DMA) using density functional theory (DFT) employing B3LYP functional with 6-311++G(d,p) basis set. HOMO-LUMO energies, band gap energies, and global reactivity descriptors were obtained from the optimized structures. The band gap energy was determined as 3.7865, 3.9348, and 3.9443 eV for 2,4DMA, 25DMA, and 2,6DMA, respectively. The reactive sites of the molecules were obtained from the molecular electrostatic potential energy. The NLO parameters such as dipole moment, polarizability, and hyperpolarizability have been investigated for the title molecules. The investigated dipole moment and first-order hyperpolarizability values are higher than the prototypical value of urea and show good NLO behavior. The NMR chemical shifts, electronic absorption spectra, and charge distribution of atoms were calculated theoretically. Furthermore, thermodynamic and rotational constants were also calculated.