1H NMR studies on the motion of water molecules in magnesium hexachlorostannate(IV) and hexachlorotellurate(IV) hexahydrates

Temperature Dependence of 2H Quadrupole Coupling Constants in 2H2O and Ionic Motions in Crystalline [M(2H2O)6] [SnCl6] (M: Mg, Ca), Studied by 2H NMR and Neutron Powder Diffraction

“…The onset of this motion is also supported by the structure at room temperature, where no disordered position of deuterium was observed. The assignment to an 180°-flip of water molecules is in good agreement with the analysis of 35 C1 NQR and *H NMR relaxation studies on Mg and Ca salts [8,11,12]. The other possible angle of 71° is unacceptable because a jump over this angle results in disordered O-D orientations, inconsistent with the neutron diffraction result.…”

“…200 K. Onset of anionic overall reorientation was found above room temperature from measurement of the 35 C1 spin-lattice relaxation time (T 1Q ) exhibiting a rapid exponential decrease at high temperatures. On the other hand, motions in cations were studied by measurement of the *H NMR linewidth and relaxation times (T 1H , T le ) on diamagnetic complexes of M n = Mg and Ca [11,12]. In these studies, the minima of T 1H observed around 200 K were attributed to a 180° flip motion of H 2 0 molecules, and the T x "-decrease observed above room temperature in [M(H 2 0) 6 ] [SnCl 6 ] (M: Mg, Ca) and T le minima were interpreted as C 3 or C 4 reorientation and overall reorientation of cations.…”

A 35Cl NQR Study on Cs2[AUICl2] [AuIIICl4]

“…The results are in good agreement with the reported value of mentioned above, assuring the purity of (I) and (II). The existence of the paramagnetic sites revealed by ESR measurements is intrinsic to the mixed valence compound and attributable to Au(II) having the configuration 5d 9 . The observed fairly broad line width in ESR spectra may largely arise from the site asymmetry at the position Au(II) in the tetragonal system.…”

“…A home made pulsed spectrometer was used for the observation of 35 C1 NQR [9]. The line shape of the resonances was determined by monitoring the dependence of the spin echo amplitudes on the rf frequencies.…”

35Cl Quadrupole Relaxation Study on Cs2[Au(I)Cl2][Au(III)Cl4] and Cs2[Ag(I)Cl2][Au(III)Cl4]

“…Therefore we have undertaken further ∆ and 1Q measurements on the same compound, but prepared in a different manner [2], because the Au(II) concentration is expected to depend on the method of preparation. Cs 2 spectrometer [7] was used for the observation of 35 Cl NQR. The line shape of the resonances was determined by monitoring the spin echo amplitude dependence on the rf frequencies.…”