The C—CI Bonds in α -2,4,6-tris(trichIoromethyl)-1,3,5-trioxane, α -Parachloral, (Cl3CCHO)3. A 35Cl-NQR Single Crystal Study

1985 ◽  
Vol 40 (4) ◽  
pp. 324-334 ◽  
Author(s):  
Masao Hashimoto ◽  
Norbert Weiden ◽  
Alarich Weiss
Keyword(s):  
Single Crystal ◽  
Coupling Constants ◽  
X Ray Diffraction ◽  
X Ray ◽  
Principal Axes ◽  
Quadrupole Coupling ◽  
35Cl Nqr ◽  
Single Crystal Study ◽  
Nuclear Quadrupole ◽  
Asymmetry Parameters

By single crystal 35C1-NQR Zeeman spectroscopy, the five independent 35Cl nuclear quadrupole coupling tensors in a-parachloral, (Cl3CCHO)3, have been studied at 24 ± 2 °C. The directions of the electric field gradient (EFG) tensor components have been determined. The principal axes Φ are within ± 0.8° parallel to the C-Cl bond directions found by X-ray diffraction. Very small asymmetry parameters in the range 0.002 ≦ η ≦ 0.046 are characteristic for the EFG tensors of chlorine atoms bound to carbon atoms in aliphatic systems. The five nuclear quadrupole coupling constants are in the range 76.752 ≦ e2qQh-1/MRz ≦ 78.155. The orientation of the principal axes Φxx and Φyy can be correlated to the molecular structure.

scholarly journals Crystal Structure Refinement and Single Crystal 81Br Zeeman NQR Study of KHgBr3· H2O

1996 ◽  
Vol 51 (12) ◽  
pp. 1197-1202 ◽  
Author(s):  
Hiromitu Terao ◽  
Tsutomu Okuda ◽  
Sachiyo Uyama ◽  
Hisao Negita ◽  
Shi-qi Dou ◽  
...  
Keyword(s):  
Single Crystal ◽  
Room Temperature ◽  
Structure Refinement ◽  
Zeeman Effect ◽  
Coupling Constants ◽  
X Ray ◽  
Quadrupole Coupling ◽  
Nuclear Quadrupole ◽  
Asymmetry Parameters ◽  
Good Agreement

Abstract Three 81Br NQR resonance lines of KHgBr3 ·H2O were detected between 77 K and room temperature. From the Zeeman effect measurement on a single crystal the nuclear quadrupole coupling constants (e2qQ/h) and the asymmetry parameters (ƞ) were obtained, which are 228.42 MHz and 0.005, 226.24 MHz and 0.005, and 108.76 MHz and 0.465 for e2qQ/h and ƞ at 295 K, respectively. Large deviations of the observed directions of electric field gradient tensors from the directions expected from previous X-ray results have been found. With the present X-ray redetermination, 81Br NQR and structure are in good agreement. The structure and bonding in the compound are discussed.

NUCLEAR MAGNETIC RESONANCE SPECTRUM OF B11 IN KERNITE

1955 ◽  
Vol 33 (5) ◽  
pp. 156-175 ◽  
Author(s):  
H. H. Waterman ◽  
G. M. Volkoff
Keyword(s):  
Magnetic Field ◽  
Coupling Constants ◽  
Monoclinic Crystal ◽  
X Ray ◽  
Principal Axes ◽  
Quadrupole Coupling ◽  
Radio Frequency Spectrum ◽  
Asymmetry Parameters ◽  
Crystallographic Axes ◽  
The Magnetic Field

The radio-frequency spectrum of B11 in a single crystal of Na2B4O7∙4H2O (kernite) is examined experimentally as the monoclinic crystal is rotated in an external magnetic field of 7060 gauss in turn about each of three axes (b, c crystallographic axes, and a third perpendicular direction) held normal to the magnetic field. A maximum of 21 lines (some of which show small additional splitting) is observed, which reduces to 11 when the b symmetry axis is perpendicular or parallel to the magnetic field. The results are interpreted in terms of four essentially non-equivalent B11 sites in kernite characterized respectively by quadrupole coupling constants [Formula: see text], 0.588 ± 0.003, 2.563 ± 0.007, 2.567 ± 0.010 Mc./sec, and asymmetry parameters 77 [Formula: see text], 0.60 ± 0.02, 0.163 ± 0.010, 0.116 ± 0.010. The orientations of the principal axes of the four [Formula: see text] tensors are also determined. These observations on boron are consistent with previous X-ray results, but preliminary observations on Na23 in kernite contradict previous X-ray position assignments.

