Fundamental understanding of the confinement of water in porous coordination polymers (PCPs) is important not only with respect to their application, such as in gas storage and separation, but also for exploring confinement effects in nanoscale spaces. Here, we report the observation of water in an exotic state in the well-designed hydrophilic nanopores of PCPs. Single-crystal X-ray diffraction finds that nanoconfined water has an ordered structure that is characteristic in ices, but infrared spectroscopy reveals a significant number of broken hydrogen bonds that is characteristic in liquids. We find that their structural properties are quite similar to those of solid-liquid supercritical water predicted in hydrophobic nanospace at extremely high pressure. Our results will open up not only new potential applications of water in an exotic state in PCPs to control chemical reactions, but also experimental systems to clarify the existence of solid-liquid critical points.

对多孔配位聚合物 (PCP) 中水的限制的基本理解不仅对其应用（例如气体储存和分离）很重要，而且对于探索纳米级空间中的限制效应也很重要。在这里，我们报告了在精心设计的 PCP 亲水性纳米孔中观察到奇异状态的水。单晶 X 射线衍射发现纳米受限水具有冰中特有的有序结构，但红外光谱揭示了液体中特有的大量断裂氢键。我们发现它们的结构特性与在极高压力下在疏水纳米空间中预测的固液超临界水的结构特性非常相似。