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Amperometric Glucose Biosensor Based on Glucose Oxidase, 1,10-Phenanthroline-5,6-dione and Carbon Nanotubes
(ELECTROCHEMICAL SOC INC, 2014) Zor, Erhan; Öztekin, Yasemin; Ramanaviciene, Almira; Anusevicius, Zilvinas; Bingöl, Haluk; Barkauskas, Jurgis; Ersöz, Mustafa
A biosensor for glucose determination was fabricated by the immobilization of glucose oxidase (GOx) on carbon nanotubes (CNTs) and/or 1,10-phenanthroline-5,6-dione (PD) modified graphite rod electrodes (GOx/PD/CNTs/GR) and its amperometric response toward glucose was investigated under aerobic and anaerobic conditions. The sensitivity of the GOx/PD/CNTs/GR electrode was found to be higher compared to that of a PD-modified GR electrode without CNTs (GOx/PD/GR), implying that CNTs play an important role in the facilitation of electron transfer between the redox active site of GOx and the electrode surface. The GOx/PD/CNTs/GR biosensor exhibited a linear dependency on substrate concentration in a range from 0.0 until 50.0 mM of glucose with oxygen present and from 0.0 until 62.5 mM of glucose in the absence of oxygen. With oxygen present, the limit of detection (LOD) values were determined to be 5.4 and 8.0 mM, and the limit of quantitation values (LOQ) were calculated as 16.2 and 24 mM for GOx/PD/GR and GOx/PD/CNTs/GR, respectively. In the absence of oxygen, the LOD values were calculated as 4.2 and 10.7 mM, and the LOQ values were calculated as 12.6 and 32.1 mM for GOx/PD/GR and GOx/PD/CNTs/GR, respectively. When examining the interference effect of uric acid for GOx/PD/GR and GOx/PD/CNTs/GR electrodes, no significant changes in the amperometric response of the modified electrodes were observed up to 100.0 mM of uric acid. (C) 2014 The Electrochemical Society. All rights reserved.
Bazı geçiş metal iyonlarının sıvı/sıvı arayüzden tiyosemikarbazon yardımlı transferlerinin voltametrik metotla incelenmesi
(Selçuk Üniversitesi Fen Bilimleri Enstitüsü, 2007-03-24) Bingöl, Haluk; Atalay, Tevfik
Bu çalışmada, polarizlenmiş su/1,2-dikloroetan (1,2-DCE) arayüzünden Cu(II), Cd(II), Co(II), Ni(II), Pb(II), Zn(II) ve Hg(II) gibi geçiş metal iyonlarının çeşitli tiyosemikarbazon türevleri ile yardımlı transferleri, dönüşümlü voltametri kullanılarak çalışıldı. Tiyosemikarbazon türevi olarak, 4-morfolinoasetofenon-4- fenil-tiyosemikarbazon (MAPPT), 9-Etil-3-karbazolkarboksaldehit-tiyosemikarbazon (ECCAT) ve 9-etil-3-karbazolkarboksaldehit-4-fenil-tiyosemikarbazon (ECCAPT) kullanıldığı zaman, voltametrik analiz için uygun sonuçlar gözlendi. ECCAT ve ECCAPT ligandları ile Cd(II) ve Pb(II) iyonlarının yardımlı transferleri analiz edilebilirken, MAPPT ligandı ile sadece Cd(II) iyonunun yardımlı transferi analiz edilebildi. Tersinir veya yarı tersinir transfer karakterine sahip ligand ve metal iyonlarının stokiyometrilerini, toplam oluşum sabitlerini ve transfer mekanizmalarını belirlemek için, Galvani transfer potansiyelinin ligand konsantrasyonuna bağlılığı kullanıldı. Su/1,2-DCE arayüzünde, dağılma katsayıları belirlenen hidrofobik tiyosemikarbazonların yardımlı iyon transferlerine ait dönüşümlü voltametri deneyleri, TIC mekanizmasıyla arayüzde meydana gelen ve 1:3 (metal:ligand) stokiyometrisine sahip komplekslerin oluştuğunu göstermiştir. [Pb(ECCAT)3]2+, [Cd(ECCAT)3]2+, [Pb(ECCAPT)3]2+, [Cd(ECCAPT)3]2+ [Cd(MAPPT)3]2+ ve komplekslerinin toplam oluşum sabitleri logaritmik olarak ( log Î²3 ), sırasıyla, o (14,03Â±0,09), (15,44Â±0,07), (13,44Â±0,08), (13,72Â±0,09) ve (15,46Â±0,11) olarak hesaplanmıştır. Diğer metal iyonları kullanıldığı zaman, bazıları için deney şartlarında herhangi bir transfer piki görülmezken, bazıları için de dönüşümlü voltametri analizi yeteri kadar değerlendirilemeyen farklı yapıdaki pikler elde edilmiştir.