scholarly journals The Bond Sn-Cl in SnIV Complex Salts A2 [(C2H5 )SnCl 5]. A Single Crystal 35Cl NQR Study of Bis(methylammonium)- pentachloroethylstannate, (CH3NH3 )2](C2H5 )SnCl5]

1990 ◽  
Vol 45 (3-4) ◽  
pp. 229-236 ◽  
Author(s):  
Peter Storck ◽  
Norbert Weiden ◽  
Alarich Weiss
Keyword(s):  
Single Crystal ◽  
Charge Distribution ◽  
Coupling Constants ◽  
General Tendency ◽  
Quadrupole Coupling ◽  
35Cl Nqr ◽  
Complex Salts ◽  
The Asymmetry ◽  
Asymmetry Parameters

AbstractZeeman 35Cl NQR spectroscopy has been applied to determine the magnitude and orientation of the EFG tensors at the chlorine sites in a single crystal of(CH3NH3)2[(C2H5)SnCl5] at 293 K. The assignment of the NQR frequencies vi(35Cl), the corresponding quadrupole coupling constants eQΦ(i)zz h-1 , and the asymmetry parameters ηi(35Cl) to certain Cl(k) atoms is discussed. The most probable assignment is (no. i of vi(35Cl), vi(35Cl)/MHz, eQΦ(i)zz h-1 / MHz ηi, (35Cl), no. k of assigned Cl(k), d(Sn-Cl(k) )/pm, ∢ (Φ(i)zz , d(Sn-Cl(k) )) :i = 1,17.032, 34.046,0.056, k= 1, 242.6, 3.1°; i = 2, 12.072, 24.089, 0.117, k = 3, 250.7, 1.9°; i = 3, 11.537, 22.992, 0.146, k = 2, 253.1, 2.8°; i = 4, 10.770, 21.455, 0.154, k = 4, 249.7, 2.9 °; i = 5,9.969,19.842,0.171, k=5,254.9,1.7°. The orientation of the tensor axes Φ(i)jj , j = x, y, z,i= 1 - 5 , in space is mainly determined by the geometry of the [(C2H5)SnCl5]2⊖ anion. The Φ(i)zz are nearly parallel to the assigned bond directions Sn-Cl(k) · η (35CI) is low, increasing with decreasing v(35Cl). The reason for the asymmetry seems not to be a π-character in the Sn-Cl bond, but the charge distribution within the anion. The rule that a longer bond corresponds to a lower NQR frequency is valid as a general tendency, but not strict.

Nuclear Quadrupole Coupling Tensors of 2H in the a-Alum RbAl(SO4)2 · 12D2O and the Dynamical Behaviour of the D2O Molecules. An Investigation by NMR and IR

1990 ◽  
Vol 45 (3-4) ◽  
pp. 511-518 ◽  
Author(s):  
J. Ramakrishna ◽  
Norbert Weiden ◽  
Alarich Weiss
Keyword(s):  
Ir Spectra ◽  
Time Scale ◽  
Nuclear Quadrupole Interaction ◽  
Dynamical Behaviour ◽  
Coupling Constants ◽  
Principal Axes ◽  
Quadrupole Coupling ◽  
Direction Cosines ◽  
Nuclear Quadrupole ◽  
Asymmetry Parameters

AbstractBy single crystal NMR the nuclear quadrupole coupling constants eQΦzz h-1 (2H), the asymmetry parameters η(2H) and the direction cosines of the principal axes of the electric field gradient tensors of the 2H atoms of the two kinds of D2O molecules have been determined at 295 K in RbAl(SO4)2 · 12D2O. The results show that the D2O molecules surrounding the ion Al3+ are “static” within the time scale of the 2H nuclear quadrupole interaction while the D2O belonging to the octahedron around the Rb+ undergoes fast reorientations around the twofold molecular axis. For the two kinds of D2O in the alum we found: eQΦzz(1)h-1 (2H) = 186.5 kHz, η(1),(2H) = 0.1234; eQΦzz(2)h-1 (2H) = 169.7 kHz,η (2)(2H) = 0.1297; eQΦzz(3)h-1(2H) = 122.1 kHz, (2H) = 0.8087. eQΦzz(1) and eQΦzz(2) belong to the "static" D2O molecules and an assignment to the two different 2H atoms has been performed. The IR spectra of RbAl(SO4)2 · 12(H1-xDx)2O have been investigated, and for the O - D stretching frequencies values of 2145 cm-1 , 2235 cm-1 , 2470 cm-1 and 2525 cm -1 have been obtained. They agree well with the relations between ṽOD and eQΦzz h-1(2H) given in the literature.

