title: Synthesis, optical characterization, and electrochemical properties of isomeric tetraphenylbenzodifurans containing electron acceptor groups.
abstract: Isomeric tetraphenylbenzodifuran systems, benzo[1,2-b:5,4]difuran and benzo[1,2-b:4,5]difuran, containing electron acceptor groups (CF(3), CN, and NO(2)) have been synthesized and studied. Their electronic absorption, fluorescence, two-photon absorption cross sections, and electrochemical properties were investigated. The absorption and emission maxima are red-shifted for the linear-conjugated systems in comparison with the corresponding isomer. Dual fluorescence was observed and the existence of a twisted intramolecular charge transfer state was confirmed by low-temperature emission experiments. Wide HOMO-LUMO energy gaps were obtained ranging from 2.53 to 3.28 eV. HOMO levels were found in the energy range of -6.03 to -6.63 eV while LUMO are within -2.55 to -3.52 eV.
authors.affiliation: NASA Glenn Research Center, Polymeric Materials Branch, Cleveland, Ohio 44135, United States. javier.santos-1@nasa.gov
authors.forename: Javier
authors.initials: J
authors.lastname: Santos-Pérez
authors.forename: Carlos E
authors.initials: CE
authors.lastname: Crespo-Hernández
authors.forename: Christian
authors.initials: C
authors.lastname: Reichardt
authors.forename: Carlos R
authors.initials: CR
authors.lastname: Cabrera
authors.forename: Ileana
authors.initials: I
authors.lastname: Feliciano-Ramos
authors.forename: Lisandra
authors.initials: L
authors.lastname: Arroyo-Ramírez
authors.forename: Michael A
authors.initials: MA
authors.lastname: Meador
mesh_terms: D001572:Benzofurans / Q000138:chemical synthesis* / Q000737:chemistry*; D004563:Electrochemistry; D005453:Fluorescence; D015394:Molecular Structure; D011789:Quantum Theory; D013237:Stereoisomerism
chemical_list: D001572:Benzofurans