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Super-pure organic solvents are widely used in the production of electronic and photo-electronic products, and micro-/nano-devices. One of the key procedures in the purification of organic solvents is de-hydration, of which fast and accurately monitoring water content in the solvents is of great importance. Karl Fisher titration is the most widely adopted method for quantitative measurement of water in the solvents. Although this approach possesses several advantages and is fully automated nowadays, some disadvantages such as the use of toxic and malodorous reagents, interference from other co-existing species, consumption of substantial amount of sample solvents in the case of very low water concentration (<10ppm), and limited sensitivity narrow its real-life applications. It is because of these reasons that development of new approaches for the measurement has never been stopped during the last few decades. Continuous exploration upon IR spectroscopy, potentiometry, solid-phase extraction, Raman spectroscopy, holographic method, flow-injection, absorbance-based film sensors, and the recently reported approach of cathodic stripping voltammetry at a gold electrodehas always been existing. These methods, however, are not perfect, and they also suffer from their own limitations:requirement of sophisticated equipment and limited application towards specific solvents. Of all analytical methods reported, optical methods, in particular fluorescence methods, have drawn great attention owing to their high sensitivity and reasonable selectivity. Based on these considerations above, this dissertation focus on to design and synthesize some new fluorescent low-molecule-mass compounds, which possess special structure and predictable sensing performances, and explore the solution behavior and fluorescence properties.In the first part, progress in the study of various fluorescent sensors based on aggregation induced excimer emission, including pyrene, poly(p-phenyleneethynylene)(PPEs), perylene and other types of sensors, used for the detection in gaseous phase and liquid phase, and at the same time, the advantages and disadvantages of each type of the sensors are briefly discussed. Among these sensors, the probe based on aggregation induced excimer emission, which possess abundant structure, remain scarce. As we all know that the excimer emission is micro-environmental sensitivity, and the micro-environment not simply means the external environment, but also the micro-environment of the structure of its own. It is anticipated that creation of new fluorescent sensors to be structurally very diverse, which may possess characteristics like good quality, high efficiency, multiple-functionalities and low cost etc., will become one of the hot points today.In the second part, we have designed and synthesized a butterfly-shaped Py derivative of Chol (ECPS). The fluorescence behavior of ECPS in various solvents has been studied, and it was revealed that ECPS is sensitive to the change both in the polarity and the viscosity of its micro-environment. For this reason, the compound can be used as a probe for the determination of trace amount of water in acetonitrile, ethanol, methanol and1,4-dioxane. The DLs of the method for water in these solvents are0.0007,0.06,0.2, and0.4(%, v/v), respectively, of which the DL for water in acetonitrile is the lowest value reported till now. The research for mechanism shows that the compound displays a strong aggregation capabilities and always in a balance between the mono-molecular state and aggregated state in all solutions. There are double features in the fluorescence spectrum which are monomer and excimer emission, and their ratio was greatly influences by the trace amount of water. Accordingly, the compound may be used as a quantitative probe for trace water monitoring. Similarly, the compound may also find uses in other fields relevant to viscosity monitoring.In the third part, a new fluorescent chemosensor, containing two pyrene and one cholesterol units, putting1,2,3-triazole unit as a binding group, was specially designed and prepared. We hope to detect metal ions using the coordination ability of1,2,3-triazole. In addition, the fluorescence intensity can be quenched by alkylation and recovered after combining with high electronegative fluoride ion, which realize the detection of fluoride ion. Further researches are in progress.
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