A 'principles and practice' tutorial-style review of the application of solution-phase NMR in the analysis of the mechanisms of homogeneous organic and organometallic reactions and processes. This review of 345 references summarises why solution-phase NMR spectroscopy is uniquely effective in such studies, allowing non-destructive, quantitative analysis of a wide range of nuclei common to organic and organometallic reactions, providing exquisite structural detail, and using instrumentation that is routinely available in most chemistry research facilities. The review is in two parts. The first comprises an introduction to general techniques and equipment, and guidelines for their selection and application. Topics include practical aspects of the reaction itself, reaction monitoring techniques, NMR data acquisition and processing, analysis of temporal concentration data, NMR titrations, DOSY, and the use of isotopes. The second part comprises a series of 15 Case Studies, each selected to illustrate specific techniques and approaches discussed in the first part, including in situ NMR (H, B, C, N, F, Si, P), kinetic and equilibrium isotope effects, isotope entrainment, isotope shifts, isotopes at natural abundance, scalar coupling, kinetic analysis (VTNA, RPKA, simulation, steady-state), stopped-flow NMR, flow NMR, rapid injection NMR, pure shift NMR, dynamic nuclear polarisation, H/F DOSY NMR, and in situ illumination NMR.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1016/j.pnmrs.2022.01.001 | DOI Listing |
J Phys Chem A
January 2025
Department of Chemistry - Ångström Laboratory, Uppsala University, Box 523, Uppsala 751 20, Sweden.
Understanding and controlling molecular motions is of pivotal importance for designing molecular machinery and functional molecular systems, capable of performing complex tasks. Herein, we report a comprehensive theoretical study to elucidate the dynamic behavior of a bis(benzoxazole)-based overcrowded alkene displaying several coupled and uncoupled molecular motions. The benzoxazole moieties give rise to 4 different stable conformers that interconvert through single-bond rotations.
View Article and Find Full Text PDFNeurology
February 2025
Department of Advanced Biomedical Sciences, University "Federico II," Naples, Italy.
Background And Objectives: Although multiple sclerosis (MS) can be conceptualized as a network disorder, brain network analyses typically require advanced MRI sequences not commonly acquired in clinical practice. Using conventional MRI, we assessed cross-sectional and longitudinal structural disconnection and morphometric similarity networks in people with MS (pwMS), along with their relationship with clinical disability.
Methods: In this longitudinal monocentric study, 3T structural MRI of pwMS and healthy controls (HC) was retrospectively analyzed.
Invest Radiol
January 2025
From the Departments of Radiology (J.F.H., S.Y.C., J.-P.G., J.S., P.N., S.B.R., T.M.G.), Biomedical Engineering (S.B.R., T.M.G.), Medical Physics (S.Y.C., S.B.R., T.M.G.), Medicine (S.B.R.), and Emergency Medicine (S.B.R.), University of Wisconsin-Madison, WI; and Department of Diagnostic and Interventional Radiology (J.F.H., J.-P.G.), University Hospital Würzburg, Würzburg, Germany.
Rationale And Objectives: Pulmonary magnetic resonance angiography (MRA) is an imaging method with proven utility for the exclusion of pulmonary embolism and avoids the need for ionizing radiation and iodinated contrast agents. High-relaxivity gadolinium-based contrast agents (GBCAs), such as gadopiclenol, can be used to reduce the required gadolinium dose for pulmonary MRA. The aim of this study was to compare the contrast enhancement performance of gadopiclenol with an established gadobenate dimeglumine-enhanced pulmonary MRA protocol.
View Article and Find Full Text PDFInorg Chem
January 2025
School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A and 2B Raja S. C. Mullick Road, Kolkata 700032, India.
The incorporation of a selenoimidazolium-based chalcogen bond (ChB) donor into a bis-heteroleptic Ru(II) complex (Ru-Se) has been designed for the first time to explore its anion-sensing properties and understand its selectivity to specific classes of anions. Photophysical studies demonstrate the receptor's selectivity toward phosphates, while H NMR displays its ability to recognize both I and HPO among the different halides and oxoanions through ChB interaction in CHCN and dimethyl sulfoxide- solvents, respectively. Additionally, microscopic studies such as DLS and TEM reveal that the selective turn-on sensing of HPO and HPO compared to I is driven by supramolecular aggregation behavior.
View Article and Find Full Text PDFScience
January 2025
Wolfson Catalysis Centre, Department of Chemistry, University of Oxford, Oxford, UK.
The distribution of substitutional aluminum (Al) atoms in zeolites affects molecular adsorbate geometry, catalytic activity, and shape and size selectivity. Accurately determining Al positions has been challenging. We used synchrotron resonant soft x-ray diffraction (RSXRD) at multiple energies near the Al K-edge combined with molecular adsorption techniques to precisely locate "single Al" and "Al pairs" in a commercial H-ZSM-5 zeolite.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!