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Synthesis, Characterization, and Electrochemical and Electrical Properties of Novel Pentaerythritol‐Bridged Cofacial Bismetallophthalocyanines and Their Water‐Soluble Derivatives
Author(s) -
Özer Metin,
Altındal Ahmet,
Özkaya Ali Rıza,
Salih Bekir,
Bulut Mustafa,
Bekaroğlu Özer
Publication year - 2007
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.200700141
Subject(s) - chemistry , dielectric spectroscopy , pentaerythritol , phthalocyanine , conductivity , hydroxymethyl , aqueous solution , electrochemistry , methanol , fourier transform infrared spectroscopy , intramolecular force , arrhenius plot , analytical chemistry (journal) , nuclear chemistry , organic chemistry , electrode , chemical engineering , fire retardant , engineering , activation energy
Novel cofacial bismetallophthalocyanines and theirwater‐soluble derivatives were prepared. The precursor4,4′‐(2‐phenyl‐1,3‐dioxane‐5,5‐diyl)bis(methylene)bis(oxy)diphthalonitrile 3 was obtained by the reaction of [5‐(hydroxymethyl)‐2‐phenyl‐1,3‐dioxan‐5‐yl] methanol 1 and 4‐nitrophthalonitrile 2 with K 2 CO 3 in DMF at 50 °C. Cyclotetramerization was achieved by heating the homogenized mixture of the precursor, bisphthalonitrile, and Zn(OAc) 2 · 2H 2 O or Co(OAc) 2 · 4H 2 O at 300 °C, which was followed by catalytic hydrogenation of the resulting product with Pd/C(10 %) in DMF. The target water‐soluble phthalocyanines were acquired from boiling suspensions of the compounds bearing eight OH side groups in aqueous KOH (20 %) solution. The structure of the target compounds was confirmed by elemental analysis, FTIR, UV/Vis, 1 H NMR, ICP‐MS, and MALDI‐TOF spectroscopic methods. The electrochemical and spectroelectrochemical measurements suggested the formation of various mixed‐valent oxidation and reduction species, as a result of the strong intramolecular interactions between the two cofacial phthalocyanine units in the compounds. Impedance spectroscopy, dc conductivity, and thermopower measurements were performed using spin‐coated films of these compounds as a function of temperature (290–440 K) and frequency (40–10 5 Hz). Dc conductivity showed typical Arrhenius behavior for all compounds. At low temperatures, a curved line was observed for the complex plane plots of impedance for all phthalocyanines. These curved lines transformed into a full semicircle with increasing temperature. The dependency of frequency exponent s on temperature suggested hopping‐type conduction. A positive Seebeck coefficient was observed for all compounds, which indicates that the compounds behave as a p ‐type semiconductor. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)