Dependence of adsorption-induced structural transition on framework structure of porous coordination polymers.
Dependence of adsorption-induced structural transition on framework structure of porous coordination polymers.
复制标题
DOI：
10.1063/1.4862735
复制
发表时间：
2014-01
期刊：
影响因子：
--
通讯作者：
R. Numaguchi;Hideki Tanaka;Satoshi Watanabe;M. Miyahara
中科院分区：
文献类型：
--
作者：
R. Numaguchi;Hideki Tanaka;Satoshi Watanabe;M. Miyahara
具有软骨架的多孔配位聚合物（pcp）表现出由客体分子吸附引起的突然结构转变的门现象。为了了解门控行为对主框架结构的依赖性，我们对堆叠层PCP的简化模型进行了大正则蒙特卡罗模拟和自由能分析。组成简化模型的刚性层的层间宽度可以通过客体吸附和改变初始层间宽度h0来改变，而初始层间宽度h0由层间柱的长度控制。我们介绍了三种类型的浇注行为，一步浇注，填充浇注和双重浇注，这取决于三个参数：初始层间宽度h0；交互参数[ss]，决定了主-客框架交互以及框架间交互；框架的弹性模量，取决于支柱的刚度。我们发现一步浇注和填充浇注行为强烈依赖于h而不是h，因此可以通过降低主体框架的刚度来实现从填充和浇注到双浇注的转变。本研究可为通过改变pcp的化学成分来控制其浇注压力提供指导。
Porous coordination polymers (PCPs) with soft frameworks show a gate phenomenon consisting of an abrupt structural transition induced by adsorption of guest molecules. To understand the dependence of the gating behavior on the host framework structure, we conduct grand canonical Monte Carlo simulations and a free-energy analysis of a simplified model of a stacked-layer PCP. The interlayer width of the rigid layers composing the simplified model can be changed by guest adsorption and by varying the initial interlayer width h0, which is controlled by the length of pillars between the layers. We introduce three types of gating behavior, one-step gating, filling and gating, and double gating, which depend on three parameters: the initial interlayer width h0; the interaction parameter ɛss, which determines the host-guest framework interaction as well as the inter-framework interaction; and the elastic modulus of the framework, which depends on the stiffness of the pillars. We show that the one-step gating and the filling and gating behaviors depend strongly on h0 rather than on ɛss, and thus a transformation from filling and gating to double gating can be achieved by reducing the stiffness of the host framework. This study should be a guideline for controlling the gating pressure of PCPs by modifying their chemical components.