Three water-stable luminescent two-dimensional CdII-based coordination polymers as sensors for highly sensitive and selective detection of Cr2O72− and CrO42− anions

Abstract

Three water-stable 2D cadmium(II)-coordination polymers (CPs), namely {[Cd(MIP)](L)·1.35H₂O}_n (1), [Cd(NTP)(L)]_n (2) and [Cd(1,4-NDC)(L)]_n (3) (L = 1,3-bis(5,6-dimethylbenzimidazol-1-yl)propane, H₂MIP = 5-methylisophthalic acid, H₂NTP = 2-nitroterephthalic acid and 1,4-H₂NDC = 1,4-naphthalenedicarboxylic acid), were synthesized and characterized. 1 exhibits a 3,4L83 framework, 2 is a 3,5L2 network and 3 exhibits a rare 3,4-connected 3,4L27 network. 1 and 3 are dual-function luminescence sensors for sensing Cr₂O₇²⁻ (pH = 3.0)/CrO₄²⁻ (pH = 13.0) in aqueous solution with high sensitivity, selectivity and excellent recyclable behaviors.