Department of Chemistry, University of Sheffield, Sheffield, S3 7HF, UK.
Chemistry. 2018 Dec 5;24(68):17986-17996. doi: 10.1002/chem.201803221. Epub 2018 Nov 8.
The modular structure of metal-organic framework nanosheets (MONs) provides a convenient route to creating two-dimensional materials with readily tuneable surface properties. Here, the liquid exfoliation of two closely related layered metal-organic frameworks functionalised with either methoxy-propyl (1) or pentyl (2) pendent groups intended to bestow either hydrophilic or hydrophobic character to the resulting nanosheets is reported. Exfoliation of the two materials in a range of different solvents highlighted significant differences in their dispersion properties, as well as their molecular and nanoscopic structures. Exchange or loss of solvent was found to occur at the labile axial position of the paddle-wheel based MONs and DFT calculations indicated that intramolecular coordination by the oxygen of the methoxy-propyl pendant groups may take place. The nanoscopic dimensions of the MONs were further tuned by varying the exfoliation conditions and through "liquid cascade centrifugation". Aqueous suspensions of the nanosheets were used as sensors to detect aromatic heterocycles with clear differences in binding behaviour observed and quantified.
金属-有机骨架纳米片（MONs）的模块化结构为创建具有可调节表面性质的二维材料提供了便捷途径。在此，报告了两种密切相关的层状金属-有机骨架的液相剥离，它们分别用甲氧基丙基（1）或戊基（2）侧基官能化，旨在赋予所得纳米片亲水性或疏水性。在一系列不同溶剂中对这两种材料的剥离突出了它们在分散性能以及分子和纳米结构方面的显著差异。发现溶剂的交换或损失发生在基于桨轮的 MONs 的不稳定轴向位置，并且 DFT 计算表明，甲氧基丙基侧基的氧可能发生分子内配位。通过改变剥离条件和“液相级联离心”进一步调整 MONs 的纳米尺度。纳米片的水性悬浮液被用作传感器来检测芳香杂环，观察到并量化了明显不同的结合行为。
