title: A Perylene Bisimide Cyclophane as a "Turn-On" and "Turn-Off" Fluorescence Probe.
abstract: A rigid, covalently linked perylene-3,4:9,10-tetracarboxylic acid bisimide (PBI) cyclophane was synthesized by imidization of a bay-substituted perylene bisanhydride with p-xylylenediamine. The interchromophoric distance of approximately 6.5 Å establishes an ideal rigid cavity for the encapsulation of large aromatic compounds such as perylene and anthracene with binding constants up to 4.6×10(4)  M(-1) (in CHCl3 ). For electron-poor guest molecules, the complexation process is accompanied by a significantly increased fluorescence, whereas the emission intensity is dramatically quenched by more electron-rich guests because of the formation of charge-transfer complexes. Furthermore, the influence of the PBI core twist on the binding constant results in a remarkable selectivity towards more flexible aromatic guest molecules.
authors.affiliation: Universität Würzburg, Institut für Organische Chemie and Center for Nanosystems Chemistry, Am Hubland, 97074 Würzburg (Germany).
authors.forename: Peter
authors.initials: P
authors.lastname: Spenst
authors.affiliation: Universität Würzburg, Institut für Organische Chemie and Center for Nanosystems Chemistry, Am Hubland, 97074 Würzburg (Germany). wuerthner@chemie.uni-wuerzburg.de.
authors.forename: Frank
authors.initials: F
authors.lastname: Würthner
keywords: cyclophanes; dyes/pigments; fluorescence probes; host-guest chemistry; perylene bisimides