Thymine-covalently decorated, AIEE-type conjugated polymer as fluorescence turn-on probe for aqueous Hg2+

A type of thymine (T)-covalently decorated conjugated polymer (P3) with the feature of aggregation-induced emission enhancement (AIEE) was successfully synthesized via Cu-catalyzed click reaction between the acetylene-substituted precursor polymer (P2) and 3'-azido-3'-deoxythymidine. Chemical structures of target polymers were verified by FT-IR and H-1 NMR analyses. With the introduction ofaqueous Hg2+, fluorescence of P3 in THF- water mixture (V-THF/V-water = 7/3) (buffered with 5 mM citricaciddisodium hydrogen phosphate, pH = 7.4) displayed gradual enhancement. The AIEE effect was activated by the formation of intermolecular aggregates, which was induced by the formation of T- Hg-Tcomplex between polymer chains. Other common metal ions brought very slight interference for P3' sresponse of Hg2+, and the detection limit of Hg2+ reached similar to 15.3 nM for such probing system. (C) 2014 Elsevier B.V. All rights reserved.