Metal-Organic Nanosheets Formed via Defect-Mediated Transformation of a Hafnium Metal-Organic Framework.
Metal-Organic Nanosheets Formed via Defect-Mediated Transformation of a Hafnium Metal-Organic Framework.
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DOI：
10.1021/jacs.7b00106
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发表时间：
2017-04-19
影响因子：
15
通讯作者：
Grey CP
中科院分区：
文献类型：
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作者：
Cliffe MJ;Castillo-Martínez E;Wu Y;Lee J;Forse AC;Firth FCN;Moghadam PZ;Fairen-Jimenez D;Gaultois MW;Hill JA;Magdysyuk OV;Slater B;Goodwin AL;Grey CP
我们报道了一种含Hf的MOF，HCP UIO-67(HF)，它是面心立方FCuUIO-67(HF)的一个缺乏配体的层状类似物。与FCuUIO-67相比，HCP UIO-67通过一种新的结构机制调节其较低的配体：金属比：形成一个缩合的“双簇合物”(Hf12O8(OH)14)，类似于配位多面体在氧化物骨架中的缩合。在氧化物骨架中，可变的化学计量比可导致更复杂的缺陷结构，例如具有不同组成的晶体剪切面或模块，这可能是进一步化学反应的来源；同样，层状HCP UIO-67可以进一步反应，以可逆地形成二维金属-有机骨架，HXL UIO-67。三维羟基磷灰石UIO-67和二维HXL UIO-67都可以分层形成金属-有机纳米薄片。HCP UIO-67的剥离是通过断裂强的Hf-羧酸键发生的，并且在温和的条件下发生，这表明缺陷有序的MOF可能是获得多孔二维材料的一条有效途径。
We report a hafnium-containing MOF, hcp UiO-67(Hf), which is a ligand-deficient layered analogue of the face-centered cubic fcu UiO-67(Hf). hcp UiO-67 accommodates its lower ligand:metal ratio compared to fcu UiO-67 through a new structural mechanism: the formation of a condensed “double cluster” (Hf12O8(OH)14), analogous to the condensation of coordination polyhedra in oxide frameworks. In oxide frameworks, variable stoichiometry can lead to more complex defect structures, e.g., crystallographic shear planes or modules with differing compositions, which can be the source of further chemical reactivity; likewise, the layered hcp UiO-67 can react further to reversibly form a two-dimensional metal–organic framework, hxl UiO-67. Both three-dimensional hcp UiO-67 and two-dimensional hxl UiO-67 can be delaminated to form metal–organic nanosheets. Delamination of hcp UiO-67 occurs through the cleavage of strong hafnium-carboxylate bonds and is effected under mild conditions, suggesting that defect-ordered MOFs could be a productive route to porous two-dimensional materials.