Chirality transfer observed in Raman optical activity spectra

Chirality transfer (also called induced chirality) is a phenomenon present in chiroptical spectra that manifests itself as a new band or bands of an achiral molecule interacting with a chiral one. In the Raman optical activity (ROA) spectroscopy, the bands of achiral solvents have been recently observed, but the latest papers have shown that they corresponded to the new ECD-Raman (eCP-Raman) effect. Here, we show an unambiguous example of chirality transfer observed in the ROA spectra. The spectra registered for the (1:1) mixtures of achiral benzonitrile with the enantiomers of 2, 2, 2-trifluoro-1-phenylethanol, 1-phenylethanol, and 1-phenylethylamine exhibited the v(CN) vibration band at about 2230 cm(-1). The ROA measurements were repeated several times to ensure the reliability of the phenomenon. Calculations revealed the CN center dot center dot center dot HO or CN center dot center dot center dot HNH hydrogen bond formation accompanied by the pi center dot center dot center dot pi or CH center dot center dot center dot pi interactions. The interaction strength was shown to be an important factor for the pronouncement of the ROA chirality transfer effect.

Automated summary

Chirality transfer is a phenomenon observed in chiroptical spectra, where a new band is formed due to interaction between a chiral molecule and an achiral molecule. In this study, a clear example of chirality transfer is observed in the ROA spectra of mixtures of achiral benzonitrile with several enantiomers.