Effect of 1D twisted water chains confined in channels formed by a Gemini amphiphile on its crystal stability
Effect of 1D twisted water chains confined in channels formed by a Gemini amphiphile on its crystal stability
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DOI：
10.1039/c4ce01879f
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发表时间：
2015-01
期刊：
影响因子：
3.1
通讯作者：
Yujie Sheng;J. Yao;Qibin Chen;Honglai Liu
中科院分区：
文献类型：
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作者：
Yujie Sheng;J. Yao;Qibin Chen;Honglai Liu
发现带有刚性间隔基的新型双子两亲物与水以1:3的主客体摩尔比形成包合物晶体。主体分子可以通过每两个相邻分子之间的分子间交叉产生疏水空腔单元，这些空腔单元可以在一个方向上相互连接，最终形成通道。同时，一维（1D）水链通过与主体分子组成的壁的弱 C-H⋯O、O-H⋯Br− 和 C-H⋯Br− 相互作用而被捕获在通道中。这些相互作用和水链以及交替的水链和主体分子层可以在晶体中形成二维网络，从而稳定晶体结构。通过比较含水晶体和无水材料之间的性能，验证了水链对主体框架稳定性的深远贡献。同时，通过非共价相互作用（NCI）分析对弱相互作用进行了理论计算和可视化，并通过光谱实验进一步证实。实验和计算都表明，这些弱氢键提供了对晶体稳定性至关重要的内聚力。
A novel gemini amphiphile bearing a rigid spacer was found to form inclusion crystals with water in 1 : 3 host-to-guest molar ratios. The host molecules can generate a hydrophobic cavity unit via intermolecular intersections between each two neighbouring molecules, which can be connected with one another in one direction, finally resulting in a channel. At the same time, one-dimensional (1D) water chains are trapped in the channels by weak C–H⋯O, O–H⋯Br− and C–H⋯Br− interactions with the walls composed of the host molecules. These interactions and water chains together with the alternating water chain and host molecule layers can form a two-dimensional network in the crystal, which can stabilise the crystal structure. The profound contribution of the water chains to the stability of the host framework is verified by comparisons of properties between water-containing crystals and anhydrous materials. Meanwhile, weak interactions are theoretically calculated and visualised by non-covalent interaction (NCI) analysis and further confirmed by spectral experiments. Both experiment and calculation reveal that these weak hydrogen bonds provide cohesion that is vital to crystal stability.