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A Click Fluorophore Sensor that Can Distinguish Cu II and Hg II via Selective Anion‐Induced Demetallation
Author(s) -
Lau Yu Heng,
Price Jason R.,
Todd Matthew H.,
Rutledge Peter J.
Publication year - 2011
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201002477
Subject(s) - fluorophore , ion , click chemistry , chemistry , fluorescence , materials science , photochemistry , biophysics , combinatorial chemistry , physics , organic chemistry , optics , biology
A cyclam‐based fluorescent sensor featuring a novel triazole pendant arm has been synthesised using click chemistry. The sensor is highly responsive to both Cu II and Hg II in neutral aqueous solution and displays excellent selectivity in the presence of various competing metal ions in 50‐fold excess. The addition of specific anions such as I − and S 2 O 3 2− causes a complete revival of fluorescence only in the case of Hg II , providing a simple and effective method for distinguishing solutions containing Cu II , Hg II or a mixture of both ions, even in doped seawater samples. X‐ray crystal structures of both the Hg II sensor complex and a model Cu II complex show that pendant triazole coordination occurs through the central nitrogen atom (N2), providing to the best of our knowledge the first reported examples of this unusual coordination mode in macrocycles. Fluorescence, mass spectrometry and 1 H NMR experiments reveal that the mechanism of anion‐induced fluorescence revival involves either displacement of pendant coordination or complete removal of the Hg II from the macrocycle, depending on the anion.