Discriminative sensing of DOPA enantiomers by cyclodextrin anchored graphene nanohybrids
(ELSEVIER SCIENCE BV, 2017) Ateş, Salih; Zor, Erhan; Akın, İlker; Bingöl, Haluk; Alpaydın, Sabri; Akgemci, Emine Güler
Discriminative sensing of chiral species with a convenient and robust system is a challenge in chemistry, pharmaceutics and particularly in biomedical science. Advanced nanohybrid materials for discrimination of these biologically active molecules can be developed by combination of individual obvious advantages of different molecular scaffolds. Herein, we report on the comparison of the performance of cyclodextrin functionalized graphene derivatives (x-CD/rGO, x: alpha-, beta-, gamma-) for discrimination of DOPA enantiomers. Within this respect, electrochemical measurements were conducted and the experimental results were compared to molecular docking method. Thanks to cavity size of g-CD and the unique properties of graphene, rGO/gamma-CD nanohybrid is capable of selective recognition of DOPA enantiomers. Limit of detection (LOD) value and sensitivity were determined as 15.9 mu M and 0.2525 mu A mu M-1 for D- DOPA, and 14.9 mu M and 0.6894 mu A mu M-1 for L-DOPA. (C) 2017 Elsevier B.V. All rights reserved.
Effect of N(4)-phenyl group on the lipophilicity scale of 2-benzoylpyridine thiosemicarbazone based on the ion transfer across the liquid/liquid interface
(2006) Akgemci, Emine Güler; Bingöl, Haluk; Özçelik M.; Atalay T.; Ersöz, Mustafa
[Abstract not Available]
Effect of N(4)-substituent groups on transfer of 2-benzoylpyridine thiosemicarbazone derivates at the water/1,2-dichloroethane interface
(PERGAMON-ELSEVIER SCIENCE LTD, 2007) Akgemci, Emine Güler; Bingöl, Haluk; Atalay, T.; Ersöz, A.
Dependent on the pH of the aqueous phase, the transfer of protonated forms of 2-benzoylpyridine N(4)-phenyl thiosemicarbazone (BPPT) (which has antimicrobial, antifungal and anticytotoxic activities) and 2-benzoylpyridine N(4)-ethyl thiosemicarbazone (BPET) across water/1,2dichloroethane (1,2-DCE) interface has been studied by cyclic voltarnmetry. The protonation constants of the ligands (pK(a1)(w) and pK(a2)(w)) were a I a2 determined by spectrophotometry. The standard partition coefficients (log P-i(0)) and the standard Gibbs energies of ionic (cationic) species of ligands (Delta G(tr,i)(0,w -> o)) were calculated from the standard transfer potentials (Delta(w)(o)phi(0)(i)). The standard Gibbs energies of their transfer (Delta G(tr,i)(0,w -> o)) and partition coefficients of neutral species (log P-N) were determined by shake-flask method. These thermodynamic parameters were evaluated as a quantitative and qualitative measure of the lipophilicities of two compounds. The differences between the partition coefficients of cationic and neutral form of compounds [diff(log P1+-N)] were interpreted by results obtained from voltammetric data. Effect of N(4)-phenyl and ethyl groups for transfer of 2-benzoylpyridine thiosemicarbazone derivatives at macro-liquid/liquid interface was investigated. The antimicrobial activity of BPET was tested against four types of bacteria and found to be active against Staphlylococcus aureus. (c) 2007 Elsevier Ltd. All rights reserved.
