6-氨基-2-硫脲嘧啶的五种假多晶型物：不存在N-H...S氢键。
Five pseudopolymorphs of 6-amino-2-thiouracil: absence of N-H...S hydrogen bonds.
作者信息
Hützler Wilhelm Maximilian, Bolte Michael
机构信息
Institut für Organische Chemie und Chemische Biologie, Goethe-Universität Frankfurt, Max-von-Laue-Strasse 7, 60438 Frankfurt am Main, Germany.
出版信息
Acta Crystallogr C. 2013 Jan;69(Pt 1):93-100. doi: 10.1107/S010827011204930X. Epub 2012 Dec 15.
In order to study the preferred hydrogen-bonding pattern of 6-amino-2-thiouracil, C(4)H(5)N(3)OS, (I), crystallization experiments yielded five different pseudopolymorphs of (I), namely the dimethylformamide disolvate, C(4)H(5)N(3)OS·2C(3)H(7)NO, (Ia), the dimethylacetamide monosolvate, C(4)H(5)N(3)OS·C(4)H(9)NO, (Ib), the dimethylacetamide sesquisolvate, C(4)H(5)N(3)OS·1.5C(4)H(9)NO, (Ic), and two different 1-methylpyrrolidin-2-one sesquisolvates, C(4)H(5)N(3)OS·1.5C(5)H(9)NO, (Id) and (Ie). All structures contain R(2)(1)(6) N-H...O hydrogen-bond motifs. In the latter four structures, additional R(2)(2)(8) N-H...O hydrogen-bond motifs are present stabilizing homodimers of (I). No type of hydrogen bond other than N-H...O is observed. According to a search of the Cambridge Structural Database, most 2-thiouracil derivatives form homodimers stabilized by an R(2)(2)(8) hydrogen-bonding pattern, with (i) only N-H...O, (ii) only N-H...S or (iii) alternating pairs of N-H...O and N-H...S hydrogen bonds.
为了研究6-氨基-2-硫脲嘧啶（C₄H₅N₃OS，(I)）的优选氢键模式，结晶实验得到了(I)的五种不同假多晶型物，即二甲基甲酰胺二溶剂化物（C₄H₅N₃OS·2C₃H₇NO，(Ia)）、二甲基乙酰胺单溶剂化物（C₄H₅N₃OS·C₄H₉NO，(Ib)）、二甲基乙酰胺倍半溶剂化物（C₄H₅N₃OS·1.5C₄H₉NO，(Ic)）以及两种不同的1-甲基吡咯烷-2-酮倍半溶剂化物（C₄H₅N₃OS·1.5C₅H₉NO，(Id)和(Ie)）。所有结构均包含R₂²(6) N-H...O氢键基序。在后四种结构中，还存在额外的R₂²(8) N-H...O氢键基序，可稳定(I)的同二聚体。未观察到除N-H...O以外的其他氢键类型。根据对剑桥结构数据库的搜索，大多数2-硫脲嘧啶衍生物形成通过R₂²(8)氢键模式稳定的同二聚体，其中（i）只有N-H...O，（ii）只有N-H...S，或（iii）N-H...O和N-H...S氢键交替配对。
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