Drebushchak Tatiana N, Chesalov Yury A, Boldyreva Elena V
Novosibirsk State University, REC-008, Pirogova 2, Novosibirsk 90, Russia.
Acta Crystallogr B. 2009 Dec;65(Pt 6):770-81. doi: 10.1107/S010876810903290X. Epub 2009 Oct 27.
Structural changes in the high-temperature -polymorph of chlorpropamide, 4-chloro-N-(propylaminocarbonyl)benzenesulfonamide, C(10)H(13)ClN(2)O(3)S, on cooling down to 100 K and on reverse heating were followed by single-crystal X-ray diffraction. At temperatures below 200 K the phase transition into a new polymorph (termed the epsilon'-form) has been observed for the first time. The polymorphic transition preserves the space group Pna2(1), is reversible and is accompanied by discontinuous changes in the cell volume and parameters, resulting from changes in molecular conformation. As shown by IR spectroscopy and X-ray powder diffraction, the phase transition in a powder sample is inhomogeneous throughout the bulk, and the two phases co-exist in a wide temperature range. The cell parameters and the molecular conformation in the new polymorph are close to those in the previously known alpha-polymorph, but the packing of the z-shaped molecular ribbons linked by hydrogen bonds inherits that of the epsilon-form and is different from the packing in the alpha-polymorph. A structural study of the alpha-polymorph in the same temperature range has revealed no phase transitions.
通过单晶X射线衍射跟踪了氯磺丙脲（4-氯-N-（丙基氨基甲酰基）苯磺酰胺，C(10)H(13)ClN(2)O(3)S）高温多晶型在冷却至100 K以及反向加热过程中的结构变化。在低于200 K的温度下，首次观察到向一种新的多晶型（称为ε'-型）的相变。该多晶型转变保持空间群Pna2(1)，是可逆的，并且伴随着晶胞体积和参数的不连续变化，这是由分子构象变化引起的。红外光谱和X射线粉末衍射表明，粉末样品中的相变在整个体积内是不均匀的，并且两相在很宽的温度范围内共存。新多晶型中的晶胞参数和分子构象与先前已知的α-多晶型中的相近，但通过氢键连接的z形分子带的堆积继承了ε-型的堆积方式，并且与α-多晶型中的堆积不同。在相同温度范围内对α-多晶型的结构研究未发现相变。