Electrochemical investigation of heavy metal ion transfer across the water/1,2-dichloroethane interface assisted by 9-ethyl-3-carbazolecarboxaldehyde-thiosemicarbazone
(WILEY-V C H VERLAG GMBH, 2007) Bingöl, Haluk; Akgemci, Emine Güler; Ersöz, Mustafa; Atalay, Tevfik
The transfer of heavy metal ions across the polarized water/1,2-dichloroethane (1,2-DCE) interface assisted by 9ethyl-3-carbazolecarboxaldehyde-thiosemicarbazone (ECCAT) in the 1,2-DCE phase has been studied by cyclic voltammetry. Voltammetric waves of Pb(II) and Cd(II) ions were reversible and quasi-reversible, respectively, whereas that of Hg(II) and Zn(II) ion were irreversible. The voltammogram of Cu(II) ion showed a two-step wave, however the nature of the transfer could not be satisfactorily evaluated by analyzing the cyclic voltammetric data. When Ni(II) and Co(II) was used no peak was visible under the experimental conditions used in this study. The dependence of the half-wave potentials of Pb(II) and Cd(II) ions on the ligand concentration reveals that their ion-transfer is assisted by the formation of 1:3 metal-ECCAT complex in 1,2-DCE. The over-all association constants of [Pb(ECCAT)(3)](2+) and [Cd(ECCAT)(3)](2+) complexes in DCE-phase have been determined to be log beta(3)(0)= 14.03 and log beta(0)(3) = 15.44, respectively.
Facilitated Transfer of Alkali and Alkaline-Earth Metal Ions by a Calix[4]arene Derivative Across Water/1,2-Dichloroethane Microinterface: Amperometric Detection of Ca2+
(Wiley-V C H Verlag Gmbh, 2010) Bingöl, Haluk; Kaykal, Ferhat; Akgemci, Emine Güler; Sırıt, Abdulkadir
The host-guest complexation reactions between 5,11,17,23-tetra-tert-butyl-25,27-diethoxycarbonylmethoxy-26,28-dimethoxy calix[4] arene ( BDDC4) and alkali and alkaline-earth metal ions were investigated by facilitated ion transfer processes across water/1,2-dichloroethane microinterface by using steady-state cyclic voltammetry and differential pulse voltammetry. The obtained facilitated transfers for Li+, Na+, K+, Rb+ and Ca2+ were evaluated under the different experimental conditions, at the excess concentrations of metal ions with respect to BDDC4 and vice versa. The association constants having 1 : 1 stoichiometry for Li+, Na+, K+ and Rb+ in 1,2-DCE were determined. Also, we demonstrated that BDDC4 can play an important role for the development of highly selective chemical sensor for Ca2+ among alkaline-metal ions in the concentration range of 0.1-1.0 mM in aqueous solution.
Facilitated transfer of alkali metal ions by a tetraester derivative of thiacalix[4]arene at the liquid-liquid interface
(WILEY-V C H VERLAG GMBH, 2008) Akgemci, Emine Güler; Bingöl, Haluk; Ersöz, Mustafa; Stibor, Ivan
The facilitated transfer of alkali metal ions (Na+, K+, Rb+, and Cs+) by 25,26,27,28-tetraetboxycarbonylmethoxy-thiacalix[4]arene across the water/1,2-dichloroethane interface was investigated by cyclic voltammetry. The dependence of the half-wave transfer potential on the metal and ligand concentrations was used to formulate the stoichiometric ratio and to evaluate the association constants of the complexes formed between ionophore and metal ions. While the facilitated transfer of Li+ ion was not observed across the water/1,2-dichloroethane interface, the facilitated transfers were observed by formation of 1: 1 (metal: ionophore) complex for Na+, K+, and Rb+ ions except for Cs+ ion. In the case of Cs+ a 1:2 (metal: ionophore) complex was obtained from its special electrochemical response to the variation of ligand concentrations in the organic phase. The logarithms of the complex association constants, for facilitated transfer of Na+, K+, Rb+, and Cs+, were estimated as 6.52, 7.75, 7.91 (log beta(1)degrees), and 8.36 (log V), respectively.
