Electrochemistry and spectral characterization of arsenic porphyrins with σ-bonded axial ligands: X-ray crystallographic analysis of [(OEP)As(F)2]+PF6−, [(OEP)As(CH3)(OCH3)]+ClO4− and [(OEP)As(C2H5)2]+PF6−

The electrochemistry of nine arsenic(V) octaethylporphyrins is reported in benzonitrile or dichloromethane containing 0.1 M tetra-n-butylammonium perchlorate as supporting electrolyte and the results compared to data for phosphorus and antimony porphyrins containing a similar set of σ-bonded and/or anionic axial ligands. The investigated compounds are divided into three groups based on the nature of the axial ligands and are represented as [(OEP)As(R)(R')]+ (group I), [(OEP)As(R)(X)]+ (group II) and [(OEP)As(F)2]+ (group III) where R and R’ = CH3 or C2H5, X = OH−, OCH3−, OC2H5−, OC3H7− or NHC4H9− and OEP = the dianion of octaethylporphyrin. Each compound was characterized in its neutral, oxidized and reduced form by UV-visible and ESR spectroscopy. An X-ray crystallographic analysis of [(OEP)As(F)2]+PF6−, [(OEP)As(CH3)(OCH3)]+ClO4− and [(OEP)As(C2H5)2]+PF6− is also presented.