Chemistry

Combichem Sensors

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Science  22 Jul 2005:
Vol. 309, Issue 5734, pp. 536
DOI: 10.1126/science.309.5734.536b

The design of fluorescent chemosensors that can be used to detect metal ions often begins by identifying a molecule with an appropriate metal-binding specificity and then derivatizing the compound so that binding initiates a fluorescent signal. However, once the binding scaffold is set, synthetic routes to fluorescent derivatives may be few.

Mello and Finney have approached the problem from the opposite direction by using fluorescence to screen combinatorial libraries. They took advantage of cases where binding of a metal ion restricts torsional motion between aryl groups and hence favors an extended aromatic network. A 2,6-biaryl-4-vinylpyridine core bound to a resin support was functionalized with identical arms that consisted of an amino acid and an acyl end group. Screening an initial library of 198 such compounds with a variety of mono- and divalent cations, they identified a fluorophore that bound Hg2+ with an affinity of about 1.8 × 10−6 M−1, which is about an order of magnitude greater than the affinity of K+ for 18-crown-6 ether. — PDS

J. Am. Chem. Soc. 10.1021/ja043682p (2005).

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