Recognition of Anions by bis Urea based Fluorescent Receptors

Three bis urea based acyclic receptors with fixed spacer and varying size of substituents have been synthesized and their binding behavior with different anions are reported along with the selectivity of these receptors towards anions. The fluorescence quenching of the receptors 2 and 3 on binding with anions is also shown. The receptor 1 binds better with Y-shaped AcO¯ ion whereas receptor 3 binds well with Cl¯ ion.