Graphene-based hybrid for enantioselective sensing applications
(ELSEVIER ADVANCED TECHNOLOGY, 2017) Zor, Erhan; Morales-Narvaez, Eden; Alpaydın, Sabri; Bingöl, Haluk; Ersöz, Mustafa; Merkoci, Arben
Chirality is a major field of research of chemical biology and is essential in pharmacology. Accordingly, approaches for distinguishing between different chiral forms of a compound are of great interest. We report on an efficient and generic enantioselective sensor that is achieved by coupling reduced graphene oxide with gamma-cyclodextrin (rGO/gamma-CD). The enantioselective sensing capability of the resulting structure was operated in both electrical and optical mode for of tryptophan enantiomers (D-/L-Trp). In this sense, voltammetric and photoluminescence measurements were conducted and the experimental results were compared to molecular docking method. We gain insight into the occurring recognition mechanism with selectivity toward D- and L-Trp as shown in voltammetric, photoluminescence and molecular docking responses. As an enantioselective solid phase on an electrochemical transducer, thanks to the different dimensional interaction of enantiomers with hybrid material, a discrepancy occurs in the Gibbs free energy leading to a difference in oxidation peak potential as observed in electrochemical measurements. The optical sensing principle is based on the energy transfer phenomenon that occurs between photo excited D-/L-Trp enantiomers and rGO/gamma-CD giving rise to an enantioselective photoluminescence quenching due to the tendency of chiral enantiomers to form complexes with gamma-CD in different molecular orientations as demonstrated by molecular docking studies. The approach, which is the first demonstration of applicability of molecular docking to show both enantioselective electrochemical and photoluminescence quenching capabilities of a graphene-related hybrid material, is truly new and may have broad interest in combination of experimental and computational methods for enantiosensing of chiral molecules. (C) 2016 Elsevier B.V. All rights reserved.
Interfacial Transfer of Cd2+ Assisted by 4 '-Morpholino-Acetophenone-4-Phenyl-3-Thiosemicarbazone Across the Water/1,2-Dichloroethane Interface
(Versita, 2010) Bingöl, Haluk; Atalay, Tevfik
The assisted transfer of heavy metal ions by interfacial complexation with 4'-morpholinoacetophenone-4-phenyl-3-thiosemicarbazone (MAPPT) at the interface between two immiscible electrolyte solutions (ITIES) was studied by cyclic voltammetry. The voltammograms obtained across the water/1,2-dichloroethane interface using the MAPPT ligand in the organic phase shows that the assisted metal ion transfers have different nature for different ions. The quasi-reversible voltammetric peak of the Cd2+ ion was obtained and is discussed in detail. The dependence of the half-wave transfer potential on MAPPT concentration showed that the equilibrium is effectively displaced towards a 1:3 (metal:ligand) stoichiometry with an association constant of log beta(0) = 15.46 (+/- 0.11) for the Cd2+ ion, corresponding to the TIC/TID mechanism.
Investigation of the lipophilicity of 2-benzoylpyridine-thiosemicarbazone based on the ion transfer across the liquid/liquid interface
(PEKING UNIV PRESS, 2008) Akgemci, Emine Güler; Bingöl, Haluk; Özçelik, Mehmet; Ersöz, Mustafa
The ion transfer reaction of 2-benzoylpyridine-thiosemicarbazone (HL), which has antimicrobial and antifungal properties and anticancer activity, has been studied to determine its lipophilicity by cyclic voltammetry at the water/1,2-dichloroethane (1,2-DCE) interface. The physicochemical parameters such as standard partition coefficient (IgP(I)) and the standard Gibbs energy of transfer of the protonated form of the ligand were measured as a function of pH in aqueous phase. The protonated form of the ligand exhibited reversible or quasi-reversible voltammograms at the 1,2-DCE in the range of pH 1-5. ne protonation constants of the ligand, pK(a1) and pK(a2), were determined spectrophotometrically and were found to be 12.14 and 3.24, respectively. The standard Gibbs energy of transfer and the partition coefficient of neutral species (lgP(N)) were also determined by the shake-flask method. The standard Gibbs energy of transfer of this compound across the water/1,2-DCE interface was evaluated as the quantitative measure of its lipophilicity. The difference between IgP(I) and lgP(N) was related to the degree of charge delocalization and was used to evaluate qualitatively the lipophilicity of the ligand.
