溴代还原青蒿晶体结构研究

溴代还原青蒿(C₁₇H₂₇O₅Br),晶体属单斜晶系,空间群P2₁。晶胞中含两个分子。晶胞参数:α=10.34?,b=9.160?,c=9.353?;β=90°,z=2。衍射数据由Philips PW-1100四圆衍射仪测定。用Patterson法求解。晶胞中两个重原子溴呈中心对称配置,故生双解。分别用立体化学知识判别和用直接法均得到同一套单解。分子的绝对构型是用反常散射法确定的。用全矩阵最小二乘法对原子坐标参数、比例关键词：

STUDIES ON THE STRUCTURE OF BROMO-QINGHAOSU

The bromo-Qinghaosu (C₁₇H₂₇O₅Br) crystal belongs to the monoclinic system, space group is P2₁, with a = 10.341?, 6 = 9.160?, c = 9.353?, β = 90°, Z = 2. The intensity data were collected on the Philips PW-1100 diffraetometer. Initial positional parameters (for double solution) were determined by a Patterson method. There are two heavy atoms bromine in the unit cell, it is centrosymmetric, that raises the problem of ambiguity. We have obtained a set of unique solution by means of chemical knowledge and direet method, respectively. Absolute configuration of molecule was determined by anomalous scattering method. Atoms coordinate parameters, ratio factor, isotropic and anisotropic temperature factors were refined by full-matrix least square method.
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