Atomically precise structure determination of porous organic cage from Ab initio PXRD structure analysis: its molecular click post-functionalization and CO2 capture application.

A novel porous organic cage (POC) was prepared via condensation reaction between 1,3,5-triformylbenzene (TFB) and (1R, 2R)-4-cyclohexene-1,2-diamine (CHEDA). This POC could pack in either an amorphous structure or a crystalline. Atomically precise structure determination of POC was achieved through Ab initio powder X-ray diffraction (PXRD) structure analysis in chiral trigonal space group of R3. The same atomically precise structure determination of POC from single crystal X-ray diffraction (SXRD) structure analysis could be obtained independently with a slight difference in cell parameter, indicating that the refinement method through Ab initio PXRD structure analysis is reliable and may serve as an essential method for atomically precise structure determination. The cage could adsorb up to 8 mmol/g CO2 at 298 K and 1 bar. Furthermore, 1-thioglycerol and 1-octadecanethiol were chosen to prove that post-modification of this POC was flexible. After post-synthetic modification (PSM) via highly efficient photoinitiated thiol-ene click reaction, the products still kept porous with relatively higher special surface area (337 m2/g of 5T and 156 m2/g of 5O) than mostly reported cages via reduced-amine approach.