Bis(2,4,6-tri-amino-1,3,5-triazin-1-ium) 2-[bis-(carboxyl-atometh-yl)aza-nium-yl]acetate trihydrate

• Published in: Acta crystallographica. Section E, Structure reports online Structure reports online, 2013-11, Vol.69 (Pt 11), p.o1674-o1675
• Main Authors: Hoxha, Kreshnik, Prior, Timothy J
• Format: Article
• Language: English
• Subjects: Organic Papers
• ISSN: 1600-5368; 1600-5368
• DOI: 10.1107/S1600536813028250

The title compound, 2C3H7N6 (+)·C6H7NO6 (2-)·3H2O, was obtained by mixing melamine and nitrilo-tri-acetic acid in aqueous solution. There is proton transfer from the nitrilo-triacteic acid to melamine to produce two melaminium cations and an inter-nal proton transfer to generate the [HN(CH2COO)](2-) zwitterion. The melaminium cations are arranged in hydrogen-bonded tapes formed by N-H⋯N inter-actions. These tapes extend parallel to the [010] direction and are stacked parallel to the a axis at a mean separation of 3.3559 (11) Å. Between these tapes lie the anions and lattice water mol-ecules. Further O-H⋯O and N-H⋯O hydrogen bonds exist between the water mol-ecules, the anions, and the melaminium cations, generating a three-dimensional array. The crystal examined was found to be twinned by a twofold rotation about the direct lattice direction [100]. The two twin components were present in the ratio 0.5918:0.4082 (14).