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Article Citation - WoS: 5Citation - Scopus: 7Design of Novel Tellurium and Selenium Containing Semiconducting Polymers Using Quantum Mechanical Tools(Elsevier, 2017) Kaya, Birnur; Kayi, HakanStructural, optical and electronic properties of the two novel donor-acceptor-donor type conjugated polymers based on 4,7-di(selenophen-2-yl)benzo[c][1,2,5]selenadiazole (SeSeSe) and 4,7-di(tellurophen-2-yl)benzo[c][1,2,5]telluradiazole (TeTeTe) are investigated by means of quantum chemical calculations utilizing conventional and long-range corrected hybrid functionals. The lowest energy structures of the SeSeSe and TeTeTe monomers and oligomers are revealed through conformational analysis, while their electronic properties are obtained from density functional theory (DFT) molecular orbital calculations and optical properties are obtained from the time dependent DFT (TD-DFT) calculations for UV-vis absorption spectra. Electronic band gaps that directly affect the semiconducting properties of these novel polymers are calculated by using linear regression analysis of DFT data, and also periodic boundary conditions calculations (PBC-DFT). Our results indicate that SeSeSe and TeTeTe polymers have considerably lower band gap values than that of their furan-, thiophene-, benzooxadiazole- and benzothiadiazole-based analogs. The novel SeSeSe and TeTeTe polymers with improved optical and electronic properties may have an important role in the near future, especially for the optoelectronic and photovoltaic applications. (C) 2016 Elsevier B.V. All rights reserved.Article Citation - WoS: 9Citation - Scopus: 10A Theoretical Investigation of 4,7-Di(furan Donor-Acceptor Type Conjugated Polymer(Elsevier, 2015) Kayi, Hakan; Elkamel, AliQuantum chemical calculations are performed using density functional theory (DFT) to investigate the HOMO-LUMO energy gap of the 4,7-di(furan-2-yl)benzo[c][1,2,5]selenadiazole-based (FSeF) donor-acceptor type conjugated polymer which ascertains the optoelectronic properties and plays a crucial role, especially in polymeric solar cell applications. In this paper, the most stable conformers of the FSeF monomer and its corresponding oligomers are investigated at the B3LYP/Def2TZV and B3LYP/LANL2DZ levels of theory, and their molecular structures are revealed. The band gap of the polymer is determined by linear-fitting and extrapolation of the DFT data. This gap is found to be 1.44 eV and 1.45 eV by the B3LYP/Def2TZV, and B3LYP/LANL2DZ with PCM calculations, respectively. Our theoretical findings related to the band gap of the FSeF polymer (PFSeF) are in good agreement with other experimental studies in the literature and, hence, the theoretical methods used in this study are promising for the design of similar donor-acceptor type novel conjugated polymers. (C) 2014 Elsevier B.V. All rights reserved.Article Citation - WoS: 4Citation - Scopus: 4Anticancer Investigation of Platinum and Copper-Based Complexes Containing Quinoxaline Ligands(Elsevier, 2022) El-Beshti, Hager Sadek; Yildizhan, Yasemin; Kayi, Hakan; Cetin, Yuksel; Adiguzel, Zelal; Gungor-Topcu, Gamze; Ozalp-Yaman, SenizThis research focuses on synthesis and anticancer activity of trans-[(dichloro)bisdipyridlquinoxalino] and [(dichloro)bisdithienylquinoxalino]copper(II)/platinum(II) compounds as prodrug candidates. The binding interaction of these compounds with calf thymus DNA (CT-DNA) and human serum albumin (HSA) of the complexes were assessed with UV titration, thermal decomposition, viscometric, and fluorometric measurements. The nature of the binding of the complexes on DNA were revealed as electrostatic interaction between the cationic metal complexes ion and the negative phosphate groups of CT-DNA upon removal of the counter ion, chloride. In addition, our complexes induced a surface contact through the hydrophobic region of protein. Antitumor activity of the complexes against human glioblastoma A172, LN229, and U87 cell lines and human lung A549, human breast MDA-231, human cervix HeLa, and human prostate PC-3 cell lines were investigated by examining cell viability, oxidative stress, apoptosis, and migration/invasion. Cytotoxicity of the complexes was evaluated by MTT test. The U87 and HeLa cells were investigated as the cancer cells most sensitive to our complexes. The exerted cytotoxic effect of dipyridlquinoxalino and dithienylquinoxalino copper(II)/platinum(II) complexes was attributed to the formation of the reactive oxygen species in vitro. It is clearly demonstrated that trans-[(dichloro)bisdithenylquinoxalino]copper (II) (Cu(dtq)) has the highest DNA degradation potential and anticancer effect among the tested complexes by leading apoptosis. Wound healing and invasion analysis results also supported the anticancer activity of Cu(dtq). (C) 2021 Elsevier B.V. All rights reserved.
