Modulation of Magnetic Behavior and Hg2+ Removal by Solvent-Assisted Linker Exchange Based on a Water-Stable 3D MOF

SC-SC solvent-assisted linker exchange (SALE) in MOF materials is of high interest due to the potential applications. In this work, we reported an efficient transformation via SALE in a water-stable 3D MOF ({[Ni-1.5(L)(4,4'-azobpy)(H(2)o)]center dot 6.5.5H(2)O}(n) (1)) (H3L = 1-aminobenzene-3,4,5-tricarboxylic acid). The reaction progress of SALE was monitored and proved by single crystal XRD, PXRD and UV-vis absorption analyses, and the structural integrity of progeny MOFs {[Ni-1.5(L)(4,4'-bpy)(H2O)]center dot 6H(2)O}(n) (2), {[Ni-1.5(L)(bpe)(H2O)]center dot 8.5H(2)O}(n) (3), and {[Ni-1.5(L)(NH2-bpy)-(H2O)]center dot 7.5H(2)O}(n) (4) were maintained very well, which is rarely in reported MOF materials. Theoretical calculations and the analyses of core shell crystals give us better understanding of the exchange process. Interestingly, MOFs 2 and 3 obtained by SALE methods showed the different magnetic behavior comparing to parent MOF 1. Especially, because of the functional -NH2 group, progeny MOF 4 displayed the good capability to remove Hg2+ ions with an adsorption capacity of 93.693 mg/g. This work provides a new way to develop multifunctional MOF materials.