Electronic energy-transfer rate constants for geometrical isomers of a bichromophoric macrocyclic complex

Abstract

The rate of electronic energy transfer (EET) between a naphthalene donor and an anthracene acceptor in [ZnL(3)](ClO(4))(2) and [ZnL(4)](ClO(4))(2) was determined by time-resolved fluorescence measurements, where L(3) and L(4) are the geometrical isomers of 6-[(anthracen-9-ylmethyl)amino]-trans-6,13-dimethyl-1,4,8,11-tetraazacyclotetradecane-13-amine (L(2)), substituted with either a naphthalen-1-ylmethyl or naphthalen-2-ylmethyl donor, respectively. The energy-transfer rate constant, k(EET), was determined to be (0.92 +/- 0.02) x 10(9) s(-1) for the naphthalen-1-ylmethyl-substituted isomer, while that for the naphthalen-2-ylmethyl-substituted isomer is somewhat faster, with k(EET) = (1.31 +/..