The crystal structure of D-valine has been determined by Mo-Ka (l = 0.71073 ? X-ray diffraction method for the first time. It crystallizes in monoclinic, space group P21 (Z = 4) with a = 9.6728(5), b = 5.2722(3), c = ...The crystal structure of D-valine has been determined by Mo-Ka (l = 0.71073 ? X-ray diffraction method for the first time. It crystallizes in monoclinic, space group P21 (Z = 4) with a = 9.6728(5), b = 5.2722(3), c = 12.0425(8) ? = 90.750(2)?at 293 K. The asymmetric unit contains two crystallographically independent molecules A (trans form) and B (gauche I form). They are rotational isomers with two kinds of conformations about the Ca Cb bond. The results of measurements of crystal structure at 293, 270, 223 and 173 K show a little change in bond lengths and geometries as a function of temperature. No evidence was obtained for the existence of configuration transformation from D- to L-valine.展开更多
基金the grant of 863 program (863-103-13-06-01) and NNSFC (29672003)
文摘The crystal structure of D-valine has been determined by Mo-Ka (l = 0.71073 ? X-ray diffraction method for the first time. It crystallizes in monoclinic, space group P21 (Z = 4) with a = 9.6728(5), b = 5.2722(3), c = 12.0425(8) ? = 90.750(2)?at 293 K. The asymmetric unit contains two crystallographically independent molecules A (trans form) and B (gauche I form). They are rotational isomers with two kinds of conformations about the Ca Cb bond. The results of measurements of crystal structure at 293, 270, 223 and 173 K show a little change in bond lengths and geometries as a function of temperature. No evidence was obtained for the existence of configuration transformation from D- to L-valine.