Kinetic study of copper(II) complexation with 9-ethyl-3-carbazolecarboxaldehyde-thiosemicarbazone and kinetic-spectrophotometric determination of copper(II)
(MAIK NAUKA/INTERPERIODICA/SPRINGER, 2006) Bingöl, Haluk; Akgemci, Emine Güler; Atalay, T.
The kinetics of complexation reaction of Cu(II) with 9-ethyl-3-carbazolecarboxaldehyde-thiosemicarbazone (ECCAT) has been examined spectrophotometrically. The ligand was synthesized for the first time. The complexation reaction was carried out in a DMF-water medium at 35 degrees C. The complex has maximum absorbance at 393 nm. Kinetic and activation parameters of the complexation reaction were calculated by the Arrhenius and Eyring equations using the data obtained from investigating the effect of temperature on reaction rates under the specified conditions. We also proposed reaction rate equations. Based on the studied complexation reaction, a simple kinetic method for the spectrophotometric determination of copper(II) has been developed. The calibration graphs are linear in the concentration range 0.2-1.9 mu g/mL. The species that caused interference were investigated.
Kiral Sensör Olarak Ferrosen Türevli YeniSchiff Bazının Sentezi
(2015) Uçar, Asuman; Fındık, Mükerrem; Bingöl, Haluk; Güler, Ersin; Özcan, Emine
Ferrosen ve ferrosenil bileşikleri enerji ve elektron transferi gerçekleştirebilmesinden dolayı floresans çalışmalarında yaygın olarak kullanılmıştır (1). Yüksek seçiciliğin yanında analitik, biyolojik, klinik ve biyokimya alanlarında potansiyel uygulamaları nedeniyle enantiyoseçici floresans sensör çalışmaları literatürlerde yer almaktadır (2). Aminoasitler hem doğal kiral moleküller olduğu için hem de amid bağları mükemmel hidrojen bağı yaptıkları için kiral reseptor eldesinde önem taşımaktadırlar (3). Bu çalışmada kiral yapıda olan 3 bileşiği sentezlenmiş ve floresans özellikleri çalışılmıştır. Bu bileşiğin çeşitli kiral aminoasitlerle (D- Metiyonine, L- Metiyonine, DAlanin, L-Alanin, D-Valin, L-Valin, L-Serin, D-Serin, D-Histidin, L-Histidin, D-Sistein, LSistein D- Treonin, L- Treonin) etkileşimi sonucu floresans değişimleri incelendiğinde D-metiyonine karşı gözle görülür bir değişim söz konusuyken incelenen diğer amino asitlere karşı bu artışın mevcut olmadığı görülmüştür. Bu sonuçlar sentezlenen bileşiğin D-metiyonin enantioselektif tanıması için kullanışlı bir sensor olduğunu göstermektedir.
New copper(II) and nickel(II) complexes of 4-morpholinoaceto-phenone thiosemicarbazone: Structural, electrochemical and antimicrobial studies
(WILEY-V C H VERLAG GMBH, 2007) Bingöl, Haluk; Coşkun, Ahmet; Akgemci, Emine Güler; Kaya, Baştürk; Atalay, Tevfik
4-Morpholinoacetophenone thiosemicarbazone, MAPT, and its nickel(II) and copper(II) complexes have been prepared and characterized by elemental analysis, magnetic susceptibility, spectral methods (FT-IR, H-1 NMR) and cyclic voltammetry. Electrochemical behaviors of the complexes have been studied by cyclic voltammetry in DMF media showing metal centered reduction processes for both of them. The redox properties, nature of the electrode processes and the stability of the complexes were discussed. [Cu(MAPT)(2)]Cl-2 complex shows Cu(II)/Cu(I) couple and quasi-reversible wave associated with the Cu(III)/Cu(II) process. The reduction/oxidation potential values depend on the structures of complexes. Also, the antimicrobial activities of these complexes were determined against S. aureus, E. coli and B. subtilis.
