title: Two hydrate pseudopolymorphs of thiamine pyrophosphate: a dihydrate and a trihydrate.
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-H···O hydrogen bonds into a phosphate-pairing dimer. N-H···O hydrogen bonds connect the dimers into a sheet parallel to (101). In (II), the TPP molecules are self-assembled solely by N-H···O hydrogen bonds, generating a tape structure along [001]. 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.
authors.affiliation: Orthopaedics Department, First Hospital, Jilin University, Changchun 130021, People's Republic of China.
authors.forename: Shu-Qiang
authors.initials: SQ
authors.lastname: Li
authors.forename: Ning-Hai
authors.initials: NH
authors.lastname: Hu
mesh_terms: D003460:Crystallization; D006860:Hydrogen Bonding; D008958:Models, Molecular; D015394:Molecular Structure; D011726:Pyridinium Compounds / Q000737:chemistry*; D011743:Pyrimidines / Q000737:chemistry*; D013835:Thiamine Pyrophosphate / Q000737:chemistry*; D013844:Thiazoles / Q000737:chemistry*
chemical_list: C438625:3-((4-amino-2-methyl-5-pyrimidin-1-io)methyl)-5-(2-hydroxyethyl)-4-methylthiazolium(2+) bis(tetrafluoroborate); C584215:3-((4-amino-2-methylpyrimidin-1-ium-5-yl)methyl)-4-methyl-1,3-thiazol-3-ium-5-yl hydrogen pyrophosphate dihydrate; D011726:Pyridinium Compounds; D011743:Pyrimidines; D013844:Thiazoles; D013835:Thiamine Pyrophosphate