title: Versatile strategy to access fully functionalized benzodifurans: redox-active chromophores for the construction of extended pi-conjugated materials.
abstract: An efficient synthetic approach to construct a fully substituted benzo[1,2-b:4,5-b']difuran (BDF) 2a via base-catalyzed double annulations is presented. Compound 2a can readily undergo Suzuki, Heck, and Sonogashira coupling reactions to afford in good yields a manifold of extended pi-conjugated BDF derivatives, e.g., with pyridine termini (4-6) and with different spacers. These are highly luminescent materials that undergo two reversible one-electron oxidations. Remarkably, their photophysical and electrochemical properties can be largely tuned by methylation or protonation. Consequently, they can function as pH-dependent fluorescence switches. Finally, the observed electronic properties are explained on the basis of density functional theory.
authors.affiliation: Departement für Chemie und Biochemie, Universität Bern, Freiestrasse 3, CH-3012 Bern, Switzerland.
authors.forename: Chenyi
authors.initials: C
authors.lastname: Yi
authors.forename: Carmen
authors.initials: C
authors.lastname: Blum
authors.forename: Mario
authors.initials: M
authors.lastname: Lehmann
authors.forename: Stephan
authors.initials: S
authors.lastname: Keller
authors.forename: Shi-Xia
authors.initials: SX
authors.lastname: Liu
authors.forename: Gabriela
authors.initials: G
authors.lastname: Frei
authors.forename: Antonia
authors.initials: A
authors.lastname: Neels
authors.forename: Jürg
authors.initials: J
authors.lastname: Hauser
authors.forename: Stefan
authors.initials: S
authors.lastname: Schürch
authors.forename: Silvio
authors.initials: S
authors.lastname: Decurtins
mesh_terms: D001572:Benzofurans / Q000138:chemical synthesis* / Q000737:chemistry; D003198:Computer Simulation; D006863:Hydrogen-Ion Concentration; D049449:Luminescence; D008163:Luminescent Measurements; D015394:Molecular Structure; D010084:Oxidation-Reduction; D011725:Pyridines / Q000737:chemistry*
chemical_list: D001572:Benzofurans; D011725:Pyridines; C023666:pyridine