HIGHLY REDOX-ACTIVE OLIGOMERIC PORPHYRINS

Can an organic pi-system be used to efficiently store charge by successive addition of electrons and is the storage capacity increased on going to higher analogues containing several redox centers? We have examined this question for the zinc complex of the meso-5,10,15,20 tetratolylporpyrin 1 as redox system. Chemical and electrochemical experiments show that the pi-system is able to accept six electrons reversibly. Furthermore, in the stilbene-linked bisporphyrinyl 5, cyclic voltammetric measurements prove that the model system can store up to twelve electrons reversibly. The ease of preparation of the porphyrinmonobenzaldehyde 2 and the isomeric porphyrinyldibenzaldehydes 3 and 4 enables us to synthesize various linked bisporphyrinyl systems.