A Novel Benzothiazole Based Azocalix[4]arene as a Highly Selective Chromogenic Chemosensor for Hg2+ İon: A Rapid Test Application in Aqueous Environment
(Elsevier Science Bv, 2010) Bingöl, Haluk; Kocabaş, Erdal; Zor, Erhan; Coşkun, Ahmet
A novel calix[4]arene derivative containing benzothiazole azo groups at the upper rim was synthesized as chromogenic chemosensor, and its binding and sensing properties with heavy metal ions (Pb2+, Hg2+, Ni2+, Cd2+, Cu2+, Zn2+, Co2+, Fe2+, Mn2+, Cr3+, Ag+) were investigated by UV-vis spectroscopy and voltammetric techniques. The results of spectroscopic and voltammetric experiments showed that the chromogenic chemosensor has high selectivity towards Hg2+ ion over the other heavy metal ions. Moreover, it was shown that the interaction between Hg2+ and the chromogenic chemosensor occurs by means of the benzothiazole azo groups at the upper rim by using differential pulse voltammetry. The stoichiometric ratio and the association constant were determined as 1:1 and (6.1 +/- 0.3) x 10(5) L mol(-1) for the complex between Hg2+ and the ionophore. Furthermore, we prepared a rapid test kit for early detection of Hg2+ in aqueous environment in the concentration range of 1 x 10(-4) to 1 x 10(-2) M.
A reduced graphene oxide/alpha-cyclodextrin hybrid for the detection of methionine: electrochemical, fluorometric and computational studies
(ROYAL SOC CHEMISTRY, 2014) Zor, Erhan; Sağlam, Muhammed Esad; Alpaydın, Sabri; Bingöl, Haluk
We report on fluorometric and voltammetric detection of L-methionine (Met) based on host-guest interactions between Met and reduced graphene oxide/alpha-cyclodextrin (rGO/alpha-CD) hybrid materials. For voltammetric measurements, rGO/alpha-CD was used as an electrode modification material and successful detection of Met was achieved. Also, rGO/alpha-CD was used as a fluorescence quencher (turn off) for luminol which was employed as a fluorescent probe. The addition of Met into the same solution gave rise to fluorescence enhancement (turn on) after the host-guest recognition between Met and rGO/alpha-CD which caused the release of luminol. Interactions of luminol and Met with rGO/alpha-CD were modeled by molecular docking using AutoDock Vina and the interaction energies were predicted to be -4.3 and -4.4 kcal mol(-1), respectively. The proposed biosensor is considered to be a promising model for the detection of Met.
Selective sodium ion transfer across a water/1,2-dichloroethane micro-interface by a calix[4]arene derivative
(ELSEVIER SCIENCE SA, 2011) Kaykal, Ferhat; Kocabaş, Erdal; Bingöl, Haluk; Akgemci, Emine Güler; Coşkun, Ahmet
The transfer of alkali and alkaline-earth metal ions facilitated by a calix[4]arene derivative, 25,27-di [(2-ethoxy)benzaldehyde]-26,28-dihydroxy-5,11,17,23-tetra(tert-butyl) calix[4]arene (DBC4), across a water/1,2-dichloroethane (1,2-DCE) micro-interface supported at the tip of a micropipette was investigated. The well-defined voltammetric behavior was obtained only for Na+ ion among the used metal ions by using the electrochemical methods. The measurements were performed when the bulk concentration of Na+ ion in the aqueous phase is much higher than that of DBC4 in the organic phase, and vice versa. The diffusion coefficient of DBC4 in the DCE phase was calculated to be equal to (4.2 +/- 0.2) x 10(-6) cm(2) s(-1). The logarithm of the association constant of DBC4-Na+ complex having 1:1 stoichiometry in 1,2-DCE was determined as 3.99. The differential pulse voltammetry was used for amperometric detection of Na+ ion in chloride medium. The results show that DBC4 can be used for many analytical applications such as ion recognition and fabrication of electrochemical sensor for Na+ ion because of its good selectivity. (C) 2011 Elsevier B.V. All rights reserved.
