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Article Citation - WoS: 16Citation - Scopus: 20Concise Synthesis, Electrochemistry and Spectroelectrochemistry of Phthalocyanines Having Triazole Functionality(Pergamon-elsevier Science Ltd, 2014) Karaca, Huseyin; Sezer, Serdar; Ozalp-Yaman, Seniz; Tanyeli, CihangirThe synthesis of novel metallophthalocyanines (M = Zn, Ni) bearing substituted benzyl protected 1,2,3-triazole moieties at peripheral positions is described for the first time via direct cyclotetramerization. These complexes have been characterized by a combination of FT-IR, H-1 NMR, HRMS and UVVis spectroscopy techniques and all the new compounds are highly soluble in most common organic solvents. In addition, the electrochemical and electrochromic behaviors of the complexes are investigated. Cyclic voltammetry and differential pulse voltammetry measurements demonstrate ligand base oxidations and reductions for both the Zn(II) and Ni(II) phthalocyanines by the transfer of one electron in each electrochemical step. The redox couples are identified in situ by monitoring the electronic absorption spectral changes during the electrolysis.Article Citation - WoS: 12Citation - Scopus: 13Novel Pt(ii) Complexes Containing Pyrrole Oxime, Synthesis, Characterization and Dna Binding Studies(Elsevier, 2014) Erdogan, Deniz Altunoz; Ozalp-Yaman, SenizSince the discovery of anticancer activity and subsequent clinical success of cisplatin (cis-[PtCl2(NH3)(2)]), platinum-based compounds have since been widely synthesized and studied as potential chemotherapeutic agents. In this sense, three novel nuclease active Pt(II) complexes with general formula; [Pt(NH3)CI(L)] (1), [Pt(L)(2)] (2), and K[PtCl2(L)] (3) in which L is 1-H-pyrrole-2-carbaldehyde oxime were synthesized. Characterization of complexes was performed by elemental analysis, FT-IR, H-1 NMR and mass spectroscopy measurements. Interaction of complexes (1-3) with calf thymus deoxyribonucleic acid (ct-DNA) was investigated by using electrochemical, spectroelectrochemical methods and cleavage studies. The hyperchromic change in the electronic absorption spectrum of the Pt(II) complexes indicates an electrostatic interaction between the complexes and ct-DNA. Binding constant values between 4.42 x 10(3) and 5.09 x 10(3) M-1 and binding side size values between 2 and 3 base pairs were determined from cyclic voltammetry (CV) and differential pulse voltammetry (DPV) studies. (C) 2014 Elsevier B.V. All rights reserved.Article Citation - WoS: 41Citation - Scopus: 48Platinated Copper(3-Clip Complexes as Effective Dna-Cleaving and Cytotoxic Agents(Wiley-v C H verlag Gmbh, 2008) Ozalp-Yaman, Seniz; de Hoog, Paul; Amadei, Giulio; Pitie, Marguerite; Gamez, Patrick; Dewelle, Janique; Reedijk, JanThe synthesis and biological activity of three heteronuclear platinum-copper complexes based on 3-Clip-Phen are reported. These rigid complexes have been designed to alter the intrinsic mechanism of action of both the platinum moiety and the Cu(3-Clip-Phen) unit. The platinum centers of two of these complexes are coordinated to a 3-Clip-Phen moiety, an ammine ligand and two chlorides, which are either cis or trans to each other. The third complex comprises two 3-Clip-Phen units and two chloride ligands bound in a trans fashion to the platinum ion. DNA-cleavage experiments show that the complexes are highly efficient nuclease agents. In addition, a markedly difference in their aptitude to perform direct double-strand cleavage is observed, which appears to be strongly related to the ability of the platinum unit to coordinate to DNA. Indeed, complex 6 is unable to coordinate to DNA, which is reflected by its incapability to carry out double-strand breaks. Nonetheless, this complex exhibits efficient DNA-cleavage activity, and its cytotoxicity is high for several cell lines. Complex 6 shows better antiproliferate activity than both cisplatin and Cu(3-Clip-Phen) toward most cancer cell lines. Furthermore, the cytotoxicity observed for 1 is for most cell lines close to that of cisplatin, or even better. Cu(3-Clip-Phen) induces very low cytotoxic effects, but a marked migratory activity. Complex 6 presents DNA-cleavage properties comparable to the one of Cu(3-Clip-Phen), but it does not show any migratory activity. Interestingly, both Cu(3-Clip-Phen) and 6 induces vacuolisation processes in the cell in contrast to complex 1 and cisplatin. Thus, the four complexes cisplatin tested, Cu(3-Clip-Phen), I and 6 stimulate different cellular responses.Article Citation - WoS: 14Citation - Scopus: 14How Can We Get Benefits of Computer-Based Testing in Engineering Education?