Bis(glycinium) oxalate: effect of deuteration, single crystal neutron diffraction and Raman spectroscopic studies

Abstract The crystal structure of bis(glycinium) oxalate (BGO) is stabilized by a very strong O–H..O hydrogen bond apart from N–H…O and C-H…O hydrogen bonds. To probe the effect of deuteration on these hydrogen bonds, fully deuterated (FDBGO), C-deuterated(CDBGO), and N-deuterated bis(glycinium) oxalate (NDBGO) crystals were grown. Single crystal neutron diffraction and Raman spectroscopic studies were carried out. It was found from neutron diffraction studies that the O…O distance of the O–H…O hydrogen bond reduced on deuteration showing an inverse Ubbelohde effect. The neutron diffraction and Raman spectroscopic studies also revealed partial deuteration. The DSC studies showed no phase transition. Variation of the melting point amongst the four crystals was in a very small range from 151 to 158 °C.