Nuclear magnetic resonance exchange processes

The term DNMR, Dynamic Nuclear Magnetic Resonance, refers to the process of recording and usually computer simulating exchange broadened NMR spectra at a number of temperatures in order to determine mechanistic and/or kinetic information. b The terms fast and slow are used rather than the more familiar labile and nonlabile because the latter imply an intermolecular reaction. 

The development of nuclear magnetic resonance spectroscopy for the measurement of the rates of fast reactions (preexchange lifetimes 1-0.001 second) has made it possible to study many alkyl-metal exchange processes which heretofore were experimentally inaccessible. A substantial number of papers dealing with the exchange reactions of Group I, II, and III... 

For the investigation of the molecular dynamics in polymers, deuteron solid-state nuclear magnetic resonance (2D-NMR) spectroscopy has been shown to be a powerful method [1]. In the field of viscoelastic polymers, segmental dynamics of poly(urethanes) has been studied intensively by 2D-NMR [78, 79]. In addition to ID NMR spectroscopy, 2D NMR exchange spectroscopy was used to extend the time scale of molecular dynamics up to the order of milliseconds or even seconds. In combination with line-shape simulation, this technique allows one to obtain correlation times and correlation-time distributions of the molecular mobility as well as detailed information about the geometry of the motional process [1]. 

Nuclear magnetic resonance measurements show that the hydrogen atoms of NH3 rapidly exchange with those of water by the process... 

Tetrakis(organophosphorus)metal hydrides (containing one, two, three, or four hydride nuclei) have recently attracted considerable attention in connection with their stereochemical behavior1 and reaction chemistry.2 Detailed nuclear magnetic resonance studies and line-shape analyses have substantiated stereochemical nonrigidity in many of these complexes in solution and have yielded mechanistic information about the intramolecular-exchange processes.3... 

Brown, T.L., 1968. Nuclear magnetic resonance studies of organometallic exchange processes. Acc. Chem. Res. 1 (1), 23-32. 

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