Solid-state NMR spectroscopy: an advancing tool to analyse the structure and properties of metal–organic frameworks

Abstract

Metal–organic frameworks (MOFs) gain increasing interest due to their outstanding properties like extremely high porosity, structural variability, and various possibilities for functionalization.

Multiple rotational rates in a guest-loaded, amphidynamic zirconia metal–organic framework

“…Conversely, solid-state NMR, as it is time-resolved, is ideal to analyze guest loaded MOFs in bulk samples, providing kinetic information such as transient pinteraction sites, 27 gas-absorption diffusional rates, 28 internal rotational dynamics, 6 and other kinetic details. 29,30…”

Doxorubicin-Loaded Metal-Organic Frameworks Nanoparticles with Engineered Cyclodextrin Coatings: Insights on Drug Location by Solid State NMR Spectroscopy

“…In an attempt to gain an understanding at the molecular level of the DOX loading processes, a ssNMR investigation on nanoMIL-100(Al) was undertaken. Indeed, ssNMR spectroscopy is well-known to provide atomic-level information about porous MOFs as drug delivery systems [ 4 , 5 , 6 , 9 , 10 , 31 ]. The 13 C cross-polarization under magic-angle spinning (CPMAS) NMR spectrum of DOX loaded nanoMIL-100(Al) shows the presence of the DOX molecules ( Figure 4 ).…”

“…Interestingly, MIL-100(Al) based metal organic gels [ 3 ] have been used as drug carriers to deliver doxorubicin (DOX). Solid-state NMR (ssNMR) spectroscopy has emerged as an essential analytical technique to achieve detailed atomic-scale characterization of complex porous systems [ 4 ], including MOFs [ 5 , 6 , 7 , 8 ] The technique is non-destructive, allows probing a local scale highly complementary to diffraction and is sensitive to millisecond timescale, hence can be used to monitor dynamic processes. For instance, the activation process of MIL-100(Al) could be followed by ssNMR [ 9 ].…”

“…In the field of biomedicine, ssNMR is also of particular interest [ 5 , 11 , 12 , 13 , 14 , 15 ]. Notably, ssNMR brought valuable insights on the supramolecular structure of highly porous core–shell drug nanocarriers, namely MIL-100 nanoMOFs coated with cyclodextrin-phosphate (CD-P) molecules.…”

Atomic resolution tracking of nerve-agent simulant decomposition and host metal–organic framework response in real space

“…Modeling methods such as SQEEZE 19 , the maximum entropy method (MEM) 20 , or the use of difference envelope densities (DED) 21,22 , can help to localize the electron density in less ordered cases, but further suffer in resolution by averaging effects and cannot typically elucidate the specific nature of the interactions. On the other hand, spectroscopic techniques such as solid-state nuclear magnetic resonance SSNMR 23 , infrared spectroscopy 24 , or inelastic neutron (or X-ray) scattering [25][26][27] can be used to measure and track the chemical or dynamical nature of guest molecules and their interactions during adsorption or reaction processes. However, while providing a powerful reference for theoretical predictions, they do not typically allow for direct refinement of physical models.…”