Yazar "Sevimli, Esra" seçeneğine göre listele
Listeleniyor 1 - 6 / 6
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe Benzotiyazol içeren Schiff bazı türevlerinin sentezi, karakterizasyonu, antioksidan ve enzim aktivitelerinin incelenmesi(Bursa Teknik Üniversitesi, 2023) Sevimli, Esra; Köksoy, BaybarsBenzotiyazol, yapısında azot ve kükürt atomu bulunduran heterosiklik bir bileşiktir. Yapısında azot, kükürt, oksijen gibi heteroatom içeren yapıların farmakolojik aktivite gösterdiği bilinmektedir. Benzotiyazol bileşiğinin 2-konumundan türevlendirilmeleri ile biyolojik aktivitenin önemli ölçüde değiştiği yapılan yapı-aktivite çalışmaları sonucu ortaya konulmuştur. Bu sebeple benzotiyazol bileşiklerinin 2-konumundan türevlendirilmeleri ve biyolojik aktivitelerinin incelenmesi literatürde önemli bir yere sahiptir. Benzotiyazollerin 2-konumundan türevlendirilmelerinde amin türevi benzotiyazol bileşikleri kullanılarak, farklı aldehit ve ketonlarla reaksiyonları sonucunda Schiff bazı bileşikleri elde edilebilmektedir. Schiff bazları azometin fonksiyonel grubunu (-C=N) içerirler ve literatürde biyolojik aktiviteleri çokça çalışılan bileşikler arasında yer almaktadırlar. Azometin grubunun azot atomu üzerindeki ortaklanmamış elektronların, hücre bileşenlerinin aktif merkezleri arasında hidrojen bağı oluşturarak hücre süreçlerini etkilediği bilinmektedir. Bu sebeple benzotiyazol iskeleti içeren Schiff bazlarının biyolojik olarak etkin olacağı görülmektedir. Literatürde biyolojik olarak etkin olan bu iki birimin birleştirilmesiyle sentezlenen türevlerin antikanser, antimikrobiyal, antimalarial ve fungisidal gibi çok çeşitli biyolojik aktiviteler sergilediği bildirilmiştir. Bu tez çalışması kapsamında, 7 tanesi orijinal olan 12 hedef benzotiyazol-azometin bileşiği (3a-3l) sentezlenmiştir. Sentezlenen tüm yapıların spektroskopik karakterizasyonları FT-IR, UV-gör, 1H NMR ve 13C NMR spektroskopik yöntemleri ile yapılmıştır. Sentezlenen türevlerde enol-imin ve keto-amin tautomer dengesi gözlenmiş ve DMF organik çözücüsü içinde asidik ve bazik ortamlarda UV-gör spektroskopik yöntemi ile ölçümü yapılarak bu tautomer dengesi incelenmiştir. Bileşiklerin bazik ortamda keto-amin formunu , asidik ortamda ise enol-imin formunu tercih ettikleri belirlenmiştir. Sentezlenen tüm türevlerin antioksidan ve enzim aktiviteleri incelenmiştir. Antioksidan aktivite ölçümleri 2,2-difenil-1-pikrilhidrazil radikal süpürücü kapasite (DPPH) yöntemi ve demir(III) iyonu indirgeyici antioksidan gücü (FRAP) yöntemi olmak üzere iki farklı yöntem kullanılarak yapılmıştır. Her iki yöntemin de antioksidan aktivite sonuçları incelendiğinde en yüksek aktiviteyi (3j-3l) bileşiklerinin gösterdiği belirlenmiştir. Bileşiklerin enzim aktiviteleri de 4 farklı enzim türüne karşı çalışılmıştır. Bu enzimler ?-glukozidaz, tirosinaz, asetilkolinesteraz ve bütirilkolinesteraz enzimleridir. Sentezlenen benzotiyazol-azometin türevlerinden sadece (3g-3ı) türevlerinin ?-glukozidaz enzimine karşı iyi enzim inhibisyon aktivitesi gösterdiği belirlenmiştir. Diğer enzim türlerine aktivite göstermemesi, (3g-3ı) türevlerinin belli bir enzime karşı seçici olduğunu göstermektedir.Öğe Effective ?