Synthesis and electrochemical properties of a novel calix[4]arene derivative for facilitated transfer of alkali metal ions across water/1,2-dichloroethane micro-interface
(TAYLOR & FRANCIS LTD, 2011) Kaykal, Ferhat; Bingöl, Haluk; Sarıgüney, Ahmet B.; Coşkun, Ahmet; Akgemci, Emine Güler
The alkali metal ion transfers facilitated by a novel calix[4]arene derivative (OPEC) across the water/1,2-dichloroethane (1,2-DCE) micro-interface supported at the tip of a micropipette were presented. The well-defined voltammetric behaviours except Cs+ was obtained by cyclic voltammetry and differential pulse voltammetry. The bulk concentration of metal ions was much higher than that of OPEC in the performed measurements. The diffusion coefficient of OPEC in the 1,2-DCE phase was calculated as 5.18 +/- 0.70 x 10(-6) cm(2) s(-1). On the basis of the changes of the half-wave transfer potentials, the logarithms of the association constants having 1:1 ionophore-ion complex stoichiometry for Li+, Na+, K+ and Rb+ in 1,2-DCE were determined as 4.80, 4.62, 4.98 and 5.32, respectively. The facilitated ion transfers were also evaluated by the Randles equivalent circuit used for ac-impedance data analysis.
Synthesis of Novel Tripodal-Benzimidazole From 2,4,6-Tris(P-Formylphenoxy)-1,3,5-Triazine: Structural, Electrochemical and Antimicrobial Studies
(ELSEVIER SCIENCE BV, 2010) Koç, Ziya Erdem; Bingöl, Haluk; Saf, Ahmet O.; Torlak, Emrah; Coşkun, Ahmet
Four new tripodal-benzimidazole derivatives were synthesized by Schiff base reaction between 2,4,6-tris(p-formylphenoxy)-1,3,5-triazine (TRIPOD) and different diamine derivatives. The structures of the obtained compounds were identified by FT-IR, (1)H NMR, (13)C NMR and UV-vis spectral data, thermal analysis and elemental analysis. Electrochemical behaviors of the compounds were studied by cyclic voltammetry in DMF including 0.1 M [NBu(4)] [PF(6)]. The voltammograms showed peaks having similar characteristics except tripodal-benzimidazole including -NO(2) derivative. In addition, their antimicrobial activities were evaluated by using the standard disk diffusion method in dimethylformamide media. The activities were determined against 4 bacteria cultures by comparing to those of gentamycin.
Voltammetric characterization of selective potassium ion transfer across micro-water/1,2-dichloroethane interface facilitated by a novel calix[4]arene derivative
(PERGAMON-ELSEVIER SCIENCE LTD, 2011) Durmaz, Müge; Zor, Erhan; Kocabaş, Erdal; Bingöl, Haluk; Akgemci, Emine Güler
In this study, transfer reactions of alkali and alkaline-earth metal ions across a micro-water/1,2-dichloroethane (1,2-DCE) interface facilitated by a novel calix[4]arene derivative, 5,11,17,23-tetra-tert-butyl-25,27-bis(2'amino-methylpyridine)-26,28-dihydroxy calix[4]arene (APHC4), were investigated by cyclic and differential pulse voltammetry techniques. Well-defined voltammetric behavior was obtained only for K(+) ion among the used metal ions. The electrochemical data were used to determine the stoichiometry and the appropriate association constant of the occurring complex between K(+) ion and APHC4. The obtained steady-state voltammograms indicated that the facilitated transfer process occurs with a TIC/TID mechanism according to 1:1 stoichiometry. The logarithm of the association constant (log beta(0)(1)) of K(APHC4)(+) complex in the DCE phase was calculated to be 6.32. Also, the availability of the facilitated transfer for the design of an amperometric screening sensor for K(+) ion was evaluated in the range of 50-500 mu mol dm(-3). (C) 2011 Elsevier Ltd. All rights reserved.

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