The Synthesis and One- and Two-Photon Optical Properties of Dipolar, Quadrupolar and Octupolar Donor-Acceptor Molecules Containing Dimesitylboryl Groups

C. Katan present address: CNRS UMR6082 FOTON, INSA de Rennes, 20 avenue des Buttes de Coësmes, CS 70839, 35708 RENNES cedex 7, FranceInternational audienceTwo series of related donor-acceptor conjugated dipolar, pseudo-quadrupolar (V-shaped) and octupolar molecular systems based on the p-dimesitylborylphenylethynylaniline, namely 4-(4-dimesitylborylphenylethynyl)-N,N-dimethylaniline, 4-[4-(4-dimesitylboryl-phenylethynyl)phenylethynyl]-N,N-dimethylaniline, 4,4'-bis(4-dimesitylborylphenyl-ethynyl)-N-n-butylcarbazole and tris[4-(4-dimesitylborylphenylethynyl)phenyl]amine, and on the E-p-dimesitylborylethenylaniline motif, namely E-4-dimesitylborylethenyl-N,N-di(4-tolyl)aniline, 4,4'-bis(E-dimesitylborylethenyl)-N-n-butylcarbazole and tris(E-4-dimesitylborylethenylphenyl)amine have been synthesized, by palladium catalyzed cross-coupling and hydroboration routes respectively. Their absorption and emission maxima, fluorescence lifetimes and quantum yields have been obtained and their two-photon absorption spectra and two-photon absorption (TPA) cross-sections have been examined. Of these systems, the octupolar compound tris-(E-4-dimesitylborylethenylphenyl)amine has been shown to exhibit by far the largest two-photon absorption cross-section among the two series and amount to about 1000 GM at 740 nm. Its TPA performance is comparable to those of other triphenylamine based octupoles of similar size