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Homonuclear Decoupling in 1 H?NMR of Solids by Remote Correlation.

ABSTRACT: The typical linewidths of 1 H?NMR spectra of powdered organic solids at 111?kHz magic-angle spinning (MAS) are of the order of a few hundred Hz. While this is remarkable in comparison to the tens of kHz observed in spectra of static samples, it is still the key limit to the use of 1 H in solid-state NMR, especially for complex systems. Here, we demonstrate a novel strategy to further improve the spectral resolution. We show that the anti-z-COSY experiment can be used to reduce the residual line broadening of 1 H?NMR spectra of powdered organic solids. Results obtained with the anti-z-COSY sequence at 100?kHz MAS on thymol, ?-AspAla, and strychnine show an improvement in resolution of up to a factor of two compared to conventional spectra acquired at the same spinning rate.

SUBMITTER: Moutzouri P

PROVIDER: S-EPMC7187420 | biostudies-literature | 2020 Apr

REPOSITORIES: biostudies-literature

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Homonuclear Decoupling in 1 H NMR of Solids by Remote Correlation.

Moutzouri Pinelopi P Paruzzo Federico M FM Simões de Almeida Bruno B Stevanato Gabriele G Emsley Lyndon L

Angewandte Chemie (International ed. in English) 20200219 15

The typical linewidths of 1 H NMR spectra of powdered organic solids at 111 kHz magic-angle spinning (MAS) are of the order of a few hundred Hz. While this is remarkable in comparison to the tens of kHz observed in spectra of static samples, it is still the key limit to the use of 1 H in solid-state NMR, especially for complex systems. Here, we demonstrate a novel strategy to further improve the spectral resolution. We show that the anti-z-COSY experiment can be used to red ...[more]

PMID: 31967378

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Project description:We recently described a family of experiments for R2n(v) Driven Spin Diffusion (RDSD) spectroscopy suitable for homonuclear correlation experiments under fast MAS conditions [G. Hou, S. Yan, S.J. Sun, Y. Han, I.J. Byeon, J. Ahn, J. Concel, A. Samoson, A.M. Gronenborn, T. Polenova, Spin diffusion drive by R-symmetry sequencs: applications to homonuclear correlation spectroscopy in MAS NMR of biological and organic solids, J. Am. Chem. Soc. 133 (2011) 3943-3953]. In these RDSD experiments, since the broadened second-order rotational resonance conditions are dominated by the radio frequency field strength and the phase shifts, as well as the size of reintroduced dipolar couplings, the different R2n(v) sequences display unique polarization transfer behaviors and different recoupling frequency bandwidths. Herein, we present a series of modified R2n(v) sequences, dubbed COmbined R2n(v)-Driven (CORD), that yield broadband homonuclear dipolar recoupling and give rise to uniform distribution of cross peak intensities across the entire correlation spectrum. We report NMR experiments and numerical simulations demonstrating that these CORD spin diffusion sequences are suitable for broadband recoupling at a wide range of magnetic fields and MAS frequencies, including fast-MAS conditions (?r=40 kHz and above). Since these CORD sequences are largely insensitive to dipolar truncation, they are well suited for the determination of long-range distance constraints, which are indispensable for the structural characterization of a broad range of systems. Using U-(13)C,(15)N-alanine and U-(13)C,(15)N-histidine, we show that under fast-MAS conditions, the CORD sequences display polarization transfer efficiencies within broadband frequency regions that are generally higher than those offered by other existing spin diffusion pulse schemes. A 89-residue U-(13)C,(15)N-dynein light chain (LC8) protein has also been used to demonstrate that the CORD sequences exhibit uniformly high cross peak intensities across the entire chemical shift range.

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Dataset Information

Homonuclear Decoupling in 1 H?NMR of Solids by Remote Correlation.

Publications

Homonuclear Decoupling in <sup>1</sup> H NMR of Solids by Remote Correlation.

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