An imidazole-functionalized polyacetylene: convenient synthesis and selective chemosensor for metal ions and cyanide

Abstract

A new light-emitting polyacetylene bearing imidazole moieties in the side chain (), was conveniently prepared through a postfunctionalization strategy, as a sensory polymer to selectively report the presence of Cu2+ (with a detection limit of 1.48 ppm) based on the fluorescence "turn-off". Interestingly, the quenched luminescence of by Cu2+ could be turned on after the addition of CN-, making a novel, sensitive, and selective cyanide probe.

Synthesis and Functionality of Substituted Polyacetylenes

“…By click chemistry, many highly polar functional groups can be conveniently attached to disubstituted PA 48 to furnish 49 [19]. 47 and 37e can undergo nucleophilic substitution and hydrolysis reactions, respectively, to provide imidazole-and carboxy-functionalized disubstituted PAs 50 and 37a [20,21]. Deprotection of imide 36(9) yields amine 51, which can further be ionized by hydrobromic acid to give polycation 52 [22,23].…”

“…We developed a sequential chemosensor based on imidazole-containing LEPA 68 (Scheme 1.7). Among the different kinds of metal ions, only Cu 2+ ion can completely and efficiently quench or turn off the strong fluorescence of 68, with a detection limit as low as 1.48 ppm [20]. The associated Stern-Volmer quenching constant (K sv ) is as high as 3.7 × 10 5 M −1 , because of the high affinity of Cu 2+ ion toward imidazole group, which enables the polymer to differentiate Cu 2+ from other metallic ions.…”

Lead ion sensor with electrodes modified by imidazole-functionalized polyaniline

“…As the doped IMPANI has higher conductivity compared to the undoped state, binding of metal ion on polymer backbone increases the conductivity [19]. The studies of imidazole containing polyacetylene and polycarbazole as a fluorescence probe for metal ion sensors have been reported [20,21].…”

Using ratiometric indicator-displacement assays in semi-quantitative colorimetric determination of chloride, bromide, and iodide anions

“…The sensing of these inorganic halide anions is, however, relatively tough, particularly in water. [14][15][16][17] This is largely due to the difficulties with recognition of anions as the anions usually posses a low charge-to-radius ratio, and makes the electrostatic binding of anions to the receptors less effective.…”