Energy transfer in a porphyrin chelate assembly

Energy transfer among isoenergetic pigments, three oxinyl-substituted free- base porphyrins in an octahedral chelate Ga(III) complex, has been studied by the femtosecond fluorescence up-conversion technique. The anisotropy dec ay of the complex has a fast component of similar to 10 ps which is assigne d to the energy transfer between the nearest porphyrin units in the complex . The anisotropy decay of the monomer (oxinyl-substituted porphyrin) is muc h slower and reflects monomer rotational dynamics in solution with decay ti mes of 50 and similar to 200 ps in dichloromethane. (C) 1999 Elsevier Scien ce B.V. All rights reserved.