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    Exploring of indole derivatives for ESIPT emission: A new ESIPT-based fluorescence skeleton and TD-DFT calculations
    (Elsevier Science Sa, 2021) Kaya, Serdal; Aydin, Hatice Gulten; Keskin, Selbi; Ekmekci, Zeynep; Menges, Nurettin
    ABS T R A C T Appropriate synthesis methods gave six different indole derivatives substituted at the C-2 or C-3 position. ESIPT emission capacities of these derivatives were investigated. It was concluded that the indole derivative containing the 1,2-dicarbonyl group at the C-2 position has ESIPT emission. Although adding water to the DMSO solution of the ESIPT-based molecule (9:1) resulted in ESIPT quenching, steady-state measurements in MeOH did not occur ESIPT quenching. TD-DFT calculation for uncovering the ESIPT mechanism emerged that the ESIPT mechanism occurred as a barrierless process. The X-ray analysis and DFT conformational analysis revealed that NH and CO groups involving proton transfer mechanisms are in the cis position. A mono-exponential decay was observed in DMSO and MeOH solutions, in which lifetimes were measured as 6.1 and 5.5 ns, respectively. pH studies revealed that acidic and basic solutions of molecule 7 did not influence ESIPT emission.
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    Magnetically separable nickel ferrite supported palladium nanoparticles: Highly reusable catalyst in Sonogashira cross-coupling reaction
    (Academic Press Inc Elsevier Science, 2022) Keskin, Selbi; Citlakoglu, Meryem; Akbayrak, Serdar; Kaya, Serdal
    There is an increasing attention in developing highly efficient and reusable palladium-based catalysts used for the coupling reactions due to the high cost of palladium metal salts. Magnetically separable palladium nanoparticles have a high potential to be used as catalysts in numerous organic reactions due to their facile separation from the reaction medium by an external magnet. Herein, NiFe2O4 supported palladium nanoparticles (Pd/NiFe2O4) were successfully prepared by impregnation and reduction method in water and used as catalysts for Sonogashira cross-coupling reactions. Magnetically separable Pd/NiFe2O4 catalysts were found to be highly active and reusable in this reaction. Pd/NiFe2O4 provided an outstanding turnover frequency value (106.4 h(-1)) in the reaction between phenylacetylene and iodobenzene in ethanol at 70 degrees C and it was also found to be highly active in the water. Magnetically separable Pd/ NiFe2O4 exhibited high catalytic performance even after the tenth use in this reaction. (C) 2022 Elsevier Inc. All rights reserved.
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    Semicarbazides Carrying Indole Core: Synthesis, Cytotoxicity Evaluation against Human Breast Cancer Cell Lines, and Molecular Modeling Studies
    (Wiley-V C H Verlag Gmbh, 2023) Celik, Beyza; Ugur, Suemeyye Buran; Baran, Muenevver; Gunduz, Miyase Gozde; Keskin, Selbi; Onder, Gozde Ozge; Bitgen, Nazmiye
    In this article, we report the synthesis and cytotoxicity evaluation of novel indole-carrying semicarbazide derivatives (IS1-IS15). The target molecules were obtained by the reaction of aryl/alkyl isocyanates with 1H-indole-2-carbohydrazide that was in-house synthesized from 1H-indole-2-carboxylic acid. Following structural characterization by H-1-NMR, C-13-NMR, and HR-MS, IS1-IS15 were investigated for their cytotoxic activity against human breast cancer cell lines, MCF-7 and MDA-MB-231. According to the data obtained from the MTT assay, phenyl ring with a lipophilic group at its para-position and alkyl moiety were preferential substituents on the indole-semicarbazide scaffold for antiproliferative activity. The effect of IS12 (N-(4-chloro-3-(trifluoromethyl)phenyl)-2-(1H-indole-2-carbonyl)hydrazine-1-carboxamide), the compound that demonstrated remarkable antiproliferative activity on both cell lines, was also evaluated on the apoptotic pathway. Moreover, the calculation of critical descriptors constituting drug-likeness confirmed the position of the selected compounds in the anticancer drug development process. Finally, molecular docking studies suggested the inhibition of tubulin polymerization as the potential activity mechanism of this class of molecules.