Division of Materials Chemistry, Ruđer Bošković Institute, Zagreb, Croatia.
Nat Protoc. 2013 Sep;8(9):1718-29. doi: 10.1038/nprot.2013.100. Epub 2013 Aug 15.
We describe the only currently available protocol for in situ, real-time monitoring of mechanochemical reactions and intermediates by X-ray powder diffraction. Although mechanochemical reactions (inducing transformations by mechanical forces such as grinding and milling) are normally performed in commercially available milling assemblies, such equipment does not permit direct reaction monitoring. We now describe the design and in-house modification of milling equipment that allows the reaction jars of the operating mill to be placed in the path of a high-energy (∼90 keV) synchrotron X-ray beam while the reaction is taking place. Resulting data are analyzed using conventional software, such as TOPAS. Reaction intermediates and products are identified using the Cambridge Structural Database or Inorganic Crystal Structure Database. Reactions are analyzed by fitting the time-resolved diffractograms using structureless Pawley refinement for crystalline phases that are not fully structurally characterized (such as porous frameworks with disordered guests), or the Rietveld method for solids with fully determined crystal structures (metal oxides, coordination polymers).
我们描述了目前唯一可用的通过 X 射线粉末衍射对机械化学反应和中间体进行原位、实时监测的方案。虽然机械化学反应（通过研磨和搅拌等机械力诱导转化）通常在市售的研磨组件中进行，但此类设备不允许直接进行反应监测。我们现在描述了研磨设备的设计和内部改装，使得在反应进行时，可以将正在运行的研磨机的反应罐置于高能（约 90 keV）同步加速器 X 射线束的路径中。使用诸如 TOPAS 等常规软件对得到的数据进行分析。使用剑桥结构数据库或无机晶体结构数据库来识别反应中间体和产物。通过使用无结构 Pawley 精修对未完全结构表征的结晶相（例如具有无序客体的多孔框架）进行拟合时间分辨衍射图，或对具有完全确定晶体结构的固体（金属氧化物、配位聚合物）进行 Rietveld 方法分析，对反应进行分析。
