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The pressure dependence of the 129Xe chemical shift tensor confined in the Tris(o-phenylenedioxy) cyclotriphosphazene (TPP) nanochannel was investigated by high-pressure 129Xe NMR spectroscopy. The observed 129Xe spectrum in the one-dimensional TPP nanochannel (0.45 nm in diameter) exhibits a powder pattern broadened by an axially symmetric chemical shift tensor. As the pressure increases from 0.02 to 7.0 MPa, a deshielding of 90 ppm is observed for the perpendicular component of the chemical shift tensor δ⊥, whereas a deshielding of about 30 ppm is observed for the parallel one, δ‖. This suggests that the components of the chemical shift tensor, δ‖ and δ⊥, are mainly dominated by the Xe-wall and Xe-Xe interaction, respectively. Furthermore, the effect of helium, which is present along with xenon gas, on the 129Xe chemical shift is examined in detail. The average distance between the Xe atoms in the nanochannel is estimated to be 0.54 nm. This was found by using δ⊥ at the saturated pressure of xenon, and comparing the increment of the chemical shift value in δ⊥ to that of a β -phenol/Xe compound.

The dynamic behavior of n-hexane-d14 and n-decane-d22, adsorbed in the micropore of [Co(en)3]Cl3 crystal was studied by 2H NMR at 144 - 345 K. The quadrupole coupling constants (QCC) are 160 kHz for the methylene group and 60 kHz for methyl group below 144 K for hexane and below 178 K for decane, suggesting that the molecular reorientation about the molecular long axis is frozen below these temperatures. The QCC of CD2 group in hexane decreases from 160 kHz to 80 kHz on heating up to 170 K. Similar reduction of QCC of CD2 observed above 280 K for decane. Assuming the three-site jump model of the guest molecule about its molecular long axis, we reproduced the experimental spectrum, and obtained the rate of the molecular motion in each guest. The temperature dependence of jump rates leads to the activation energies for the molecular reorientation of 20 kJ mol-1 and 30 kJ mol-1 for n-hexane and n-decane, respectively, suggesting that the length of the guest molecule influences greatly its dynamics in the micropore

Ab initio Hartree-Fock molecular orbital calculations were applied to the crystalline imidazole and its derivatives in order to examine systematically the effect of possible N-H---N type hydrogen bond-ing on the nuclear quadrupole interaction parameters in these materials. The nitrogen quadrupole coupling constant (QCC) and the asymmetry parameter (η) of the electric field gradient (EFG) were found to depend strongly on the size of the molecular clusters, from single molecule, to dimer, trimer and to the infinite molecular chain, i.e., crystalline state, implying that the intermolecular N-H -N hydrogen bond affects significantly the electronic structure of imidazole molecule. A certain correla-tion between the QCC of 14N and the N-H bond distance R was also found and interpreted on the basis of the molecular orbital theory. However, we found that the value of the calculated EFG at the hy-drogen position of the N-H group, or the corresponding QCC value of 2 H, increases drastically as R-3 when R is shorter than about 0.1 nm, due probably to the inapplicability of the Gaussian basis sets to the very short chemical bond as revealed in the actual imidazole derivatives. We suggested that the ob-served N-H distances in imidazole derivatives should be re-examined.

The structure of NASICON-type compounds, Na1+xScxTi2-x(PO4)3 (O ≤ x ≤ 2), and the dynamics of Na+ have been investigated by 23Na NMR spectroscopy. It was found that the 23Na 1D and 2D MQMAS spectra depend on the Na concentration, suggesting strongly that the Na+ ions are distributed between two crystallographically nonequivalent sites, one is a special position with axial symmetry, and the other a position of low symmetry. The chemical exchange between these different sites in the crystal takes place at room temperature, which may cause the high Na ion conduction of this material

