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 [ZnL3](ClO4)2 and [ZnL4](ClO4)2 was determined by time-resolved fluorescence measurements, where L3 and L4 are the geometrical isomers of 6-[(anthracen-9-ylmethyl)amino]-trans-6,13-dimethyl-1,4, 8,11-tetraazacyclotetradecane-13-amine (L2), substituted with either a naphthalen-1-ylmethyl or naphthalen-2-ylmethyl donor, respectively. The energy-transfer rate constant, kEET, was determined to be (0.92 ± 0.02) × 109 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 ± 0.01) × 109 s-1. The solid..