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首页> 外文期刊>Crystal growth & design >Use of Topotactic Phase Transformations To Obtain Solutions of the Crystal Structures of Highly Disordered Materials
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Use of Topotactic Phase Transformations To Obtain Solutions of the Crystal Structures of Highly Disordered Materials

机译：使用拓扑相变化以获得高紊乱材料的晶体结构解

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摘要

A straightforward procedure is outlined for prediction of the complete three-dimensional coordinate set for a highly disordered phase. For a mother and daughter phase, where one of the pair has an “unsolvable” structure, one needs only to (a) establish the topotaxy using previously published techniques, (b) obtain the topotactic transformation matrix, Φ, between the ordered and highly disordered phase, and (c) apply the transpose of Φ–1 to obtain a trial set of coordinates for refinement using the reflection data set of the highly disordered phase. For the inclusion compound [Fe(η-C5H5)]·3(NH2)2CS (1), which contains highly disordered ferrocene molecules above 160 K (polymorph 1_I), we found a more ordered structure at low temperature. At 135 K (polymorph 1_II), two ferrocene moieties are present in the thiourea channel in an approximately 1:1 ratio. One is nearly orthogonal (87.0°) to the channel axis, while the other is tipped 16.2° from that direction. Using steps (a–c) outlined above, a trial structure may be obtained for 1_I, and refinement leads to R1 = 4.25%. The structure of 1_1, containing 12-fold disordered ferrocene molecules, is similar to that found at temperatures below the phase transition, with a greater amount of the orthogonal orientation (55:45 vs 51:48), consistent with, but lower than, amounts found using solid-state NMR techniques. The low temperature polymorph is a trill, with an approximately 3:1:1 ratio of twin components. The exact alignment of the mother phase and the three daughters has been established using the methods of topotactic analysis described previously.]]>
机译：<！[cdata [ src ='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/cgdefu/2018/cgdefu.2018.18.issue-1/acs.cgd.7b01406/ 20171227 / Images / Medium / CG-2017-014069_0005.gif“>简单的程序概述了预测完整的三维坐标，为高紊乱的阶段设定。对于母亲和女儿的阶段，其中一个对具有“无法解决的”结构的情况下，只有（a）使用先前公布的技术建立拓扑的一个需要，（b）获得拓扑变换矩阵，φ，在有序和高度之间混乱的相，和（c）施加φ -1 / sup>的转置，以使用高度无序相的反射数据集来获得用于改进的试验坐标。对于包含化合物[Fe（η-c 5 h 5 ）]·3（NH 2 ） 2 Cs（ 1 ），其含有高度无序的二茂烯分子（多晶型B> 1_i），我们在低温下发现了更有序的结构。在135K（多晶型B> 1_II）中，在硫脲通道中存在两种二茂铁部分，其约为1：1。一个接近沟道轴几乎是正交的（87.0°），而另一个方向倾斜16.2°。使用上述步骤（A-C），可以获得用于 1_I / B>的试验结构，并且细化导致 R 1 = 4.25％。含有12倍无序的二茂茂分子的 1_1 / b>的结构类似于在相变低于相变的温度下发现，具有较大量的正交取向（55:45 Vs 51:48），与使用固态NMR技术发现的相一致，但低于使用量。低温多晶型物是棘手，约3：1：1的双胞胎组分的比例。使用先前描述的拓扑分析方法建立了母相和三个女儿的确切对准。]]>

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  • 来源
    《Crystal growth & design》 |2018年第1期|共7页
  • 作者

    Logan C. Lorson; Onkei Tai; Bruce M. Foxman;

  • 作者单位

    Department of Chemistry MS 015 Brandeis University Waltham Massachusetts 02453-2700 United States;

    Department of Chemistry MS 015 Brandeis University Waltham Massachusetts 02453-2700 United States;

    Department of Chemistry MS 015 Brandeis University Waltham Massachusetts 02453-2700 United States;

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  • 正文语种 eng
  • 中图分类 晶体学;
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