High-Pressure-Induced Phase Transition in 1,3-Diphenylurea: the Approaching of N−H^...O Hydrogen-Bonded Chains

Under extreme pressure conditions, supramolecular materials can undergo many novel phenomena such as phase transition, polymerization, piezochromism, and negative compression. In our research plan, we selected a series of low-dimensional supramolecular materials to study the evolution of crystal structure and intermolecular interactions under high pressure. In this study, the crystal structure and hydrogen-bonded chains of 1,3-diphenylurea were found to appear abrupt changes when the pressure increased to 1.8 GPa. The intermolecular interactions, the vibrations of chemical groups and the molecular conformation were clearly distinguished from the initial state. The anisotropic compression of the original crystal structure and the occurrence of structural phase transition were derived from the remarkable shrink of distance between hydrogen-bonded chains. This study demonstrates that excessively reducing the space between of hydrogen-bonded chains will rearrange the self-assembly of supramolecular materials.

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