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Updated: Aug 13, 2026

Excitonic Hamiltonians for Calculating Optical Absorption Spectra and Optoelectronic Properties of Molecular Aggregates and Solids
Published on: May 27, 2020
Electronic energy-transfer rate constants for geometrical isomers of a bichromophoric macrocyclic complex
Evan G Moore1, Paul V Bernhardt, Mark J Riley
1Department of Chemistry, School of Molecular and Microbial Science, University of Queensland, Brisbane, Australia. EGMoore@lbl.gov
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 +/- 0.01) x 10(9) s(-1). The solid-state structure of [ZnL(3)Cl]ClO(4) has been determined, and using molecular modeling calculations, the likely distributions of solution conformations in CH(3)CN have been evaluated for both complexes. The calculated conformational distributions in the common trans-III N-based isomeric form gave Förster EET rate constants that account for the differences observed and are in excellent agreement with the experimental values. It is shown that the full range of conformers must be considered to accurately reproduce the observed EET kinetics.
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