Recognition and sensing properties of a quinazolinylaminothiourea-based anion receptor in non-aqueous and aqueous CH3CN–DMSO medium

Quinazolinylaminothiourea 1 selectively recognized AcO−, F− and H2PO4− over other anions in CH3CN–DMSO (99:1, v/v), which was accompanied with a visible color change from colorless to yellow. Interestingly, the selectivity of receptor 1 for AcO− over F− and H2PO4− could be obviously improved in aqueous CH3CN–DMSO medium. UV–vis and 1H NMR titration experiments showed that intermolecular hydrogen-bonding interactions between receptor 1 and guest anions were responsible for the observed recognition behaviors.