Asymmetric Synthesis of Chiral Bimetallic [Ag28Cu12(SR)24]4- Nanoclusters via Ion Pairing
Yan, J., Su, H.-F., Yang, H., Hu, C., Malola, S., Lin, S.-C., . . . Zheng, N. (2016). Asymmetric Synthesis of Chiral Bimetallic [Ag28Cu12(SR)24]4- Nanoclusters via Ion Pairing. Journal of the American Chemical Society, 138 (39), 12751-12754. doi:10.1021/jacs.6b08100
Published inJournal of the American Chemical Society
© 2016 American Chemical Society. This is a final draft version of an article whose final and definitive form has been published by ACS. Published in this repository with the kind permission of the publisher.
In this work, a facile ion-pairing strategy for asymmetric synthesis of optically active negatively charged chiral metal nanoparticles using chiral ammonium cations is demonstrated. A new thiolated chiral three-concentric-shell cluster, [Ag28Cu12(SR)24] 4- was first synthesized as a racemic mixture and characterized by single-crystal X-ray structure determination. Mass spectrometric measurements revealed relatively strong ion-pairing interactions between the anionic nanocluster and ammonium cations. Inspired by this observation, the as-prepared racemic mixture was separated into enantiomers by employing chiral quaternary ammonium salts as chiral resolution agents. Subsequently, direct asymmetric synthesis of optically pure enantiomers of [Ag28Cu12(SR)24] 4- was achieved by using appropriate chiral ammonium cations (such as Nbenzylcinchoninium vsN-benzylcinchonidinium) in the cluster synthesis. These simple strategies, ion-pairing enantioseparation and direct asymmetric synthesis using chiral counterions, may be of general use in preparing chiral metal nanoparticles. ...