Solution-phase molecular recognition of an azafullerene-quinoline dyad by a face-to-face porphyrin-dimer tweezer.

A face-to-face porphyrin dimer, (H 2 P) 2 "porphyrin tweezer", was explored as a photo- and redox-responsive host for the molecular recognition of an azafullerene (C 59 N) derivative bearing an amphoteric pentafluoroquinoline (FQ) domain. The intramolecular electronic coupling between the FQ substituent and the C 59 N cage, within the newly synthesized C 59 N-FQ dyad was evaluated, while the neutral and protonated form of the covalently attached FQ moiety were utilized as recognition motifs for the (H 2 P) 2 tweezer. Complementary photophysical and electrochemical techniques were applied to investigate the electronic communication between the porphyrin-dimer (H 2 P) 2 tweezer and the azafullerene cage as mediated by the FQ unit.