Design And Synthesis Of Phenol Derivatives For Anion Recognition

Host-guest chemistry based on molecular recognition has been a hot topic of current research in supramolecular chemistry. And supramolecular chemistry includes sensing of neutral molecular, cations and anions. A anion coordination chemistry is less developed compared with the former ones. It is therefore necessary to construct novel anion receptors. Anions can form typical inclusion complexes with many receptors via various interactions, such as electrostatic, hydrogen-bonding, hydrophobic. In this thesis, we constructed chromophores with ground-state charge transfer. Several highly selective and sensitive sensors for anions were developed. And naked-eye detection came true. The thesis consists of five chapters.In Chapter 1, there is literature review. Researches in the development of anion recognition were briefly summarized. The coordination chemistry of anions has received little attention before compared to that devoted to coordination chemistry of cations. However, anion sensors play key roles in many fields. Therefore a number of anion recognition systems have been reported. The content of this chapter includes: (1) structural characters of anions. (2) noncovalent interactions existed in anion coordination, (3) methods in anion recognition.In Chapter 2, compounds based on p-nitrobenzene azophenol were designed and synthesized. The properties of absorption spectra and association constants of complexes between hosts and anions were investigated and compared. The results indicated that the three compounds, which are l-naphthol-4-azo-4'-nitrobenzene, 8-hydroxyl-quinoline-5-azo - 4' -nitrobenzene and l-phenol-4-azo-4"-nitrobenzene, respectively, could act as efficient chromogenic reagents for the anion sensing. Upon addition of various anions, the spectra, profiles and color of the solution of hosts changed significantly. The affinity of hosts for anions was measured by UV-vis spectroscopic titration experiments. For the same host, the. association constants followed the order of AcO^- >F^- >H-2PO₄^- >>Cl^-, which was i(?). agreement with the basicity order of anions. And for the same anions such as AcO^-, the association constants followed the order of 3 (a-naphthol) >2 (8-hydroxyl-quinoline) >I (phenol), which is attributed to electronic withdrawing effect of substituents and the conjugated system of host cmpounds.In Chapter 3, a selevtive colorimetric assay for fluoride and acetate anion based on alizarin was developed. The effect of hydroxyl configuration to anionic complex formation was investigated by UV-vis spectra titration. Results indicated that 1:2 complex between alizarin and fluoride was formed in acetonitrile. However, 1:1 complex formed between...