Anion Sensing Based On PET And Hydrogen Bonding

Inorganic anions and organic anions play a fundamental role in a wide range of chemicaland biological processes.A great deal of attention has been focused on the selective sensing ofinorganic anions by means of synthetic colorimetric receptors. In particular, moleculescontaining polarized N-H fragments behave as H-bond donors toward anions are widely usedas receptors for recognition and sensing purposes. However, there are only limited number ofbinding and sensing mechanisms employed, such as hydrogen bonding, etc. Meanwhile, muchattention has been paid to the development of chemosensors for organic anions such as chiralsugar acid or sugar alcohols. But more chiral fluorescent sensors which are chemoselective,and enantioselective to sugar acids are needed. In order to be used in biological analysis, thebinding and sensing process should be carried out in aqueous solution, but most of the presentchemosensors failed to meet this requirement.In order to selectively sensing the inorganic anions or organic anions, such as F~- andsugar acid, the following work have been done in this thesis:A series of thiocarbonohydrazone compounds al-al2 was developed as sensitive,selective, colorimetric F~- sensors. The recognition performance of the sensors was found to bestrongly dependent on the sensor structure, such as the electron push/pull substitution. It waspostulated that a CH…F interaction exists in the sensor-anion system. Evidence in support ofthis conjecture comes from the ~1H NMR titration data, and single crystal structure analysis.Novel colorimetric sensor b4 for fluoride anion containing phenothiazine aschromogenic subunit has been reported. Enol-keto tautomerization was used for selectivefluoride anion sensing. UV-Vis absorption, ~1H NMR, single crystal X-ray structures analysiswas used to characterize the recognition of anions with the sensors.A series of chiral boronic acid molecular receptors (c5, d5 and e2) for chiral sugar acid aresynthesized. Sensor e2 is found to be sensitive, chemoselective, and enantioselective to sugaracids, such as tartaric acid and gluconic acid.New fluorescent chemosensors g8 based on fluorescence resonance energy transfer (FRET)have been developed. Preliminary experiments demonstrated the FRET process. Sensor g8 isfound to be sensitive and enantioselective to tartaric acid.