Deuterium quadrupole coupling constants and asymmetry parameters in bridging metal hydride complexes

1991 ◽  
Vol 113 (24) ◽  
pp. 9090-9096 ◽  
Author(s):  
Ae Ja Kim ◽  
Frank R. Fronczek ◽  
Leslie G. Butler ◽  
Shixiong Chen ◽  
Ellen A. Keiter
Keyword(s):  
Metal Hydride ◽  
Coupling Constants ◽  
Hydride Complexes ◽  
Quadrupole Coupling ◽  
Asymmetry Parameters

Theory of Nuclear Quadrupole Interactions of 14N, 17O, and 35Cl Nuclei in p-Cl-Ph-CH-N=TEMPO

2002 ◽  
Vol 57 (6-7) ◽  
pp. 527-531
Author(s):  
Junho Jeong ◽  
Tina M. Briere ◽  
N. Sahoo ◽  
T. P. Das ◽  
S. Ohira ◽  
...  
Keyword(s):  
Muon Spin ◽  
Hyperfine Interactions ◽  
Rotation Frequency ◽  
Coupling Constants ◽  
Muon Spin Rotation ◽  
Hartree Fock ◽  
Nuclear Quadrupole Interactions ◽  
Quadrupole Coupling ◽  
Nuclear Quadrupole ◽  
Asymmetry Parameters

The nuclear quadrupole coupling constants and asymmetry parameters have been studied for the 35Cl, 17O, and 14N nuclei in the molecular ferromagnet 4-(p-chlorobenzylideneamino)-TEMPO (2,2,6,6-tetramethyl- piperidin-1-yloxyl) using elctronic stuctures obtained by the Hartree-Fock procedure for the bare system and systems with trapped muon and muonium. Trends in the sizes of the coupling constants and asymmetry parameters for the various nuclei have been studied, and possible physical explanations have been proposed. For the systems with trapped muon or muonium, very substantial influences of the muon and muonium on the coupling constants and asymmetry parameters for the nuclei close to the trapping sites have been observed. The coupling constants and asymmetry parameters are found to be very different for the various nuclei, for the two cases where muon is trapped near chlorine and muonium near oxygen, indicating that, if experimental data were available to compare with theory, one could make conclusions about which of these two centers is responsible for the observed muon spin rotation frequency associated with the muon magnetic hyperfine interactions in these two trapped systems

scholarly journals Hydrogen Bond Studies. 125. A Deuteron Magnetic Resonance Study of Strontium Formate Dihydrate, Sr(HCOO)2 · 2D2O

1977 ◽  
Vol 32 (9) ◽  
pp. 1025-1029 ◽  
Author(s):  
Bo Berglund ◽  
Jörgen Tegenfeldt
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Magnetic Resonance ◽  
Electric Field Gradient ◽  
Room Temperature ◽  
Coupling Constants ◽  
Water Molecules ◽  
Magnetic Resonance Study ◽  
Quadrupole Coupling ◽  
Asymmetry Parameters

AbstractA room temperature (25 °C) deuteron magnetic resonance (DMR) study of a single crystal of Sr (HCOO)2 · 2 D2O is reported. Signals from all water molecules in the unit cell have been detected, and all four independent electric field gradient (EFG) tensors at the water deuterons have been determined from 409 quadrupole splittings. All spectra were recorded by rotating the crystal about one arbitrarily selected axis. The following quadrupole coupling constants and asymmetry parameters for the deuterons were obtained: 213.5(4), 189.3(4), 195.7(4) and 200.7(5) kHz and 0.117(3), 0.110(4), 0.116(4) and 0.098(3). The directions of the eigenvalues are qualitatively consistent with the crystal structure refined by Galigné 1; the result is in disagreement, however, with the earlier DMR study of Sr (DCOO)2 · 2 D2O (Reference 2).

