When crown ethers finally click: novel, click-assembled, fluorescent enantiopure pyridino-crown ether-based chemosensors – and an N-2-aryl-1,2,3-triazole containing one

Three novel, click-assembled fluorescent pyridino-18-crown-6 ethers have been synthesized for enantiomeric sensing. We also prepared new azide- and ethynyl-substituted pyridino-18-crown-6 ethers as their precursors, which open the way to further interesting applications using click chemistry. An optically active pyridino-18-crown-6 ether containing an N-2-aryl-1,2,3-triazole type fluorophore unit was also synthesized via post-triazole arylation. The four fluorescent sensor molecules were studied regarding their optical properties as well as the enantiomeric recognition abilities toward the hydrogen perchlorate salts of 1-phenylethylamine, 1-(1-naphthyl)ethylamine, phenylglycine methyl ester and phenylalanine methyl ester in acetonitrile.