A comparison of electron density from Hirshfeld-atom refinement, X-ray wavefunction refinement and multipole refinement on three urea derivatives
A comparison of electron density from Hirshfeld-atom refinement, X-ray wavefunction refinement and multipole refinement on three urea derivatives
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DOI：
10.1039/c2ce26964c
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发表时间：
2013-01-01
期刊：
影响因子：
3.1
通讯作者：
Dottrich, Birger
中科院分区：
文献类型：
--
作者：
Checinska, Lilianna;Morgenroth, Wolfgang;Dottrich, Birger
用单晶X射线衍射法测定了N-甲基脲、N-苯基脲和N，N‘-二苯基脲三种尿素衍生物的电子密度分布。用同步辐射测量高分辨率数据。使用Hansen-Coppens多极模型对数据进行多极精化，在有和没有周围点电荷/偶极子簇的情况下进行Hirshfeld原子精化，以及进行X射线波函数精化。根据形变和剩余电子密度图以及Bader分子原子理论中定义的键临界点、原子体积和电荷来评估电子密度分布。给定一个充分扩展的基组，Hirshfeld原子精化得到的结果优于多极模型精化；最佳品质因数是通过X射线波函数精化获得的。结果表明，传统的结晶学研究可以如何系统地改进。
Electron density distributions of three urea derivatives N-methylurea, N-phenylurea and N,N'-diphenylurea were determined by single-crystal X-ray diffraction. High-resolution data were measured with synchrotron radiation. Data were subjected to a multipole refinement using the Hansen-Coppens multipole model, to Hirshfeld-atom refinement with and without a surrounding cluster of point charges/dipoles and to X-ray wavefunction refinement. Electron density distributions were evaluated in terms of deformation and residual electron density plots as well as bond critical points, atomic volumes and charges as defined in Bader's Theory of Atoms In Molecules. Given a sufficiently extended basis-set Hirshfeld-atom refinement yields results superior to multipole model refinements; best figures of merit were achieved by X-ray wavefunction refinement. Results indicate how conventional crystallographic studies can be systematically improved.