Guang-Yan Qing

‘Naked‐eye’ enantioselective chemosensors for N‐protected amino acid anions bearing thiourea units

Four linear thiourea anion receptors (1-3) derived from simple amino acid have been synthesized and their bonding properties with various chiral N-protected amino acid anions were examined by using UV-vis and fluorescence titration experiments. Receptors 1a, 2, and 3 exhibit excellent enantioselective recognition abilities towards N-Boc-protected alanine anion in the UV-vis spectra, obvious difference in the color of solution indicate that the enantiomers of N-Boc-alanine anion could be distinguished by naked eye directly. Receptor 1a is also found to carry out enantioselective fluorescent recognition of the N-acetyl-glutamate. (1)H NMR experiments suggest that hydrogen-bonding interaction between the host and guest is the main factor in the recognition process.

Chiral Fluorescent Receptors based on Amino Acid Unit: Synthesis and Their Enantioselective Recognition

Three chiral fluorescent receptors (1, 2 and 3) were synthesized and their structures were characterized by IR, 1H NMR, 13C NMR, MS spectra and elemental analysis. The enantioselective recognition of receptors 1, 2 and 3 were studied by fluorescence spectra and 1H NMR spectra. The results demonstrate that receptors 1, 2 and 3 with the N-Boc-protected phenylalanine anion formed a 1:1 complex. The receptor 3 exhibits good enantioselective recognition ability toward the enantiomers of the N-Boc-protected phenylalanine anion.

Highly selective fluorescent recognition of amino alcohol based on chiral calix[4]arenes bearing L-tryptophan unit

Four two-armed chiral calix[4]arenes (1a–1d) functionalised at the lower ring with amino acid units have been synthesised and the structures of these compounds were characterised by IR, MS, 1H NMR, 13C NMR spectra and elemental analysis. Their molecular recognition abilities towards amino alcohol were examined by fluorescence titration experiment in three kinds of solution. The results indicated that these receptors exhibited excellent fluorescent response to phenylglycinol and could distinguish phenylglycinol from phenylalaninol rapidly through the obvious difference in the fluorescent response. Solvent comparative experiments also indicated that acetonitrile was the best solvent to detect these phenomena.