254
Strong Emission Enhancement in pH-Responsive 2:2 Cucurbit[8]uril Complexes

graphical abstract

graphical abstract

S. Schoder, H.V. Schröder, L. Cera, R. Puttreddy, A. Güttler, U. Resch-Genger, K. Rissanen, C.A. Schalley – 2019

Organic fluorophores, particularly stimuli-responsive molecules, are very interesting for biological and material sciences applications, but frequently limited by aggregation- and rotation caused photoluminescence quenching. A series of easily accessible bipyridinium fluorophores is reported, whose emission is quenched by a twisted intramolecular charge transfer (TICT) mechanism. Encapsulation in a cucurbit[7]uril host yields a 1:1 complex exhibiting a moderate emission increase due to destabilization of the TICT state inside the apolar cucurbituril cavity. A much stronger is the fluorescence enhancement is observed in 2:2 complexes with the larger cucurbit[8]uril, which is caused by additional conformational restriction of rotations around the aryl-aryl bonds. As the cucurbituril complexes are pH switchable, this system represents an efficient supramolecular ON/OFF fluorescence switch.

Title
254
Strong Emission Enhancement in pH-Responsive 2:2 Cucurbit[8]uril Complexes
Author
S. Schoder, H.V. Schröder, L. Cera, R. Puttreddy, A. Güttler, U. Resch-Genger, K. Rissanen, C.A. Schalley
Date
2019-01-12
Identifier
DOI: 10.1002/chem.201806337
Citation
Chem. Eur. J. 2019, 25, 3257-3261
Type
Text