(Wiley, 2013) Cagiltay, Nergiz; Yaman, Seniz-Ozalp; Ozalp-Yaman, SenizUsing computers for assessment can provide several benefits for educators and test-takers. However, in the literature, there is no consensus on the equivalence of paper-and-pencil (P&P) and computer-based test (CBT) environments. Additionally, these studies fail to address the engineering domain. Our main assumption is that, if we could define the confounding factors to satisfy that these two versions of the tests provide equivalent results, then especially in the first year courses of the engineering education programs, we could get several benefits of the CBT environments. Accordingly, in this study, students' performance on different test modes was evaluated on 209 first year engineering students of a chemistry course. The results of this study showed that there is no significant performance difference between P&P and CBT. By comparing results with the previous studies, this study concludes that personal characteristics of test takers, the features of CBT systems, and the test content are all possible confounding factors when comparing test modes and need to be considered by the implementers. The results of this study show that once these factors are controlled, students' performance on CBTs and P&P tests in chemistry courses will not vary. This finding is encouraging the educators to get benefits of CBTs without any affect on students' performance. (c) 2010 Wiley Periodicals, Inc. Comput Appl Eng Educ 21: 287293, 2013; View this article online at wileyonlinelibrary.com/journal/cae; DOI 10.1002/cae.20470Article Citation - WoS: 8Citation - Scopus: 6A platinum blue complex exerts its cytotoxic activity via DNA damage and induces apoptosis in cancer cells(Wiley, 2017) Adiguzel, Zelal; Ozalp-Yaman, Seniz; Celik, Gokalp; Salem, Safia; Bagci-Onder, Tugba; Senbabaoglu, Filiz; Acilan, CeydaHere, we describe the characteristics of a Pt-blue complex [Pt-4(2-atp)(8)(H2O)(OH)] (2-atp: 2-aminothiophenol) as a prodrug for its DNA-binding properties and its use in cancer therapy. The nature of the interaction between the Pt-blue complex and DNA was evaluated based on spectroscopic measurements, the electronic absorption spectra, thermal behavior, viscosity, fluorometric titration, and agarose gel electrophoresis. Our results suggested that the compound was able to partially intercalate DNA and appeared to induce both single- and double-stranded breaks (DBS) on DNA in vitro, but no DSBs in cells. The ability of the compound to induce DNA damage was dependent on reactive oxygen species (ROS) in vitro. There was also elevated formation of ROS and SOD expression in response to drug treatment in cell culture. The complex was found to be more cytotoxic to cancer cells in comparison with noncancer controls using WST-1 assay. The mean of cell death was determined to be apoptosis as assessed via biochemical, morphological, and molecular observations, including DNA condensation/fragmentation analysis, live cell imaging microscopy, TUNEL analyses, and increase in the levels of pro-apoptotic genes such as Bag3, Bak, Bik, Bmf, and Hrk. Hence, the Pt-blue complex under study grants premise for further studies.Article Citation - WoS: 3Citation - Scopus: 3Spectroelectrochemical Investigation of Nuclease Active Pt(II) Complexes Containing Pyrrole Oxime(Pergamon-elsevier Science Ltd, 2015) Erdogan, Deniz Altunoz; Kayi, Hakan; Ozalp-Yaman, SenizIn this paper, the electrochemical oxidation of three Pt(II) complexes containing pyrrole oxime (HL) having a general formula of [Pt(NH3)Cl(L)] (1), [Pt(L)(2)] (2), and K[PtCl2(L)] (3) has been investigated by in-situ spectroelectrochemistry in dimethylformamide (DMF). An irreversible metal-based oxidation process occurs during the anodic scan for each of the three complexes. The electronic absorption spectral changes indicate that all the three complexes generate similar Pt(IV) compounds and free ligand. Our experimental data is supported by quantum chemistry calculations utilizing density functional theory. In addition, the frontier orbital energy distributions indicate that electron densities