Compounds I, II and III, were used as models resembling gear systems (bods connecting CR3 groups to the skeletal molecule are parallel) in surveying the potential energy surface for their internal rotation. The magnitude of the barriers calculated for averaging the NMR signals, placed these compounds in the range of measurement accessible by dynamic NMR spectroscopy (which is cur...

Measurement of polymerization degree of condensed phosphates was examined by solid-state NMR. Broad peaks of the NMR of endand middle-PO4 groups of condensed phosphates were observed at about 1 and -20 ppm, respectively. The NMR. peak area ratio (Ro) of middle-PO4 group to end-PO4 group has the following relation with the polymerization degree (n) of polyphosphate: Ro (middle-PO4/end-PO4) = (n-...

NMR technology has advanced significantly during the past year. Four-dimensional NMR spectroscopy is a feasible approach for unraveling the extremely crowded NOE spectra of medium-sized proteins. Alternatively, the use of selective deuteration also shows promise in this area. New three-dimensional NMR techniques can be used for accurate measurement of multiple-bond J couplings and improved meth...

Multidimensional NMR techniques used in the measurement of molecular displacements, whether by diffusion or advection, and in the measurement of nuclear spin relaxation times are categorised. Fourier-Fourier, Fourier-Laplace and Laplace-Laplace methods are identified, and recent developments discussed in terms of the separation, correlation and exchange perspective of multidimensional NMR spect...

Low-temperature (6)Li, (13)C, and (15)N NMR spectroscopies reveal that mixtures of n-BuLi and (1R,2S)-R'(2)NCH(R)CH(Ph)OLi (ROLi; R = Ph or Me; R'(2)N = pyrrolidino or Me(2)N) in THF/pentane afford a (n-BuLi)(3)(ROLi) (3:1) mixed tetramer and a C(2)-symmetric (n-BuLi)(2)(ROLi)(2) (2:2) mixed tetramer depending on the proportions of the reactants. The corresponding (n-BuLi)(ROLi)(3) (1:3) mixed ...

We have used nuclear magnetic resonance (NMR) to obtain spatially and temporally resolved profiles of gas flow in microfluidic devices. Remote detection of the NMR signal both overcomes the sensitivity limitation of NMR and enables time-of-flight measurement in addition to spatially resolved imaging. Thus, detailed insight is gained into the effects of flow, diffusion, and mixing in specific ge...