title: Medium-dependent type selectivity in photoreactions of a crown ether-annelated dibenzobarrelene derivative.
abstract: [reaction: see text] A concept for modifying the photochemical properties of a dibenzobarrelene derivative by the combination of supramolecular assembly and solid-state photochemistry is presented. The irradiation of dibenzobarrelene 1b and alkali metal complexes thereof (1:1) in acetonitrile or benzene solution leads preferentially to the dibenzocyclooctatetraene 4b as the photoproduct. In contrast, the dibenzosemibullvalene 5b is formed as the main photoproduct in the solid state because of a strong cation effect.
authors.affiliation: Institute of Organic Chemistry, University of Würzburg, Am Hubland, Germany. ihmels@chemie.uni-wuerzburg.de
authors.forename: Heiko
authors.initials: H
authors.lastname: Ihmels
authors.forename: Michael
authors.initials: M
authors.lastname: Schneider
authors.forename: Michael
authors.initials: M
authors.lastname: Waidelich