Unexpected isolation and characterization of a chloroiron complex with a 10-acetylcorrole ligand
The chloroiron complex of 10-acetyl-2,3,7,8,12,13,17,18-octaethylcorrole was isolated as an unexpected product from an attempted preparation of chloroiron-2,2'-bidipyrrin when acetone was used in the solvent mixture. In the molecular structure derived from X-ray crystallographic analysis the orthogonal arrangement of the acetyl group with the corrole macrocycle is clearly apparent, and the UV-vis spectrum of the compound indicates only a small electronic influence of the acetyl group on the corrole π-system. The paramagnetic 1 H NMR spectrum taken at ambient temperature shows two signal sets in a ratio of 2.2:1, indicating two stable orientations of the acetyl group in solution. Attempts to prepare the species from chloroiron-2,2'-bidipyrrin with iron(III)chloride in acetone were successful but gave inconsistent and generally low yields. A rationale for the formation of the new corrole is proposed.