Browsing by Author "Kaya, Serdal"

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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.
Gold-Catalyzed Oxime-Oxime Rearrangement
(Amer Chemical Soc, 2015) Guven, Sinem; Ozer, Merve Sinem; Kaya, Serdal; Menges, Nurettin; Balci, Metin
The gold-catalyzed reaction of pyrrole and indole oximes having a propargyl group attached to the nitrogen atom was studied. The selective 6-endo-dig mode of cyclization was observed for the terminal alkynes giving rise to the formation of pyrazine N-oxides in the presence of a gold catalyst. However, the reaction with substituted alkyne transferred the oxime functionality intramolecularly from one carbon atom to another via the 7-endo-dig cyclization process. This transformation is unprecedented in the literature and is named an oximeoxime rearrangement.
Mechanistic Insights Into the Reaction of N-Propargylated Pyrrole- and Indole-Carbaldehyde With Ammonia, Alkyl Amines, and Branched Amines: a Synthetic and Theoretical Investigation
(Wiley-v C H verlag Gmbh, 2019) Sari, Ozlem; Seybek, Ali Fatih; Kaya, Serdal; Menges, Nurettin; Erdem, Safiye Sag; Balci, Metin
The reaction of pyrrole- and indole-carbaldehydes having a propargyl group attached to the nitrogen atom with various amines was studied. The reaction with ammonia formed pyrrolo[1,2-a]pyrazine and pyrazino[1,2-a]indole while the reaction with alkylamines such as methyl, ethyl, hexyl, and benzylamines formed the corresponding pyrazinone derivatives. Unexpectedly, the reaction with allylamine and propargylamine formed pyrazine derivatives in which the allyl and propargyl groups were removed from the molecule. On the other hand, the reaction of N-propargylated pyrrole-carbaldehyde formed indolizine derivatives upon reaction with sterically bulky adamantyl- and tert-butylamines. To understand the main factors causing these differences in reactivity, the reaction mechanisms were studied by means of computational methods. Our calculations showed that bulky amines tend to attack the central carbon of allene formed by the isomerization of N-propargyl functionality, while the attack on the carbonyl carbon by aliphatic amines is more profound.
Synthesis of Carbazole-Substituted Thiosemicarbazone and Its Cu(Ii) Complex, Dna/Protein Binding, Cytotoxic, Antiproliferative Activities and Molecular Docking Studies
(Elsevier, 2023) Findik, Mukerrem; Kuzu, Burak; Pehlivanoglu, Suray; Kaya, Serdal; Sayin, Ulku; Akgemci, Emine Guler; Saf, Ahmet Ozgur
In this study, 9-ethyl-3-carbazolecarboxaldehyde-4-ethyl-thiosemicarbazone (ECCAET) and its copper(II) com-plex (Cu(ECCAET)2) were firstly synthesized and characterized. DFT and EPR studies confirmed that the complex is mononuclear and has square planar geometry. The interaction of all synthesized compounds with calf thymus DNA (CT-DNA) was examined by absorption and fluorescent spectroscopy. The experimental results showed that Cu(ECCAET)2 interacts with DNA via an intercalative binding mode. The binding interactions of the complex with CT-DNA have been confirmed through viscosity measurements revealing that the complex interacts with DNA via intercalation. Furthermore, the protein binding ability of ECCAET and Cu(ECCAET)2 was investigated using BSA via electronic absorption spectral titration, fluorescence quenching, and synchronous fluorescence spectrum studies, which revealed that the Cu(ECCAET)2 strongly bound to BSA over the ligand. Molecular docking studies were also performed to support the bonding mechanism of ECCAET and Cu(ECCAET)2 with DNA and BSA. The biological activity studies of ECCAET and Cu(ECCAET)2 against cancer cells were also investigated. A panel of cancer cell lines, including A2780 human ovarian adenocarcinoma, MDA-MB-231 human triple-negative breast adenocarcinoma, and as a control non-cancerous L929 fibroblast cell lines were also used to test the compounds' anticancer activities. Cytotoxic and antiproliferative properties of Cu(ECCAET)2 were visibly higher than its ligand (ECCAET) for all tested cell lines. The Cu(ECCAET)2 had a distinctive biological effects on A2780, and MDA-MB-231 cells compared to non-cancerous cells. Within these results, Cu(ECCAET)2 was found a promising drug candidate against gynecologic cancer diseases.