-glycosidase inhibitors based on polyphenolic benzothiazole heterocycles(Academic Press Inc Elsevier Science, 2024) Sevimli, Esra; Seyhan, Gokce; Akkaya, Didem; Sari, Suat; Barut, Burak; Koksoy, Baybarsalpha-Glycosidase inhibition is one of the main approaches to treat Diabetes mellitus. Polyphenolic moieties are known to be responsible for yielding exhibit potent alpha-glycosidase inhibitory effects. In addition, compounds containing benzothiazole and Schiff base functionalities were previously reported to show alpha-glycosidase inhibition. In this paper, the synthesis of seven new phloroglucinol-containing benzothiazole Schiff base derivatives through the reaction of 6-substituted-2-aminobenzothiazole compounds with 2,4,6-trihydroxybenzaldehyde using acetic acid as a catalyst was reported. The synthesized compounds were characterized using spectroscopic methods such as FT-IR, 1 H NMR, 13 C NMR, and elemental analysis. The synthesized compounds were evaluated for their inhibitory effects on alpha-glycosidase, compounds 3f and 3g were found to show significant inhibitory properties when compared to the positive control. The IC 50 values of 3f and 3g were calculated as 24.05 +/- 2.28 and 18.51 +/- 1.19 mu M, respectively. Kinetic studies revealed that compounds 3f and 3g exhibited uncompetitive mode of inhibition against alpha-glycosidase. Molecular modeling predicted druglikeness for the title compounds and underpinned the importance of phloroglucinol hydroxyls for interacting with the key residues of alpha-glycosidase.Öğe ?-Glycosidase activity of novel coumarin-triazole-coumarin dyads(Tubitak Scientific & Technological Research Council Turkey, 2025) Sirin, Ersin; Sevimli, Esra; Seyhan, Gokce; Barut, Burak; Kaya, Yunus; Koksoy, BaybarsNovel coumarin-triazole-coumarin dyads were synthesized and characterized, and their alpha-glycosidase inhibitory activities were evaluated spectrophotometrically. Compound 4e exhibited the most pronounced inhibitory effect, with an IC50value of 38.98 +/- 0.77 mu M. The IC50 values for 4d and 4a were 93.55 +/- 1.70 mu M and 95.04 +/- 3.55 mu M, respectively. The Lineweaver-Burk plot showed that 4e inhibited alpha-glycosidase in a mixed type. In addition, the Ki value obtained from the Dixon plot was 19.95 +/- 0.15 mu M for alpha-glycosidase.Öğe Heavy Atom-Enhanced Photooxidation Performance of Carbazole-Substituted BODIPY Dyes(Wiley-V C H Verlag Gmbh, 2025) Ozdemir, Mucahit; Sevimli, Esra; Ozan, Gulsema; Salan, Umit; Yalcin, Bahattin; Koksoy, BaybarsIn this study, halogenated BODIPYs (C-Br-2-BDPY and C-I-2-BDPY) bearing a carbazole group at the meso position are synthesized and characterized using various spectroscopic techniques. Single-crystal X-ray diffraction analysis of the C-I-2-BDPY revealed that it crystallizes in a triclinic crystal system with a P-1 space group. The optical properties, singlet oxygen generation capacities, and photocatalytic activities of the BODIPY derivatives are evaluated with respect to juglone synthesis. While the nonhalogenated BODIPY (C-BDPY) exhibit negligible singlet oxygen generation (Phi(Delta) < 0.05), the iodinated (C-I-2-BDPY) and brominated (C-Br-2-BDPY) derivatives demonstrate considerably higher singlet oxygen quantum yields of 0.82 and 0.73, respectively. In the photooxidation reaction of 1,5-dihydroxynaphthalene (DHN) to juglone, these halogenated BODIPY compounds achieve conversion yields of 62.6% for C-Br-2-BDPY and 87.8% for C-I-2-BDPY within one hour. The turnover number values of the BODIPY photosensitizers show a continuous increase over time, indicating sustained product formation, whereas the turnover frequency values gradually decline, reflecting the decrease in reaction rate as the process progress. Density functional theory calculations support the experimental results by demonstrating that the presence of heavy atoms facilitates intersystem crossing and enhances the thermodynamic feasibility of the photooxidation reactions.