Chemistry of Iron(III) in a Hemin-like Macrocyclic [N(4)](2)(-) Environment: Relationship between CT Absorption and EPR Spectra.

The visible/near-IR and EPR spectra of the octahedral low-spin diadducts of the ethylene-bridged complex 6,13-diethoxycarbonyl-5,14-dimethyl-1,4,8,11-tetraazacyclotetradeca-4,6,12,14-tetraenato[2(-)]iron(III) iodide (1a-I), the ethylene/phenylene 1b-I, and the phenylene-bridged analogous complex 1c-I were investigated as a function of the axial and equatorial ligands. 1a-I forms octahedral low-spin diadducts in polar solvents (water, methanol) with a large variety of bases (pyridines, imidazoles, ammonia, amines, hydroxide, pseudohalides, sulfite, thiosulfate, nitrite, isonitriles, phosphines, phosphites, etc.).