Corroles with group 15 ions. 2. Synthesis and characterization of octaethylcorroles containing a phosphorus central atom

The synthesis, spectroscopic characterization, and electrochemistry of five new phosphorus corroles are reported. The investigated complexes contain alkyl, aryl, oxo, or hydrido axial ligands and are represented as (OEC)P(H)2, (OEC)P(CH3)2, (OEC)P(C6H5)2, (OEC)P=O, and (OEC)P(CH3)]+ClO4-, where OEC is the trianion of octaethylcorrole. The products of electrooxidation and/or electroreduction were also characterized by UV-vis and ESR spectroscopy. Correlations are shown to exist between reversible half-wave potentials for the first oxidation and first reduction of each compound and the combined electronegativity of the central ion and the axial ligand(s). The electrochemical HOMO-LUMO gap, defined as the difference between first reduction and first oxidation, was found to be independent of the electron-transfer site and similar in magnitude to the value generally observed for metalloporphyrins with planar macrocycles, i.e., 2.25 +/- 0.15 V.