Static Solid Relaxation Ordered Spectroscopy: SS-ROSY

Abstract

A two-dimensional pulse sequence is introduced for correlating nuclear magnetic resonance anisotropic chemical shifts to a relaxation time (e.g., T1) in solids under static conditions. The sequence begins with a preparatory stage for measuring relaxation times, and is followed by a multiple pulse sequence for homonuclear dipolar decoupling. Data analysis involves the use of Fourier transform, followed by a one-dimensional inverse Laplace transform for each frequency index. Experimental results acquired on solid samples demonstrate the general approach, and additional variations involving heteronuclear decoupling and magic angle spinning are discussed.

Combined High-Resolution Solid-State 1H/13C NMR Spectroscopy and 1H NMR Relaxometry for the Characterization of Kerogen Thermal Maturation

“…pyrolysis). For this reason, spectroscopic methods such as Raman spectroscopy (RS), Fourier transform infrared (FT-IR), X-ray photoelectron spectroscopy (XPS), X-ray absorption near edge structure (XANES), and solid-state nuclear magnetic resonance (ssNMR) , have been successfully applied to study solid-like materials such as kerogen . These techniques may be used to analyze the whole solid sample without the need to alter its structure (during the sample workup for the measurements), the obtained information representing an averaged composition for the bulk sample.…”

3D relaxation-assisted separation of wideline solid-state NMR patterns for achieving site resolution

“…23 Iijima and Shimizu implemented RAS for static 2 H NMR, 24 while Boutis and Kausik used it for separating patterns influenced by chemical shift anisotropy (CSA). 25 We have extended RAS methods for resolving overlapped UW patterns, 26 including those exceeding 250 kHz in breadth due to large anisotropic NMR interactions, 27 using stabilized solutions of the NNLS with Tikhonov regularization (Non-Negative Tikhonov Fitting -NNTF). RAS measurements based on T 1 and T eff 2 (i.e., effective T 2 ) were used to resolve patterns of both half-integer and integer-spin quadrupolar nuclei, as well as spin-1/2 patterns influenced by large CSAs.…”

“…23 Iijima and Shimizu implemented RAS for static 2 H NMR, 24 while Boutis and Kausik used it for separating patterns influenced by chemical shift anisotropy (CSA). 25…”