5,10,15,20-Mesotetrakis(3,5-di-t-butyl-4-quinomethide)porphyrinogen: a highly puckered tetrapyrrolic macrocycle from the facile aerial oxidation of a phenolic porphyrin

The unusually highly puckered macrocyclic core of the title compound confirms proposed conformational changes which are essential for the facile aerial oxidation of phenolic porphyrins, such as meso-tetrakis(3,5-di-t-butyl-4-hydroxyphenyl)porphyrin (1).