Chiral separation and asymmetric synthesis and catalysis are crucial processes for obtaining enantiopure compounds, which are especially important in the pharmaceutical industry. The efficiency of the separation processes is readily increased by using porous materials as the active material can interact with a larger surface area. Silica, metal-organic frameworks, or chiral polymers are versatile porous materials that are established in chiral applications, but their instability under certain conditions in some cases requires the use of more stable porous materials such as carbons. In addition to their stability, porous carbon materials can be tailored for their ability to adsorb and catalytically activate different chemical compounds from the liquid and the gas phase. The difficulties imposed by the functionalization of carbons with chiral species were tackled in the past by carbonizing chiral ionic liquids (CILs) together with a template to create pores, which results in the entire body of a material that is built up from the precursor. To increase the atomic efficiency of ionic liquids for better economic utilization of CILs, the approach presented here is based on the formation of a composite between CIL-derived chiral carbon and a pristine carbon material obtained from carbohydrate precursors. Two novel enantioselective carbon composite materials are applied for the chiral recognition of molecules in the gas phase, as well as in solution. The enantiomeric ratio of the l-composite for phenylalanine from the solution was (L/D) = 8.4, and for 2-butanol from the gas phase, it was (S/R) = 1.3. The d-composite showed an opposite behavior, where the enantiomeric ratio for phenylalanine was (D/L) = 2.7, and for 2-butanol from the gas phase, it was (R/S) = 1.3.
|Number of pages||10|
|Journal||ACS applied materials & interfaces|
|State||Published - 26 May 2021|
Bibliographical noteFunding Information:
The authors kindly acknowledge contributions from our colleagues at the Max Planck Institute of Colloids and Interfaces. Many thanks to Rona Pitschke and Heike Runge (TEM, SEM, and EDX), Antje Völkel (thermogravimetric and elemental analysis), and Ines Below-Lutz for general help in the lab. We would also like to thank a student assistant from the University of Potsdam, Henrik Schröter, for his immense help with synthesis. This research was supported by the German-Israeli Foundation for Scientific Research and Development (GIF, grant no. I-87-302.10-2015).
© 2021 The Authors. Published by American Chemical Society.
- chiral carbon
- chiral composite
- chiral separation
- enantioselective seperation
- ionic liquid
- porous carbon