Covalent linking of coordination-organized slipped cofacial porphyrin dimers

Coordination-organized porphyrin chillers of 5,15-bis[2-(allyloxycarbonyl)ethyl]- and bis[3-(allyloxy)propyl]-20-(1- methyl-2-imidazolyl)porphyrinatozine were covalently linked by an intramolecular olefin metathesis reaction in excellent yields (93-98%). It was found that the yields of the intramolecular metathesis reaction depended strongly on the molecular length of the substituent at the 5 and 15 positions. Introducing longer 3-(allyloxycarbonyl)propyl and 4-(allyloxycarbonyl)butyl substituents decreased sharply the yields of the covalent linking reaction to 26% and 16%, respectively. The covalently linked dimers maintained their coordination structures even when dissolved in as polar a solvent as pyridine.