Three N-(substituted-benzamido)urea-based receptors (substituent＝p-OC2H5, H, p-Cl) 1～3, were designed and synthesized. Their interactions with anions such as , F－, , , Cl－ and Br－ in acetonitrile were investigated by using absorption spectroscopy. 1H NMR titrations and Job plots confirming that 1∶1 hydrogen-bonding complexes were formed between the receptors and anions. Results showed that varying substituent could efficiently tune the hydrogen bonding interaction with anions and modulate the selectivity and sensitivity to anion recognition. Receptor 1 bearing an electron-donating substituent showed a highly selective recognition of a fluoride anion, which may result from the formation of an intramolecular seven-membered ring hydrogen bond in the receptor molecule that affords a suitable arrangement of the anion binding sites matching well for a fluoride anion.

Key words: N-benzamidourea, anion recognition, hydrogen bonding, fluoride