The static and dynamics properties of hydration water molecules in (±)-[Co(en)3]Cl3 were studied by means of 1H, 2H, and , 17O solid state NMR. By 'H pulsed field gradient (PFG) NMR the apparent diffusion coefficient of mobile water through a micropore along the crystalline unique c-axis was found to be 1.0 x 10-9 m2 s-1 . The 2H NMR spectrum at 141 K consists of two components, one being a Pake doublet corresponding to a quadrupole coupling constant (QCC) of (226 ± 2) kHz and an asymmetry parameter of the electric field gradient η of 0.08 ± 0.01, and another being a Gaussian line with a linewidth of 3.5 kHz. The 17O NMR spectrum at 300 K also consists of a narrow Gaussian peak and a broad powder pattern with a second order quadrupole effect corresponding to QCC = (6.3 ± 0.5) MHz and η = 0.55±0.02. The broad and narrow components are assigned to water molecules accommodated at general 12g positions and special 2a and 2b positions in the trigonal lattice with space group P1c1. From the ratio of the populations at these positions their potential energy difference was estimated to be between (2.7 ±0.1) and (3.5 ± 0.1) kJmol-1 . The 2H NMR spectrum at room temperature indicates a finite quadrupole interaction which is attributable to the rapid rotation of water molecule about the molecular C2-axis. When the water content exceeds 2.7, the QCC is reduced sharply to (5.0 ±0.1) kHz at 285 K, suggesting that there occurs rapid rotation of water and rapid exchange of 2H between nonequivalent positions.

Intermolecular hydrogen bonds of the type N-H...N in crystals of imidazole and its 4-substituted and 4,5-disubstituted derivatives were studied by 15N CP/MAS NMR and an ab initio molecular orbital (MO) calculation. In the 15N CP/MAS NMR spectrum of each of the imidazole derivatives, two peaks due to the two different functional groups, >NH and =N-, were observed. The value of the 15N isotropic chemical shift for each nitrogen atom depends on both the length of the intermolecular hydrogen bond and the kind of the substituent or substituents. It was found that the difference between the experimen-tal chemical shifts of >NH and =N-varies predominantly with the hydrogen bond length but does not show any systematic dependence on the kind of substituent. The ab initio MO calculations suggest that the hydrogen bond formation influences the 15N isotropic chemical shift predominantly, and that the difference between the 15N isotropic chemical shift of >NH and =N-varies linearly with the hydrogen bond length.

Ionic motion and local structure of phenethylammonium ion (C6H5CH2CH2NH3+) in a series of phenethylammonium lead(II) halides, [C6H6CH2CH2NH3]2PbX4 (X = Cl, Br, I) were studied by means of 13C cross polarization/magic angle sample spinning (CP/MAS) NMR technique. Among the three salts, remarkable differences in the spectra were observed in the signals corresponding to the phenyl carbons. The peaks from C2, C3, C5, and C6 in the phenyl group were split into three for the chloride and into two for the bromide, although in the iodide those were observed as a single peak. Coalescence of those peaks, as well as line broadening were observed on heating. This indicated that peak split brings about disorder of the orientation in the phenyl group around the C1-C4 axis, suggesting to have three and two orientations for the chloride and the bromide, respectively. Above room temperature the phenyl group undergoes chemical exchange among these orientations, and at higher temperature, reorientation with a large amplitude takes place around its axis. The apparent activation energies of the reorientation of the phenyl group for the chloride and bromide were estimated from the temperature dependence of the linewidth of the resonance peaks to be about 24 kJ mol-1 , 25 kJ mol-1 , respectively, which is similar to in the iodide (25.0 kJ mol-1). Ab initio molecular orbital energy calculation was carried out to evaluate the potential barrier of the internal rotation of the phenyl group in a free phenethylammonium ion. The intramolecular interaction was evaluated to be 13.9 kJ mol-1 from the calculation, and the intermolecular interaction results to be 10 kJ mol-1 .

