Synthesis and investigation of the effects of position and nature of substituent on the spectral, electrochemical and spectroelectrochemical properties of new cobalt phthalocyanine complexes
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Date
2010-01-04
Authors
Akinbulu, I.A
Nyokong, T
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Abstract
The syntheses of new cobalt phthalocyanine (CoPc) complexes, tetra-substituted with diethylaminoethanethio at the peripheral (complex 3a) and non-peripheral (complex 3b) positions, and with benzylmercapto at the non-peripheral position (complex 5), are reported. The effects of the nature and position of substituent on the spectral, electrochemical and spectroelectrochemical properties of these complexes are investigated. Solution electrochemistry of complex 3a showed three distinctly resolvedredox processes attributed to CoIIIPc2/CoIIPc2 (E½ = +0.64 V versus Ag|AgCl), CoIIPc2/CoI Pc2 (E½ = 0.24 V versus Ag|AgCl) and CoI Pc2/CoI Pc3 (E½ = 1.26 V versus Ag|AgCl) species. No ring oxidation was observed in complex 3a. Complex 3b showed both ring-based oxidation, attributed to CoIIIPc1 / CoIIIPc2 species (Ep = +0.86 V versus Ag|AgCl), and ring-based reduction associated with CoI Pc2/CoI Pc3 species (E½ = 1.46 V versus Ag|AgCl), with the normal metal-based redox processes in CoPc complexes: CoIIIPc2 /CoIIPc2 (Ep = +0.41 V versus Ag|AgCl) and CoIIPc2 /CoI Pc2 (E½ = 0.38 V versus Ag|AgCl). Solution electrochemistry of complex 5 showed the same type and number of species observed in complex 3a: CoIIIPc2 /CoIIPc2 (Ep = +0.59 V versus Ag|AgCl), CoIIPc2 /CoI Pc2 (E½ = 0.26 V versus Ag|AgCl) and CoI Pc2 /CoI Pc3 (E½ = 1.39 V versus Ag|AgCl) species. These processes were confirmed using spectroelectrochemistry.
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Keywords
Cobalt phthalocyanine (CoPc) complexes , Diethylaminoethanethio , spectroelectrochemical properties , Ring-based oxidation , Research Subject Categories::NATURAL SCIENCES::Chemistry
Citation
Akinbulu, I. A., & Nyokong, T. (2010). Syntheses and investigation of the effects of position and nature of substituent on the spectral, electrochemical and spectroelectrochemical properties of new cobalt phthalocyanine complexes. Polyhedron, 4(29), 1257-1270.