10.1002/ejic.201900110
The research focuses on the development of luminescent nanothermometers through the post-synthetic modification of Metal-Organic Frameworks (MOFs), specifically MIL-68. The purpose of this study was to explore the potential of modifying MOF linkers to design lanthanide coordination spheres, which can tune the emission properties of the material for use as thermometers. The researchers synthesized nanocrystals of MIL-68-NH2 and modified them via a cross-linking reaction with 1,4-Bis{4-[(E)-3(N,N-dimethylamino)prop-2-enoyl]phenoxy}butane (HL), followed by coordination to Eu3+ and Tb3+ ions. The resulting material, Tb90Eu10-MIL-68-HL, was found to be an excellent cryogenic (< 100 K) ratiometric luminescent nanothermometer, exhibiting a maximum relative sensitivity of 9.4 % K–1 at 12 K. The chemicals used in the process included 2-aminoterephthalic acid, indium nitrate, N,N-dimethylformamide (DMF), chloroform, 4-hydroxyacetophenone, europium nitrate hexahydrate, and terbium nitrate hexahydrate. The conclusions of the research highlight the effectiveness of post-synthetic modification of MOFs as a tool for designing ratiometric luminescent nanothermometers, with Tb90Eu10-MIL-68-HL being a standout example due to its high sensitivity in the cryogenic temperature range.