A luminescent turn-off sensor for Cr(VI) anions recognition derived from a Zn(II)-based metal–organic framework

Abstract A mixed-ligand constructed Zn(II) metal–organic framework (MOF) namely{[(CH3)2NH2]0.5[Zn(BTA) (TAZ)0.5·0.5DMA]}n (1) has been synthesized from the combination of benzotriazole-5-carboxylic acid (HBTA) and tetrazole (HTAZ) and structurally characterized in details. Single-crystal data reveals 1 shows a three-dimensional (3,4)-connected fsc pillared-layer structure with uncoordinated O atoms of HBTA and uncoordinated N atoms of HTAZ and HBTA, facilitating the interactions between the framework and analytes. Luminescent study indicates that 1 could be exploited as a luminescent turn-off sensor for CrO42− and Cr2O72− anions recognition with the quenching Ksv values of 5.7 × 103 M−1and 6.04 × 103 M−1, respectively. And the detection limit can reach as low as 252 µmol·L−1 and 56.7 µmol·L−1, respectively. Besides, the luminescent quenching mechanism of 1 toward CrO42− and Cr2O72− anions is investigated as well.