A strategy for constructing chiral covalent organic frameworks from achiral crystalline precursors

A rational chiral covalent organic framework (CCOF) synthesis strategy is essential to unlock their potential applications. In this work, a new method was developed for the synthesis of crystalline CCOFs, R/S-PPI-2-COF (<i>P</i>6 space group), which were transformed from the achiral PI-2-COF. To demonstrate the generality of the synthetic strategy, two additional reported achiral COFs (PI-3-COF and COF_TFPY-PPDA) were also converted into CCOFs. Notably, R-PPI-2-COF with its nitrogen- and oxygen-rich framework exhibits high porosity and enables enantioselective separation of racemic methyl mandelate.