Structural Approaches to Control Interlayer Interactions in 2D Covalent Organic Frameworks

Abstract

• 2D COFs are porous. Piling-up holey 2D polymers in a periodic fashion gives rise to porous channels, whose structure will depend on both the lattice and the packing. The ability to design and synthesize monomers can affect fundamental aspects in 2D covalent organic frameworks, such as dimensionality, topology, and pore size. Besides this, the structure of the monomers can also affect interlayer interactions, which provide an additional means to influence crystallinity, layer arrangement, interlayer distances, and exfoliability. Herein, some of the effects that the structure of monomers can have on the interlayer interactions in 2D covalent organic frameworks and related materials are illustrated.

Ionic Covalent Organic Frameworks for Energy Devices

“…The above‐mentioned facile chemical reactions assemble COFs into periodically ordered 2D or 3D crystalline networks. [ 265–270 ] These porous crystalline COFs feature tunable, designable, and functionalizable nanospaces, which together with the frameworks of COFs allow the predesigned integration of different functionalized moieties for targeted applications. [ 271 ] For example, Feng et al.…”

“…[260] We refer readers to Díaz de Greñu et al, Clayson et [261][262][263][264] The above-mentioned facile chemical reactions assemble COFs into periodically ordered 2D or 3D crystalline networks. [265][266][267][268][269][270] These porous crystalline COFs feature tunable, designable, and functionalizable nanospaces, which together with the frameworks of COFs allow the predesigned integration of different functionalized moieties for targeted applications. [271] For example, Feng et al prepared 2D porphyrin COFs that exhibited high rates of electron and hole conductivity; [272] Xu et al synthesized oligo(ethylene oxide) functionalized COFs that conducted Li + at 5.49 × 10 −4 S cm −1 at 363 K; [163] and Zhou et al prepared gel guest-assisted COF membranes that exhibited high H + conductivity (1.3 × 10 −4 S cm −1 ) at 313 K. [167] Wang et al reported imine-linked COFs with a high S loading (60 wt%), which was generated by strong binding interactions between the N atoms of the COF backbones and polysulfide; these imine-linked COFs were used to form a Li-S battery with a high discharge capacity (1357 mAh g −1 at 0.2 A g −1 ).…”

Light-Driven Molecular Motors Embedded in Covalent Organic Frameworks

“…64,65 This is particularly the case in structures with a parallel spacer orientation (Figure 3a), rendering parallel models energetically unfavorable. 66 With an antiparallel orientation of the unit, a regular conformation of the imine linkages is equally needed to construct evenly shaped pore channels, but due to the curvature of the fluorene unit, the imine conformation also determines the possibility for sufficient stacking interactions across the layers. 67,68,69,70 This constraint led to the development of three possible unit cell structure models, which differ mainly in their imine configuration (Figure S11).…”

Unraveling the Effect of Defects, Domain Size, and Chemical Doping on Photophysics and Charge Transport in Covalent Organic Frameworks

“…37 However, t intra−x and t intra−y can vary depending on functionalization and/or the presence of out-of-plane defects, either along the x or y directions in the 2D plane (these effects will be taken into consideration in the next sections). 64 All the other parameters of the Hamiltonian are given in the Supporting Information. Fig.…”