Synthesis, characterization, and electrocatalytic and electrical properties of novel ball-type four cyclopentyldisilanoxy-POSS bridged metallophthalocyanines

The novel ball-type four cyclopentyldisilanoxy-POSS bridged binuclear metallophthalocyanines 4-6 (M = Zn, Co, Cu) were synthesized from the corresponding phthalodinitrile derivative 3 which can be obtained from the reaction of cyclopentyldisilanol-POSS 1 with 4-nitrophthalonitrile 2 in THF in the presence of K2CO3 as the base by nucleophilic substitution of an activated nitro group in an aromatic ring. The structures of the target compounds have been characterized by elemental analysis, UV-Vis, IR, MALDI-TOF mass and H-1-NMR spectroscopy techniques. The catalytic activity of the 5-based catalyst towards oxygen reduction in a fuel cell-similar medium involving carbon support and Nafion (R) was observed to be superior when compared to those of 4- and 6-based catalysts, suggesting clearly that the presence of two cofacial redox-active metal centres in the ball-type structure increases the oxygen binding capability of the metal centre and the tendency for the formation of mu-peroxo species. The effect of heat treatment on the dc electrical conductivity and the impedance spectra of the films of 4 and 5 were also studied. The results showed that there were no considerable effects of heat treatment on the dc conductivity of the film of 4. On the other hand, after the films of 5 were annealed at 448 K in vacuum, the conductivity of the films increased similar to 10(3) times

Synthesis and characterization of novel 4-nitro-2-(octyloxy)phenoxy substituted symmetrical and unsymmetrical Zn(II), Co(II) and Lu(III) phthalocyanines

Compounds 3 and 4 have been prepared by the reaction of 4-nitrocatechol 1 and 4-nitrophthalonitrile 2 by a common method, aromatic nucleophilic subtitution of the nitro group in 4-nitrophthalonitrile. Starting from 4 and 1-bromooctane, their alkylation reaction gave compound 5. Zn(II) 8, Co(II) 9 and Lu(III) 10 complexes were synthesized from the corresponding metal salts by the tetramerization of compound 5. Compound 7 was prepared by the statistical condensation of 5 and 4,5-bis(hexylthio)phthalonitrile 6 with CoCl2 center dot 6H(2)O in dry dimethylformamide. The new compounds were characterized by FT-IR, UV/Vis, NMR and mass spectra. The electrochemical properties of the complexes were also investigated by cyclic voltammetry in non-aqueous medium. The effect of temperature on the dc conductivity and the impedance spectra of spin coated film of the compounds was investigated at temperatures between 295 and 433 K and in the frequency range 40-10(5) Hz. Thermally activated conductivity dependence on temperature was observed for all compounds. (C) 2007 Elsevier Ltd. All rights reserved

Synthesis, characterization, and electrochemical, electrical and gas sensing properties of a novel tert-butylcalix[4]arene bridged bis double-decker lutetium(III) phthalocyanine

