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Fluorescence Regeneration as a Signaling Principle for Choline and Carnitine Binding: A Refined Supramolecular Sensor System Based on a Fluorescent Azoalkane
Author(s) -
Bakirci H.,
Nau W. M.
Publication year - 2006
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.200500219
Subject(s) - fluorescence , supramolecular chemistry , binding constant , choline , ion , quenching (fluorescence) , carnitine , ammonium , materials science , combinatorial chemistry , chemistry , molecule , organic chemistry , biochemistry , physics , quantum mechanics
The fluorescent azoalkane, 2,3‐diazabicyclo[2.2.2]oct‐2‐ene (DBO), forms inclusion complexes with p ‐sulfonatocalix[4]arene (CX4). The binding constants are on the order of 10 3 M –1 in water. The addition of CX4 to DBO solutions results in an efficient fluorescence quenching (up to 90 %). This supramolecular system can be used as a truly water‐soluble sensor system to signal the binding of organic ammonium ions over a large pH range. Addition of choline and carnitine derivatives and tetraalkylammonium ions results in regeneration of this fluorescence, from which the binding constants ( K C = 10 3 –10 5 M –1 ) are calculated by means of a competitive complexation model. Electrostatic effects are observed, namely, a more‐than‐one order of magnitude weaker binding of the carnitines in neutral solution.