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 supermolec ular zinc porphyrin containing four tris(4,4 ' -dimethyl-2,2 ' -bipyridine) ruthenium(II) complexes as substituents at the meso position. In this syste m, the lowest energy singlet excited state of the zinc porphyrin is energet ically close to the tris(bipyridine)ruthenium(II) triplet MLCT excited stat e. The fact that the zinc porphyrin states are sensitive to ligand coordina tion effects, in contrast with the ruthenium(II) moieties, has allowed a se lective tuning of the ruthenium complex and porphyrin excited states, provi ding an efficient control of the vectorial energy transfer process. (C) 200 1 Elsevier Science B.V. All rights reserved.