Desymmetrized Vertex Design toward a Molecular Cage with Unusual Topology

Abstract

A novel low‐symmetry organic molecular cage with distinctive geometry was successfully synthesized from 5,5′‐(propane‐2,2‐diyl)bis(2‐hydroxyisophthalaldehyde) and 1,2‐cyclohexanediamine building blocks, through the desymmetrized vertex design strategy. Single‐crystal X‐ray crystallographic analysis shows that the cage contains asymmetrical and nonplanar windows, exhibiting an unprecedented C2 symmetry and an efficient packing. The molecular cage structure was also characterized by FTIR, NMR, and MALDI‐TOF. Quantum chemistry studies show that the cage structure contains rare intramolecular hydrogen‐hydrogen (C−H⋅⋅⋅H−C) bonding interactions. The cage crystals exhibit high iodine vapor uptake (3.78 g g−1), which is among the highest for porous molecular materials. The knowledge gained in this study would open new possibilities for the design and synthesis of molecular cages with novel topologies targeting a broad range of applications.

Racemic Porous Organic Cage Crystal with Selective Gas Adsorption Behaviors

“…Porous organic cages (POCs) constructed from covalently linked discrete functional organic modules have been emerged as a new member of porous reticular frameworks. [24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42] In comparison with other artificial counterparts including MOFs, COFs, and hydrogen-bonded organic frameworks (HOFs), [43][44][45][46][47][48][49][50] POCs possess diverse interesting cage molecules with intrinsic cavities as building blocks. Increasingly, skilled crystal engineering connects the molecular cavities to form the highly intercrossing porosities of POCs, [24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42] achieving the high surface area of 3758 m 2 g À 1 for storage.…”

“…[24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42] In comparison with other artificial counterparts including MOFs, COFs, and hydrogen-bonded organic frameworks (HOFs), [43][44][45][46][47][48][49][50] POCs possess diverse interesting cage molecules with intrinsic cavities as building blocks. Increasingly, skilled crystal engineering connects the molecular cavities to form the highly intercrossing porosities of POCs, [24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42] achieving the high surface area of 3758 m 2 g À 1 for storage. [40] In addition, the pore shape and size of POCs as well as functional module surrounding the cavities/channels exert ef...…”

Chiral self-sorting and guest recognition of porous aromatic cages

“…For the synthesis of chiral POCs, imine condensation has been the prevailing route, and a large number of structures have been reported, normally adopting flexible skeletons with central chiral amines as building blocks 6,10,11,20,[29][30][31][32][33][34] . Although selfcorrection mechanism of the reversible covalent bond greatly facilitates the accessibility of chiral POCs, the intrinsic dynamic character of imine makes this bond low-energetic stability, and prone to be attacked e.g.…”