A conformational polymorphic transition in the high-temperature -form of chlorpropamide on cooling: a new '-form. Acta crystallographica. Section B, Structural science [Acta Crystallogr B] Journal article | | Title | A conformational polymorphic transition in the high-temperature -form of chlorpropamide on cooling: a new '-form. | | Author(s) | Drebushchak TN, Chesalov YA, Boldyreva EV | | Institution | Novosibirsk State University, REC-008, Pirogova 2, Novosibirsk 90, Russia. | | Source | Acta Crystallogr B 2009 Dec 1; 65(Pt 6):770-781. | | Abstract | 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 '-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 -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. | | Language | ENG | | Pub Type(s) | JOURNAL ARTICLE
| | PubMed ID | 19923705 |
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