Yazar "Serin, Sumeyya" seçeneğine göre listele

Listeleniyor 1 - 2 / 2
  • Küçük Resim Yok
    Öğe
    Computational insights into E/Z isomerism of fluoxastrobin, an antifungal agent: A DFT/TD-DFT study
    (Elsevier, 2023) Serin, Sumeyya
    Herein, inspired by the success of strobilurins in fungicidal activity bioassays, DFT (Density Functional Theory) -based quantum chemical computations were performed on fluoxastrobin, a fluorinated strobilurin fungicide. Its formulation has E/Z isomerism around the C=N bond. It is highly advantageous to utilize quantum chemical methods to acquire more insights into E/Z isomerism and to gain supplemental confirmations in terms of experimental results. In this respect, the geometries of the E and Z isomers of fluoxastrobin were optimized both in the vacuum and in 1-octanol, acetonitrile, DMSO, and water phases using the DFT/B3LYP/6-311++G (d, p) methodology. Both experimental and theoretical FTIR and UV-vis evaluations were performed for the isomers. TD-DFT/B3LYP/6-311++G (d, p) theory level computations were determined that the observed peaks were mostly caused from the pi ->pi* and n ->pi* transitions. Also, quantum chemical reactivity descriptors and physi-cochemical parameters were calculated for both vacuum and solvent phases. Accordingly, computations in all studied phases estimate the E isomer to be preferred with energy values in the range of 2.51-3.77 kcal/mol. Natural bond orbital (NBO) analysis was also carried out to determine the intermolecular interactions and their corresponding stabilization energies. Last, with the help of Gibbs solvation free energy values, 1-octanol/water partition coefficients were calculated and lipophilicity evaluations of both isomers were performed.
  • Küçük Resim Yok
    Öğe
    DFT-based computations on some structurally related N-substituted piperazines
    (Elsevier, 2022) Serin, Sumeyya
    In order to focus on more promising drug candidates by reducing the failures that occur in the time-consuming and expensive discovery process of new drugs, it is highly efficient to predict the bioactivity and metabolism behaviors of drug candidates using computational chemistry methods. In this context, this study presents a comparative quantum chemical analysis of the buspirone, used in the treatment of anxiety, and its three structurally related derivatives, kaspar, mesmar, and gepirone, based on Density Functional Theory (DFT) cal-culations. Geometry optimization and frequency calculations of each molecule were implemented at B3LYP/ 6-31G (d, p) and B3LYP/6-311++G (d, p) levels of theory. Linear correlation coefficients (R2) were calculated for each piperazine derivative to detect the power of the relationship between theoretical and experimental structural parameters. Subsequently, frontier molecular orbital (FMO) analysis, quantum chemical reactivity descriptors, electrostatic surface properties (ESP), and natural bond orbital (NBO) analysis were examined in detail. The lipophilicity evaluations of mentioned piperazine derivatives were interpreted not only according to the data obtained from the DFT calculations, but also according to the results obtained from the Molinspiration software. As a result of both methods, the order of lipophilicity emerged as kaspar > mesmar > buspirone > gepirone. It is revealed that on account of the substitution of the pyrimidine ring in buspirone and gepirone with the quinoline ring, both lipophilicity increased and the direction of the lipophilic interaction predominantly changed. Based on all the obtained results, it is concluded that although the studied molecules are structurally very similar, they support different lipophilic interactions. Therefore, their pharmacological activities differ.