ELECTRONIC INTERACTION AND CHARGE-TRANSFER EFFICIENCIES IN TRIAROMATIC DONOR-ACCEPTOR SYSTEMS - AN EXPERIMENTAL AND THEORETICAL-STUDY

To address the issue of electronic interaction between donor (D) and a cceptor (A) moieties in intramolecular charge transfer reactions a ser ies of chemically closely related extended pi-systems has been investi gated, These compounds contain pyrene and organic methyl ester derivat ives connected via a phenyl group. Our steady-state fluorescence studi es reveal that only particular compounds exhibit strong charge transfe r (CT) emission in solution. To elucidate the experimental results we have performed semiempirical CNDO/S-CI calculations which indicate tha t the electronic coupling and Coulomb stabilization of the CT state ar e strongly dependent on the nodal properties of the D/A orbitals. (C) 1998 Elsevier Science B.V.