Effect of coordination restriction on pressure-induced fluorescence evolution

The usage of flexible ligands in constructing MOF materials (FL-MOFs) has been widely studied due to its numerous advantages, including the structural diversity, polynuclear MOFs, transmitting magnetic exchanges, enantioselective separation, asymmetric catalysis, etc. However, the field still faces challenges in deeply understanding the effect of ligand configuration on the properties of these materials. Here, we employ a flexible aggregation-induced emission ligand (4,4′-((1E,1′E)-anthracene-9,10-diylbis(ethene-2,1-diyl))dibenzoic acid) with great mechanical stability to construct FL-MOFs to lock the ligand configuration to explore the pressure-induced evolution of the ligand with coordination restriction, involving changes in fluorescence and intermolecular interaction. In-situ high-pressure fluorescence, Raman, and FT-IR experiments have revealed that the intermolecular interaction of AIE-Mn-MOF with configuration restriction increased more rapidly than that of free AIE-L. This discovery offers valuable insights for synthesizing MOF materials with exceptional mechanical stability and significantly advances our understanding of the impact of coordination restriction in FL-MOFs on their response to external stimuli.