A micrometer-sized europium(iii)-organic framework for selective sensing of the Cr2O7(2-) anion and picric acid in water systems.

A micrometer-sized europium(iii)-organic framework with asymmetric binuclear metal subunits extended by 4,5-dichlorophthalaten (DCPA), [Eu2(H2O)(DCPA)3]n, was easily obtained using a reverse microemulsion method. The framework exhibits good dispersibility, excellent thermal and environmental stability and easy regeneration ability. More importantly, the complex displays strong red emission and can selectively and sensitively detect both inorganic Cr2O7(2-) anions (Ksv = 8.7 × 10(3) M(-1)) and organic picric acid contaminants (Ksv = 1.07 × 10(4) M(-1)) in water systems through fluorescence quenching. A luminescent film of 1 was further prepared and successfully used to detect the Cr2O7(2-) anion in an aqueous system. These interesting results indicate that the well-dispersed europium(iii)-organic framework can serve as a promising dual-responsive luminescent sensor for environmental pollutant monitoring.