Öğe Investigating the Photochemical Properties of a Clickable Silicon (IV) Phthalocyanine Core(Wiley-V C H Verlag Gmbh, 2025) Ozdemir, Mucahit; Sevimli, Esra; Ozturkkan, Fureya Elif; Durmus, Mahmut; Yalcin, Bahattin; Koksoy, BaybarsIn this study, a new azido-functionalized silicon(IV) phthalocyanine (SiPcN3) was synthesized and comprehensively characterized, revealing its promising photochemical characteristics. Despite the common challenges associated with crystallizing phthalocyanine-based compounds, SiPcN3 was successfully obtained as single crystals in the monoclinic P21/c space group. The incorporation of -N3 groups not only enhanced the compound's solubility and thermal stability but also introduced a reactive site suitable for future functionalization via copper-catalyzed azide-alkyne click chemistry. The molecular design enables straightforward integration into extended macromolecular systems, such as covalent organic frameworks (COFs) or cross-linked polymers. UV-Vis and photoluminescence analyses demonstrated intense Q-band absorption in the red region and tunable emission characteristics. The measured singlet oxygen quantum yield (Phi Delta = 0.14) indicates moderate photosensitizing activity, but this performance can potentially be enhanced through appropriate derivatization, improving its applicability in photodynamic therapy (PDT). Overall, these findings position SiPcN3 as a structurally versatile and functionally adaptable molecular platform, with promising potential for future development of PDT agents, photocatalytic/photooxidative materials, and optoelectronic devices, especially when embedded into porous or cross-linked polymeric networks.Öğe Light-Induced Performance Enhancement of Supercapacitors through Thiol-Ene Click Surface Functionalization of Thienothiophene-BODIPY Porous Polymers(Amer Chemical Soc, 2025) Ozdemir, Mucahit; Ulucay, Sude; Sevimli, Esra; Altinisik, Sinem; Koksoy, Baybars; Yalcin, Bahattin; Koyuncu, SermetPhotoassisted supercapacitors are emerging as next-generation energy storage devices that synergistically combine light harvesting and electrochemical energy storage. BODIPY-based semiconductors, known for their strong light absorption, tunable electronic properties, and photostability, have recently attracted attention as efficient photoactive components in such systems. This study investigates the potential use of cross-linked thieno[3,2-b]thiophene-BODIPY polymer as an electrode material for photoassisted supercapacitors, prepared through a surface functionalization approach using thiol-ene click chemistry. The polymer exhibited broad-band absorption and a low band gap due to extended conjugation, as confirmed by UV-vis and fluorescence spectroscopy, along with comprehensive optical, electrochemical, and morphological characterization. DFT calculations showed that the HOMO-LUMO energy gap narrows under illumination, indicating improved charge transport. Cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS) measurements confirmed that the cross-linked polymer offers high capacitance, low internal resistance, and long cycle stability. In terms of supercapacitor performance, a photoinduced enhancement of up to 50% in specific capacitance was observed under light. At a current density of 1.0 A/g, the specific capacitance increased from 240 F/g in the dark to 362 F/g under illumination. Stability tests conducted over 2000 cycles demonstrated that the supercapacitor retained 90% of its initial capacitance.
