Host–Guest Assembly of H-Bonding Networks in Covalent Organic Frameworks for Ultrafast and Anhydrous Proton Transfer

Abstract

An anhydrous proton conductor represents a key material for the manufacture of high-energy electrical devices. Incorporation of proton carriers into the vacancies of the porous solid provides an effective method for their preparation, but the weak or even no interactions between the ion carriers and the porous solids causing a serious leaking of ion carriers result in trade-off of long-term conductivity. In this term, we developed a host−guest supramolecular chemistry-induced strategy to assemble hydrogen bond networks along the 1D nanochannels of covalent organic frameworks (COFs) for ultrafast and anhydrous proton transfer (1.33 × 10 −2 S cm −1 at 140 °C). Solid-state NMR was applied to explore guest interaction between protic ionic liquids (PILs) and the COFs to investigate the proton transport mechanism. This work presents an excellent example of accumulation of PILs into the nanochannels of COFs for anhydrous proton conduction at high temperature, demonstrating great advantages of COFs to serve as a supramolecular host for holding/transiting ions in the solid state.

Immiscible Polymer Blends Compatibilized through Noncovalent Forces: Construction of a “Quasi-Block/Graft Copolymer” by Interfacial Stereocomplex Crystallites

“…Besides covalent bonds, there are many noncovalent bond forces, 32−34 such as Van der Waals forces, 35,36 π−π interaction forces, 37,38 hydrogen bonds, 39,40 and ionic bond forces. 41,42 Compared with covalent bonds, the interaction energy of noncovalent bond forces is slightly lower, 43,44 which provides us the possibility of using covalent bond forces to construct "block" or "graft" copolymers.…”

“…Besides covalent bonds, there are many noncovalent bond forces, − such as Van der Waals forces, , π–π interaction forces, , hydrogen bonds, , and ionic bond forces. , Compared with covalent bonds, the interaction energy of noncovalent bond forces is slightly lower, , which provides us the possibility of using covalent bond forces to construct “block” or “graft” copolymers. − We hope that we can find a suitable noncovalent interaction to realize the transformation from a covalently linked diblock copolymer to a noncovalently linked block copolymer.…”

High-density sulfonic acid-grafted covalent organic frameworks with efficient anhydrous proton conduction

“…As for the FTIR spectrum of PIL-TB-COF shown in Fig. 2a, the new peaks appearing at 3154 cm À1 and 1140 cm À1 are ascribed to the ]C-H of the imidazole ring 32 and HSO 4 À stretching of PIL, 33 respectively, proving the existence of PIL. The peak positions in the PXRD pattern of TB-COF remain unchanged in PIL-TB-COF with a slight reduction in peak intensity (Fig.…”

“…3c, d and Table S4 †). 16,17,19,33,[41][42][43][44][45][46] The parameter of activation energy (E a ) is used to investigate the proton transfer mechanisms. Depending on the value of activation energy, there are two commonly recognized mechanisms, the Grotthuss mechanism (E a < 0.4 eV) and the vehicular mechanism (E a > 0.4 eV).…”

Hierarchically Macro–Microporous Covalent Organic Frameworks for Efficient Proton Conduction

“…First, forming an intrinsic proton conduction site through monomer design such as sulfonate, [ 6 ] imidazole, [ 7 ] and phenolic hydroxy groups [ 8 ] owing to their dissociable proton. Moreover, adding extrinsic proton conductivity to COFs via doping proton carriers such as H 3 PO 4 , [ 9 ] organic acid, [ 10 ] phosphotungstic acid, [ 11 ] and ionic liquid [ 12 ] into COF pores could increase proton conductivities. Nevertheless, the majority of reported COFs are obtained as crystalline powders with porosities limited to the microporous or small mesopore domain, which might severely restrict their working performance for diffusion‐limited processes.…”