Intramolecular excited charge-transfer states in donor-acceptor derivatives of naphthalene and azanaphthalenes

Electronic structure and molecular conformation of selected donor-acceptor isomeric derivatives of naphthalene, quinoline and quinazoline as well as a family of isomeric triazanaphthalenes containing N,N-dimethylaniline as an electron donor in the excited charge transfer singlet ((CT)-C-1) states ha ve been investigated. The mechanism of the (CT)-C-1 <-- S-0 absorption and (CT)-C-1 --> S-0 emission is discussed in terms of the Mulliken-Murrell mod el of the CT complexes and the Marcus formalism of radiative charge transfe r. The determination of the electronic transition dipole moments correspond ing to the CT absorption and fluorescence and the band-shape analysis of th e corresponding spectra lead to the quantities relevant for the (CT)-C-1 -- > S-0 charge recombination in the Marcus inverted region. It is shown that some of the photophysical properties of the compounds can be predicted in t erms of a simple LCAO MO description from the properties of individual chro mophores.