A Reversible and Highly Selective Fluorescent Sensor for Mercury(II) Using Poly(thiophene)s that Contain Thymine Moieties

Summary: A reversible and highly selective assay methodhas been developed to detect mercury( II )(Hg 2þ ) ionsusing aconjugated polymer (CP). The transduction mechanism isbased on Hg 2þ -mediated interpolymer p-stacking aggrega-tion, which results in the fluorescence self-quenching of theCP. CPs that contain thymine moieties, poly[3-(N-thymin-1-ylacetyl)ethylamine-thiophene] (PTT), have been synthe-sizedandcharacterized.IntheabsenceofHg 2þ ions,thePTTchains remain separated from each other and the CP exhibitsstrong fluorescence emission. Upon adding Hg 2þ ions, theformationofinterpolymerp-stackingaggregationinducedbyspecific thymine–Hg–thymine interactions results in thefluorescencequenchingofPTT.Distinguishingaspectsofthisassayinclude thesignalamplificationofCPsandthespecificbinding of Hg 2þ ions to thymine-thymine (T–T) base pairs.The binding of Hg 2þ ions causes the separate conductingpolymer chains to aggregate with subsequent fluorescenceself-quenching. Macromol. Rapid Commun. 2006, 27, 389–392 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim