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

Abstract

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.

Rational design of hyper‐crosslinked polymers for biomedical applications

“…Over the past decade, there has been significant development in the field of porous organic polymers (POPs), [1][2][3][4] which includes hyper-crosslinked polymers (HCPs), 5,6 polymers of intrinsic microporosity (PIMs), 7,8 covalent organic frameworks (COFs), [9][10][11] conjugated microporous polymers (CMPs), [12][13][14] covalent triazine frameworks (CTFs), 15,16 and porous aromatic frameworks (PAFs). 17,18 These POPs have shown potential in various applications such as energy storage, 19,20 catalysis, 21,22 gas separation, 23,24 sensing, 25 and drug delivery 26,27 due to their advanced properties resulting from the combination of different porous structures and types of polymers.…”

Solvation of Nanoscale Materials

“…78 The commonly used PIM-1, however, dissolves only in tetrahydrofuran (THF) and chloroform (CHCl3), leading to reduced solution processability and restricting the incorporation of fillers or other composites. Recent work has introduced post-synthetic modifications of PIMs to improve their solubility, 79 with the key result that specific solvent interactions with appended moieties improves solubility. In understanding the solvation of porous materials discussed in Section 3, these reports of porous polymers offer the insight that solution stability of nanoscale materials benefits from monomer units accessible to solvent.…”

Removal of dyes using polymers of intrinsic microporosity (PIMs): a recent approach

“…PIMs can be modified further through PSM to introduce various functionalities without affecting the structural integrity of the polymers. 22,30 A typical example of PIM is PIM-1, which happens to be the first reported PIM as well and it can be prepared in high molecular weight through base-mediated polycondensation of 5,5′6,6′-tetrahydroxy-3,3,3′,3′-tetramethyl-1,1′-spirobisindane and 2,3,5,6-tetrafluoroterephthalonitrile monomers (Scheme 1a). 31 The nitrile group on PIM-1 can be postsynthetically modified to introduce a variety of functional groups (Scheme 1b).…”