Metalloporphyrins and metallochlorins are important biological molecules in nature. To examine the effect of macrocyclic structures on removal of central metals from these cyclic tetrapyrrole molecules without peripheral substitution effects, demetalation of zinc methyl pyropheophorbide a (zinc chlorin 1) and zinc methyl protopyropheophorbide a (zinc porphyrin 2) was kinetically analyzed under acidic conditions. Both 1 and 2 exhibited ...
