Preparation Of Anionic Colorimetric Sensor

Anions recognition and detection have been extensively used in environmental, chemical, biological, catalysis and medical fields. Colorimetic sensors are also chemosensors, they are especially attractive for the reason that they allow’naked-eye’ detection of the analyte without expensive instruments. In recent years, a variety of colorimetric anion receptors have been designed and synthesized, however, materials based colorimetric anion receptors are still rarely reported. In this thesis, a novel colorimetric anion receptor, (4-(4-hydroxystyryl)-1-(3-(triethoxysilyl) propyl)pyridine-l-ium, HSTESPS), were designed and synthesized. HSTESPS was supported on the surface of nanoscale SiO2.Their anion-recognition properties were investigated through UV-Vis and’naked-eye’detection. It is found that the SiO2-surface-supported materials could selectively and reversibly recognize F- and AcO-. The results are summarized as follows:In Chapter 1, the definition of anionic chemical sensors, its classification and davantages were firstly described; the design principles of colorimetric anion sensor was then discussed with the combination of characteristics of anions;subsequentlythe research and development of anionic chemical sensors was reviewed; the research on materials based anionic chemical sensors was finally summarized.In Chapter 2, a colorimetric anion receptor, HSTESPS, was prepared by hydroxybenzaldehyde condensation reaction with iodine-substituted silane using 4-Hydroxybenzaldehyde and 4-methylpyridine as the starting materials.The chemical structure of HSTESPS was confirmed by 1HNMR and 13CNMR. The influence of solvents on anion (F-) recognition was studied using UV-Vis absorption spectroscopy, it is found that DMSO is a good medium compared with MeOH、EtOH、DMF. The interaction between the receptor and anions such as F-、Cl-、Br-、I-、AcO-、HSO4- in DMSO solvent have been investigated. An obvious change inUV-Vis absorption and spectroscopy was observed upon the introduce of F- and AcO- to the solution of HSTESPS in DMSO. It is found that a 1:1 stoichiometry complex was formed between receptors and F" or AcO- calculated by Job’s method. The results of the competitive experiment indicated that the other halogen anions hardly interfered with the detection of F-, demonstrating good selectivity. The influence of water was also studied, HSTESPS could detect F- (1.0×10-5 mol/L) when water content in solvent is less than 5.0%(v%)In Chapter 3, uniform nanoparticles (PHSTESPS) were prepared through sol-gel method under optimal condition inH2O-DMSO (15:5, v:v)), As characterized by AFM, the height of PHSTESPS nanoparticles is～70 nm. The interaction of PHSTESPS with F-(AcO-) in DMSO solvent was investigated using UV-Vis absorption spectroscopy, however, desired result couldn’t obtain. The possible reason was proposed.In Chapter 4, SiO2 particles at nano meter scale were firstly prepared by sol-gel method. SPHSTESPS was then prepared by modification of SiO2-surface. The morphology of SiO2 and SPHSTESPS1T10 were characterized by AFM, it is found the the averaged diameters are 49.4 nm and 62.3 nm, respectively. The interactions of SPHSTESPS1T10 with anions such as F-、Cl-、Br-、I-、AcO-、HSO4- in DMSO solvent were investigated, as characterized by UV-Vis, SPHSTESPS1T10 could recognize F-and AcO- with good selectivity and repeatibility, furthermore, the color of the solution changed from yellow to pink, demonstrating SPHSTESPS is a good colorimetric anion receptor.