Introduction of porosity into supramolecular gels endows soft materials with functionalities for molecular encapsulation, release, separation and conversion. Metal-organic polyhedra (MOPs), discrete coordination cages containing an internal cavity, have recently been employed as building blocks to construct polymeric gel networks with potential porosity. However, most of the materials can only be synthesized in organic solvents, and the examples of porous, MOP-based hydrogels are scarce. Here, we demonstrate the fabrication of porous hydrogels based on [Rh2(OH-bdc)2]12, a rhodium-based MOP containing hydroxyl groups on its periphery (OH-bdc = 5-hydroxy-1,3-benzenedicarboxylate). By simply deprotonating [Rh2(OH-bdc)2]12 with the base NaOH, the supramolecular polymerization between MOPs and organic linkers can be induced in the aqueous solution, leading to the kinetically controllable formation of hydrogels with hierarchical colloidal networks. When heating the deprotonated MOP, Nax[Rh24(O-bdc)x(OH-bdc)24-x], to induce gelation, the MOP was found to partially decompose, affecting the mechanical property of the resulting gels. By applying a post-synthetic deprotonation strategy, we show that the deprotonation degree of the MOP can be altered after the gel formation without serious decomposition of the MOPs. Gas sorption measurements confirmed the permanent porosity of the corresponding aerogels obtained from these MOP-based hydrogels, showing potentials for applications in gas sorption and catalysis.

中文翻译：

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由带电金属-有机多面体的配位驱动自组装形成的多孔胶体水凝胶

在超分子凝胶中引入孔隙度赋予了柔软的材料以分子封装，释放，分离和转化的功能。金属有机多面体（MOP），包含内部空腔的离散配位笼，最近已被用作构建具有潜在孔隙度的聚合物凝胶网络的基础。但是，大多数材料只能在有机溶剂中合成，并且缺乏基于MOP的多孔水凝胶的例子。在这里，我们演示了基于[Rh2（OH-bdc）2] 12的多孔水凝胶的制备，[Rh2（OH-bdc）2] 12是基于铑的MOP，其外围含有羟基（OH-bdc = 5-羟基-1,3-苯二甲酸）。通过用碱式NaOH简单地使[Rh2（OH-bdc）2] 12质子化，可以在水溶液中诱导MOP和有机连接基之间的超分子聚合，导致在动力学上可控地形成具有分层胶体网络的水凝胶。当加热去质子化的MOP Nax [Rh24（O-bdc）x（OH-bdc）24-x]诱导胶凝时，发现MOP会部分分解，从而影响所得凝胶的机械性能。通过应用合成后的去质子化策略，我们表明，在凝胶形成后，MOP的去质子度可以改变，而MOPs不会严重分解。气体吸附测量结果证实了从这些基于MOP的水凝胶获得的相应气凝胶的永久孔隙度，显示了在气体吸附和催化中的应用潜力。发现MOP会部分分解，影响所得凝胶的机械性能。通过应用合成后的去质子化策略，我们表明，在凝胶形成后，MOP的去质子度可以改变，而MOPs不会严重分解。气体吸附测量结果证实了从这些基于MOP的水凝胶获得的相应气凝胶的永久孔隙度，显示了在气体吸附和催化中的应用潜力。发现MOP会部分分解，影响所得凝胶的机械性能。通过应用合成后的去质子化策略，我们表明，在凝胶形成后，MOP的去质子度可以改变，而MOPs不会严重分解。气体吸附测量结果证实了从这些基于MOP的水凝胶获得的相应气凝胶的永久孔隙度，显示了在气体吸附和催化中的应用潜力。