Molecular ferroelectric pyridin-2-ylmethanaminium perchlorate with phase transition induced by disorder of perchlorate

Abstract

A new molecular ferroelectric pyridin-2-ylmethanaminium perchlorate with phase transition induced by disorder of perchlorate.

Temperature-Stimulus Responsive Ferroelastic Molecular–Ionic Crystal: (C8H20N)[BF4]

“…Proton and Fluorine Magnetic Resonance ( 1 H NMR and 19 F NMR). The NMR T 1 relaxation times (determined by the saturation method) of 1 H and 19 F NMR measurements were performed on an ELLAB TEL-Atomic PS 15 spectrometer working at a frequency of 25 MHz for both nuclei in the temperature range between 85 and 400 K. The second moment of 1 H and 19 F NMR line was measured in the temperature range between 99 and 400 K by a continuous wave ELLAB TEL-Atomic CWS 12−50 spectrometer working on protons at the frequency of 28.2 MHz for both nuclei. The M 2 values were found by a numerical integration of the absorption curve derivatives.…”

“…3.5. 1 H and 19 F Nuclear Magnetic Resonance Analysis. The temperature dependencies of the 1 H and 19 to up to 115 K, the magnetization recovery observed in measurements of T 1 relaxation times for both atomic nuclei have a nonexponential form.…”

“…1 H and 19 F Nuclear Magnetic Resonance Analysis. The temperature dependencies of the 1 H and 19 to up to 115 K, the magnetization recovery observed in measurements of T 1 relaxation times for both atomic nuclei have a nonexponential form. In the following temperature regions: (b) between 115 K and the PT (259 K) and (c) above the PT for both studied atomic nuclei, only one-exponential magnetization recovery was observed.…”

“…Molecular–ionic salts, with stoichiometry ratio 1:1-AMX 4 , where [MX 4 ] − is a tetrahedral monoanion, such as perchlorate, tetrafluoroborate, or perrhenate, and A + is a monocation, exhibit ferroic and/or nonlinear optical physical properties. − The AMX 4 materials form the zero-dimensional (0D) molecular–ionic salts. The cations and anions are connected by the electrostatic attraction, e.g .…”

“…The compound under investigations has been found to undergo a reversible order−disorder ferroelastic transition at 257/259 K (cooling/heating) with a relatively narrow thermal hysteresis. The phase transition (PT) and its concomitant phenomena have been studied here by means of the thermal, structural, electric, optical, and solid-state 1 H and 19 F NMR (spin−lattice relaxation time T 1 and M 2 ) measurements.…”