TY  - JOUR
TI  - CONFORMATIONAL ANALYSIS OF THIAZOLE-5-CARBOXYLIC ACID USING DFT/TD-DFT METHODS
AB  - In this work, structures of the conformers of the thiazole-5-carboxylic acid (T5CA) were studied using density functional theory(DFT) with B3LYP/6-311++G(d,p) level of approximation. From calculations of the potential energy distribution dependingon the orientation of the carboxylic group (C-C-OH and O=C-OH) attached to the five-membered heterocyclic ring, fourconformers were found at minimum energy. Considering that the relative energy in the most stable structure is zero. The relativeenergies of the other conformations were found to be about 0.14, 27.11, 29.84 kJ mol-1, respectively. It was found that thecarboxylic acid group of the T5CA_3 and 4 were not planar, while T5CA_1 and T5CA_2 were planar. Stabilization and donoracceptor orbital interaction energies were calculated for all conformations and orbitals were plotted using natural bond orbitalanalysis (NBO) method. The excited state energies were calculated and graphed using Time-Dependent Density FunctionalTheory (TD-DFT) calculations. The singlet state energies were tabulated for all conformations and it was seen that the moststable form with the highest oscillator strength was at the second singlet state (S2). In addition, HOMO-LUMO energy gapswere calculated and electrostatic potential surface maps were drawn for all conformations.
AU  - Kus, Nihal
DO  - 10.18038/estubtda.820152
PY  - 2020
JO  - Eskişehir Technical University Journal of Science and and Technology A- Applied Sciences and Engineering
VL  - 21
IS  - -
SN  - 2667-4211
SP  - 63
EP  - 73
DB  - TRDizin
UR  - http://search/yayin/detay/434260
ER  -