Bottom-up synthesis of chiral covalent organic frameworks and their bound capillaries for chiral separation.

Hai-Long Qian,Cheng-Xiong Yang,Xiu-Ping Yan

doi:10.1038/ncomms12104

Abstract

Covalent organic frameworks (COFs) are a novel class of porous materials, and offer great potential for various applications. However, the applications of COFs in chiral separation and chiral catalysis are largely underexplored due to the very limited chiral COFs available and their challenging synthesis. Here we show a bottom-up strategy to construct chiral COFs and an in situ growth approach to fabricate chiral COF-bound capillary columns for chiral gas chromatography. We incorporate the chiral centres into one of the organic ligands for the synthesis of the chiral COFs. We subsequently in situ prepare the COF-bound capillary columns. The prepared chiral COFs and their bound capillary columns give high resolution for the separation of enantiomers with excellent repeatability and reproducibility. The proposed strategy provides a promising platform for the synthesis of chiral COFs and their chiral separation application.

Highlights

Covalent organic frameworks (COFs) are a novel class of porous materials, and offer great potential for various applications
The results reveal the promising aspects for the fabrication of chiral COFs via the bottom-up strategy and the great potential of chiral COFs as a platform for chiral separation
We found that baseline separation of enantiomers such as (±)-1-phenylethanol, (±)-1-phenyl-1-propanol, (±)-limonene and (±)-methyl lactate on chiral COF-bound capillary columns within 5 min (Fig. 5; Supplementary Figs 42 and 49)

Summary

Introduction

Covalent organic frameworks (COFs) are a novel class of porous materials, and offer great potential for various applications. Covalent organic frameworks (COFs) are a novel type of crystalline porous materials with highly ordered structures solely constructed from organic building units via strong covalent bonds[1,2,3,4,5] Owing to their strong covalent linkages between light elements (H, B, C, N and O), COFs possess lots of unique properties[4,5] such as rigid structures (two dimensional[1,6,7,8] or three dimensional9,10), low densities[9], high thermal stabilities[11] and permanent porosity with large specific surface areas[10], which make COFs potential in diverse fields including gas storage[12,13,14], photoconduction[15,16,17], catalysis[18,19,20] and chromatography[21]. The results reveal the promising aspects for the fabrication of chiral COFs via the bottom-up strategy and the great potential of chiral COFs as a platform for chiral separation

Methods

Results

Conclusion