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Squaramide hydroxamate-based chemidosimeter responding to iron(III) with a fluorescence intensity increase
Nathaniel C Lim1, Svetlana V Pavlova, Christian Brückner
1Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269-3060, USA.
Inorganic Chemistry
|December 31, 2008
Summary
A novel squarate hydroxamate-coumarin conjugate acts as a sensitive fluorescent sensor for Fe(III) and other oxidants. This chemodosimeter shows a significant fluorescence increase upon oxidation, enabling detection down to 1 ppm.
Area of Science:
- Analytical Chemistry
- Organic Chemistry
- Materials Science
Background:
- Development of sensitive fluorescent probes for metal ion detection is crucial.
- Existing chemosensors often face limitations in sensitivity or selectivity.
- The squarate platform offers potential for novel sensor design.
Purpose of the Study:
- To synthesize and evaluate a squarate hydroxamate-coumarin conjugate (12) as a chemodosimeter.
- To investigate its sensing capabilities for Fe(III) and other oxidants.
- To demonstrate the squarate diamide platform's ability to relay a chelation-enhanced fluorescence (CHEF) response.
Main Methods:
- Synthesis of a squarate hydroxamate-coumarin conjugate (12).
- In vitro evaluation of 12 as a chemodosimeter for Fe(III), Cr(VI), and Ce(IV).
- Spectroscopic analysis to monitor fluorescence changes upon analyte exposure.
- Independent synthesis to confirm reaction product identities.
Main Results:
- Compound 12 exhibits low fluorescence yield due to photoinduced electron transfer.
- Exposure to Fe(III) or other oxidants causes an irreversible 9-fold fluorescence increase.
- The sensing mechanism involves oxidation and hydrolysis of the coumarin moiety to a highly fluorescent coumarinaldehyde.
- Fe(III) acts as a catalyst, enabling sensitive detection down to 1 ppm in aqueous solutions.
Conclusions:
- The squarate hydroxamate-coumarin conjugate (12) functions as an effective chemodosimeter for Fe(III) and other oxidants.
- The squarate diamide platform successfully relays a CHEF response.
- The developed sensor offers high sensitivity and a clear fluorescent signal for detecting Fe(III).
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