New chemistry of amethyrin

✍ Scribed by Sharon Hannah; Daniel Seidel; Jonathan L Sessler; Vincent Lynch

• Book ID: 104138473
• Publisher: Elsevier Science
• Year: 2001
• Tongue: English
• Weight: 154 KB
• Volume: 317
• Category: Article
• ISSN: 0020-1693
• DOI: 10.1016/s0020-1693(01)00363-2

✦ Synopsis

As a first step towards studying the metallation chemistry of amethyrin, a previously reported hexapyrrolic expanded porphyrin [Chem. Eur. J. 1 (1995) 56], a simpler and higher-yielding synthesis of the macrocycle has been developed. The single crystal X-ray crystallographic structure of the free-base form of this easily protonated product has also been determined. The non-planar macrocycle is coordinated to two methanol molecules through hydrogen bonding interactions. The 1 H NMR spectrum of this methanol complex, combined with disorder observed in the solid-state structure, supports the contention that the two pyrrolic protons and the two hydroxyl protons of the methanol may be involved in a fast exchange process. Exploration of the metal-coordination chemistry of amethyrin has led to the conclusion that new metal complexes such as the bis-Ni(II) complex reported here are best obtained under non-protic conditions. UV-Vis spectral analysis of the bis-Ni(II) complex lends credence to the conclusion that coordination of metals may lead to oxidation of the macrocycle thereby yielding aromatic metal complexes.