Effective Mercury Sorption by Thiol-Laced Metal-Organic Frameworks: in Strong Acid and the Vapor Phase

摘要

Free-standing, accessible thiol (-SH) functions have been installed in robust, porous coordination networks to provide wide-ranging reactivities and properties in the solid state. The frameworks were assembled by reacting ZrCl_4 or A1C1_3 with 2,5-dimercapto-1,4-benzenedicarboxylic acid (H_2DMBD), which features the hard carboxyl and soft thiol functions. The resultant Zr-DMBD and Al-DMBD frameworks exhibit the UiO-66 and CAU-1 topologies, respectively, with the carboxyl bonded to the hard Zr(Ⅳ) or Al(Ⅲ) center and the thiol groups decorating the pores. The thiol-laced Zr-DMBD crystals lower the Hg(Ⅱ) concentration in water below 0.01 ppm and effectively take up Hg from the vapor phase. The Zr-DMBD solid also features a nearly white photoluminescence that is distinctly quenched after Hg uptake. The carboxyl/thiol combination thus illustrates the wider applicability of the hard-and-soft strategy for functional frameworks.