N-Unsubstituted-1,2,3-triazole-tethered, AIEE type conjugated polymer as a ratiometric fluorescence probe for silver ions

Abstract

A type of N-unsubstituted-1,2,3-triazole-decorated conjugated polymer (P3), with the feature of aggregation-induced emission enhancement (AIEE), was successfully synthesized via a Cu⁺-catalyzed click reaction between an acetylene-substituted precursor polymer (P2) and azidotrimethylsilane. Except for Ag⁺, the introduction of other metal ions had only a slight influence on the optical properties of P3. With the introduction of aqueous Ag⁺, the fluorescence of P3 in a THF–water mixture (v_THF/v_water = 4/1) (buffered with Tris–CA, 1 mM, pH = 7.4) displayed a ratiometric alteration at the blue (∼420 nm) and green (∼495 nm) bands. The corresponding I₄₉₅/I₄₂₀ ratio values maintained an upward trend throughout the titration process of Ag⁺. The detection limit of Ag⁺ reaches ∼1.4 μM (3σ/k), as evaluated from the corresponding relationship between I₄₉₅/I₄₂₀ and [Ag⁺]. The aggregation between the polymer chains induced by a Ag⁺–triazole interrelation is the plausible reason for the alteration of P3's optical properties.