A Self‐Assembled Homochiral Radical Cage with Paramagnetic Behaviors

Abstract

Condensation of an inherently C3‐symmetric polychlorotriphenylmethyl (PTM) radical trisaldehyde with tris(2‐aminoethyl)amine (TREN) yields a [4+4] tetrahedral radical cage as a racemic pair of homochiral enantiomers in 75 % isolated yield. The structure was characterized by X‐ray crystallography, confirming the homochirality of each cage framework. The homochirality results from intramolecular [CH⋅⋅⋅π] and hydrogen‐bonding interactions within the cage framework. The four PTM radicals in a cage undergo weak through‐space coupling. Magnetic measurements demonstrated that each cage bears 3.58 spins.

A Self‐Assembled Homochiral Radical Cage with Paramagnetic Behaviors

“…Figure 3. Single crystal structures and super-structures of M 4 C 4 -PTM-TC and P 4 A 4 -PTM-TC [19]. Front and diagonal views of the M 4 C 4 -PTM-TC (a, b) and P 4 A 4 -PTM-TC (c, d).…”

Recent advances and perspectives on supramolecular radical cages

“…Very recently, Jiao, Cao, Li and co-workers reported a purely covalent radical cage ( 16 ) containing four PTM spins via dynamic covalent chemistry (DCC). 28 An interesting chiral self-sorting behaviour in the cage formation was observed, and the two enantiomers 16a and 16b were successfully separated by chiral high-performance liquid chromatography (HPLC) ( Fig. 7b ).…”

“…For example, organic radical restricted in a confined cage usually causes the significant change of the EPR signal, which can be applied to investigate the supramolecular phenomena. Nicholas and Chechik systematically investigated the host-guest interactions between nitroxide stable radicals (28)(29)(30)(31)(32) and supramolecular coordination cages (33 and 34) in water and acetonitrile by means of EPR spectroscopy (Fig. 12a).…”

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.…”