Study of Structural Phase Transitions in [Mg(H₂O)₆][SiF₆] by Means of Single Crystal ²H NMR

Abstract

2+ about the 3 axis were obtained from the simulation of 2 H NMR spectra. The jumping rate at infinite temperature and the activation energy were estimated from the temperature dependence of as 0 = 9 10 17 s 1 and a = 78 kJmol 1 , respectively. The II-III phase transition was found to be related with the freeze of this motion.

Molecular Dynamics in Paramagnetic Materials as Studied by Magic-Angle Spinning 2H NMR Spectra

“…The line shape of a broadline 2 H NMR spectrum is sensitive to the molecular motion in the dynamic range of 10 3 s -1 e k e 10 7 s -1 . [2][3][4][5][6][7][8][9][10] Since the ordinary quadrupole-echo sequence refocuses only dephasing due to the quadrupole interaction, the distortion of the line shape is caused by the paramagnetic shift in the measurements of broadline 2 H NMR spectra of paramagnetic compounds. Two-or four-pulse sequences which remove the distortion of a spectrum because of the paramagnetic shift have been proposed.…”

“…The line shape of a 2 H NMR spectrum depends on the anisotropic interactions, such as nuclear quadrupole interaction, chemical shift, and dipolar interaction, and is affected by the molecular motion. The line shape of a broadline 2 H NMR spectrum is sensitive to the molecular motion in the dynamic range of 10 3 s -1 ≤ k ≤ 10 7 s -1 . − Since the ordinary quadrupole-echo sequence refocuses only dephasing due to the quadrupole interaction, the distortion of the line shape is caused by the paramagnetic shift in the measurements of broadline 2 H NMR spectra of paramagnetic compounds. Two- or four-pulse sequences which remove the distortion of a spectrum because of the paramagnetic shift have been proposed. , The simulation method for the 2 H NMR broadline spectrum of paramagnetic compounds obtained by these pulse sequences has been developed for the study of molecular dynamics in paramagnetic compounds. ,− …”