Acta Cryst. (2013). C69, 794-797 [ doi:10.1107/S0108270113015783 ]
Abstract: Two hydrate pseudopolymorphs of 3-[(4-amino-2-methylpyrimidin-1-ium-5-yl)methyl]-4-methyl-1,3-thiazol-3-ium-5-yl hydrogen pyrophosphate (TPP), viz. a dihydrate, C12H18N4O7P2S·2H2O, (I), and a trihydrate, C12H18N4O7P2S·3H2O, (II), were obtained during a structural study of vitamin B1 coenzyme. In both compounds, TPP is a neutral zwitterion, with its pyrophosphate group doubly deprotonated and its pyrimidine ring protonated, and it assumes the usual `F' conformation in terms of the two torsion angles about the bonds by which the methylene group links the thiazolium and pyrimidinium rings [1.1 (3) and 79.7 (3)° for (I), and 2.0 (3) and 75.5 (3)° for (II)]. In (I), two TPP molecules are linked by a pair of O-HO hydrogen bonds into a phosphate-pairing dimer. N-HO hydrogen bonds connect the dimers into a sheet parallel to (101). In (II), the TPP molecules are self-assembled solely by N-HO hydrogen bonds, generating a tape structure along . A comparison of the four known hydrate pseudopolymorphs of TPP shows that the phosphate-pairing dimers are basic building units for the formation of two-dimensional networks.
Formula: C12H18N4O7P2S·2H2O and C12H18N4O7P2S·3H2O
Structure factor file (CIF format) (159.8 kbytes)
Structure factor file (CIF format) (176.2 kbytes)
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