Synthesis And Properties Of New Double Schiff Base Compounds

As everyone knows,various ions exist in the natural environment. Such as Fe3+,Zn²⁺, HPO42-, H2PO4-, Mg²⁺ have a significant impact for ecosystems and humans, but Ag+, Hg²⁺, CN-, Cd²⁺ have biological toxicity. ions recognition chemistry has received considerable attention in the past decades due to their important role in a wide range of biological, environmental and chemical applications. In this paper, the several probes of metal ions and anions have been synthesized successfully through condensation reaction. And we respectively investigated the spectral response behaviors of the probes to metallic ions and nonmetallic ions in the different solution.The main research results description as follows:1. A new simple molecule colorimetric and fluorescent turn-on probe M1 has high selectivity to cyanide anion, was synthesized successfully by the condensation reaction between 2-phenyl-1,2,3-triazole-4-carboxaldehyde and 2-aminophenyl disulfide. The addition of CN- to M1 solution induced a change in the solution color from colorless to yellow and a bright blue fluorescence was observed under a hand-held UV lamp. Optical properties of M1 were scarcely affected by the addition of other common background anions under the same condition. The detection limit of CN- reaches 1.11 μM by M1. And the reaction mechanism of between M1 and CNwas investigated by 1H NMR titrations experiments.2. A Schiff base fluorescent probe M2 was synthesized through condensation reaction between salicylaldehyde and 2-aminophenyl disulfide. We found that M2 as fluorescent turn on chemosensor for the detection of Zn²⁺ in DMF（buffered with 1.67 mM hepes, pH=7.4）. Optical properties of M2 were scarcely affected by the addition of other common background cations under the same condition. The detection limit of CN- reaches 6.2 × 10-8 M by M2. And the reaction mechanism of between M2 and Zn²⁺was investigated by MS.3. Based on the reaction of 2-aminophenyl disulfide with p-nitrobenzaldehyde, a new Schiff base colorimetric probe M3 has been synthesized as a colorimetric chemosensor for CN-. The addition of CN- to M3 solution induced a change in thesolution color from yellow to pink. Optical properties of M3 were scarcely affected by the addition of other common background anions under the same condition.4. A small molecule Schiff base probe M4 was synthesized through condensation reaction between 2-aminophenyl disulfide and 4-（diethylamino）salicylaldehyde. The probe M4 exhibited highly selective and sensitive to Zn²⁺ and CN- with fluorescence enhancement in solution. However, other background ions without obvious spectral changes and brought very slight interference under the same condition.