Electrochemical, spectroelectrochemical, and dielectric properties of metallophthalocyanines bearing redox active cobalt and manganese metal centres


UZUNMEHMETOGLU H. Z. , Yenilmez H. Y. , Kaya K. , Koca A., ALTINDAL A., Bayir Z. A.

INORGANICA CHIMICA ACTA, vol.459, pp.51-62, 2017 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 459
  • Publication Date: 2017
  • Doi Number: 10.1016/j.ica.2017.01.017
  • Title of Journal : INORGANICA CHIMICA ACTA
  • Page Numbers: pp.51-62

Abstract

We report herein the synthesis of symmetrical metallophthalocyanines having cobalt, zinc, and manganese as the metal ions, and having tetrakis(4-phenyl-1,3-thiazole-2-thiolate) groups substituted at the peripheral positions of the phthalocyanine. Electrochemical responses of the complexes were determined with voltammetric and in situ spectroelectrochemical measurements. Cobalt and mu-oxo manganese phthalocyanines (CoPc and mu-oxo MnPc) illustrated metal-based electron transfer reactions in addition to the Pc based reactions.-oxo-manganese phthalocyanine exhibited completely different redox properties than those of the monomeric manganese phthalocyanine. Thiazole substituents of the complexes caused oxidative electropolymerisation of the complexes on the working electrode. Electropolymerised-oxo manganese phthalocyanine catalyzed oxygen evolution reaction (OER) in basic aqueous solution. The ac behaviour of the tetrasubstituted metallophthalocyanines was studied by impedance spectroscopy technique over a temperature range of 300-450 K and frequency of 100 Hz-13 MHz. The results show that the new compounds exhibit abnormally high dielectric constants even at room temperature. It was concluded that Maxwell-Wagner polarisation is an appropriate model to explain the behaviour of the dielectric function at low frequencies. Frequency dependent measurements revealed that the compounds exhibits non-Debye type relaxation behaviour. (C) 2017 Elsevier B.V. All rights reserved.