Crystallinity of Imide-Linked Two-Dimensional Polymers Depends on the Nucleophilicity of Triamine Building Blocks

Abstract

Dynamic covalent chemistry, associated with reversible reactions, has allowed the synthesis of crystalline two-dimensional polymers (2DPs). However, strategies for the formation of imide-linked 2DPs have not yet been extensively explored, because of the poor reversibility of amide linkages in amic acid intermediates. Here, we report how to control the reaction conditions for the formation of crystalline PI-2DPs. After studying five PI-2DPs cases, we found that the formation rate of amic acid intermediates before their imidization into imide rings plays a crucial role in the subsequent crystallinity of PI-2DPs. Furthermore, calculating the pK a values of the triamine monomers, which is closely related to their nucleophilicity (reactivity), also allows the crystallinity of the resulting PI-2DPs to be predicted. The findings may offer criteria for the design and synthesis of crystalline PI-2DPs.

Electron-rich Pt anchored on covalent triazine frameworks for the selective hydrogenation of halogenated nitrobenzenes

“…The extended structure of TAPT-COF fitted the space group of trigonal P3, while TAPB-COF was modeled for the space group of hexagonal P6. 34,44 In addition, Pt/TAPT-COF exhibited the characteristic peaks of the Pt (111), ( 200), (220), and (311) planes at 39.7°, 46.1°, 67.5°, and 81.9°, respectively, indicating that active Pt sites were successfully anchored on the COF. The PXRD spectrum of Pt/TAPB-COF showed the major peaks at 39.5°, 45.9°, 67.2°, and 80.9°, which corresponded to the Pt (111), ( 200), (220), and (311) crystal planes.…”

Polyimide covalent organic frameworks bearing star-shaped electron-deficient polycyclic aromatic hydrocarbon building blocks: molecular innovations for energy conversion and storage

“…Study implies that the crystallinity of the final polyimide is strongly associated with the generating rate of the amic acid intermediate rather than the imidization rate. 49 However, the reaction rate constant of the amidation reaction is generally several orders of magnitude larger than that of the reverse reaction. Accordingly, the overall imide condensation usually proceeds in an irreversible manner, resulting in less ordered amorphous kinetic product (Scheme 4b).…”

Construction of microporous covalent organic frameworks for high gas uptake capacities

“…9–21 These advantages make COFs effective candidates for a wide range of functions, including gas storage, chemical sensors, and energy storage, among others. 22–36…”

“…[9][10][11][12][13][14][15][16][17][18][19][20][21] These advantages make COFs effective candidates for a wide range of functions, including gas storage, chemical sensors, and energy storage, among others. [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36] In terms of gas adsorption, the designable pore channels and structures of COFs provide an ideal platform to enhance their gas uptake capabilities. [36][37][38][39][40][41][42][43][44][45][46] For example, a well-defined microporous structure provides for a powerful approach to improve gas adsorption through pore functionality.…”