Self-Diffusion and Reorientation of Methylammonium Ions in (CH₃NH₃)₂ZnCl₄ Crystals as Studied by ¹H-NMR

Abstract

Differential thermal analysis, differential scanning calorimetry, and measurements of the

1H and 19 F NMR Studies on Molecular Motions in Two Solid Phases of t-Butylammonium Tetrafluoroborate

“…The differences between the observed and calculated values are attributable to intermolecular contributions. With increasing temperature, M 2F decreased rapidly and a constant value of 2.3 ± 0.2 G 2 was obtained above 120 K. This value can be attributed to the isotropic reorientation of the BF 4 -ion, referring to the M 2F results obtained in…”

“…The deep T 1F minimum of 18 ms around 160 K is assignable to the isotropic rotation of the BF 4 -ion based on the above discussion on M 2f . Since the observed T 1F yielded an asymmetric log T 1F VS. T -1 curve, we can expect that at least two kinds of crystallographically nonequivalent anions exist in Phase II.…”

“…In the present study, 1 4 by three times repeated crystallization from D 2 0 (99.8 D%). Because of the hygroscopicity of the purified crystals, they were handled in a dry bag and dried under a vacuum (ca.…”

“…The spin-lattice relaxation times of ! H and 19 F NMR (abbreviated to T m and T 1F , respectively) were measured using a pulsed NMR spectrometer [4] with the 180° -1 -90° pulse sequence.…”

Self-Diffusion in the Ionic Plastic Phase of (CH3 )3 NHClO4 Studied by 1H NMR and Electrical Conductivity

“…X H NMR spin-lattice relaxation times were measured at 8.5, 18, 32 MHz with a 180°-T-90° pulse sequence by a pulsed spectrometer already reported [12].…”