手性无机材料的三维电子晶体学结构研究

Chiral inorganic materials have attracted great interests due to their unique asymmetric structures and material properties, which would open new horizons in many potential applications such as optical devices, pharmacy, catalysis, metamaterials, etc. The crystal structure of these chiral inorganic materials and their formation mechanisms involved in the synthesis are crucial issues in understanding their chemical and physical properties. This raises the bar in terms of the structural characterisation and extends a real challenge to the scientific community to fully understand the crystal structures and the chiral arrangements. However, the structural characterisations of these chiral inorganic materials are very challenging and new methods employing the three-dimensional electron crystallography need to be developed. In this proposal, we will focus on the electron crystallographic structural solution of these materials based on our previous research results, including (i) Various metal, metal oxides with different chiral structures, including the crystal with twisted lattice or screw dislocations, chiral stacking of nanocrystals, etc., will be selected and synthesised. (ii) The detailed structural study of these materials will be performed by electron crystallography from both reciprocal space and the real space. Two new techniques, the three-dimensional electron diffraction tomography and the atomic resolution electron tomography, will be applied to the materials to reveal the crystal structures and the chiral features, including structural relationship, epitaxial intergrowth and defects, will be studied thoroughly. (iii) The formation mechanisms of these chiral inorganic materials through the interaction between organic template and the inorganic species will be studied experimentally. Finally, a facial analytical method will be developed to reveal the geometrical and structural features of the materials and feed back to the new synthesis for creating novel functional materials. This project could provide significant opportunities in various research areas and open new horizons in chiral materials, nanotechnology and electron crystallography.

手性无机材料由于独特的理化特征引起了广泛关注，深入理解其晶体结构及形成机理对其性质和应用有着关键作用。然而这类材料的结构解析存在很大困难，限制了新材料的开发和应用。本课题拟在前期基础上，对手性无机材料开展电子晶体学结构研究。(1)选取具有非手性空间群的金属、金属氧化物等无机材料体系，制备具有不同手性结构的系列材料；(2)发展结构解析方法，分别从倒易空间和正空间进行三维电子晶体学研究，通过三维电子衍射重构获取材料三维倒易空间的衍射信息，通过原子分辨断层成像解析晶体的原子排布与扭转关系，分析其晶体结构、手性关系、扭转缺陷等。(3)揭示不同类型模板单元导向相应手性结构的机制，探讨结构变化规律、形成机理，建立晶体扭转的几何学和晶体学模型及快速易行的三维复杂结构分析方法，研究结构与性能的关系并反馈新的合成。本研究对于手性科学、纳米化学和晶体学具有重要理论价值，并将为新材料的表征和应用打下良好基础。

手性结构及手性材料由于其独特的理化特征引起了广泛关注，深入理解手性无机材料的晶体结构及形成机理对其性质和应用有着关键作用。然而，手性无机材料的结构解析存在很大困难，在很大程度上限制了新材料的开发和应用。本项目针对手性无机材料的电子晶体学结构解析展开研究，通过电子晶体学解析出系列手性无机材料的结构；建立了快速易行的手性无机材料三维结构的分析方法，取得了一系列创新性研究成果：.（1）发展了手性无机结构的电子晶体学结构解析方法。根据手性介观结构无机材料结构特征的不同，实现了通过倾转样品使得同一样品不同区域分别对正晶带轴，通过选区电子衍射或傅立叶变换图谱测量不同区域的倾转方向和倾转角来计算样品手性信息的方法；对于纳米晶堆积形成的多级手性结构，通过摩尔纹/双重衍射分析或建立结构模型并模拟电镜照片来确认样品的手性结构。.（2）提出了基于三维电子衍射重构解析手性无机结构的新方法，基于倒易空间调制的电子衍射花样与正空间晶体结构对应关系以及相应的衍射数据处理与计算方法来同步求解无机晶体的多级手性结构信息。即手性无机材料的一级手性扭转可以通过三维倒易空间点阵中衍射点的强度分布形状来揭示，而主衍射点及其周围卫星衍射点的关系代表了纳米晶体堆叠的二级螺旋手性，根据衍射点变化和相应的样品测量长度即可精确计算出手性材料的扭转方向、螺距、多级手性等信息。.通过以上方法，解析了系列具有不同组成、不同性能的手性无机材料的晶体结构及介观尺度组装方式，揭示了不同材料的组装机理和形成机制，阐明了手性无机材料组装形式与其手性各向异性的构效关系。项目执行期间，共发表标注本项目资助的SCIE论文17篇，项目研究内容在大型国际及国内会议做主题报告2次，邀请报告1次。参与项目学生博士研究生毕业2人，在读4人，硕士研究生毕业3人。本项目的实施，将促进电子晶体学方法的发展和新材料的表征应用，对手性科学、纳米科学、化学及材料科学具有重要理论价值。

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