Meso-functionalized octamethoxyporphyrins: A new class of nonasubstituted porphyrins

Abstract

Octamethoxyporphyrin containing multiple-donor substituents has been functionalized for the first time. A large number of its mono-meso-substituted derivatives with substituents such as nitro, amino, N-methylamino, formyl, hydroxymethyl, oxime, cyano and carboxy functional groups have been synthesized and characterized. They form a new class of nonasubstituted porphyrins. Crystallographic studies on the cyano derivative show that the -C N group is in conjugation with the prophyrin π-system. The calculated optical transition energies and the electron densities on the imino nitrogens of the synthesised porphyrins using AMI calculations correlate well with the experimentally observed data. Meso-substituted porphyrins are found to be essentially planar.