M. Kasım Şener

Photophysical and photochemical properties of novel phthalocyanines bearing non-peripherally substituted mercaptoquinoline moiety

The synthesis, photophysical and photochemical properties of nonperipherally (α) mercaptoquinoline substituted Zn(II), TiO(IV) and Mg(II) and quaternized Zn(II) phthalocyanines are described for the first time. These complexes (2 to 5) and their precursor are characterized by elemental analysis, FT-IR, 1H NMR, electronic spectroscopy as well as mass spectroscopy. Complexes 2, 4 and 5 have good solubility in organic solvents such as CHCl3, DCM, DMSO, DMF, THF and toluene and are not aggregated in all solvents within a wide concentration range. Complex 3 showed very good solubility in water as well as DMSO and DMF. General trends are described for singlet oxygen, photodegradation and fluorescence quantum yields of these complexes in DMSO and DMF. While complex 2 has higher singlet oxygen and fluorescence quantum yields than 3, 4 and 5, complex 4 has higher fluorescence quantum yields in DMF and DMSO than 2, 3 and 5. The effect of the solvents and metal on the photophysical and photochemical parameters of the metallophthalocyanines are also reported.

EDOT-Functionalized Calix(4)pyrrole for the Electrochemical Sensing of Fluoride in Water

A new calix[4]pyrrole compound bearing an electropolymerizable EDOT substituent (1) was synthesized, and its electrochemical behavior was investigated. The anion sensor ability of 1 was also studied in solution and in the solid state. Compound 1 interacts with halide ions selectively in solution, which illustrates its possible application as an anion sensor. To test possible practical applications, 1 and EDOT were electropolymerized on an ITO electrode, and this electrode was used as an effective fluoride anion sensor in the solid state.

Synthesis and characterization of poly{2-[3-(1H-pyrrol-2-yl)phenyl]-1H-pyrrole} and its copolymer with EDOT

A pyrrole-functionalized monomer 2-[3-(1H-pyrrol-2-yl)phenyl]-1H-pyrrole (PyPhPy) was synthesized. The structure of monomer was investigated by Nuclear Magnetic Resonance (1H NMR) and Fourier Transform Infrared (FTIR) spectroscopy. The chemical polymerization of PyPhPy (CPyPhPy) was realized using FeCl3 as the oxidant. The electrochemical oxidative polymerization of polymer P(PyPhPy) and its copolymer with 3,4-ethylenedioxythiophene poly(2-[3-(1H-pyrrol-2-yl)phenyl]-1H-pyrrole-co-3,4-ethylenedioxythiophene) [P(PyPhPy-co-EDOT)] were achieved via potentiodynamic method by using NaClO4/LiClO4 as the supporting electrolyte in CH3CN. Characterizations of the resulting polymers were performed by cyclic voltammetry (CV), FTIR, scanning electron microscopy (SEM), UV-Visible spectrophotometry (UV-Vis) and thermogravimetry analyses (TGA). Electrical conductivity of CPyPhPy, P(PyPhPy), and P(PyPhPyco-EDOT) were measured by four-probe technique.

Electrochemical pesticide sensor based on Langmuir–Blodgett film of cobalt phthalocyanine-anthraquinone hybrid

A cathode active and selective pesticide electrochemical sensor based on Langmuir–Blodgett (LB) film of cobalt phthalocyanine-anthraquinone hybrid (CoPc-AQ) was constructed for the first time in this study. Cobalt-based, Pc ring-based, and anthraquinone-based reduction processes of CoPc-AQ indicated suitability of the complex as a possible electrochemical catalyst and sensor for detection of target species. LB film of CoPc-AQ on ITO (ITO/CoPc-AQ electrode) was titrated with eserine and carbofuran pesticides and interaction of the electrode with these pesticides was tested with square wave voltammetry (SWV), electrochemical impedance spectroscopy (EIS), and double potential step chronocoulometry (DPSCC) techniques. ITO/CoPc-AQ electrode selectively sensed carbofuran and eserine pesticides. While ITO/CoPc-AQ electrode senses carbofuran with the voltammetric responses recorded at anodic potentials (1.20 V), eserine sensing affected antraquinone based reduction peaks recorded at cathodic potentials (-0.80 V). Modification of ITO/CoPc-AQ electrode with nano-platinum and nano-gold particles (ITO/CoPc-AQ-nPt and ITO/CoPc-AQ-nAu) increased the sensitivity of the electrode. All basic sensor parameters of modified electrodes were derived with different measurement techniques and compared with each other. The lowest detection limit (2.30 × 10-9 M) was recorded with EIS techniques on ITO/CoPc-AQ-nPt electrode for sensing of eserine.

