A novel water soluble chemosensor based on carboxyl functionalized NDI derivatives for selective detection and facile removal of mercury(ii)

Abstract

Mercury(II) (Hg²⁺) has acute toxicity. It is still a challenge to design and synthesize chemosensors for selective detection and removal of Hg²⁺ in water solutions. By rationally combining the carboxyl group and naphthalene diimide moieties, we obtained a novel water-soluble Hg²⁺ chemosensor (M2). Interestingly, the sensor M2 showed a dramatic fluorescent “turn-on” response for Hg²⁺ in water. Moreover, the sensor M2 displayed a high specificity for Hg²⁺, other cations (including Fe³⁺, Ag⁺, Ca²⁺, Cu²⁺, Co²⁺, Ni²⁺, Cd²⁺, Pb²⁺, Zn²⁺, Cr³⁺, and Mg²⁺) had no influence on the Hg²⁺ detection process. Moreover, the sensor M2 showed high sensitivity for Hg²⁺, with detection limits of 1.18 × 10⁻⁶ M. Even more meaningfully, the sensor M2 can remove Hg²⁺ from water solutions effectively via the formation of a M2–Hg²⁺ coordination polymer, which can increase the possibility of M2 being used for practical applications.