This paper reports the observation of water in an exotic state within the hydrophilic nanopores of porous coordination polymers (PCPs). Single-crystal X-ray diffraction revealed an ordered water structure reminiscent of ice, while infrared spectroscopy indicated a significant number of broken hydrogen bonds, typical of liquid water. This exotic state exhibits properties similar to predicted solid-liquid supercritical water under high pressure in hydrophobic nanospace. The findings suggest potential applications in controlling chemical reactions and provide an experimental system to study solid-liquid critical points.