Single-crystal study of the m = 2 tubular cobalt oxide, Bi4Sr12Co8O30−δ

2002 ◽  
Vol 58 (2) ◽  
pp. 191-197 ◽  
Author(s):  
O. Perez ◽  
A. C. Masset ◽  
H. Leligny ◽  
G. Baldinozzi ◽  
D. Pelloquin ◽  
...  
Keyword(s):  
Single Crystal ◽  
Cobalt Oxide ◽  
Accurate Description ◽  
Orthorhombic Symmetry ◽  
X Ray Diffraction ◽  
X Ray ◽  
Single Crystal Study

The structure of the m = 2 tubular compound Bi4Sr12Co8O30−δ, bismuth strontium cobalt oxide, was determined by single-crystal X-ray diffraction. This phase of orthorhombic symmetry exhibits a very strong tetragonal pseudosymmetry. The structure consists of 90°-oriented Bi2Sr2CoO6+δ slices, four Co atoms wide, forming [Sr4Co4O13]∞ pillars at their intersection. The Co atoms in these pillars form four corner-sharing CoO5 bipyramids. In the resulting [Co4O13] cluster, an anionic disorder is evidenced and discussed. Then, an accurate description of the particular structure of the pillars is given. Finally, a comparison with the Mn tubular compound Bi3.6Sr12.4Mn8O30−δ is carried out.

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

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.

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.

A cyanide-bridged FeIII–MnII heterobimetallic one-dimensional coordination polymer: synthesis, crystal structure, experimental and theoretical magnetism investigation

2019 ◽  
Vol 75 (11) ◽  
pp. 1475-1481 ◽  
Author(s):  
Wenlong Lan ◽  
Zhen Zhou ◽  
Jie Li ◽  
Yong Dou ◽  
Xiaoyun Hao ◽  
...  
Keyword(s):  
Coordination Polymer ◽  
Single Crystal ◽  
Density Functional ◽  
Linear Chain ◽  
Coupling Constants ◽  
Antiferromagnetic Coupling ◽  
Chain Model ◽  
X Ray Diffraction ◽  
One Dimensional ◽  
X Ray

A new cyanide-bridged FeIII–MnII heterobimetallic coordination polymer (CP), namely catena-poly[[[N,N′-(1,2-phenylene)bis(pyridine-2-carboxamidato)-κ4 N,N′,N′′,N′′′]iron(III)]-μ-cyanido-κ2 C:N-[bis(4,4′-bipyridine-κN)bis(methanol-κO)manganese(II)]-μ-cyanido-κ2 N:C], {[FeMn(C18H12N4O2)(CN)2(C10H8N2)2(CH3OH)2]ClO4} n , (1), was prepared by the self-assembly of the trans-dicyanidoiron(III)-containing building block [Fe(bpb)(CN)2]− [bpb2− = N,N′-(1,2-phenylene)bis(pyridine-2-carboxamidate)], [Mn(ClO4)2]·6H2O and 4,4′-bipyridine, and was structurally characterized by elemental analysis, IR spectroscopy, single-crystal X-ray crystallography and powder X-ray diffraction (PXRD). Single-crystal X-ray diffraction analysis shows that CP 1 possesses a cationic linear chain structure consisting of alternating cyanide-bridged Fe–Mn units, with free perchlorate as the charge-balancing anion, which can be further extended into a two-dimensional supramolecular sheet structure via inter-chain π–π interactions between the 4,4′-bipyridine ligands. Within the chain, each MnII ion is six-coordinated by an N6 unit and is involved in a slightly distorted octahedral coordination geometry. Investigation of the magnetic properties of 1 reveals an antiferromagnetic coupling between the cyanide-bridged FeIII and MnII ions. A best fit of the magnetic susceptibility based on the one-dimensional alternating chain model leads to the magnetic coupling constants J 1 = −1.35 and J 2 = −1.05 cm−1, and the antiferromagnetic coupling was further confirmed by spin Hamiltonian-based density functional theoretical (DFT) calculations.

Sign in / Sign up

Export Citation Format

Share Document