Related Experiment Video
Updated: Jul 31, 2025

High-Pressure NMR Experiments for Detecting Protein Low-Lying Conformational States
Published on: June 29, 2021
Phase transitions of L-histidinium hydrogen oxalate crystal under high pressures investigated by Raman spectroscopy
E K S Pinho1, J G da Silva Filho1, F F Sousa2
1Centro de Ciências de Imperatriz, Universidade Federal do Maranhão, CEP, 65900-410 Imperatriz, MA, Brazil.
Abstract:
L-histidinium hydrogen oxalate (L-HisH)(HC2O4) crystal is formed from amino acid. L-histidine with oxalic acid whose vibrational high pressures behavior have not yet been investigated in the literature. Here we synthesized (L-HisH)(HC2O4) crystal by slow solvent evaporation method in a 1:1 ratio of L-histidine and oxalic acid. In addition, a vibrational study of (L-HisH)(HC2O4) crystal as a function of pressure was performed via Raman spectroscopy in the pressure range of 0.0-7.3 GPa. From analysis of the behavior of the bands within 1.5-2.8 GPa, characterized by the disappearance of lattice modes, the occurrence of a conformational phase transition was noted. A second phase transition, now from structural type, close to 5.1 GPa was observed due to the incidence of considerable changes in lattice and internal modes, mainly in vibrational modes related to imidazole ring motions.
More Related Videos
08:42High-Sensitivity Nuclear Magnetic Resonance at Giga-Pascal Pressures: A New Tool for Probing Electronic and Chemical Properties of Condensed Matter under Extreme Conditions
Published on: October 10, 2014
07:26Synthesis and Microdiffraction at Extreme Pressures and Temperatures
Published on: October 7, 2013
Related Concept Videos
Raman Spectroscopy: Overview
However, a small fraction of the scattered light exhibits a frequency shift due to the exchange of energy between the incident photons and...
Raman Spectroscopy Instrumentation: Overview
The monochromatic laser source, typically using visible or near-infrared radiation, generates a highly focused beam of light. This light interacts with the molecules of the sample, scattering some of the light. Liquid and gaseous samples are usually tested in ordinary glass capillaries, while solids can be analyzed as powders packed in capillaries or as potassium...
UV–Vis Spectroscopy: Molecular Electronic Transitions
¹H NMR of Conformationally Flexible Molecules: Temporal Resolution
IR Spectroscopy: Hooke's Law Approximation of Molecular Vibration
According to Hooke's law, the vibrational frequency is directly proportional to...
¹H NMR of Conformationally Flexible Molecules: Variable-Temperature NMR