High-Resolution NMR Correlation Spectra of Disordered Solids

Abstract

We show how high-resolution NMR spectra can be obtained for solids for which the spectra are normally broadened due to structural disorder. The method relies on correlations in the chemical shifts between pairs of coupled spins. It is found experimentally that there are strong correlations in the chemical shifts between neighboring spins in both phosphorus-31 and carbon-13 spectra. These correlations can be exploited not only to provide resolution in two-dimensional spectra, but also to yield "chains" of correlated chemical shifts, constituting a valuable new source of structural information for disordered materials.

Studying natural structural protein fibers by solid‐state nuclear magnetic resonance

“…In addition, these fibers often are heterogeneous samples which present variations in magnetic susceptibilities. The resulting 13 C MAS spectra can, thus, present two types of peak broadening, one resulting from an isotropic chemical shift distribution due to structural disorder, and one to changes in chemical shifts from one part of the sample to another (60). The inhomogeneous peak broadening due to an isotropic chemical shift distribution can be exploited to extract valuable information on the actual conformations existing in a structural biofiber.…”

Dynamics and Disorder in Surfactant-Templated Silicate Layers Studied by Solid-State NMR Dephasing Times and Correlated Line Shapes

“…In particular, the nonrefocusable line width ∆′ can be considered for disordered solids to be approximately the limiting homogeneous line width associated with a spin in a given local environment. 16,17 In protonated solids, ∆′ is generally dominated by the residual heteronuclear dipolar couplings to the protons, 23,24 and therefore, measurements of transverse dephasing times T 2 ′ have not, so far, been related to structural or dynamic parameters.…”

High-resolution NMR of anisotropic samples with spinning away from the magic angle

“…Of course, to the extent that the residual linewidth also scales with the angle this is not a problem. We mention here that related two-dimensional correlations experiments of amorphous solids exhibiting inhomogeneous broadening, can yield highly resolved projections (see [16] and references therein).…”