34265-97-9Relevant academic research and scientific papers
A Bumper Crop of Boiling-Water-Stable Metal-Organic Frameworks from Controlled Linker Sulfuration
Diao, Yingxue,He, Jun,He, Yonghe,Liao, Wei-Ming,Wong, Yan-Lung,Xian, Wan-Ru,Xu, Zhengtao,Zheng, Sai-Li,Zhou, Hua-Qun
, (2020)
The series of highly stable porous solids here feature systematic, regiospecific sulfur substitutions on the organic linkers for versatile functions. One major surprise lies in the controllable sequential reactions between sodium thiomethoxide (NaSMe) and octafluorobiphenyl-4,4′-dicarboxylic acid (H2bpdc-8F; this was readily made without precious metal catalysts). Namely, 3, 4, 6, and 8 methylthio-substitutions can be respectively achieved with regiospecificity (i.e., to produce the four molecules H2bpdc-3S5F, H2bpdc-4S4F, H2bpdc-6S2F, H2bpdc-8MS). A second surprise lies in their persistent formation of the UiO-67-type net with Zr(IV) ions, e.g., even in the case of the fully sulfurated H2bpdc-8MS. In addition to the remarkable breadth of functional control, all the Zr(IV)-based crystalline solids here are stable in boiling water (e.g., for 24 h) and in air as solventless, activated porous solids. Moreover, the thioether groups allow for convenient H2O2 oxidation to fine-tune the hydrophilicity and luminescence properties and improve proton conductivity.
Tuning Lewis Acidity of Metal-Organic Frameworks via Perfluorination of Bridging Ligands: Spectroscopic, Theoretical, and Catalytic Studies
Ji, Pengfei,Drake, Tasha,Murakami, Akiko,Oliveres, Pau,Skone, Jonathan H.,Lin, Wenbin
, p. 10553 - 10561 (2018/08/03)
The Lewis acidity of metal-organic frameworks (MOFs) has attracted much research interest in recent years. We report here the development of two quantitative methods for determining the Lewis acidity of MOFs - based on electron paramagnetic resonance (EPR) spectroscopy of MOF-bound superoxide (O2?-) and fluorescence spectroscopy of MOF-bound N-methylacridone (NMA) - and a simple strategy that significantly enhances MOF Lewis acidity through ligand perfluorination. Two new perfluorinated MOFs, Zr6-fBDC and Zr6-fBPDC, where H2fBDC is 2,3,5,6-tetrafluoro-1,4-benzenedicarboxylic acid and H2fBPDC is 2,2′,3,3′,5,5′,6,6′-octafluoro-4,4′-biphenyldicarboxylic acid, were shown to be significantly more Lewis acidic than nonsubstituted UiO-66 and UiO-67 as well as the nitrated MOFs Zr6-BDC-NO2 and Zr6-BPDC-(NO2)2. Zr6-fBDC was shown to be a highly active single-site solid Lewis acid catalyst for Diels-Alder and arene C-H iodination reactions. Thus, this work establishes the important role of ligand perfluorination in enhancing MOF Lewis acidity and the potential of designing highly Lewis acidic MOFs for fine chemical synthesis.
