Phys.org May 22, 2024
The isoreticular principle, which allows families of structurally analogous frameworks to be built in a predictable strategies do not translate to other common crystalline solids, such as organic salts, in which the intermolecular ionic bonding is less directional. Researchers in the UK showed that chemical knowledge could be combined with computational crystal-structure prediction (CSP) to design porous organic ammonium halide salts that contain no metals. The nodes in the salt frameworks were tightly packed ionic clusters that directed the materials to crystallize in specific ways on the predicted lattice energy landscapes. The energy landscapes allowed them to select combinations of cations and anions that formed thermodynamically stable, porous salt frameworks with channel sizes, functionalities and geometries that could be predicted a priori. Some of these porous salts adsorbed molecular guests in quantities that exceeded those of most MOFs, and this could be useful for applications such as radio-iodine capture. The synthesis of the salts was scalable, involving simple acid–base neutralization, and the strategy made it possible to create a family of non-metal organic frameworks that combined high ionic charge density with permanent porosity… read more. Open Access TECHNICAL ARTICLEÂ
Inverse reticular design strategy for porous salt frameworks. Credit: Nature, 22 May 2024