Synthesis, electrochemical and spectroelectrochemical studies of octaphenylthio-substituted phthalocyanines

Cobalt (4) and iron (5) phenylthio-substituted phthalocyanines ( MPc ( SR ) 8 ) have been synthesized and characterized. Cyclic square wave voltammetry in dimethylformamide containing tetrabutylammonium perchlorate revealed five and six redox processes, respectively, for complexes 4 and 5. The complexes are easier to reduce compared to the corresponding unsubstituted MPc and to butylthio substituted derivatives. The first oxidation and reduction occurs on the metal for both complexes. Spectroelectrochemistry (in dimethylformamide containing tetrabutylammonium perchlorate) was employed to assign the cyclic voltammetry peaks, and gave spectra characteristic of Fe I Pc for reduction of 5 and Co I Pc for the reduction of 4. The spectrum of the former is particularly of importance since such species have not received much attention in the literature.