Chiral Self-Sorting Directed Supramolecular Organic Framework of Imine Cages for Iodine Capture

Supramolecular organic frameworks (SOFs) with nanotubular pores, assembled through weak non-covalent interactions, are highly sought-after for storage, separation, and pollutant capture but are limited. Herein, a SOF assembled with a chiral imine cage is reported by leveraging kinetically driven dynamic covalent chemistry, chiral self-sorting, and dispersion interactions for efficient iodine capture. The crystallization-driven synthesis involves a triamine and a racemic mixture of axially chiral dialdehyde equipped in bimesityl (BM) skeleton that undergoes narcissistic chiral self-sorting to form racemic mixture of homochiral imine cage (BM-PIC) enantiomers, which result in the SOF (BM-PIC-SOF). Notably, excess triamine drives the chiral self-sorting into heterochiral cages in a favorable solvent. The BM-PIC-SOF is templated by solvent molecules and features nanotubular pores (1.4 nm) that are stabilized by non-covalent interactions, notably, dispersion forces between mesitylene rings. Further, the kinetic crystals of BM-PIC-SOF, upon exchange with volatile solvents, undergo single-crystal-to-single-crystal transformation at high temperature into a thermodynamic polymorph with large structural difference. BM-PIC-SOF demonstrates remarkable efficacy in adsorbing iodine not only from vapor (6.0 g.g^-1) but also from organic (3.88 g.g^-1) and aqueous mediums (5.01 g g^-1).