PROTONATION OF COBALT TETRANEOPENTOXYPHTHALOCYANINE AS A FUNCTION OF OXIDATION-STATE

The protonation of cobalt tetraneopentoxyphthalocyanine (CoTNPc) has been studied as a function of the oxidation state of this species. Data are reported for phthalocyanine cobalt(I), cobalt(II), cobalt(III) and cobalt(III) cation radical species, usually dissolved in dichlorobenzene (DCB). Upto four stepwise protonation processes were observed using trifluoroacetic (TFAA), hydrochloric or sulfuric acid. These were followed by recording the electronic spectra of these species as a function of acid concentration. Analysis of these spectra, which usually displayed isosbestic points, yielded stoichiometry and stability constant data and allowed for the identification of the spectra of the species generated. The spectra are discussed in terms of a previously reported model for protonation of phthalocyanine species. Electronic spectroscopic data are reported for protonated phthalocyanine radical species, for the first time. The basicity of these species decreases from the cobalt(I) species to the cobalt(III) radical cation species, in order of increasing oxidation state.