POLYHEDRON, vol.26, no.14, pp.3505-3512, 2007 (SCI-Expanded)
New mononuclear phthatocyanines [Zn(II) 4 and Co(II) 6] and ball-type bisphthalocyanines [Zn(II) 5 and Co(II) 7] have been synthesized from the corresponding compound 3, which can be obtained from the reaction of 4-nitrophthalonitrile I with la,8b-dihydro-naphtho[b]naphthofuro[3,2-d]furan-7,10-diol 2. The novel compounds have been characterized by elemental analysis, UV/Vis, IR, H-1 NMR and MASS spectroscopy. The electrochemical measurements show the formation of various mixed-valence oxidized and reduced species, due to intramolecular interactions between the two phthalocyanine units in the ball-type binuclear metallophthalocyanines. Detailed studies of the effect of temperature on the electronic properties of the films were investigated by dc conductivity and impedance spectroscopy techniques at temperatures between 290 K and 460 K. Thermally activated conductivity dependence on temperature was observed from the dc measurements. The ac results give a power law behavior in which the frequency exponent decreases with temperature. It was observed that the impedance spectra consist of a curved line at low temperature. These curved lines transform into a full semicircle with increasing temperature. (c) 2007 Elsevier Ltd. All rights reserved.