| Abstract
| - The oxidative electrodeposition of NiTSPP (tetrakis(4-sulfonatophenyl) Ni porphyrin) on ITO electrodefrom 0.1 M NaOH aqueous solution has been studied, and UV−visible and reflection FTIR spectroscopieshave been used to analyze the composition of such film. By use of UV−vis spectroscopy, small absorbanceof the film and an almost nulling effect on the Soret band of the porphyrin along the Ni(III)/Ni(II) redoxprocess were observed. The reflection FTIR spectroscopy detected the presence of Ni−OH groups in thereduced film and as well the state of the porphyrin molecules as radical cation. Moreover, the porphyrinhas been quantified by means of the area of the vibration bands assigned to the sulfonate groups by usingas reference a Langmuir−Blodgett film containing a known surface concentration of NiTSPP. These resultslead us propose the formation of a conductor salt by electrocrystallization, with stoichiometries TSPP/NiII(OH)2 and TSPP/NiIIIOOH, for its reduced and oxidized forms, respectively. In these two forms, theporphyrin rings will be present as radical cation, which may be stabilized through its dimerization orpolymerization.
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