In situ solid-state NMR of a magnetically oriented microcrystal suspension

Ryosuke Kusumi; Hiroshi Kadoma; Masahisa Wada; Kazuyuki Takeda; Tsunehisa Kimura

doi:10.1016/j.jmr.2019.106618

In situ solid-state NMR of a magnetically oriented microcrystal suspension

J Magn Reson. 2019 Dec:309:106618. doi: 10.1016/j.jmr.2019.106618. Epub 2019 Oct 10.

Authors

Ryosuke Kusumi¹, Hiroshi Kadoma², Masahisa Wada³, Kazuyuki Takeda⁴, Tsunehisa Kimura⁵

Affiliations

¹ Division of Forest and Biomaterials Science, Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan. Electronic address: r_kusumi@kais.kyoto-u.ac.jp.
² Division of Forest and Biomaterials Science, Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan.
³ Division of Forest and Biomaterials Science, Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan; College of Life Science, Kyung Hee University, Yongin-si, Gyeonggi-do 446-701, Republic of Korea.
⁴ Division of Chemistry, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan.
⁵ Division of Forest and Biomaterials Science, Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan; Fukui University of Technology, 3-6-1 Gakuen, Fukui 910-8505, Japan.

PMID: 31670012
DOI: 10.1016/j.jmr.2019.106618

Abstract

In situ solid-state NMR measurements of a magnetically oriented microcrystal suspension (MOMS) were demonstrated. Under modulated rotation of the static field, or equivalently, of the sample tube, randomly oriented microcrystals in a viscous liquid medium feel a torque arising from the anisotropic bulk susceptibility and eventually aligned in the same direction. In this way, a three-dimensional MOMS (3D-MOMS) was obtained. To apply an elliptically rotating magnetic field to microcrystals in suspension, a probe to rotate the sample tube around an axis perpendicular to the static magnetic field was developed. Single-crystal (SC) rotation patterns were obtained from the 3D-MOMS by solid-state CP measurements triggered in synchronous with the sample-tube rotation. Unlike the traditional SC method, the 3D-MOMS approach presented here does not require the elaborate adjustment of the direction of the reference frame. The process of three-dimensional magnetic alignment was also studied by monitoring the spectral changes during continuous application of the modulated sample rotation.

Keywords: Chemical shift anisotropy; In situ measurement; Magnetically oriented microcrystal suspension (MOMS); Single-crystal rotation pattern.