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A Cyclam‐Based Fluorescent Ligand as a Molecular Beacon for Cu 2+ and H 2 S Detection
Author(s) -
Mirra Silvia,
Strianese Maria,
Pellecchia Claudio
Publication year - 2017
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201700623
Subject(s) - cyclam , chemistry , fluorescence , copper , ligand (biochemistry) , fluorescence spectroscopy , spectroscopy , stoichiometry , proton nmr , nuclear magnetic resonance spectroscopy , photochemistry , analytical chemistry (journal) , crystallography , metal , stereochemistry , organic chemistry , biochemistry , physics , receptor , quantum mechanics
A pentadentate cage‐like cyclam‐based fluorescent ligand has been designed, synthesized, and characterized by 1D and 2D NMR spectroscopic analysis. To further characterize the title ligand, ESI‐MS, UV/Vis spectroscopy, and fluorescence experiments have been also performed. Its suitability as a chemosensor for the detection of Cu 2+ ions has been successfully explored with a variety of spectroscopic techniques (i.e., ESI‐MS, UV/Vis, and fluorescence). A Job's plot experiment, together with ESI‐MS experiments, indicate a 1:1 stoichiometry for the binding of Cu 2+ to the cyclam‐based ligand. Fluorescence experiments corroborate this hypothesis. The resulting system is selective in the recognition of copper and is stable for a week, as assessed by fluorescence spectroscopy. The Cu II complex has been isolated and tested as a fluorescent probe for the detection of H 2 S. NMR spectroscopy and ESI‐MS investigations have provided evidence that H 2 S recognition occurs through a copper‐displacement mechanism, as reported in the literature for different copper complexes. The system functions with a selective response to HS – , harnessing a concentration‐dependent “turn‐on” of the initial fluorescence intensity.