Crystal structure and phase transition of diglycine perchlorate

Panicker, Lata ; Mathur, Pradeep ; Mobin, Shaikh M. (2010) Crystal structure and phase transition of diglycine perchlorate Journal of Chemical Crystallography . ISSN 1074-1542

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Official URL: http://www.springerlink.com/index/K7210375456H3PU8...

Related URL: http://dx.doi.org/10.1007/s10870-010-9854-z

Abstract

Diglycine perchlorate (DGPCl), a new 2:1 adduct formed between glycine and perchloric acid has been obtained and studied using differential scanning calorimetry and single crystal X-ray diffraction. DGPCl undergoes a reversible first-order phase transition at 261.5 K. The crystal structures at 150 and 293 K have been determined to be triclinic, space group P-1, Z = 2, suggesting the first-order phase transition to be an isostructural phase transition. The DGPCl crystal consists of five glycinium-monoprotonated glycinium dimers and five perchlorate anions in an asymmetric unit. The glycine moieties in the glycinium-monoprotonated glycinium dimers are non-planar. Two types of hydrogen bonds are present in the crystal, strong O-H···O hydrogen bonds and a weak N-H···O hydrogen bonds. The short, strong O-H···O hydrogen bond connects the glycinium ion and mono protonated glycinium ion. In four of the dimers, the O-H and H···O bond lengths are different, indicating the hydrogen atom to be located more close to the monoprotonated glycinium ion. However, in one of the glycinium-monoprotonated glycinium dimer the O··H and H··O bond lengths are nearly equal, suggesting the hydrogen atom (O···H···O) to be attached to the oxygen atoms of both glycine moieties. On thermal transition some of these hydrogen bonds are weakened and in all dimers the hydrogen atom seems to be located more close to the mono protonated glycinium ion.

Item Type:Article
Source:Copyright of this article belongs to Springer-Verlag.
Keywords:Diglycine Perchlorate; Single Crystal X-ray Diffraction; DSC
ID Code:24889
Deposited On:01 Dec 2010 12:31
Last Modified:01 Mar 2011 04:38

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