Non-solvent post-modifications with volatile reagents for remarkably porous ketone functionalized polymers of intrinsic microporosity

Chemical modification of porous materials is important for realising advanced applications, but often has a negative impact on other properties. Here, the authors report a method for the modification of polymers of intrinsic porosity to introduce a range of functional groups. Chemical modifications of porous materials almost always result in loss of structural integrity, porosity, solubility, or stability. Previous attempts, so far, have not allowed any promising trend to unravel, perhaps because of the complexity of porous network frameworks. But the soluble porous polymers, the polymers of intrinsic microporosity, provide an excellent platform to develop a universal strategy for effective modification of functional groups for current demands in advanced applications. Here, we report complete transformation of PIM-1 nitriles into four previously inaccessible functional groups - ketones, alcohols, imines, and hydrazones - in a single step using volatile reagents and through a counter-intuitive non-solvent approach that enables surface area preservation. The modifications are simple, scalable, reproducible, and give record surface areas for modified PIM-1s despite at times having to pass up to two consecutive post-synthetic transformations. This unconventional dual-mode strategy offers valuable directions for chemical modification of porous materials.

Automated summary

Chemical modification of porous materials often leads to negative impacts on their properties, but the authors of this study propose a method for modifying polymers of intrinsic porosity without sacrificing their structural integrity or porosity. By using soluble porous polymers as a platform, the authors were able to successfully introduce a variety of functional groups. The modifications were simple, scalable, and reproducible, making them valuable for the chemical modification of porous materials.