A New Multifunctional Zinc–Organic Framework with Rare Interpenetrated Tripillared Bilayers as a Luminescent Probe for Detecting Ni<sup>2+</sup> and PO<sub>4</sub><sup>3–</sup> in Water
Bowen Qin, Xiaoying Zhang, Jingping Zhang
Abstract
Herein, we synthesized two isostructural metal–organic frameworks (MOFs) [(CH3)2NH2]6[M6(OBA)6(L1)3(SO4)2]·SO4·x(solvent) (M: Zn for 1, Co for 2, H2OBA = 4,4′-oxybis(benzoic acid), L1 = 4-amino-3,5-bis(4-pyridyl)-1,2,4-triazole) under solvothermal conditions. Interestingly, the anion SO42– connected three metal centers to form trimetal node [M3(SO4)(COO)6] as a secondary building unit (SBU). Then the SBUs are further linked to each other by OBA2– and L1 ligands, obtaining a rare two-dimensional interpenetrated tripillared bilayer. Compound 1 is highly stable in water and different organic solvents. Because of the high luminescence intensity of compound 1, it could be used to selectively detect Ni2+ and PO43– in aqueous solution with relatively low detection limits of 0.46 and 6.5 μM, respectively. Compound 1 is the first example luminescent MOF that can sense Ni2+ and PO43– simultaneously. Meanwhile, compound 1 has a potential application as a thermometer at the temperature range of 87.4–277.4 K. For compound 2, this Co-MOF synthesized with CoSO4·7H2O shows antiferromagnetic interactions.