Related Experiment Video
Updated: Mar 13, 2026

Novel Techniques for Observing Structural Dynamics of Photoresponsive Liquid Crystals
Published on: May 29, 2018
Electronic Circular Dichroism Spectroscopy of Jet-Cooled Phenylalanine and Its Hydrated Clusters
Aram Hong1, Heeseon Jang1, Changseop Jeong1
1Department of Chemistry, Chungbuk National University , Chungbuk 28644, Korea.
Abstract:
We obtained resonant two-photon ionization circular dichroism (R2PICD) spectra of jet-cooled phenylalanine (Phe) and its hydrated clusters (Phe(H2O)n, n = 1-2) near the origin band of the S0-S1 transition. The R2PICD spectra of Phe exhibit well-resolved CD bands of six different conformers present in the jet, which vary in sign and magnitude depending on their conformations. We revised the previous structural assignments of the Phe conformers based on the comparison between the experimental and theoretical CD signs, infrared spectra, and rotational band contours. The R2PICD spectra of Phe(H2O)n reveal that hydration with one or two water molecule(s) does not affect the CD signs of Phe conformers but significantly increases their CD magnitudes. Furthermore, conformational selection by solvation alters relative populations of Phe conformers, leading to a sign inversion in the CD spectra of Phe(H2O)n compared with that of Phe monomer.
Related Concept Videos
¹H NMR of Conformationally Flexible Molecules: Variable-Temperature NMR
UV–Vis Spectroscopy: Molecular Electronic Transitions
π Electron Effects on Chemical Shift: Aromatic and Antiaromatic Compounds
¹³C NMR: Distortionless Enhancement by Polarization Transfer (DEPT)
¹H NMR: Interpreting Distorted and Overlapping Signals
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are...
π Electron Effects on Chemical Shift: Overview