A novel tert-butylcalix[4]arene bridged bis double-decker lutetium(III) phthalocyanine (Lu2Pc4) (5) has been synthesized by the reaction of dimeric lutetium(III) phthalocyanine (4) with two equiv. of dilithium octakis hexylthiophthalocyanine in amyl alcohol. The phthalonitrile derivative 1 was obtained through the displacement reaction of 4-nitrophthalonitrile with 1,3-dimethoxy-4-tert-butyl-calix[4]arene and was converted to the isoindoline derivative 2 by bubbling ammonia gas in dry MeOH. Compound 4 was prepared from 2, 4,5-bis(hexylthio)-1,2-diimilioisoindoline (3), and lutetium acetate in dry DMF. The new compounds and phthalocyanines were characterized by elemental analysis, IR, UV-Vis, H-1 NMR, ESR and MALDI-TOF MS spectra. The electrochemical properties of 4 and 5 have been examined by cyclic voltammetry, and compared. Distinctive differences between the voltammetric behaviour of 4 and 5 were detected. These differences were compatible with the structures of the compounds. A detailed study of the effect of temperature on the d.c. conductivity and impedance spectra (40-10(5) Hz) of spin coated films of 4 and 5 at temperatures between 290 K and 420 K was carried out. By analyzing the d.c. electrical behaviour of the 5 film, it was found that the experimental data are described by a thermally activated conductivity dependence on temperature with an activation energy of 0.77 eV. The a.c. results give a power law behaviour, sigma(a.c.) = A(T)omega(s), in which the frequency exponent s decreases with temperature. The sensing behaviour of the film for the online detection of volatile organic solvent vapors was investigated by utilizing an AT-cut quartz crystal resonator. It was observed that the adsorption of the target molecules on the coating surface cause a reversible negative frequency shift of the resonator. Thus, a variety of solvent vapors can be detected by using the 5 film as sensitive coating, with sensitivity in the ppm and response times in the order of several seconds depending on the dipole moment of the organic solvent. (c) 2006 Elsevier Ltd. All rights reserved

Electrochemical and in situ Spectroelectrochemical Properties of Phthalocyanines Bearing N-Benzyl-4-Phenyloxyacetamide Moieties

The general redox behaviour of phthalocyanines bearing N-benzyl-4-phenyloxyacetamide moieties (H2Pc, ZnPc, NiPc, CuPc, and CoPc) has been identified by cyclic voltammetry and differential pulse voltammetry on Pt in dimethylsulfoxide/tetrabutylammonium perchlorate. These measurements showed that the complexes indicate subsequent one-electron reduction and oxidation processes. Although the voltammetric measurements implied the association of the redox processes of some complexes with aggregation phenomenon, the complete evaluation of the aggregation effects by only these measurements was not possible. In situ UV-Vis spectroelectrochemical measurements enabled us to assign the ligand- and metal-based redox processes, and identify if the aggregation affects these processes. These measurements suggested that the redox processes of H2Pc, NiPc, and CuPc are coupled by aggregation phenomenon, while those of ZnPc and especially CoPc are not, probably due to the difference in their axial coordinating properties

Synthesis, characterization, spectroscopic and electrochemical properties of phthalocyanines substituted with four 3-ferrocenyl-7-oxycoumarin moieties

The synthesis, spectroscopic and electrochemical properties of the tetra-(3-ferrocenyl-7-oxycoumarin)substituted zinc (II) and cobalt (II) phthalocyanines (3 and 4) are reported for the first time. The synthesis of novel 3-ferrocenyl-7-hydroxycoumarin (1) was performed according to Perkin reaction, and the ligand, 7-(3,4-dicyanophenoxy)-3-ferrocenylcoumarin (2), was synthesized by the reaction of 3-ferrocenyl-7-hydroxycoumarin with 4-nitrophthalonitrile in the presence of K(2)CO(3) as the base in dry dimethylformamide. The preparation of the corresponding zinc (II) and cobalt (II) metallo phthalocyanines (3 and 4) substituted with 3-ferrocenyl-7-oxycoumarin moieties at beta-positions of the phthalocyanine ring was achieved by the cyclotetramerization of the coumarin ligand (2) with relevant metal(II) acetates in dry 2-dimethylaminoethanol. The new compounds have been characterized by elemental analyses, FT-IR, (1)H NMR, Mass and electronic spectroscopy. The fluorescence property of the zinc metallo phthalocyanine (3) is strongly affected by the presence of ferrocenyl moiety. The ferrocenyl moieties were very efficient in quenching the excited state of 3, which show very poor fluorescent intensity. The electrochemical properties of the complexes were also investigated by cyclic and differential pulse voltammetry techniques in non-aqueous medium. It was found that the redox-active ferrocene substituents are reduced concurrently at one potential. (C) 2011 Elsevier B.V. All rights reserved

