Acta Crystallographica Section E: Crystallographic Communications | |
Crystal structures of three halide salts of l-asparagine: an isostructural series | |
Kennedy, A.R.1  Moraes, L.S. de2  | |
[1] Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow G1 1XL, Scotland, UK;WestCHEM, Department of Pure & | |
关键词: CRYSTAL STRUCTURE; AMINO-ACID; SALT SELECTIONS; ISOSTRUCTURAL SERIES; | |
DOI : 10.1107/S2056989018014603 | |
学科分类:数学(综合) | |
来源: International Union of Crystallography | |
【 摘 要 】
The structures of three monohydrated halide salt forms of l-asparagine are presented, viz.l-asparaginium chloride monohydrate, C4H9N2O3+·Cl−·H2O, (I), l-asparaginium bromide monohydrate, C4H9N2O3+·Br−·H2O, (II), and l-asparaginium iodide monohydrate, C4H9N2O3+·I−·H2O, (III). These form an isomorphous and isostructural series. The C—C—C—C backbone of the amino acid adopts a gauche conformation in each case [torsion angles for (I), (II) and (III) = −55.4 (2), −55.6 (5) and −58.3 (7)°, respectively]. Each cation features an intramolecular N—H⋯O hydrogen bond, which closes an S(6) ring. The extended structures feature chains of cations that propagate parallel to the b-axis direction. These are formed by carboxylic acid/amide complimentary O—H⋯O + N—H⋯O hydrogen bonds, which generate R22(8) loops. These chains are linked by further hydrogen bonds mediated by the halide ions and water molecules to give a layered structure with cation and anion layers parallel to the ab plane. Compound (III) was refined as an inversion twin.
【 授权许可】
CC BY
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