Modulation of vectorial energy transfer in the tetrakis[tris(bipyridine)ruthenium(II)]porphyrinate zinc complex

Reported are the synthesis and photophysical properties of a new supermolecular zinc porphyrin containing four tris(4,4 ' -dimethyl-2,2 ' -bipyridine)ruthenium(II) complexes as substituents at the meso position. In this system, the lowest energy singlet excited state of the zinc porphyrin is energetically close to the tris(bipyridine)ruthenium(II) triplet MLCT excited state. The fact that the zinc porphyrin states are sensitive to ligand coordination effects, in contrast with the ruthenium(II) moieties, has allowed a selective tuning of the ruthenium complex and porphyrin excited states, providing an efficient control of the vectorial energy transfer process. (C) 2001 Elsevier Science B.V. All rights reserved.