A Bumper Crop of Boiling-Water-Stable Metal-Organic Frameworks from Controlled Linker Sulfuration

The series of highly stable porous solids here feature systematic, regiospecific sulfur substitutions on the organic linkers for versatile functions. One major surprise lies in the controllable sequential reactions between sodium thiomethoxide (NaSMe) and octafluorobiphenyl-4,4'-dicarboxylic acid (H₂bpdc-8F; this was readily made without precious metal catalysts). Namely, 3, 4, 6, and 8 methylthio-substitutions can be respectively achieved with regiospecificity (i.e., to produce the four molecules H₂bpdc-3S5F, H₂bpdc-4S4F, H₂bpdc-6S2F, H₂bpdc-8MS). A second surprise lies in their persistent formation of the UiO-67-type net with Zr(IV) ions, e.g., even in the case of the fully sulfurated H₂bpdc-8MS. In addition to the remarkable breadth of functional control, all the Zr(IV)-based crystalline solids here are stable in boiling water (e.g., for 24 h) and in air as solventless, activated porous solids. Moreover, the thioether groups allow for convenient H₂O₂ oxidation to fine-tune the hydrophilicity and luminescence properties and improve proton conductivity.