Chiral-mesoporous-polypyrrole nanoparticles: Its chiral recognition abilities and use in enantioselective separation

Abstract

Chiral-mesoporous-polypyrrole (CMPPy) nanoparticles are synthesized by templating chiral block copolymers (CBCs) of poly(ethylene oxide), (PEO) and chiral L-/D- glutamic acid [PEO-b-(L-/D-GluA)10] and blocks of chiral L-/D-phenylalanine [PEO-b-(L-/D-Phe)10]. The well ordered chiral mesopores of nanoparticles are characterized by HRTEM and BET. The CMPPy nanoparticles have well organized pores with sizes ca. 3.5–3.7 nm in diameter and with a high surface area. These CMPPy nanoparticles are able to recognize chiral molecules. Using the selective chiral recognition abilities, the chiral resolution of the copolymer-extracted CMPPy nanoparticles and the chiral separation kinetics using a racemic mixture of valine are probed by circular dichroism (CD) and optical polarimetry. Further, the chiral resolution of the CMPPy is confirmed with a racemic mixture of alanine. The chiral selectivity factor is 5.05 for a specific enantiomer which is adsorbed preferably by the CMPPy. These results allow a new approach towards the enantiomeric separation and other enantiomeric applications of novel CMPPy.