Highly Stable Single Crystals of Three-Dimensional Porous Oligomer Frameworks Synthesized under Kinetic Conditions.

Herein, various robust, crystalline, and porous organic frameworks based on in-situ-formed imine-linked oligomers were investigated; these oligomers self-assembled through collaborative intermolecular hydrogen bonding interactions via liquid-liquid interfacial reactions. The soluble oligomers were kinetic products with multiple unreacted aldehyde groups that acted as hydrogen bond donors and acceptors and directed the assembly of the resulting oligomers into three-dimensional frameworks. The sequential formation of robust covalent linkages and highly reversible hydrogen bonds enforced long-range symmetry and facilitated the production of large single crystals, with structures that were unambiguously determined and refined based on high-quality single-crystal X-ray diffraction data. Impressively, the unique hierarchical arrangements increased the steric hindrance of the imine bond, which prevented attacks from water molecules, thereby greatly improving the stability. Furthermore, the multiple binding sites in the resultant frameworks enabled the rapid sequestration of micropollutant in water.