Ionic Covalent Organic Frameworks with Spiroborate Linkage

Abstract

A novel type of ionic covalent organic framework (ICOF), which contains sp(3) hybridized boron anionic centers and tunable countercations, was constructed by formation of spiroborate linkages. These ICOFs exhibit high BET surface areas up to 1259 m(2) g(-1) and adsorb a significant amount of H2 (up to 3.11 wt %, 77 K, 1 bar) and CH4 (up to 4.62 wt %, 273 K, 1 bar). Importantly, the materials show good thermal stabilities and excellent resistance to hydrolysis, remaining nearly intact when immersed in water or basic solution for two days. The presence of permanently immobilized ion centers in ICOFs enables the transportation of lithium ions with room-temperature lithium-ion conductivity of 3.05×10(-5) S cm(-1) and an average Li(+) transference number value of 0.80±0.02. Our approach thus provides a convenient route to highly stable COFs with ionic linkages, which can potentially serve as absorbents for alternative energy sources such as H2, CH4, and also as solid lithium electrolytes/separators for the next-generation lithium batteries.

Ionic Covalent Organic Frameworks: Design of a Charged Interface Aligned on 1D Channel Walls and Its Unusual Electrostatic Functions

“…[1,2] Recent progress in the chemistry of COFs had significant effect on enhancing their structural diversity and complexity. [1,4] In this sense,t he wall surface of the one-dimensional (1D) channels of COFs is of great interest because it constitutes the interface between molecules and COFs. [1,4] In this sense,t he wall surface of the one-dimensional (1D) channels of COFs is of great interest because it constitutes the interface between molecules and COFs.…”

“…[4] Therefore,t here is ac ontra-diction between the charged layers and the crystallinity and porosity of COFs.H ere,w er eport ag eneral strategy for designing ionic COFs with high crystallinity and porosity, through the combination of ionic linkers and neutral knots for the construction of ionic interfaces that are well aligned yet spatially confined on the pore walls.T he COFs assume an unconventional reverse AA-stacking mode in which the cationic benzimidazolium linkers [4d] are alternately orientated and aligned on both sides of the pore walls.W ehighlight that such an alternate alignment exerts profound effects on the ionic interface and triggers unusual electrostatic functions of COFs.Byvirtue of reduced charge repulsion between layers, the ionic COFs possess high crystallinity and porosity.W ith electric dipoles on both sides of the walls,the COF enhances the CO 2 adsorption by even three fold. [4] Therefore,t here is ac ontra-diction between the charged layers and the crystallinity and porosity of COFs.H ere,w er eport ag eneral strategy for designing ionic COFs with high crystallinity and porosity, through the combination of ionic linkers and neutral knots for the construction of ionic interfaces that are well aligned yet spatially confined on the pore walls.T he COFs assume an unconventional reverse AA-stacking mode in which the cationic benzimidazolium linkers [4d] are alternately orientated and aligned on both sides of the pore walls.W ehighlight that such an alternate alignment exerts profound effects on the ionic interface and triggers unusual electrostatic functions of COFs.Byvirtue of reduced charge repulsion between layers, the ionic COFs possess high crystallinity and porosity.W ith electric dipoles on both sides of the walls,the COF enhances the CO 2 adsorption by even three fold.…”

Kovalente organische Netzwerke und Käfigverbindungen: Design und Anwendungen von polymeren und diskreten organischen Gerüsten

“…Diese Nachteile lassen sich durch eine dynamisch-kovalente Bindungsknüpfung [44,45,[74][75][76][77][78][79] vermeiden, was sich als die am besten geeignete Strategie fürd ie Synthese von porçsen Materialien mit hoher struktureller Präzision herausgestellt hat. Darüber hinaus wurden auch Borosilicat-, [87] Borazin- [88] und ionische Spiroboratverknüpfungen [89] fürC OF-Synthesen eingesetzt. Die beiden mit weitem Abstand am häufigsten eingesetzten Reaktionstypen fürd ie Synthese von COFs und Käfigen sind Boronatester- [75,76,80] (Schema 1) und Iminkondensationen [59,77,81] [83][84][85] als auch Boroxinkondensationen [86] wurden auch fürd ie Herstellung von kovalenten organischen Käfigen eingesetzt.…”

“…[354] Durch postsynthetische Modifikation erhielten Xu et al zwei [TEMPO] x -NiP-COFs mit x = 50 und 100 %B eladung durch redoxaktive 2,2,6,6-Te tramethylpiperidinyloxyl(TEMPO)-Einheiten sowie Kapazitäten von bis zu 150 Fg À1 . [356] Ionische COFs zeigten effizienten Li + -Tr ansport, [89] und konjugierte COFs wurden sowohl als Ka-thoden- [357] wie auch als Anodenmaterial [358] in Li + -Batterien eingesetzt. [356] Ionische COFs zeigten effizienten Li + -Tr ansport, [89] und konjugierte COFs wurden sowohl als Ka-thoden- [357] wie auch als Anodenmaterial [358] in Li + -Batterien eingesetzt.…”

Moving Beyond Boron: The Emergence of New Linkage Chemistries in Covalent Organic Frameworks

“…29 Recently, Zhang and co-workers developed boron-based COFs based on spiroborate linkages, which are stable to aqueous and basic conditions and showed promising Li ion conductivity. 30 Nevertheless, this Perspective highlights a clear trend in COF synthesis toward new linkages based on reactions of amines or other nitrogen-containing functional groups ( Figure 1B) that generally impart increased stability over their boron-containing counterparts ( Figure 2). These more robust COFs have shown redox activity, 11,14,31,32 ionic conductivity, 12,33 and catalytic activity, 34 among other interesting properties.…”