Wenbei Chen,Huixian Liu,Yuting Chen,Jian Ke,Xin Qiu,Jianqiu Chen,Yibing Ji
Membrane separation technology has infinite potential to produce optically pure drugs. However, there are still challenges regarding chiral membranes, such as the single separation object, poor mechanical properties, and constrained relationship between permeability and enantioselectivity. To improve the membrane properties, heptakis (6-amino-6-deoxy)- β -CD-modified carboxyl-functionalized COF (TpBD-Am7CD) was introduced as a chiral functional material for the preparation of a TpBD-Am7CD stainless steel I-Net cellulose acetate membrane (COF/SSCAM) via interfacial polymerization. Using tryptophan as the template molecule, the membrane preparation and filtration conditions were optimized to achieve maximum enantioselectivity. The optimized COF/SSCAM achieved a better enantiomeric excess percentage (e.e.% = 100.00%) and solute permeation flux (J S = 37 × 10 −6 mol m −2 h −1 ) for racemic tryptophan than the support membrane, which was attributed to the enantioselectivity and hydrophilicity of TpBD-Am7CD. Moreover, COF/SSCAM achieved enantiomeric separation of racemates of propranolol, warfarin, atenolol, and metoprolol, and the e.e.% values were 39.51%, 5.60%, 16.04%, and 3.09%, respectively. In addition, the chiral recognition mechanism was investigated by molecular docking simulation.
Siqi Zhuo,Xuehua Wang,Lingyu Li,Shan Yang,Yibing Ji
Combining chiral molecules and covalent organic frameworks (COFs) with ordered pores can result in chiral COFs, which may be employed in the fields of chiral chemistry. In this study, we constructed a novel carboxyl-functionalized COF TpBD-3COOH first and then integrated a chiral molecule, heptakis (6-amino-6-deoxy)-β-CD (Am7CD), into TpBD-3COOH to obtain TpBD-Am7CD. Comparing TpBD-3COOH with TpBD-Am7CD, it could be observed that chiral selectivities improved significantly after decorating TpBD-3COOH with Am7CD in the adsorption experiment. Meanwhile, TpBD-Am7CD exhibited similar chiral selective abilities as the previously reported β-CD COF when it was employed to adsorb amino acid enantiomers, while the content of Am7CD was much less than that in β-CD COF. This indicated that the framework of TpBD-3COOH enhanced the chiral selective ability of Am7CD, which would be a great chiral carrier material for further application. This work provides a new insight for establishing materials for application in the chiral recognition field. Besides, TpBD-Am7CD resulted in an insoluble powder, which endowed this material with the possibility to be an adsorbent and a stationary phase in chromatography.