UiO-66 framework with an encapsulated spin probe: synthesis and exceptional sensitivity to mechanical pressure

Abstract

Probes sensitive to mechanical stress are in demand for analysis of pressure distribution in materials, and the design of the pressure sensors based on metal–organic frameworks (MOFs) is highly promising...

Nanoscale solvent organization in metal–organic framework ZIF-8 probed by EPR of flexible β-phosphorylated nitroxides

“…In this work it was exemplified using ZIF-8; however, the properties of many other MOFs (for instance, other MOFs of the ZIF family and recent example of UiO-66 (ref. 50 )) can be accessed in the same way. Therefore, we believe that the methodology and conclusions of this paper may find broad implementation in MOF science in the future.…”

“…44,45 assessing pressure effects and aiding in the formation of MOF pellets and composites. [46][47][48][49][50] All information obtained using TEMPO@MOF systems relied on the sensitivity of the EPR spectrum to the presence of oxygen or solvent molecules in the cavity, as well as to the integrity of MOF cavities. However, this TEMPO-based approach provides only basic information on the properties of MOF cavities inside and their changes upon adsorption of various guests.…”

Properties of Aliphatic Ligand-Based Metal–Organic Frameworks

“…Electron paramagnetic resonance (EPR) is also a very sensitive method for which the high crystallinity of the sample is not required. This method involves the study of paramagnetic centers in various components of the metal-organic framework: metal centers [58][59][60], guests [61][62][63], and organic bridging ligands [64][65][66], where, in the absence of their own paramagnetism, the corresponding functionalization may be carried out. Doping of a diamagnetic MOF lattice by trace amounts of paramagnetic centers in a metal node (for example, by partial substitution of diamagnetic Zn 2+ cations for Cu 2+ ) or within pores (for The activated form of [Al(OH)(chdc)] was found to be similar to the as-synthesized framework, except some alignment of metal coordination environment with a change of Al-O bond length intervals from 1.79(3).…”

“…Electron paramagnetic resonance (EPR) is also a very sensitive method for which the high crystallinity of the sample is not required. This method involves the study of paramagnetic centers in various components of the metal-organic framework: metal centers [58][59][60], guests [61][62][63], and organic bridging ligands [64][65][66], where, in the absence of their own paramagnetism, the corresponding functionalization may be carried out. Doping of a diamagnetic MOF lattice by trace amounts of paramagnetic centers in a metal node (for example, by partial substitution of diamagnetic Zn 2+ cations for Cu 2+ ) or within pores (for example, by introducing a stable nitroxide radical as a paramagnetic probe) should be singled out, as a high dilution of the paramagnetic signal source makes it possible to study the behavior of an almost unperturbed MOF structure where local changes around the dopant do not affect the overall structure and bulk properties of the polymeric network, including its breathing.…”