一个用于确定分子有序但非晶体酸框架结构的通用协议
Darren H Brouwer1, Sylvian Cadars, Juergen Eckert
1Department of Chemistry, Redeemer University College, Ancaster, Ontario, Canada, L9K 1J4.
Journal of the American Chemical Society
|April 9, 2013
概括
本研究提出了一种结合X射线衍射 (XRD) 和固态核磁共振 (NMR) 的新方法,用于确定非晶体固体的结构. 该方法成功地确定了三种相似的框架结构,用于分层的酸盐材料.
科学领域:
- 材料科学 材料科学 材料科学
- 固态化学 固态化学
- 晶体学 晶体学是指结晶学.
背景情况:
- 确定具有短距离顺序的非晶体固体的结构是具有挑战性的.
- 像X射线衍射 (XRD) 这样的传统方法由于缺乏远程周期性而受到限制.
- 层状酸盐往往表现出复杂的结构,抵御常规分析.
研究的目的:
- 开发和演示一种通用协议,用于阐明分子有序,非晶体固体的结构.
- 将本协议应用于缺乏三维 (3D) 长距离的表面活性剂导向层状酸盐.
- 识别和完善与实验数据兼容的候选框架结构.
主要方法:
- 对单元细胞参数的X射线衍射 (XRD) 的整合.
- 利用一维和二维固态核磁共振 (NMR) 光谱来进行详细的站点分析和连接.
- 应用第一原则的量子化学计算,包括密度函数理论 (DFT),用于结构细化和验证.
主要成果:
- 该研究成功地确定了没有远程3D周期性的多层酸盐的结构约束.
- 结合XRD和固态 (29) Si NMR数据,以及DFT计算,确定了一小组候选结构.
- 发现三个密切相关且在拓上相当的框架配置与所有实验和理论数据一致.
结论:
- 开发的协议对于描述复杂的非晶体固体是有效的.
- 鉴定到的结构突出显示了多层酸框架的复杂性质.
- 这些发现表明,材料可能包含共存或微妙分布的结构顺序.
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