Fabricating Industry‐Compatible Olefin‐Linked COF Resins for Oxoanion Pollutant Scavenging

Abstract

Large-scale and low-cost synthesis of covalent organic frameworks (COFs) to meet the demands of industrial application remains formidably challenge. Here we report using 2,4,6-collidine as monomer to produce a series of highly crystalline olefin-linked COFs by a melt polymerization method. This method enables the kilogram-scale fabrication of self-shaped monolithic robust foams. The afforded COFs possess extremely low cost (< 50 USD/kg), superior to all the reported COFs. Furthermore, using one-pot or post-modification methods can conveniently transform neutral COFs to ionic COFs, which can be applied as highly efficient ionexchange sorbents for scavenging oxoanion pollutants. Remarkably, the superior adsorption capacity of a model oxoanion (ReO 4 À ) is the highest among crystalline porous materials reported so far. This work not only expands the scopes of olefin-linked COFs but also enlightens the route for the industrial production of crystalline ion exchange sorbents.

Construction of Covalent Organic Frameworks via Multicomponent Reactions

“…MCRs are expected to generate COFs with complex topologies and pore environments. For the majority of the presented examples, the employed MCR usually involves two organic monomers containing multiple symmetrically distributed functional groups and one monomer with a single functional group that only reacts once, which is basically an additional functionalization of an in situ constructed framework . The framework topology and underlying structure are not changed compared to the simpler connection of the building blocks via a two-component reaction.…”

“…For the majority of the presented examples, the employed MCR usually involves two organic monomers containing multiple symmetrically distributed functional groups and one monomer with a single functional group that only reacts once, which is basically an additional functionalization of an in situ constructed framework. 74 The framework topology and underlying structure are not changed compared to the simpler connection of the building blocks via a two-component reaction. Logically, owing to reticular chemistry design, 75 the full potential of MCRs can be utilized to construct more complex topologies, for which each type of monomer defines a new covalent connection and is connected to at least two other monomers.…”

Two-Dimensional Benzobisthiazole-Vinylene-Linked Covalent Organic Frameworks Outperform One-Dimensional Counterparts in Photocatalysis

“…Two-dimensional covalent organic frameworks (2D COFs), featuring porous and extended structures with repeat organic units, have attracted considerable attention due to their wide potential applications in gas storage, energy storage and conversions. − To date, most 2D COFs are synthesized via the formation of dynamic covalent bonds, which possess highly polarized B–O, , C–N, or CN , bonds and consequently impede the in-plane π-electron delocalization of 2D COFs and thus cause possible chemical stability issues . In contrast, vinylene-linked covalent organic frameworks (v-2D-COFs) can integrate the advantages of superb stability and excellent π-conjugation over the in-plane networks of 2D COFs for exceptional prospects. , Thus far, two types of v-2D-COFs have been developed successfully: cyano-substituted v-2D-COFs can be constructed via Knoevenagel polymerization together with in situ dynamic Michael addition elimination; − unsubstituted v-2D-COFs can be synthesized by Aldol-type − or Horner–Wadsworth–Emmons (HWE) polycondensations . The resultant v-2D-COFs have attracted rapid interest and demonstrated novel properties for photocatalysis, − energy storage, luminescence, − etc.…”

Carbon–Carbon Linked Organic Frameworks: An Explicit Summary and Analysis

“…Large-scale, low-cost, and green methods are getting more attention nowadays. [100,136,137] This section comprises the conventional techniques employed in the synthesis of C-C linked organic frameworks.…”

“…The Knoevenagel polycondensation reaction can be carried out in solvent‐free conditions also for synthesis of COF. [ 100 ] By heating 2,4,6‐collidine and benzoic anhydride at 180 °C for 5 days, Zhang et al synthesized vinylene linked COF without solvent. The authors also explored the generality of this strategy to develop collidine based COFs by employing aldehydes of different symmetry.…”