A dual-responsive luminescent sensor based on a water-stable Cd(II)-MOF for the highly selective and sensitive detection of acetylacetone and Cr2O72- in aqueous solutions

Abstract

Two new water-stable cadmium(ii)-metal organic frameworks (MOFs), namely [Cd-2(L1)(1,4-NDC)(2)](n) (1) and [Cd(L2)(1,4-NDC)](n) (2) (L1 = 1,4-bis(benzimidazol-1-yl)-2-butylene, L2 = 1,4-bis(2-methylbenzimidazol-1-yl)-2-butylene and 1,4-H2NDC = 1,4-naphthalenedicarboxylic acid), were synthesized and characterized. 1 exhibits an unusual 3D framework with the Schlafli symbol of {4(2).5.6(2).7}{4(2).5(2).7(2)}{4(2).5(3).6(2).7(3)}(2), and 2 is a classical sqc6 network. 1 and 2 display excellent pH and water stability, and the integrity of the frameworks was well maintained at different pH values (pH = 3-13) and after long-term water treatment. 1 is the first dual-function luminescent sensor for sensing acetylacetone and Cr2O72- in aqueous solutions with high sensitivity, selectivity and excellent recyclability. This material is an excellent dual-responsive recyclable luminescent sensor.