Enantiomeric Discrimination by Surface‐Enhanced Raman Scattering–Chiral Anisotropy of Chiral Nanostructured Gold Films

Abstract

A surface‐enhanced Raman scattering‐chiral anisotropy (SERS‐ChA) effect is reported that combines chiral discrimination and surface Raman scattering enhancement on chiral nanostructured Au films (CNAFs) equipped in the normal Raman scattering Spectrometer. The CNAFs provided remarkably higher enhancement factors of Raman scattering (EFs) for particular enantiomers, and the SERS intensity was proportional to the enantiomeric excesses (ee) values. Except for molecules with mesomeric species, all of the tested enantiomers exhibited high SERS‐ChA asymmetry factors (g), ranging between 1.34 and 1.99 regardless of polarities, sizes, chromophores, concentrations and ee. The effect might be attributed to selective resonance coupling between the induced electric and magnetic dipoles associated with enantiomers and chiral plasmonic modes of CNAFs.

Chiral molecular imprinting-based SERS detection strategy for absolute enantiomeric discrimination

“…Creating the chiral anisotropy by a polarizable chiral platform following SERS detection 55 , label-free based on charge transfer 21 , and direct sensing 19 are three commonly accepted mechanisms used for the identification of enantiomers by SERS. In these chiral SERS discrimination strategies producing asymmetric recognition sites on the nanostructure surface to provide local chiral environments for preferential adsorption of enantiomers is essential, which is face five main challenges: (i) Creating asymmetric colloidal nanostructures is difficult and sophisticated owing to the lack of easy control over the formation of chiral characteristics.…”

Recent advances in chiral nanomaterials with unique electric and magnetic properties

“…g Raman spectra (top) and dependencies (bottom) of the largest SERS peak areas on ee values from − 100% to + 100% for 2-butanol, showing SERS-ChA effect of R-CNAFs. Reproduced with permission from [ 73 ]. Copyright 2020 Wiley …”

“…Another chiroplasmonic NM with intrinsic chirality was recently reported by Che's group with similar synthesis method, but the seeds were anchored on the 2D surfaces [ 73 ]. Surface-enhanced Raman scattering-chiral anisotropy (SERS-ChA) effect was demonstrated with normal Raman measurements of enantiomeric molecules using chiral nanostructured Au films (CNAFs) substrates.…”

Rapid chiral analysis based on liquid-phase cyclic chemiluminescence

“…[1][2][3] The simultaneous determination of the absolute conguration and enantiopurity of chiral substrates is highly signicant in the elds of synthetic, biological and pharmaceutical chemistry. [4][5][6] However, chiral analysis remains a great challenge because enantiomers have nearly identical physical properties. 7 In the past several decades, many effective methods have been developed for chiral analysis, such as gas chromatography, 8,9 high-performance liquid chromatography (HPLC), 10,11 capillary electrophoresis, [12][13][14] nuclear magnetic resonance (NMR) spectroscopy 7,[15][16][17] and mass spectrometry.…”