Synthesis, spectroscopy, electrochemistry and in situ spectroelectrochemistry of partly halogenated coumarin phthalonitrile and corresponding metal-free, cobalt and zinc phthalocyanines

In this study, the preparation of novel 7-hydroxy-3-(2-chloro-4-fluorophenyl)coumarin (1), the ligand, 7-(3,4-dicyanophenoxy)-3-(2-chloro-4-fluorophenyl)coumarin (2), metal-free phthalocyanine 3 and metallophthalocyanine complexes 4 and 5 (MPcs, M = Co, Zn), beta-substituted with 7-oxo-3-(2-chloro-4fluorophenyl)coumarin functional group was achieved. By the reaction of 7-hydroxy-3-(2-chloro-4-fluorophenyl)coumarin (1) with 1,2-dicyano-4-nitrobenzen in dry DMF as the solvent in the presence of K2CO3 as the base, the 7-(3,4-dicyanophenoxy)-3-(2-chloro-4-fluorophenyl)coumarin (2) was synthesized. Compound 2 reacted with Co(CH3COO)2 center dot 4H(2)O in 2-N,N-dimethylaminoethanol to furnish a novel coumarin containing cobalt(II) Phthalocyanine 4. The cyclotetramerization of 2 with Zn(CH3COO)(2)center dot 2H(2)O in 2-N,N-dimethylaminoethanol gave the novel coumarin containing Zn(II)phthalocyanine 5; while tetramerization without any metal salts in 2-N,N-dimethylaminoethanol gave the metal-free phthalocyanine 3. The structures of obtained compounds were confirmed by elemental analysis. UV-Vis, IR, MALDI-TOF mass and H-1 NMR spectra. The cyclic and differential pulse voltammetry, and in situ spectroelectrochemistry of 7-oxo-3-(2-chloro-4-fuorophenyl)coumarin substituted phthalocyanines 3, 4 and 5 allowed us to identify metal- and phthalocyanine ring-based redox processes of the complexes. (C) 2009 Elsevier Ltd. All rights reserved

DBU-catalyzed condensation of metal free and metallophthalocyanines containing thiazole and azine moieties: Synthesis, characterization and electrochemical properties

Schiff base that contains carbothioamide moiety, substituted thiazole derivative, novel phthalonitrile compound and its corresponding metal free and metal phthalocyanines (Zn(II), Ni(II), Co(II) and Cu(II)) were synthesized and characterized for the first time. The solubility of these novel phthalocyanines were high in organic solvents and they did not aggregate in chloroform within the concentration range of 1.6 x 10(-5)-4 x 10(-6) M. Electrochemical properties of the phthalocyanines have been examined by cyclic voltammetry, square wave voltammetry and in situ UV-vis spectroelectrochemistry on Pt in dimethylsulfoxide/tetrabutylammonium perchlorate. These measurements suggested that the compounds display subsequent ligand- and/or metal-based one-electron reduction and oxidation processes. Cobalt complex showed both metal-based and ring-based one-electron redox processes, while the other complexes displayed only ring-based one-electron couples. It was observed that the redox processes of metal free, Zn(II), Ni(II) and Cu(II) phthalocyanines are coupled by aggregation phenomenon, whereas those CoPc are not, probably due to the difference in their axial coordinating properties. (C) 2013 Elsevier B. V. All rights reserved

H-type aggregation of functional metal ion sensing phthalocyanines: Synthesis, characterization and electrochemistry

