DFT/TD-DFT ANALYSIS OF 2-CHLORO-7-METHYLQUINOLINE-3-CARBALDEHYDE USING COMPUTER COMPUTING METHOD

Abstract

Quinolines are the essence of many natural products, drugs and were found in synthetic compounds. Quinoline derivatives containing a quinoline ring are used in a variety of biological and pharmaceutical activities, e.g. anticancer, antibacterial, antifungal, antiplasmodial, antihistamine, antimalarial and antituberculosis. In this study, 2-Chloro-7-Methylquinoline-3-Carbaldehyde (ClMQC) molecule, which is a quinoline derivative, was selected and analyzed. The stable structures of ClMQC molecule with minimum energy were investigated by density functional theory (DFT) together with B3LYP/6-311++G(d,p) method. It was seen that there are two different conformers (trans and cis) with minimum energy in the scanning made depending on the C─C─C=O dihedral angle. As a result of the calculation with the B3LYP/6-311++G(d,p) level, the energy difference (E+ZPV) between the two conformers was calculated as 14.60 kJ mol-1. Oscillator strength and excitation energies were analyzed by calculating the time-dependent DFT (TD-DFT). The energy differences between the excited energy levels are given in the graph. This was done by adding the ground state energies of both conformers. The energy corresponding to HOMO-LUMO was calculated to correspond to the S0→S2 transition for both conformers. The excitation energy values were calculated as 3.75 and 3.84 eV for trans and cis, respectively.