Proton and carbon-13 nmr spectra of unsonicated lipid bilayers and biological membranes are generally dominated by strong proton–proton and proton–carbon dipolar interactions. As a result the spectra contain a large number of overlapping resonances and are rather difficult to analyse. Nevertheless, important information on the structure and dynamic behaviour of lipid systems has been provided by these techniques (Wennerstrom & Lindblom, 1977).

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Deuterium magnetic resonance: theory and application to lipid membranes.

Kraitchman has shown that a single isotopic substitution on an atom is sufficient to determine directly the coordinates of that atom with respect to the principal axes of the original molecule. Kraitchman's formulas represent exact solutions of the equations for the equilibrium moments of inertia. However, the effects of the zero‐point vibrations are such that the coordinates obtained by substitution from the ground state moments of inertia I0 are systematically less than r0. These coordinates have here been called r (substitution) or rs, and it is found that rs≃(r0+re)/2, and Is= ∑ imirsi2≃(I0+Ie)/2.In the usual method of solution, the coordinate of one atom is determined from the equation for I0, and therefore the difference I0—Is must be made up by this one coordinate. This introduces a large error in the structures normally determined from ground state constants, and results in variations of 0.01 A in structures determined from different sets of isotopic species. If instead, we obtain the structure on...

A new criterion for the determination of molecular structures from ground state rotational constants

Deuterium Magnetic Resonance: Applications in Chemistry, Physics and Biology

The reorientational correlation function for liquid methyl iodide has been measured by analysis of the Raman 526 cm−1 ν3 (a1) band as a function of pressure up to 2.5 kbar within the temperature range 0 to 90°C. These reorientational correlation functions have been obtained from the anisotropic component of the vibrational Raman scattered light using a method of Fourier deconvolution. Density and viscosity of methyl iodide over the same range of temperatures and pressures have also been determined. In order to obtain information about the effects of density and temperature on the internal C3 rotation of the methyl group the NMR deuteron spin‐lattice relaxation times in liquid methyl iodide‐d3 have been measured under the same experimental conditions. In addition the vibrational relaxation rates have been determined from the isotropic Raman band shapes. The Raman experiments enable us to calculate the reorientational correlation function describing the reorientational motion of the CH3I molecules about an ...

Density and temperature effects on the molecular reorientation and vibrational relaxation in liquid methyl iodide

https://www.cell.com/biophysj/pdf/S0006-3495(05)73246-X.pdf

2H-NMR study and molecular dynamics simulation of the location, alignment, and mobility of pyrene in POPC bilayers.

The analysis of the NMR spectra of suitable nematic liquid‐crystal solutions appears to offer a convenient and desirable method for the determination of small nuclear quadrupole coupling constants for molecules in the liquid state. Nuclear quadrupole coupling constants have been determined for deuterium in the C–H bond of a number of small molecules. Assuming that the field gradient has axial symmetry, values of e2qQ/h along the bond axis are as follows: CH3CD3167± 18 kHzC3D6184± 20C2D2198± 7CH3C2D199.4± 2.0DCN199.0± 3.0. The results are discussed in terms of various theoretical calculations of the field gradient at the deuteron, and a compilation of some of the accurate experimentally determined deuterium coupling constants is presented.

William J. Caspary

Papers

NMR Determination of Deuterium Quadrupole Coupling Constants in Nematic Solutions