Duygu Akyüz

Electrochemical and spectroelectrochemical properties of thiadiazole substituted metallo-phthalocyanines

4-Thiadiazole substituted phthalonitrile and peripherally tetra-substituted phthalocyanine Cu(II), Fe(II) and Ti(IV)O complexes have been synthesized for the first time. Electrochemical properties of these complexes were determined with voltammetric and in situ spectroelectrochemical measurements. CuPc has redox inactive Cu(2+) center, therefore it gave three Pc based reduction and two Pc based oxidation processes. TiOPc and FePc complexes gave metal based redox processes in addition to Pc based redox reactions due to the redox activity of Ti(4+)O and Fe(2+) metal centers. Although FePc also gave three reduction and two oxidation reactions, peak potentials of these processes are different than those of CuPc due to the different assignments of the redox reactions. TiOPc went to five reduction and one oxidation reactions. Assignments of the redox processes were carried out with in situ spectroelectrochemical measurements. Spectra and color of the electrogenerated redox species of the complexes were also determined with in situ spectroelectrochemical and in situ electrocolorimetric measurements. Distinct color differences between the electrogenerated redox species were observed, which indicated their possible electrochromic usages.

The electrochemical and spectroelectrochemical properties of metal free and metallophthalocyanines containing triazole/piperazine units

The synthesis and characterization of novel peripherally tetra [1,2,4]-triazole substituted metal-free phthalocyanine and its metal complexes (Zn(II), Ni(II), Pb(II), Cu(II) and Fe(II)) and the investigation of electrochemical and spectroelectrochemical properties of metal-free, Zn(II), Pb(II), Fe(II) phthalocyanines were performed for the first time in this study. Electrochemical characterizations of the complexes were performed with voltammetric and in situ spectroelectrochemical measurements. Voltammetric responses of the complexes supported the proposed structures, since complexes bearing redox inactive Pc ring metal centers just gave Pc based electron transfer reactions, while iron phthalocyanine went to metal based electron transfer reaction in addition to the Pc based ones. Electron withdrawing nature of [1,2,4]-triazole substituents shifted the redox processes toward the positive potentials. All complexes were electropolymerized during the oxidation reactions in dichloromethane (DCM) solvent. Types of the metal center of the complexes altered the electropolymerization reactions of the complexes. Spectra and colors of the electrogenerated redox species of the complexes were also determined with in situ spectroelectrochemical and in situ electrocolorimetric measurements.

Synthesis and electropolymerization of EDOT modified 1,3-bis(5-methyl-2-thiazolylimino)isoindolinato palladium(II) complex for electrochemical detection of hydrogen peroxide

Abstract 1,3-Bis(5-methyl-2-thiazolylimino) isoindoline derivative (EDOT-BTI) containing an electropolymerizable group is prepared using the Linstead method. According to this two-step method phthalonitrile derivative EDOT-Pht is converted to 1,3-diiminoisoindoline EDOT-DII first then EDOT-DII is reacted with 2-amino-5-methylthiazole in ethanol during 5 day reflux. Palladium(II) complex (EDOT-PdBTI) of EDOT-BTI is synthesized in benzene using [Pd(PhCN)2Cl2] as the palladium(II) precursor and triethylamine as auxiliary base. In order to show the H2O2 sensing properties of EDOT-PdBTI, electrochemical characterizations of EDOT-BTI and EDOT-PdBTI are performed and then modified glassy carbon electrode is constructed with electropolymerization of EDOT-PdBTI. GCE/PEDOT-PdBTI shows a wave at 0.215 V. With increasing H2O2 concentration, this wave shifts to −0.075 V. A linear range is observed between 0.72 and 13.6 μmol dm−3 with a limit of detection of 0.21 μmoldm−3 and sensitivity of 0.0153 mV μmol−1 dm−3. These data illustrate possible use of the electrode as a potentiometric H2O2 sensor.

Synthesis and investigation of spectroelectrochemical properties of peripherally tetra-substituted phthalocyanine bearing 3-(4-{[3-(trifluoromethyl)benzyl]oxy}phenyl)propan-1-ol and its metallo compounds

In this study, the new compounds; 3-(4-{[3-(trifluoromethyl)benzyl]oxy}phenyl)propan-1-ol 3 was prepared by the reaction of 4-(3-hydroxypropyl)phenol 1 with 1-(bromomethyl)-3-(trifluoromethyl)benzene 2 and 4-[3-(4-{[3 (trifluoromethyl)benzyl]oxy}phenyl)propoxy] phthalonitrile 5 was synthesized by the reaction of 4-nitrophthalonitrile 4 with 3-(4-{[3-(trifluoromethyl)benzyl]oxy}phenyl)propan-1-ol 3. Novel peripherally tetra substituted H2Pc 6, Co(II) 7, Cu(II) 8, Ni(II) 9 and Fe(II) 10 phthalocyanines, which have peripheral positions with 4-[3-(4-{[3 (trifluoromethyl)benzyl]oxy}phenyl)propoxy] groups, were synthesized and all of the new compounds characterized by IR, 1H NMR, 13C NMR, UV–Vis, mass spectroscopies and elemental analysis. The electrochemical and spectroelectrochemical investigation of the phthalocyanines carrying 4-[3-(4-{[3 (trifluoromethyl)benzyl]oxy}phenyl)propoxy] groups were studied using various electrochemical techniques in DMF on a glassy carbon electrode. Cyclic voltammetry and square wave voltammetry studies show that the complexes have either metal based or ligand-based diffusion controlled electron transfer properties. To shed more light on the electron-transfer steps of the complexes and assignments of the redox couples were carried out by spectroelectrochemical measurements. The color changes during spectral changes of redox species were recorded with in situ electrocolorimetric measurements. The electrochemical and in situ UV–Vis spectral change of complexes indicated their applicability in the fields of the electrochemical technologies.