INTRAMOLECULAR ELECTRONIC-ENERGY TRANSFER BETWEEN RIGIDLY LINKED NAPHTHALENE AND ANTHRACENE CHROMOPHORES

Abstract

The rate of intramolecular singlet-singlet electronic energy transfer (EET) between naphthalene and anthracene chromophores that are held in a well-defined orientation and separation by a rigid bis(norbornyl)bicyclo-[2.2.0]hexane bridge, six σ-bonds in length, is measured to be 2.9 × 1010 s-1 (n-hexane). EET between the lowest-energy naphthalene 1Lb and anthracene 1La states (via a direct Coulombic mechanism) is forbidden in this molecule because of the orthogonality of donor and acceptor transition dipoles. EET involving a Coulombic interaction between the naphthalene 1Lb and the nonfluorescent anthracene 1Lb electronic states is also considered. Although Coulombic EET is vibronically allow..