University of KashanIranian Journal of Mathematical Chemistry2228-648913320220901Development of Mathematical Methods of DFT by Using the Physical Chemistry Parameters of Quinolines C26H23ClN4 and C26H23FN422723711287810.22052/ijmc.2022.246403.1627ENRahimEsmkhaniDepartment of Chemistry, Khoy Branch, Islamic Azad University, Khoy, Iran0000-0002-3672-089XMounesHanaforoushDepartment of Chemistry, Khoy Branch, Islamic Azad University, Khoy, IranJournal Article20220522Quinolones are synthetic compounds which are part of the antibiotics family. Quinolines were first obtained in 1834 and isoquinolines were obtained from coal tar in 1885. In this paper, exchange and correlation energies of C<sub>26</sub>H<sub>23</sub>ClN<sub>4</sub> and C<sub>26</sub>H<sub>23</sub>FN<sub>4</sub> are calculated by using the DFT methods with STO-3G, 3-21G, 6-31G, 6-311G and 6-21G basis sets. The optimized structure and electronic properties calculations for the studied molecule have been performed by using Gaussian 09 program. A mathematical equation of second grade was exploited for the correlation and exchange energy with the number of primitives. The chemical reactivity of the C<sub>26</sub>H<sub>23</sub>ClN<sub>4</sub> and C<sub>26</sub>H<sub>23</sub>FN<sub>4</sub> have been investigated at B3LYP/6-31G (d) level of theory. The band gap energy, total energy (E), chemical hardness (η), electronic chemical potential (μ), and global electrophilicity index (ω), ionization potential (IP) and electron affinity (EA) for the C<sub>26</sub>H<sub>23</sub>ClN<sub>4</sub> and C<sub>26</sub>H<sub>23</sub>FN<sub>4</sub> have been calculated for the chemical activity of the above molecules. According to the results, the C<sub>26</sub>H<sub>23</sub>ClN<sub>4</sub> molecule is more stable and the chemical activity of C<sub>26</sub>H<sub>23</sub>FN<sub>4</sub> is greater.https://ijmc.kashanu.ac.ir/article_112878_8841916c38d2a12f309effc44088cda4.pdf