Pressure regulates the Piezofluorochromic Behavior of Chiral Tb(III)-MOF

A team of scientists led by Dr. Zhiqiang Chen from HPTAR, in collaboration with Prof. Zhi Su from Nanjing Normal University, has discovered that the piezofluorochromic behavior of rare-earth MOFs is closely linked to the stretchability of interactions between binuclear Tb(III) clusters. In this study, they verified and quantified the evolution of these interactions under high-pressure conditions using in-situ high-pressure X-ray absorption spectra. This research not only resulted in the development of an ultrastable Tb-MOF but also, for the first time, elucidated the relationship between piezofluorochromic behavior and detailed structural transformations. The findings have been published in JACS Au.

A 2D Tb-MOF, based on a chiral semi-flexible ligand, exhibits luminescence from rare-earth metal ions and has been thoroughly investigated under high-pressure conditions. Crystallizing in the piezoelectric P1 space group, microcrystals of Tb-MOF showed notable mechanoluminescence upon manual compression, providing a basis for studying pressure-induced fluorescence evolution. Under high-pressure compression in DAC, the luminescence intensity of Tb-MOF exhibited a pattern of decreasing-increasing-decreasing, accompanied by a progressive shortening of lifetime. In-situ high-pressure XAS revealed that the transformation in photoluminescence during compression was attributable to the stretchability of Tb-Tb interactions. Additionally, in-situ high-pressure UV absorption spectra and FT-IR analyses demonstrated reversible transformations in the coordination environment around Tb(III) centers in Tb-MOF upon compression/decompression cycles.

Using a chiral semi-flexible ligand, the researchers constructed an ideal platform to explore how metal nodes influence the fluorescence performance of MOF materials under external pressure. This work not only provided insights into the mechanism of high-pressure luminescence in RE-MOFs but also illustrated, for the first time, the relationship between piezofluorochromic performance and detailed structural transformations.

近日，北京高压科学研究中心（HPSTAR）陈志强课题组与南京师范大学苏志教授课题组合作，通过手性半柔性配体成功构建了结晶于三斜P1手性压电空间群的二维Tb-MOF，并对其压致荧光演化及双核Tb(III)簇间相互作用进行了深入研究。这项研究不仅发现了超稳定的MOF材料结构，还为压致荧光效应的应用开辟了新的思路。相关结果以“Stretchable Tb–Tb Distance Regulates the Piezofluorochromic Behavior of Chiral Tb(III)-MOF upon Compression”为题，发表于近期的《JACS Au》上。