Free Base Porphyrin Dimers Research Articles

Bis-Porphyrins Containing Diimine Chelates of Variable Geometry as Spacer

Etio or meso type free base porphyrin dimers bridged by either 6,6′-diphenyl-2,2′-bipyridine or 2,9-diphenyl- 1,10-phenanthroline spacers were synthesized following parallel routes. Mctallation of one of the porphyrins with zinc(II) allowed to study the intramolecular fluorescence quenching of the zinc(II) porphyrin component by the free base component within the dimers. It was shown to depend on the nature of the heterocyclic spacer.

A time-resolved ESR study on triplet-triplet energy transfer processes in a copper(II)-free-base porphyrin dimer

Energy transfer from a copper porphyrin moiety to its free-base partner is observed in a copper(II)-free-base hybrid porphyrin dimer. By the measurements of T-T transient absorption spectra in toluene, the triplet yield of the free-base porphyrin was found to be increased in the hybrid dimer compared with that in a monomeric free-base porphyrin. Time-resolved ESR study revealed that this intramolecular energy transfer occurs between the triplets. From the simulation of the TR-ESR spectrum, the mean value of the dihedral angle between the donor and the acceptor is estimated as 30 degrees.