【摘要】 青蒿素降解产物桥酮倍半萜内酯(C₁₄H₂₀O₃)晶体属于正交晶系,空间群为P2₁2₁2₁,晶胞参数a=16.997A,b=10.298A,c=7.394A,α=β=γ=90°,晶胞内分子数z=4。在PW-1100四圆衍射仪上收集三维衍射强度数据,其结构是用多解法求得,经块对角线矩阵最小二乘法修正,最后偏离因子R=0.084。 此化合物的分子结构中的A/B两个六元环为顺式联结。更多还原

【Abstract】 This compound is a QINGHAOSU degradation product. The molecule consists of 14 carbon, 20 hydrogen, and 3 oxygen atoms. It crystallizes in the orthorhombic system with space group P2i 21 21. There are four molecules in a unit cell, the lattice parameters are a = 16.997 A, b = 10.298 A, and c = 0.394 A .The three-dimensional intensity data were collected by using PW-1100 four-circle diff-ractometer and the number of the independent diffractions amounts to 1377.The crystal structure was solved by direct methods. The positions of 14 atoms were given by E map and the additional carbon atom sites were obtained by cycle of Fourier synthses.The structure was refined by block-diagonal least square method. The final .R-factor is 0.084.更多还原