Electrochemistry and spectroelectrochemistry of strongly electron-withdrawing metallated octanitrophthalocyanines

The spectral and electrochemical properties of metallated octanitrophthalocyanines, [M¹¹{(NO₂)₈pc}] where M = Zn, Cu or Co, were studied by electrochemical and spectroelectrochemical methods as well as electronic absorption and magnetic circular dichroism spectroscopy. Aggregation is observed for several species. The octanitrophthalocyanines are easier to reduce and more difficult to oxidize than most other metallophthalocyanines. Indeed, the first ring-localized reduction potential observed with these phthalocyanine species, is the most positive of the metallated, neutral phthalocyanines in the literature. These data are added to existing Hammett free energy relationship database to extend design protocols for substituted metallophthalocyanines. Optical spectra for several redox series are presented and related to the existing literature.