Study of Enantiomeric Separation of Propylene Oxide Using L- or D-Penicillamine Modified Au Nanoparticles

Several pharmaceutical drugs synthesized in the laboratory are chiral. However, while one enantiomer of the drug is beneficial, the other enantiomer could be harmful. As a result, the enantiomers of chiral pharmaceutical drugs have to be separated before using the drug. The current method used for separation of enantiomers of chiral pharmaceuticals is High Pressure Liquid Chromatography (HPLC). This method is expensive and time-consuming. In response to the issue, we are exploring the idea of using chirally modified gold nanoparticles for enantiomeric separations of chiral pharmaceutical drugs. This work investigates the use of chirally modified urchin-like gold nanoparticles for enantioselective separation of racemic propylene oxide (PO) from the solution phase. Urchin-like gold nanoparticles were successfully synthesized according to Li, Jing, and [1]. Surface of the gold nanoparticles was modified with L- or D-Penicillamine in order to make them chiral. Gold nanoparticles were used to study separation of racemic mixture of PO. Propylene oxide is used as a probe molecule this work. Polarimetry was used to determine the optical rotation of the solutions and the extent of enantiomeric separations.

[1] Li, Jing, et al. “Controllable Synthesis of Stable Urchin-like Gold Nanoparticles Using Hydroquinone to Tune the Reactivity of Gold Chloride.” The Journal of Physical Chemistry C, vol. 115, no. 9, Oct. 2011, pp. 3630–3637., doi:10.1021/jp1119074.