Synthesis Of Azo Hydroxybenzo[h]Quinoline Derivatives And Recognition Of Fluoride Ion

1:The role of anions, structural features, interaction with the receptor, research methods of anion recognition and design of anion recognition receptors are introduced in detail. A brief commentary and research progress on azo and azo phenols receptors are summarized from the recent years at home and abroad. Finally contents and significance of this paper is introduced.2:7-(4-cyano phenyl) azo-10-hydroxybenzo[h] quinoline (host 1) and 7-(2-cyano phenyl) azo-10-hydroxybenzo[h] quinoline (host 2) were synthesized. Their identification with anions F-, Cl-, Br-, I-, Ac- and HSO4-were explored using UV-vis spectroscopy. The results showed that the hosts could selectively identified F- ion via naked eye. The maximum absorption peak of host 1 and 2 both appeared at 410nm.While, when F- was added, a new absorption peak appeared at 565nm and 555nm respectively, and the absorbance at 410nm significantly reduced. Meanwhile, the solution color changed from yellow to purple and orange respectively. However, nothing changed with addition of other anions. Within a certain range, concentration of fluoride and the absorbance ratio shows a linear relationship. Other anions (except HSO4-) do not interfere with host-F- recognition system.1HNMR titration and effect of CH3OH experiments showed that fluoride ion could form hydrogen bond with hydroxy of host molecules, which was conducive to intramolecular charge transfer, resulting in a red shift of absorption spectra and increase of absorbance value.3:7-(2-chloro phenyl) azo-10-hydroxybenzo[h] quinoline (host 3) was synthesized. The main impact on UV-vis absorption and the color of the solution by anions such as F-, Cl-, Br-, I-, Ac- and HSO4- were studied. The results of experiments showed that the maximum absorption peak of host 3 appeared at 390nm. While, when F- was added, the maximum absorption peak was red-shifted(from 390nm to 535nm) and the solution color changed from yellow to red. However, nothing changed with addition of other anions.It showed that host 3 could selectively identified F- ion via naked eye. Within a certain range, concentration of fluoride and the absorbance ratio shows a linear relationship. Their identification mechanism was verified by 1HNMR titration and effect of CH3OH experiments.4:The effects of substituents of 7-(substituent benzene) azo -10-hydroxybenzo[h] quinoline on the systems’absorption spectra were discussed, it showed a certain regularity, that is, the specific absorption spectra of azo band shifted red along with the ability of electron withdrawing of substituents after the hosts and fluoride ion formed complexes. The results provide a theoretical foundation for the design of such systems in the future. Ion test strips which could detect fluoride quickly and easily were made.