14N Quadrupole Cross-Relaxation Spectroscopy of a Compound of Pharmacological Interest

1986 ◽  
Vol 41 (1-2) ◽  
pp. 195-199 ◽  
Author(s):  
P. M. G. Bavin ◽  
D. Stephenson ◽  
J. A. S. Smith
Keyword(s):  
Relaxation Times ◽  
Cross Relaxation ◽  
Coupling Constants ◽  
Relaxation Techniques ◽  
Quadrupole Coupling ◽  
Quadrupole Resonance ◽  
Pharmacological Interest ◽  
Polymorphic Forms ◽  
Spectral Intensities ◽  
Asymmetry Parameters

Cross-relaxation spectroscopy has been used to record the 14N quadrupole resonance spectrum of two of the polymorphic forms of the pharmacologically-important compound: 2-4-(5-Bromo- 3-methylpyrid-2-yl)butylammo-5-(6-methylpyrid-3-yl)methyl-pyrimidin-4-one.Three 14N frequencies for four of the non-equivalent nitrogen sites within the molecule have been identified by combined irradiation and cross-relaxation techniques and quadrupole coupling constants and asymmetry parameters deduced therefrom; the absence of 14N (and 79Br) signals from the bromine-substituted pyridine ring suggests that this part of the molecule is disordered in the crystal. The spectral intensities have been used to derive approximate values for the 14N and 1H relaxation times, which show clear differences between the two polymorphs.

NQR Studies of the Structure of Glasses and Crystalline Compounds

1992 ◽  
Vol 47 (1-2) ◽  
pp. 30-38 ◽  
Author(s):  
P. J. Bray ◽  
DongHoon Lee ◽  
De Gen Mao ◽  
G. L. Petersen ◽  
S. A. Feller ◽  
...  
Keyword(s):  
Nuclear Quadrupole Resonance ◽  
Nmr Spectra ◽  
Coupling Constants ◽  
Borate Glasses ◽  
Low Frequencies ◽  
Structure Of Glasses ◽  
Quadrupole Coupling ◽  
Quadrupole Resonance ◽  
Nuclear Quadrupole ◽  
Asymmetry Parameters

AbstractPure nuclear quadrupole resonance (NQR) spectroscopy at low frequencies (down to 275 kHz) has been used to investigate a number of borate, aluminate, and vanadate crystalline compounds and borate glasses. The values of the quadrupole coupling constants (Qcc) and asymmetry parameters (η) are obtained with error limits that are one or two orders of magnitude less than those for values obtained from NMR spectra. New sites, not resolved in NMR spectra, have been detected for boron in borate glasses.

ChemInform Abstract: Karplus-Type Relationship for Quadrupole Coupling Constants and Asymmetry Parameters for Substituted Acetic Acids.

ChemInform ◽  
1988 ◽  
Vol 19 (18) ◽  
Author(s):  
M. A. JACKISCH ◽  
W. L. JARRETT ◽  
K. GUO ◽  
F. R. FRONCZEK ◽  
L. G. BUTLER
Keyword(s):  
Coupling Constants ◽  
Quadrupole Coupling ◽  
Asymmetry Parameters ◽  
Acetic Acids

High Pressure NQR Study of the Phase Transition in Anilinium Iodide

1986 ◽  
Vol 41 (1-2) ◽  
pp. 290-293
Author(s):  
Mariusz Maćkowiak ◽  
Maria Zdanowska-Fra̧zek ◽  
Piotr Kozioł ◽  
Jan Stankowski ◽  
Alarich Weiss
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Transition Temperature ◽  
Hydrogen Bonds ◽  
Transition Point ◽  
Pressure Coefficient ◽  
Coupling Constants ◽  
Quadrupole Coupling ◽  
Nuclear Quadrupole ◽  
Asymmetry Parameters

The 127I NQR frequency in anilinium iodide C6H5NH3⊕I⊖ was studied at pressures up to 300 MPa and within the temperature range 77 K - 290 K. With increasing pressure the order-disorder transition point Tc is shifted to higher temperatures. The pressure coefficient of the phase transition temperature amounts to dTc/dp = 4.2 x 10-2 deg MPa-1. The pressure coefficient of the NQR frequency is negative. In addition, the 12'I nuclear quadrupole coupling constants and the respective asymmetry parameters η were evaluated as a function of pressure. The results confirm the close connection between the mechanism of the phase transition and the dynamics of the N - H⊕ ...I⊖ hydrogen bonds.

