Long-range electrostatic effects from intramolecular Lewis acid binding influence the redox properties of cobalt-porphyrin complexes.

A Co-porphyrin complex (1) with an appended aza-crown ether for Lewis acid (LA) binding was synthesized and characterized. NMR spectroscopy and electrochemistry show that cationic group I and II LAs (, Li, Na, K, Ca, Sr, and Ba) bind to the aza-crown ether group of 1. The binding constant for Li is comparable to that observed for a free aza-crown ether.