Synthesis, electrochemical and spectroelectrochemical properties of peripherally tetra-imidazole substituted metal free and metallophthalocyanines (original) (raw)
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Polyhedron, 2011
A novel type of ionophore ligands, 3 0-(2,3-dihydroxypropylthio)-phthalonitrile and 4 0 (2,3-dihydroxypropylthio)-phthalonitrile, and their aand b-tetrasubstituted metallo phthalocyanines, (MPc), (M = Zn II , Co II , Mn III Cl, Fe III Ac, Cu II) have been prepared and fully characterized by elemental analysis, FT-IR, 1 H and 13 C NMR, and MS (ESI and Maldi-TOF). The complexes are soluble in both polar and non-polar solvents, such as MeOH and EtOH, THF, CHCl 3 and CH 2 Cl 2. The spectroscopic properties of the complexes are affected strongly by the electron-donating sulfanyl units on the periphery of the phthalocyanines. The cation binding properties of the complexes, for example using Ag I and Pd II , were evaluated by UV-Vis spectroscopy and the results show the formation of polynuclear phthalocyanine complexes. Functional donors on the periphery of the zinc and copper complexes coordinate to Ag I and Pd II to give ca. a 2:1 metal-phthalocyanine complex binding ratio for the concentration of 2.5 Â 10 À5 M (Pc) and 1.0 Â 10 À3 M (Metal ions). Voltammetric and in-situ spectroelectrochemical studies were performed to characterize the redox behavior of the complexes. An in-situ electrocolorimetric method was applied to investigate the colors of the electro-generated anionic and cationic forms of the complexes.
Polyhedron, 2008
4-[2-(Phenylthio)ethoxy]phthalonitrile 3 was synthesized by nucleophilic displacement of nitro group in 4-nitrophthalonitrile with 2-(phenylthio)ethanol 1. The metal-free phthalocyanine 4 was prepared by the reaction of a dinitrile monomer with 2-(dimethylamino)ethanol. Ni(II), Co(II), Cu(I) phthalocyanines 5, 7, 8 were prepared by reaction of the dinitrile compound with the chlorides of Ni(II), Co(II), Cu(I) in DMAE. Zn(II) phthalocyanine 6, was prepared by reaction of the dinitrile compound with the acetates of Zn(II) in DMAE. Electrochemical behaviours of novel metal-free, Co(II) and Zn(II) phthalocyanines were investigated by cyclic voltammetry, potential differential pulse voltammetry techniques. The new compounds were characterized by a combination of IR, 1H NMR, 13C NMR, UV–Vis, elemental analysis and MS spectral data.4-[2-(phenylthio)ethoxy]phthalonitrile 3 was synthesized by nucleophilic displacement of nitro group in 4-nitrophthalonitrile with 2-(phenylthio)ethanol 1. The metal-free phthalocyanine 4 was prepared by the reaction of a dinitrile monomer with 2-(dimethylamino)ethanol. Ni(II), Co(II), Cu(I)- phthalocyanines 5, 7, 8 were prepared by reaction of the dinitrile compound with the chlorides of Ni(II), Co(II), Cu(I) in DMAE. Zn(II)-phthalocyanine 6, was prepared by reaction of the dinitrile compound with the acetates of Zn(II) in DMAE. Electrochemical behaviours of novel metal-free, Co(II) and Zn(II) phthalocyanines were investigated by cyclic voltammetry, potential differential pulse voltammetry techniques. The new compounds were characterized by a combination of IR, 1H-NMR, 13C-NMR, UV-vis, elemental analysis and MS spectral data.
The synthesis of new metal-free, nickel, zinc, cobalt and copper phthalocyanines with four 6oxyquinoline groups on the non-peripheral position were prepared by cyclotetramerization of a novel 3-(quinolin-6-yloxy)phthalonitrile. All new compounds were characterized by the ways of IR, 1 H NMR, 13 C NMR and MS spectral data, all of which were compatible with the proposed structures. Electrochemical properties of metal-free, Ni(II) and Zn(II) phthalocyanines were investigated by using cyclic voltammetry and differential pulse voltammetry techniques. The metal-free phthalocyanine exhibits two reversible Pc ring-based one-electron reduction couples. The Ni(II) and Zn(II) phthalocyanines give very similar voltammetric responses with slightly potential shift due to the different metal center.