are localized on mainly platinum atom. (C) 2015 Elsevier Ltd. All rights reserved.Article Citation - WoS: 3Citation - Scopus: 5Spectroelectrochemical Studies of Nuclease-Active Zinc(ii) Coordination Compounds From the Ligands Hpyramol and Hpyrimol(Pergamon-elsevier Science Ltd, 2010) Ozalp-Yaman, Seniz; de Hoog, Paul; Maheswari, Palanisamy Uma; Casellas, Helene; Golobic, Amalija; Kozlevcar, Bojan; Reedijk, Jan; Özalp-Yaman, EnizThe electrochemical oxidation of four zinc(II) coordination compounds from the ligands 4-methyl-2-(2-pyridylmethyl)aminophenol (Hpyramol()) and 4-methyl-2-(2-pyridylmethylene)aminophenol (Hpyrimol) with chloride or acetate as counter-ions has been studied by in situ spectroelectrochemistry in dimethylformamide (DMF) Low-temperature EPR studies of electrolyte solutions of all zinc compounds indicate the presence of a phenoxyl radical with a g-value in the range 2 070-2 099 which is illustrative for an electron delocalization over the metal centre The final product of this oxidative process is shown to be a benzoquinone methide derivative (C) 2010 Elsevier Ltd All rights reservedArticle Citation - WoS: 2Citation - Scopus: 3Spectroelectrochemical Investigations of Pyrimidine-2 Binuclear Platinum(iii) Complexes(Pergamon-elsevier Science Ltd, 2014) Ozbek, Ozge; Özalp Yaman, Şeniz; Ozalp-Yaman, Seniz; Ozkan, Ilker; Onal, Ahmet M.; Isci, Huseyin; Özalp Yaman, Şeniz; Chemical Engineering; Chemical EngineeringThe electrochemical behavior of the binuclear platinum(III-III) complexes [Pt-2(C4H3N2S)(4)X-2] (C4H3N2S- = pyrimidine-2-thionate; X- = Cl--,Cl- Br--,Br- I-) have been studied by cyclic voltammetry and insitu spectroelectrochemistry in an acetonitrile-tetrabutylammonium tetrafluoroborate solventelectrolyte couple. An irreversible metal based reduction appears during the cathodic scan for each of the three complexes. The changes in UV-Vis spectra observed in-situ during the reductive electrolysis indicate that all three complexes give the same product, [Pt-2(C4H3N2S)(4)], with a Pt(II)-Pt(II) system. The changes in the reduction potentials of the complexes on changing the axial ligands are interpreted by the changes in the energy of the LUMO level, which is determined by the degree of sigma- and it-interactions of the axial halide ligands with the metal atoms. DFT (B3LYP/LanL2DZ) calculations support our experimental data. (c) 2014 Elsevier Ltd. 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, Seniz; El–Beshti, Hager SadekThis 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.Article Citation - WoS: 5Citation - Scopus: 5Radicalic Cleavage Pathway and Dna Docking Studies of Novel Chemotherapic Platinum Agent of 5,6-Di(Pergamon-elsevier Science Ltd, 2019) El Hag, Rabia; Abdusalam, Mohamed Musbah; Acilan, Ceyda; Kayi, Hakan; Ozalp-Yaman, SenizA new Pt(II) complex of the general formula ([PtCl2(L)]center dot H2O), where L is 5,6-di-2-thienyl-2,3-dihydropyrazine is synthesized as a potential antitumor agent and its structure is elucidated using a variety of physical and chemical procedures. DNA attaching ability of the complex is studied spectroscopically. UV and fluorometric titration, viscometric measurements and thermal decomposition studies agreed that two binding mode of actions, covalent and non-covalent bindings, are possible simultaneously. DNA helix cleavage studies clearly indicated OH center dot radical pathway in the presence of the reducing agent. Quantum mechanical calculations are carried out to call the minimum energy structures of the ligand and the complex, and to determine the FTIR, H-1 NMR and UV-Vis spectra using the density functional theory (DFT) at the B3LYP/LANL2DZ level of theory. Calculated geometrical parameters for the complex indicated a square-planar structure around the metallic center through the dithiopyridyl ring and two chlorine atoms. The minimum energy structure of the complex obtained from DFT conformational analysis is used in docking studies to investigate complex-DNA binding mechanisms. The complex interacts with DNA through three different mechanisms, namely, intercalation, covalent and electrostatic interaction. The most stable mode of interaction with lowest binding energy (-333.6 kcal/mol) was intercalation mode. Comparisons between theoretical and experimental findings are performed and a good agreement is obtained. (C) 2019 Elsevier Ltd. All rights reserved.
