Probing Molecular Mechanisms of Self-Assembly in Metal-Organic Frameworks
Probing Molecular Mechanisms of Self-Assembly in Metal-Organic Frameworks
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DOI：
10.1021/acsnano.6b05444
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发表时间：
2017-01-01
期刊：
影响因子：
17.1
通讯作者：
Kusalik, Peter G.
中科院分区：
文献类型：
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作者：
Biswal, Debasmita;Kusalik, Peter G.
金属有机骨架材料（M0 F）是一类纳米多孔材料，对于许多应用（例如，气体储存、分离），以及它们的合成已经受到相当大的关注。然而，对MOFs自组装的机制知之甚少。在这里，我们通过分子动力学模拟，为表现出复杂顶点拓扑结构（例如，桨轮组）。本研究的一个关键发现是表征的随机和多级有序过程固有的自组装的锌-羧酸MOF系统。在结构演化过程中观察到了由各种类型的锌离子簇和羧酸盐配体配位组成的各种瞬态中间结构，并具有一系列的几何排列。这里推导出的这种原型MOF系统的自组装机制的一般特征暴露了在这个过程的早期阶段可能发生的各种分子水平事件的复杂性，这些事件跨越了纳米到微秒的时间尺度。更一般地说，我们提供了基本的见解，阐明了一个重要的一类纳米多孔材料的自组装机制的早期阶段的关键方面，以及探索在这种材料的成核和生长过程的实验研究。
Metal-organic framework materials (MOFs) are a class of nanoporous materials, important to many applications (e.g., gas storage, separation), and their synthesis has received considerable attention. Yet, very little is known about the mechanisms of self-assembly of MOFs. Here, we provide molecular-level insights into the previously unexplored behavior of the self-assembly process, through molecular dynamics simulations, for an archetypal Zn-carboxylate MOF system exhibiting complex vertex topologies (e.g., paddle-wheel clusters). A key finding of this study is the characterization of a stochastic and multistage ordering process intrinsic to self-assembly of the Zn-carboxylate MOF system. A variety of transient intermediate structures consisting of various types of Zn-ion clusters and carboxylate-ligand coordination, and featuring a range of geometric arrangements, are observed during structural evolution. The general features deduced here for the mechanism of the self-assembly of this archetypal MOF system expose the complexities of the various molecular-level events that can occur during the early stages of this process spanning time scales of nano- to microseconds. More generally, we provide fundamental insights that elucidate key aspects of the early stages of the self-assembly mechanism for an important class of nanoporous materials, and of experimental studies exploring nucleation and growth processes in such materials.