Conversion of amorphous polymer networks to covalent organic frameworks under ionothermal conditions: a facile synthesis route for covalent triazine frameworks

Abstract

The conversion of an amorphous, non-porous polymer network into an ordered, microporous covalent organic framework under ionothermal conditions is presented. The amorphous polymer network is prepared by trimerization of carbonitrile monomers using strong Broensted acids. In a second step the polymer network is converted into a porous covalent triazine framework (CTF) under ionothermal conditions, i.e. in molten zinc chloride. This two-step process largely facilitates the synthesis of CTFs as the application of a polymeric precursor avoids early evaporation of small organic compounds at the high temperatures of the ionothermal process and therefore no evacuated and sealed quartz ampoules have to be used, which makes the CTF synthesis easier, safer and scalable.

Covalent Triazine‐based Frameworks—Tailor‐made Catalysts and Catalyst Supports for Molecular and Nanoparticulate Species

“…Unfortunately, none of these materials partially carbonized for a very short time period showed any sign of specific surface area. Still, long‐term ionothermal treatment for 40 h at 400 or 600 °C in an open crucible yielded comparable porosity and specific surface areas as observed for the reported approach within quartz ampules …”

“…More recently,both Brønsted acidcatalyzed and ionothermal synthesis strategy have been combined in order to upscalet he CTF synthesis andt os horten the ionothermal high temperature procedure. [31,32] This approach offers several advantages to both of the separately conducted methods. In af irst step, the Brønsteda cid catalyzed synthesis yields ap olymericm aterial at ambient temperature.…”

“…Still, long-term ionothermal treatment for 40 ha t4 00 or 600 8Ci na no pen crucibley ielded comparable porositya nd specific surface areasa so bserved for the reported approachwithin quartz ampules. [32] Various other synthesis approaches for CTF materials have been discussed more recently.F or example, as ulfur-mediated route withouta ny catalysts or solvents has been published by Ta lapanenie tal. [33] Within this approach, CTF is formed in the presenceo fe lementals ulfur via in situ vulcanization at 400 8C.…”

Manipulation of Amorphous‐to‐Crystalline Transformation: Towards the Construction of Covalent Organic Framework Hybrid Microspheres with NIR Photothermal Conversion Ability

“…By varying the monomer concentrations for the polyimine polymerization, the amorphous shell was formed with different thickness. [25] To modify the surface chemistry of COF-based microspheres for biomedical applications,a mine-terminated PEG was allowed to react with the residual aldehyde groups around the edges of the honeycomb-like COF structure,r eaching al oading content of 14 wt % ( Figure S12). This is also unparalleled because so far, there has been no method reported for modulation of the grain sizes of nanoCOFs.A ni nsight was made into the evolution of the COF(TpBD) shell.…”

Self‐Assembled, Fluorine‐Rich Porous Organic Polymers: A Class of Mechanically Stiff and Hydrophobic Materials

“…Both FPOPs are insoluble in a wide range of organic solvents (DMF, dimethylacetamide, methanol, ethanol, THF, chloroform and hexane) and water. Despite extensive washing, their pronounced insolubility revealed the robust nature of the FPOPs owing to extended network formation coupled with the inherently stable triazine rings . Preparation of the polymeric trimerised compounds was monitored by means of the FTIR spectra of the products (Figure S24 in the Supporting Information).…”