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 CHCl 3 ). 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.