Investigating rotational disorder by inexpensive multi-temperature X-ray diffraction experiments

通过廉价的多温度 X 射线衍射实验研究旋转紊乱

• 批准号: 259033420
• 负责人: Privatdozent Dr. Birger Dittrich
• 金额: --
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2014
• 资助国家: 德国
• 起止时间: 2013-12-31 至 2017-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/259033420?language=en
• 关键词: Investigating; rotational; disorder; inexpensive; multi

A unique single-crystal diffractometer measurement setup had been established at the Free University Berlin. It combined a) a cryostat for multi-temperature measurements to approx. 30K, b) a vacuum cylinder permeable for X-rays and c) CCD-area detection. The setup was purchased and the diffractometer setup rebuild. Its functionality provides the foundation for this application. Rotational disorder is of fundamental interest in crystallography and there are strong indications that it is relevant for the stability of polymorphic crystal structures, an important topic in the pharmaceutical industry. Establishing an understanding of the conditions that lead to the occurrence of such disorder using suitable compounds is the main aim of this project. Multi-temperature experiments are vital to characterize continuous rotational disorder. Answering this scientific question requires carrying out diffraction experiments of several samples in a wide temperature range of 30 to 300 K on the same specimen; the X-ray source should be updated to reduce the duration of these measurements and to enable the study of smaller samples. Experimental data will be evaluated with special difference electron-density maps that allow accurate characterization of rotational disorder. In parallel, molecular dynamics simulations and QM/MM computations will be performed to complement the experiments. We ultimately aim to provide better modeling tools to deal with disorder in small-molecule crystallography. The new measurement setup will subsequently allow to study of a range of other solid-state research questions in the future. To enable the technical implementation as well as to carry out the proposed research we apply for a 2/3 TV-L E13 PhD position for three years.

柏林自由大学建立了一套独特的单晶衍射仪测量装置。它结合了a)一个低温恒温器，用于多个温度的测量，大约。30K，b)可穿透X射线的真空筒和c)面阵面阵探测器。购买了该设置，并重建了衍射仪设置。它的功能为该应用程序提供了基础。转动无序是结晶学中的一个基本问题，有强有力的迹象表明，它与多晶性晶体结构的稳定性有关，这是制药工业中的一个重要课题。使用适当的化合物了解导致这种紊乱发生的条件是本项目的主要目的。多温度实验是表征连续转动无序的关键。回答这一科学问题需要在30至300K的宽温度范围内对同一样品进行几个样品的衍射实验；应更新X射线源，以缩短这些测量的持续时间，并使研究更小的样品成为可能。实验数据将用特殊的差值电子密度图进行评估，这些图可以准确地描述旋转无序。同时，将进行分子动力学模拟和QM/MM计算，以补充实验。我们的最终目标是提供更好的建模工具来处理小分子结晶学中的无序。新的测量装置随后将允许在未来研究一系列其他固态研究问题。为了能够在技术上实施以及开展拟议的研究，我们申请了2/3的L E13级博士职位，为期三年。

项目成果

Molecular Electrostatic Potentials from Invariom Point Charges.

Invariom 点电荷的分子静电势

• DOI: 10.1002/cphc.201600213
• 发表时间: 2016
• 期刊: Chemphyschem : a European journal of chemical physics and physical chemistry
• 作者: C. M. Wandtke;J. Lübben;B. Dittrich
• 通讯作者: B. Dittrich