The temperature dependences at 110 to 400 K of the : 1H spin-lattice relaxation time (7\) of the phenethylammonium ion in phenethylammonium lead(II) halides, [C6H5CH2CH2NH3]2PbX4 (X = Cl, Br, I), revealed that this ion shows reorientation of the NH3 moiety around the three-fold axis and torsional motion of the alkyl chain (CH2CH2). Below room temperature, the chloride and the bromide yielded two minima of 1H T1 originating from NH3 reorientation, whereas the iodide yielded only one minimum. These findings indicate that there are two kinds of NH3 sites in the chloride and bromide but only one in the iodide. The T1 minimum observed below room temperature gave similar activation energies of the NH3 reorientation, Ea = 15.7,15.1 and 15.5 kJ mol 1 for the chloride, bromide and iodide, respectively, suggesting that the corresponding NH3 groups are located at similar environments. Above room temperature, the T1 minimum in the chloride and bromide gave larger Ea values of the NH3 reorientation: Ea - 23.6 and 20.2 kJ mol-1 for the chloride and bromide, respectively. These findings suggest that the NH3 groups form stronger hydrogen bonding with halogen atoms (N-H ... X). Furthermore, the amplitude of the CH2CH2 motion is discussed, using the two sites jump model. The activation energies for the CH2CH2 motion in these compounds are almost equal (Ea = 29.1, 30.0 and 28.2 kJ mol -1 for the chloride, bromide and iodide, respectively), but that the torsional angles become larger in the order iodide ⪡ bromide

13C CP/MAS NMR spectra were measured on the layered compounds [C6H5CH2CH2NH3]2[CH3NH3]n - 1PbnI3n + 1 (w = 1, 2). The linewidth of the resonance peak corresponding to the phenyl carbons changed with temperature. The maximum broadening took place at 363 K for both com-pounds. The activation energy E a for the reorientation of the phenyl group was determined to be 25 kJ mol- 1 for n = 1 and 26 kJ mol- 1 for n = 2. The frequency factor τ 0 was evaluated from the linewidth at 363 K. The value of the second moment, estimated from the maximum linewidth, was interpreted by assuming a 180° flip of the phenyl group around its two-fold axis. The similarity of the activation energies for the reorientation of the phenyl group suggested that the local structure and the molecular motion of the organic cations is little affected by the difference in the sub-structure of the inorganic layer in those compounds.

Cs2SbCl6 is known as a typical mixed-valence compound. It crystallizes into a tetragonal space group I41/amd and contains two different complex anions, Sb(III)Cl3- 6 and Sb(V)Cl- 6 . The dark blue color of this compound has been considered to originate from a charge transfer between the above two anions. In order to study the electronic structure of these complex anions and the existence of charge transfer between them we measured the 121Sb NMR spectrum and carried out molecular orbital calculations on the electronic states of these anions. The 121Sb NMR spectrum consists of two peaks at 0 and 30 kHz which can be assigned to the central transition of 121Sb in Sb(V)Cl- 6 and Sb(III)Cl3- 6 , respectively. The line shape analyses of the spectra led to nuclear quadrupole coupling constants of nearly zero for Sb(V)Cl- 6 and 4.9 ± 0.5 MHz for Sb(III)Cl3- 6 at room temperature. The quadrupole coupling constant of 121Sb(III) decreases steadily on heating. The calculations of the electronic ground state energies of both anions were calculated by the MS-Xα molecular orbital method. The calculated charge-transfer band from the A1g state of Sb(III)Cl3- 6 to the A1g state of Sb(V)Cl- 6 appears at 610 nm and can account for the experimental electronic spectrum, the calculated quadrupole coupling constant in Sb(III)Cl3- 6 however is far larger than the experimental one. The contribution of the charge-transferred state to the ground state is negligible and so the temperature dependence of the quadrupole coupling constant of 121Sb(III) is attributed to an anisotropic thermal expansion of the compound.