Efficient synthesis of EDOT modified ABBB-type unsymmetrical zinc phthalocyanine: optoelectrochromic and glucose sensing properties of its copolymerized film

A new unsymmetrical zinc(II) phthalocyanine (ZnPc2) bearing one EDOT group was efficiently synthesized as a monomer through the statistical condensation reaction. The other products of mixed cyclotetramerization ZnPc1, ZnPc3 and ZnPc4 were also isolated. Obtained ZnPc2 is a good precursor for the synthesis of new functional linear electropolymers. This was approved by the successful electrochemical copolymerization reaction between ZnPc2 and SNS type monomer HKCN in which the amino group was desired for the enzyme immobilization. The electrochromic and glucose sensing properties of copolymer P(ZnPc2-co-HKCN) obtained by electrochemical oxidative polymerization were investigated. Based on spectroelectrochemical studies, the P(ZnPc2-co-HKCN) copolymer showed a greenish yellow colour in the reduced state and a dark blue colour in the oxidized state as a film. An optical contrast ratio of 44% at 471 nm was achieved with a fast switching time (2.5 s). Meanwhile, the novel biosensor constructed from P(ZnPc2-co-HKCN) showed a linear amperometric response to glucose within a concentration range of 0.1 mM to 1.5 mM (LOD: 0.049 mM). These data illustrate the possible use of the P(ZnPc2-co-HKCN) modified electrode as an amperometric glucose sensor.

Synthesis of non-peripherally substituted tetra(dihexylmalonate) alcohol soluble phthalocyanines

Dimethyl-(2,3-dicyanophenyl)malonate was prepared by the reaction of dimethylmalonate and 3-nitrophthalonitrile. A cyclotetramerization reaction of dimethyl-(2,3-dicyanophenyl)malonate with the corresponding divalent metal salt was achieved in hexanol in the presence of DBU, affording the non-peripherally substituted tetra(dihexylmalonate) Cu(II), Pd(II), and Co(II) phthalocyanines. Transesterification occurred under these reaction conditions, so that methyls in the phthalonitrile derivative were converted into hexyl groups during phthalocyanine formation in hexanol. The new compounds were characterized by elemental analyses, FT-IR, 1H-NMR, 13C-NMR, UV-Vis, and mass spectral data.

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, photophysicochemical properties and TD-DFT calculations of tetrakis(2-benzoyl-4-chlorophenoxy) phthalocyanines

The synthesis of metal free, magnesium and zinc tetrakis(2-benzoyl-4-chlorophenoxy) phthalocyanine derivatives (2–4) is described along with their characterization by elemental analysis, IR, UV-visible absorption, and 1H NMR spectroscopy and mass spectrometry. Trends observed in the fluorescence, triplet state, singlet oxygen and photodegradation quantum yields and the triplet state lifetimes are also analyzed. The compounds exhibit high solubility in a wide range of organic solvents and no evidence of aggregation was observed over a wide concentration range. The Zn(II) complex (4) was found to have a very high singlet oxygen quantum yield (ΦΔ = 0.78) in dimethylsulfoxide (DMSO) and a reasonably large triplet state quantum yield (ΦT = 0.82). The photophysical and photochemical properties clearly demonstrate that these compounds could prove useful in singlet oxygen applications such as photodynamic therapy (PDT). DFT and TD-DFT calculations were used to assess the impact of the positional isomerism of the 2-benzoyl-4-chlorophenoxy substituents on the electronic structures and optical spectroscopy.

Synthesis, thermal, and electrical properties of stilbene-bridged polymeric zinc phthalocyanine

Diethylstilbesterol diphthalonitrile ether (1) was synthesized by nucleophilic aromatic substitution of diethylstilbesterol onto 4-nitrophthalonitrile. A polymeric zinc phthalocyanine (2) was prepared by polymeric tetramerization of the tetranitrile monomer with Zn(CH3COO)2·2H2O. Thermal analysis of the polymeric zinc phthalocyanine was performed by differential scanning calorimetry and thermal gravimetric analysis. Dc and ac conduction properties of polymeric zinc phthalocyanine pellet were investigated in the frequency range of 100 to 1.6 × 106 Hz and temperature 300–505 K. σdc was found to follow a variable range hopping mechanisms up to ∼400 K. Above this temperature, σdc followed thermally activated conduction mechanism only. Based on the existing theories of ac conduction, it was concluded that the temperature dependence of the exponent ‘s’ and conductivity, the correlated barrier hopping model is the dominant conduction mechanism for electron transport in the polymeric zinc phthalocyanine pellet.