We report, in this study, the preparation and physical characterization of the peripherally functionalized ionophore ligand, 4,5-bis(6-hydroxyhexan-3ylthio)-1,2-dicyanobenzene (1) and its branched thioalcohol-substituted phthalocyanines, 2,3,7,8,12,13,17,18-octakis{6-hydroxyhexan-3-ylthio)-metal (II) or (III) phthalocyanines (M(Pc[SCH(C(3)H(7))(C(2)H(5)OH)](8)) {M = Pb(II) (2), Zn(II) (3), Cu(II) (4), Co(II) (5) and Mn(III), X = Cl(-) (6)) which can selectively bind soft-metal ions such as silver (I) and palladium (II). It was observed by means of UV-Vis absorption spectrophotometry that the aggregates formed lead to a low solubility of the phthalocyanines in protic solvents, such as low molecular alcohols. However, the addition of AgNO(3) and Na(2)PdCl(4) into a THF-MeOH solution of {M{Pc[SCH(C(3)H(7))(C(2)H(5)OH)](8)X) (M = Pb(II) (2), Zn(II) (3), Cu(II) (4), Co(II) (5) and Mn(III), X = Cl- (6)) induced optical changes, which indicated the formation of twisted H-type dimers (blue shift, face-to-face fashion) of (M(Pc[SCH(C3H7)(C2H5OH)18) complexes, bound by four PdCl(2) and AgNO(3) units in THF solution. Elemental analysis data, matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF/MS), FT-IR, (1)H, (13)C NMR, and UV-Vis spectral data were used as complementary techniques. Voltammetry and in situ spectroelectrochemistry of the complexes were performed on Pt in DMSO/TBAP. The first reduction and oxidation processes of 5 were found to be split due to the presence of facile equilibria between the species coordinated differently at axial positions. The Mn(III)Pc(-2)X(-) complex (6) displayed well-defined colour changes during its reduction processes. The redox behaviour of the Mn(III)Pc( -2)X- complex was observed to be affected significantly by the existence of oxygen in solution due to the formation of mu-oxo MnPc species, Mn(III)Pc-O-PcMn(III). This effect was clarified well by in situ spectroelectrochemical measurements. (C) 2010 Elsevier Ltd. All rights reserved

Redox-Switchable New Phthalocyanines Containing Hydrazono-Thiazole-Carboxylate Fragments: Synthesis, Electrochemical, Spectroelectrochemical and Electrocolorimetric Investigation

New phthalonitrile compound with Schiff base, carbothioamide and thiazole moieties as substituents and its corresponding metal-free and metallophthalocyanines (Zn(II), Ni(II), Co(II), and Cu(II)) were synthesized and characterized for the first time. The solubilities of these novel phthalocyanines were high in organic solvents. The redox properties of the compounds have been researched by cyclic voltammetry, square wave voltammetry, controlled-potential coulometry and in situ spectroelectrochemistry in dimethylsulfoxide. The compounds displayed metal and/or phthalocyanine ring-based, generally reversible or quasi-reversible reduction and oxidation processes. The effect of aggregation on the redox behavior of these complexes was also discussed. In general, decreased intensity and broadening in the main Q absorption band and the appearance of a new blue-shifted band confirmed the presence of H-type aggregates in the solutions of the complexes 4, 6 and 8 in DMSO/TBAP. The color changes associated with the redox processes and electrogenerated anionic and cationic redox species were also recorded with in situ electrocolorimetric measurements. In situ UV-vis spectral and associated color changes monitored during the reduction processes of the complexes suggested their applicability in the fields of the electrochemical technologies

Novel phthalocyanines bearing four 4-phenyloxyacetic acid functionalities

Metal-free (2) and Co(II), Zn(II), Ni(II), Cu(II) metalloplithalocyanines (2a-d) with four 4-phenyloxyacetic acid groups on the periphery were prepared by cyclotetramerization of new p-(3,4-dicyanophenoxy)phenylacetic acid (1) and the corresponding divalent metal salts. Further reactions of these products with thionylchloride and then benzylamine in tetrahydrofuran, and octanol in pyridine gave amide (3, 3a-d) and ester (4, 4a-d) derivatives, respectively. The new compounds have been characterized by elemental analyses, IR, UV-Vis, mass and H-1 NMR spectroscopy. The redox. properties of compounds 2 and 2a-d were identified by cyclic voltammetry. (C) 2007 Elsevier Ltd. All rights reserved