O'Keeffe Michael, Peskov Maxim A, Ramsden Stuart J, Yaghi Omar M
Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287, USA.
Acc Chem Res. 2008 Dec;41(12):1782-9. doi: 10.1021/ar800124u.
During the past decade, interest has grown tremendously in the design and synthesis of crystalline materials constructed from molecular clusters linked by extended groups of atoms. Most notable are metal-organic frameworks (MOFs), in which polyatomic inorganic metal-containing clusters are joined by polytopic linkers. (Although these materials are sometimes referred to as coordination polymers, we prefer to differentiate them, because MOFs are based on strong linkages that yield robust frameworks.) The realization that MOFs could be designed and synthesized in a rational way from molecular building blocks led to the emergence of a discipline that we call reticular chemistry. MOFs can be represented as a special kind of graph called a periodic net. Such descriptions date back to the earliest crystallographic studies but have become much more common recently because thousands of new structures and hundreds of underlying nets have been reported. In the simplest cases (e.g., the structure of diamond), the atoms in the crystal become the vertices of the net, and bonds are the links (edges) that connect them. In the case of MOFs, polyatomic groups act as the vertices and edges of the net. Because of the explosive growth in this area, a need has arisen for a universal system of nomenclature, classification, identification, and retrieval of these topological structures. We have developed a system of symbols for the identification of three periodic nets of interest, and this system is now in wide use. In this Account, we explain the underlying methodology of assigning symbols and describe the Reticular Chemistry Structure Resource (RCSR), in which about 1600 such nets are collected and illustrated in a database that can be searched by symbol, name, keywords, and attributes. The resource also contains searchable data for polyhedra and layers. The database entries come from systematic enumerations or from known chemical compounds or both. In the latter case, references to occurrences are provided. We describe some crystallographic, topological, and other attributes of nets and explain how they are reported in the database. We also describe how the database can be used as a tool for the design and structural analysis of new materials. Associated with each net is a natural tiling, which is a natural partition of space into space-filling tiles. The database allows export of data that can be used to analyze and illustrate such tilings.
在过去十年中，人们对由原子延伸基团连接的分子簇构建的晶体材料的设计与合成兴趣大增。最值得注意的是金属有机框架（MOF），其中多原子含无机金属簇通过多齿连接体相连。（尽管这些材料有时被称为配位聚合物，但我们更倾向于对它们进行区分，因为MOF基于能产生坚固框架的强连接。）认识到MOF可以从分子构建块以合理的方式设计和合成，催生了一门我们称之为网状化学的学科。MOF可以表示为一种特殊的图，称为周期性网络。这种描述可以追溯到最早的晶体学研究，但最近变得更加普遍，因为已经报道了数千种新结构和数百种基础网络。在最简单的情况下（例如金刚石的结构），晶体中的原子成为网络的顶点，键是连接它们的链路（边）。对于MOF，多原子基团充当网络的顶点和边。由于该领域的爆炸式增长，出现了对这些拓扑结构进行命名、分类、识别和检索的通用系统的需求。我们已经开发了一套用于识别三个感兴趣的周期性网络的符号系统，该系统目前正在广泛使用。在本综述中，我们解释了分配符号的基本方法，并描述了网状化学结构资源（RCSR），其中约1600个此类网络被收集并展示在一个可以通过符号、名称、关键词和属性进行搜索的数据库中。该资源还包含多面体和层的可搜索数据。数据库条目来自系统枚举或已知化合物或两者皆有。在后一种情况下，会提供出现情况的参考文献。我们描述了网络的一些晶体学、拓扑学和其他属性，并解释了它们在数据库中的报告方式。我们还描述了如何将数据库用作新材料设计和结构分析的工具。与每个网络相关联的是一个自然平铺，它是空间的自然划分，将空间划分为填充空间的瓷砖。该数据库允许导出可用于分析和说明此类平铺的数据。
