Synthesis and Electrochemical Reactivity of σ-Bonded and N-Substituted Cobalt Porphycenes

• Published in: Inorganic chemistry Vol. 37; no. 11; pp. 2693 - 2700
• Main Authors: Kadish, K. M, Boulas, P. L, Kisters, M, Vogel, E, Aukauloo, A. M, D'Souza, F, Guilard, R
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 01.06.1998
• ISSN: 0020-1669; 1520-510X
• DOI: 10.1021/ic971534c

The first synthesis and characterization of σ-bonded and N-substituted cobalt porphycenes is reported. The investigated compounds are represented as (Pc)Co(R) and (N-CH3OEPc)CoCl, where R is CH3 or C6H5, Pc is the dianion of 2,3,6,7,12,13,16,17-octaethylporphycene (OEPc), 2,7,12,17-tetrapropylporphycene (TPrPc), or 2,7,12,17-tetraethyl-3,6,13,16-tetramethylporphycene (EtioPc), N-CH3OEPc is the monoanion of N-methyl-2,3,6,7,12,13,16,17-octaethylporphycene. Each σ-bonded (Pc)Co(R) derivative can be reversibly reduced or oxidized by two electrons, but a slow migration of the σ-bonded R group occurs following electrogeneration of [(Pc)Co(R)] + • leading, as a final product, to an N-substituted cobalt(II) porphycene which is also electroactive and undergoes two reductions in PhCN. The singly reduced product of this reaction is formulated as a Co(II) π-anion radical which undergoes a slow “back-migration” of the CH3 group to regenerate (OEPc)Co(CH3).