Chetry Sibo, Lukman Muhammad Fernadi, Bon Volodymyr, Warias Rico, Fuhrmann Daniel, Möllmer Jens, Belder Detlev, Gopinath Chinnakonda S, Kaskel Stefan, Pöppl Andreas, Krautscheid Harald
Faculty of Chemistry and Mineralogy, Universität Leipzig, Johannisallee 29, Leipzig 04103, Germany.
Felix-Bloch-Institute of Solid-State Physics, Faculty of Physics and Earth Sciences, Universität Leipzig, Linnéstrasse 5, Leipzig 04103, Germany.
Inorg Chem. 2024 Jun 10;63(23):10843-10853. doi: 10.1021/acs.inorgchem.4c01589. Epub 2024 May 29.
Synthesis and characterization of DEMOFs (defect-engineered metal-organic frameworks) with coordinatively unsaturated sites (CUSs) for gas adsorption, catalysis, and separation are reported. We use the mixed-linker approach to introduce defects in Cu-paddle wheel units of MOFs [Cu(Me-trz-ia)] by replacing up to 7% of the 3-methyl-triazolyl isophthalate linker (L) with the "defective linker" 3-methyl-triazolyl m-benzoate (L), causing uncoordinated equatorial sites. PXRD of DEMOFs shows broadened reflections; IR and Raman analysis demonstrates only marginal changes as compared to the regular MOF (ReMOF, without a defective linker). The concentration of the integrated defective linker in DEMOFs is determined by H NMR and HPLC, while PXRD patterns reveal that DEMOFs maintain phase purity and crystallinity. Combined XPS (X-ray photoelectron spectroscopy) and EPR (continuous wave electron paramagnetic resonance) spectroscopy analyses provide insights into the local structure of defective sites and charge balance, suggesting the presence of two types of defects. Notably, an increase in Cu concentration is observed with incorporation of defective linkers, correlating with the elevated isosteric heat of adsorption (Δ). Overall, this approach offers valuable insights into the creation and evolution of CUSs within MOFs through the integration of defective linkers.
报道了具有配位不饱和位点（CUSs）的缺陷工程金属有机框架（DEMOFs）用于气体吸附、催化和分离的合成与表征。我们采用混合连接体方法，通过用“缺陷连接体”3 - 甲基 - 三唑基间苯二甲酸酯（L）取代高达7%的3 - 甲基 - 三唑基间苯二甲酸酯连接体（L），在金属有机框架[Cu(Me - trz - ia)]的铜桨轮单元中引入缺陷，从而产生未配位的赤道位点。DEMOFs的粉末X射线衍射（PXRD）显示反射峰变宽；红外（IR）和拉曼分析表明，与常规金属有机框架（ReMOF，无缺陷连接体）相比，只有微小变化。通过核磁共振氢谱（H NMR）和高效液相色谱（HPLC）确定了DEMOFs中整合的缺陷连接体的浓度，而PXRD图谱表明DEMOFs保持了相纯度和结晶度。结合X射线光电子能谱（XPS）和连续波电子顺磁共振（EPR）光谱分析，深入了解了缺陷位点的局部结构和电荷平衡，表明存在两种类型的缺陷。值得注意的是，随着缺陷连接体的引入，观察到铜浓度增加，这与吸附等量热（Δ）升高相关。总体而言，这种方法通过整合缺陷连接体，为金属有机框架内CUSs的产生和演化提供了有价值的见解。