Synthesis and electrochemistry of new octa-substituted metal-free and metallophthalocyanines
Journal of Coordination Chemistry, 2015
The synthesis and characterization of metal-free (H 2 -Pc) and metal-containing (Zn, Co, and Cu) derivatives of a symmetrically octa-substituted phthalocyanine derived from 4,5-bis[2-(phenylthio) ethoxy]phthalonitrile were carried out by microwave irradiation. The electrochemical properties of the metal-free phthalocyanine 4 and metallophthalocyanine complexes 5 and 6 were investigated by cyclic voltammetry and differential pulse voltammetry. We have previously investigated the electrochemical properties of the tetra substituted 2-(phenylthio)ethoxy phthalocyanines. The reduction potential of the octa-substituted metal-free phthalocyanine shifted to more negative potential as a result of the electron donating of the 2-(phenylthio)ethoxy groups on the periphery compared to those of tetra substituted. The H 2 Pc and ZnPc demonstrated ligand-based electron transfer processes, while CoPc complex has a metal-based reduction process. Similar aggregation behavior was observed for octa-substituted phthalocyanines. The compounds were characterized using IR, 1 H NMR, 13 C NMR, elemental analysis, and MS spectral data.
Metal-free 4 and metallophthalocyanine complexes 5-7 (MPcs, M = Ni, Co, Cu) substituted with the electropolymerizable (2-{2-[3-(dimethylamino)phenoxy]ethoxy}ethoxy) group have been synthesized and their structure have been identified by IR, 1 H and 13 C NMR, mass and UV-Vis spectroscopy techniques. The electrochemical characterization of the phthalocyanines sustained the submitted structures of the complexes, since the half wave peak potentials of the redox processes are in harmony with the common electrochemical behavior of MPcs. CoPc gives a metal based reduction process in addition to the ligand based electron transfer processes, which enrich the possible usage of the complex in various electrochemical technologies. All the complexes were coated on the working electrode with an oxidative electopolymerization process during the anodic potential scans.
Polyhedron, 2014
The synthesis of novel metallophthalocyanines (M = Zn, Ni) bearing substituted benzyl protected 1,2,3triazole moieties at peripheral positions is described for the first time via direct cyclotetramerization. These complexes have been characterized by a combination of FT-IR, 1 H NMR, HRMS and UV-Vis 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.
Polyhedron, 2007
The phthalodinitrile derivative 1 was prepared by the reaction of 4-nitrophthalonitrile and 1,3-dimethoxy-4-tert-butylcalix[4]arene in dry dimethylsulfoxide as the solvent, in the presence of the base K 2 CO 3 , by nucleophilic substitution of an activated nitro group in an aromatic ring. The tetramerization of compound 1 gave a binuclear zinc(II) phthalocyanine and a metal-free phthalocyanine of the ball type, 2 and 3, respectively. Its condensation with 4,5-bis(hexylthio)phthalonitrile results in a binuclear phthalocyanine of the clamshell type, 4. The newly synthesized compounds were characterized by elemental analysis, UV-Vis, IR, MS and 1 H NMR spectra. The electronic spectra exhibit an intense p ! p * transition with characteristic Q and B bands of the phthalocyanine core. The electrochemical properties of 2-4 were examined by cyclic voltammetry in non-aqueous media. The voltammetric results showed that while there is no considerable interaction between the two phthalocyanine rings in 4, the splitting of a molecular orbital occurs as a result of the strong interaction between the phthalocyanine rings in 2 and 3.
Journal of Organometallic Chemistry, 2013
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 Â 10 À5 e4 Â 10 À6 M. Electrochemical properties of the phthalocyanines have been examined by cyclic voltammetry, square wave voltammetry and in situ UVevis 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.
Dyes and Pigments, 2011
A new class of soluble unsymmetrically substituted metallophthalocyanines (M ¼ Zn, Ni, Co) bearing a crown ether and six alkylthio substituents was synthesized and their electrochemical and spectroelectrochemical properties studied. Cyclic and square wave voltammetry revealed well-defined ligand-based oxidation and reduction processes within the complexes. Assignment of the redox processes was performed by in-situ spectroelectrochemical measurements. The disappearance of the redox processes for the monomeric species and the observation of new waves indicated that intermolecular dimer formation occurred during the potentiometric titration of the complexes with K þ and Na þ ions.
Transition Metal Chemistry, 2005
The focus of the present work is to gain more insight into the electrochemical behavior of newly synthesized Co II , Zn II , Cu II , and Pd II phthalocyanines with tetra-tricarbethoxyethyl substituents at the peripheral position. A more exhaustive electrochemical study of the complexes was done to determine the desired wisdom for the usage of the complexes as a functional material. A comparative study of the voltammetric measurements of these complexes showed that while Zn II , Cu II , and Pd II phthalocyanines exhibited up to four common phthalocyanine ring reductions, Co II phthalocyanine gave a metal-centered oxidation, a reduction and a ligand-centered reduction process. By contrast observation of the splitting of the second reduction process of Pd II phthalocyanine suggests aggregation of the complex. Diffusion coefficients of all complexes were determined by both the cyclic voltammetry and the potential step chronocoulometry techniques. Diffusion coefficients of the reduced and oxidized forms of the redox couples of the complexes were also calculated by the potential step chronocoulometry technique. Diffusion coefficients of the reduced forms of the electrode products of the complexes were found to be slightly higher than that of the oxidized forms.