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用乙醇-水溶液体系从黄芩中提取黄芩苷,纯化得黄芩苷纯度为95.2%.在步长0.0167°,停留时间7.62ms条件下对其粉末进行扫描,获得较高质量粉末衍射谱图.在运用密度泛函方法获得其分子低能量构象基础上,采用直接空间搜索法解析其晶体结构,得该样品属于单斜晶系,P21空间群,晶胞参数为:a=13.02,b=17.22,c=4.49,α=γ=90°,β=95.40°,Z=2,V=1016.13.结合自然键轨道理论分析,表明结构中苷元部分杂环可能具有芳香性.红外振动光谱结果发现,共轭效应导致了羰基伸缩振动频率红移,氢键的存在导致了羟基伸缩振动频率红移.由分子间氢键的影响,预测了其晶体生长特性.
The baicalin was extracted from Astragalus membranaceus with ethanol-water solution system. The purity of baicalin was 95.2%. The powder was scanned at a step length of 0.0167° and a residence time of 7.62ms to obtain a higher-quality powder diffraction spectrum. Density-functional method was used to obtain the low-energy conformation of its molecule. The crystal structure was analyzed by direct space search. The sample was monoclinic, P21 space group, and the unit cell parameters were: a=13.02, b=17.22. , c = 4.49 , α = γ = 90°, β = 95.40°, Z = 2, V = 1016.1 3. Combined with natural bond orbital theory analysis, it is indicated that a heterocyclic part of the aglycones in the structure may have aromaticity. The spectral results show that the conjugate effect leads to the red shift of the stretching vibration frequency of the carbonyl group. The presence of hydrogen bonds leads to the red shift of the hydroxy stretching vibration frequency. The crystal growth characteristics are predicted by the intermolecular hydrogen bonds.