Crystal structures of three halide salts of l-asparagine: an isostructural series

Acta Crystallographica Section E: Crystallographic Communications

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