Hydrogen migration in oxalic acid di-hydrate at high pressure?

Abstract

Single crystal X-ray diffraction of oxalic acid dihydrate H(2)C(2)O(4).2H(2)O (1), at pressures up to 5.3 GPa, shows significant changes in the molecular geometries, probably accompanied by a proton migration from H(2)C(2)O(4) to H(2)O and formation of ionic species, as predicted by periodic DFT calculations.

Correlation between Accurate Electron Density and Linear Optical Properties in Amino Acid Derivatives:l-Histidinium Hydrogen Oxalate

“…4 In HB species, the hydrogen atom might be subjected to dynamic phenomena that are crucial for the (bio)material properties; among these, the most important is the proton transfer, which can be induced by changing the thermodynamic conditions. 5 More efforts are nowadays devoted to material science oriented research on HB crystal species. In this respect, the determination of the accurate electron distribution is fundamental to fully appreciate the nature of the chemical bonding 6 and the contribution of the HB to the genesis of material properties.…”

Evidence of Polaron Excitations in Low Temperature Raman Spectra of Oxalic Acid Dihydrate

“…Early vibrational spectroscopic 4 studies by Villepin and Novak [10][11][12] and single crystal far infrared study by Wyncke et al 13 attracted many other researchers to tackle the dynamics of this crystal using deuteron NMR 14 , ac conductivity measurements 15 , Raman 16,17 , high pressure X-ray 18 and neutron diffraction 19 , teraherz spectroscopy accompanied with density functional theory calculation 20 and Car-Parrinello molecular dynamics simulation 21 .…”

Multicomponent organic crystals at high pressure

“…Both the symmetrization and, oppositely, an increase of ionicity of the hydrogen bonds (OH … O or NH … N) has been reported in the literature [10,21,22,[87][88][89][90][91][92][93][94][95][96][97][98][99]. An increase in the ionicity of the intermolecular NH … O bonds between the terminal amino-and carboxygroups with increasing pressure has been reported for L-alanine [63,64].…”

“…An increase in the ionicity of the intermolecular NH … O bonds between the terminal amino-and carboxygroups with increasing pressure has been reported for L-alanine [63,64]. A bright example of a complete intermolecular hydrogen transfer, to give a salt starting from a molecular hydrate was reported for oxalic acid dihydrate [93,94]. Interestingly, this transfer takes place only if α-polymorph is compressed, but was not observed for the β-polymorph [94].…”