The DFS enhancement method as applied to O MAS NMR was critically assessed, first on NaPO, a simple binary glass system, and in a second step, on a series of catalysis-related organometallic molecules and materials. The robustness of DFS was investigated for the wide range of anisotropic parameters (quadrupolar coupling and chemical shift anisotropy) encountered in these samples. Emphasis has been put on the variation of signal enhancements with respect to the DFS final sweep frequency, pulse amplitude and pulse duration, while line shape distortion issues were also addressed. Finally, the robustness of DFS enhancement of the O MAS NMR signal is shown through its successful application to silica-supported olefin metathesis catalysts.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1039/c6cp04667c | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Investigating Cell Wall Diffusion in Wood Modified with Phenol Urea Formaldehyde Resin in Different Length Scales.
Biomacromolecules
January 2025
BioComposites Centre, Bangor University, Bangor LL57 2UW, U.K.
Wood modification using low molecular weight thermosetting resins improves the biological durability and dimensional stability of wood while avoiding increasingly regulated biocides. During the modification process, resin monomers diffuse from the cell lumen to the cell wall, occupying micropore spaces before curing at 150 °C. This study investigated the mechanism of cell wall diffusion at multiple scales, comparing two test groups where diffusion was either facilitated or restricted.
View Article and Find Full Text PDFOptimization of the Heterogeneous Synthesis Conditions for Cellulose Tosylation and Synthesis of a Propargylamine Cellulosic Derivative.
Polymers (Basel)
December 2024
Institute of Chemistry, Federal University of Uberlândia, Uberlândia 38400-902, Brazil.
Cellulose tosylate (MCC-Tos) is a key derivative for surface modification and a crucial precursor for cellulose compatibilization in click reactions, enabling its functionalization for advanced applications. Replacing tosyl groups with alkyne groups broadens cellulose's potential in biocompatible reactions, such as thiol-yne click chemistry and protein/enzyme immobilization. To achieve this, we optimized the heterogeneous synthesis of MCC-Tos using a Doehlert matrix statistical design, evaluating the influence and interaction of the reaction conditions.
View Article and Find Full Text PDFH-F cross-polarization magic angle spinning dynamic nuclear polarization NMR investigation of advanced pharmaceutical formulations.
J Magn Reson
December 2024
Oral Product Development, Pharmaceutical Technology & Development, Operations, AstraZeneca, Gothenburg, Sweden.
A new 3.2 mm H-F-X magic angle spinning dynamic nuclear polarization NMR (MAS DNP-NMR) probe was developed with a unique coil design with separate radiofrequency channels for H excitation and C or F detection to enable acquisition of H-F cross-polarization (CP) MAS experiments, direct-detected F spectra with proton decoupling, and acquisition on C with simultaneous double decoupling on the H and 19F channels as well as H-F-C double-CP experiments under low temperature MAS DNP conditions. We use these sequences to study AZD2811, which is an active pharmaceutical ingredient (API), in its pure dry state as well as in its corresponding drug delivery formulation consisting of drug-loaded polymeric nanoparticles (PNPs).
View Article and Find Full Text PDFLiAlClS: a low-cost and high-performance solid electrolyte for solid-state batteries.
Chem Sci
January 2025
Materials Science and Engineering Program, The Graduate School, Florida State University 2005 Levy Ave. Tallahassee FL 32310 USA
Solid electrolytes (SEs) are crucial for advancing next-generation rechargeable battery technologies, but their commercial viability is partially limited by expensive precursors, unscalable synthesis, or low ionic conductivity. Lithium tetrahaloaluminates offer an economical option but exhibit low Li conductivities with high activation energy barriers. This study reports the synthesis of lithium aluminum chalcohalide (LiAlClS) using inexpensive precursors one-step mechanochemical milling.
View Article and Find Full Text PDFIndirect Detection of the Protons in and around Biradicals and their Mechanistic Role in MAS-DNP.
J Phys Chem Lett
January 2025
National High Magnetic Field Laboratory, Florida State University, 1800 E. Paul Dirac Dr, Tallahassee, Florida 32310, United States.
The contribution of protons in or near biradical polarizing agents in Dynamic Nuclear Polarization (DNP) has recently been under scrutiny. Results from selective deuteration and simulations have previously suggested that the role of protons in the biradical molecule depends on the strength of the electron-electron coupling. Here we use the cross effect DNP mechanism to identify and acquire H solid-state NMR spectra of the protons that contribute to propagation of the hyperpolarization, via an experimental approach dubbed Nuclear-Nuclear Double Resonance (NUDOR).
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!