2,5-Diketopiperazine was found to undergo a high-pressure phase transition at about 11.0 GPa through in situ high-pressure synchrotron X-ray diffraction experiments. The anisotropic compression of the samples before the phase transition was discussed. The subsequent results of in situ high-pressure Raman scattering experiments illustrated that the wrinkle of the N–H···O hydrogen-bonded tapes was the major mechanism that drove this phase transition. The first-principle calculations and Hirshfeld surfaces further confirmed that the anisotropic compression of N–H···O hydrogen-bonded tapes was derived from the reduction of molecular interlayer spacing. This study demonstrated the evolutions of low-dimensional intermolecular interactions under continuous compression, which would help to understand the self-assembly of supramolecular materials.

中文翻译：

---

2,5-二酮哌嗪中的高压诱导相变：N–H···O氢键键合带的各向异性压缩

通过原位高压同步加速器X射线衍射实验，发现2,5-二酮哌嗪在约11.0 GPa处经历高压相变。讨论了相变之前样品的各向异性压缩。原位高压拉曼散射实验的后续结果表明，N–H···O氢键键合带的褶皱是驱动该相变的主要机理。第一性原理和Hirshfeld表面的计算进一步证实了NH···O氢键带的各向异性压缩是由于分子夹层间距的减小而引起的。这项研究证明了在连续压缩下低维分子间相互作用的演化，这将有助于理解超分子材料的自组装。