Solid-State Chemical Transformations to Enhance Gas Capture in Benzoxazine-Linked Conjugated Microporous Polymers

We describe the first examples of benzoxazine (BZ)-linked tetraphenylethylene (TPE)- and pyrene (Py) containing conjugated microporous organic polymers (CMPs)-TPE-TPE-BZ and Py-TPE-BZ, respectively-having high surface areas and pore volumes, prepared through multistep syntheses (Schiff base, reduction, Mannich, and Sonogashira-Hagihara coupling), and their solid-state transformations through ring-opening polymerizations (ROPs) to give BZ linkages have never been reported previously. The chemical structures and, particularly, the presence of BZ units in the TPE-TPEBZ and Py-TPE-BZ CMPs were confirmed through Fourier transform infrared and solid-state nuclear magnetic resonance spectroscopic analyses. The TEP-TPE-BZ CMP had a high BET specific surface area and a high total pore volume (325 m(2) g(-1) and 0.69 cm(3) g(-1), respectively). Because BZ units can undergo ROP through simple thermal treatment without the need for a curing agent or catalyst, the CMPs readily underwent one-step chemical transformations in the solid state to form new CMPs featuring phenolic OH and Mannich bridges as functional groups capable of forming strong intermolecular hydrogen bonds and/or acid/base interactions with molecules of CO, gas to enhance the gas uptake ability.

Automated summary

The study presents the first examples of benzoxazine-linked tetraphenylethylene and pyrene containing conjugated microporous organic polymers, demonstrating high surface areas and pore volumes. The synthesis involved multistep processes and the solid-state transformations to form new CMPs with functional groups capable of enhancing gas uptake ability.