Preliminary Results of a 20 K X-Ray Study of Citrinin

1993 ◽  
Vol 48 (1-2) ◽  
pp. 99-104 ◽  
Author(s):  
R. Destro ◽  
F. Merati
Keyword(s):  
Dipole Moment ◽  
Hydrogen Bonds ◽  
Charge Density ◽  
Topological Analysis ◽  
Coupling Constants ◽  
Molecular Dipole ◽  
X Ray ◽  
A Value ◽  
Quadrupole Coupling ◽  
Asymmetry Parameters

Abstract A total of about 37 000 diffracted intensities has been measured at 20 K for a spherical single crystal of citrinin. Using a multipole formalism to interpret the X-ray data, maps of the charge density and of its Laplacian, as well as for the electrostatic potential have been derived. A value of 7(2) D has been obtained for the magnitude of the molecular dipole moment. A study of the electric field gradient (EFG) at the nuclei has yielded the atomic quadrupole coupling constants (QCC) and asymmetry parameters (η). A topological analysis of the charge density has been performed to characterize the intramolecular covalent and hydrogen bonds.

(CH3)3CCOOSbCl4: Structure Determination by Zeeman Perturbed NQR

1986 ◽  
Vol 41 (1-2) ◽  
pp. 129-133 ◽  
Author(s):  
Maria L. S. Garcia ◽  
Edwin A. C. Lucken
Keyword(s):  
Molecular Structure ◽  
Magnetic Field ◽  
Crystal Structure ◽  
Single Crystal ◽  
Structure Determination ◽  
Organic Ligand ◽  
Coupling Constants ◽  
Zero Field ◽  
Quadrupole Coupling ◽  
Asymmetry Parameters

A single crystal of tetrachloro(0,0-pivaloylato)antimony(V) has been studied at 77 K, byZeeman perturbed 35Cl NQR, using a FT-NQR pulsed spectrometer. The four lines at zero-field, ν1 = 27.6468, ν2= 27.3070, ν3= 25.7341 and ν4= 25.3438 MHz yield eight EFG tensors in themagnetic field, related by a twofold symmetry element in the crystal. The correspondingasymmetry parameters are η1, = 0.134, η2 = 0.13, η3= 0.07, and η4 = 0.09. The molecular structurededuced from the relative orientations of the principal Z-axes of the EFG tensors confirms that thehigher quadrupole coupling constants are associated with the chlorine atoms in equatorial positions,relative to the plane of the organic ligand, as predicted from NQR powder studies. It is concludedthat the crystal structure is monoclinic with two (class m or 2) or four (class 2/m) moleculesper unit cell. The molecular packing is such that the planes formed by equatorial or axial chlorineatoms are approximately at right angles to their symmetry related images.

Experimental Study of Nuclear Electric Quadrupole Splittings of 59Co in Co(NH3)6Cl3

1974 ◽  
Vol 52 (15) ◽  
pp. 1398-1404 ◽  
Author(s):  
E. C. Reynhardt
Keyword(s):  
Experimental Study ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Electric Field Gradient ◽  
Room Temperature ◽  
Electric Quadrupole ◽  
Coupling Constants ◽  
Principal Axes ◽  
Quadrupole Coupling ◽  
Asymmetry Parameters

The nuclear magnetic resonance of 59Co in a single crystal of Co(NH3)6Cl3 has been investigated at room temperature at 15 kG. Observed quadrupolar perturbations have been analyzed by the method of Volkoff for three orthogonal planes to yield five electric field gradient tensors. The cobalt sites associated with these tensors are nonequivalent. The quadrupole coupling constants and asymmetry parameters vary from 1.0 to 17.2 MHz and 0.10 to 0.57 respectively. One of the principal axes of each tensor is found to coincide with the crystallographic b axis of the monoclinic unit cell.

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