Spektroskopische Untersuchungen in der Festkörperchemie, XII* Re-NQR-und 1H-Breitlinien-NMR -Studien an Rhenium(YII)- Sauerstoffverbindungen / Spectroscopic Investigations in Solid State Chemistry, XII* Re NQR and 1H Wideline NMR Studies on Rhenium(VII) Oxygen Compounds

1978 ◽  
Vol 33 (8) ◽  
pp. 896-898 ◽  
Author(s):  
Paul K. Burkert ◽  
Frank M. Hutter
Keyword(s):  
Solid State ◽  
Crystal Field ◽  
Coupling Constants ◽  
Solid State Chemistry ◽  
Nmr Studies ◽  
Electrical Field ◽  
Spectroscopic Investigations ◽  
Octahedral Environment ◽  
Octahedral Crystal Field

The first Re NQR spectra of rhenium oxygen compounds with rhenium atoms in the pseudo-octahedral environment of Re2O7(H2O)2 and Re2O7(H2O)2 · 2(1,4)-dioxane were found. The values of the Re NQR coupling constants of these rhenium atoms are the highest measured until now. They show, that the gradient of the electrical field is much more sensitive to distortions of an octahedral crystal field than to distortions of a tetrahedral field.

Spekktroskopische Untersuchungen in der Festkörperchemie, IX / Spectroscopic Investigations in the Solid-State Chemistry, IX

1975 ◽  
Vol 30 (3-4) ◽  
pp. 198-201 ◽  
Author(s):  
Paul K. Burkert ◽  
Frank Hutter ◽  
Detlev Koth
Keyword(s):  
Solid State ◽  
Temperature Dependence ◽  
Temperature Coefficient ◽  
Asymmetry Parameter ◽  
Lattice Parameters ◽  
Coupling Constants ◽  
Solid State Chemistry ◽  
Spectroscopic Investigations ◽  
Experimental Correlation ◽  
The Absolute

The four 185Re, 187Re—NQR-transitions of RbReO4 were measured. From the NQR-coupling constants, asymmetry-parameter and normal temperature-coefficient in the range of 77-300°K one can conclude, that the anomalons temperature dependence of the NQR-frequencies of NH4ReO4 is not caused by the absolute values of certain lattice parameters.An experimental correlation of the Re—NQR-coupling constants of scheelite-structured perrhenates with the length of the elementar cell was found and discussed.

Spektroskopische Untersuchungen in der Festkörperchemie, XI 127I-NQR-Untersuchungen an Perjodaten / Spectroscopic Investigations in the Solid State Chemistry, XI 127I NQR Investigations on Periodates

1977 ◽  
Vol 32 (1) ◽  
pp. 15-17 ◽  
Author(s):  
Paul K. Burkert ◽  
Frank M. Hutter
Keyword(s):  
Solid State ◽  
Unit Cell ◽  
Coupling Constants ◽  
Solid State Chemistry ◽  
Spectroscopic Investigations

A number of periodates show 127I NQR transitions. The correlation of the NQR coupling constants with the length of the unit cell was compared with the results of NQR measurements on perrhenates.

Spektroskopische Untersuchungen in der Festkörperchemie, X Re–NQR-Untersuchungen an TlReO4 und LiReO4 · 2 H2O / Spectroscopic Investigations in the Solid State Chemistry, X Re-NQR Investigations on TlReO4 and LiReO4 · 2 H2O

1976 ◽  
Vol 31 (2) ◽  
pp. 145-148 ◽  
Author(s):  
Paul K. Burkert ◽  
Frank M. Hutter
Keyword(s):  
Solid State ◽  
Solid State Chemistry ◽  
Scheelite Structure ◽  
Temperature Range ◽  
Temperature Coefficients ◽  
Spectroscopic Investigations ◽  
Asymmetry Parameters

The 187Re–NQR transitions of TlReO4 and their temperature dependencies were measured. In the temperature range, in which TlReO4 is crystallizing in pseudo scheelite structure, one obtains normal temperature coefficients with asymmetry parameters η = 0.3. For Τ < 200 Κ, however, another modification with η = 0 was found.For LiReO4 • 2 H2O complex 187Re and 185Re NQR spectra with 16 transition frequencies were measured and discussed.

Solid State NMR Measurements for Preliminary Lifetime Assessments in λ-Irradiated and Thermally Aged Siloxane Elastomers

2004 ◽  
Vol 851 ◽  
Author(s):  
Sarah C. Chinn ◽  
Julie L. Herberg ◽  
April M. Sawvel ◽  
Robert S. Maxwell
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Solid State ◽  
Magnetic Resonance ◽  
Coupling Constants ◽  
Screening Tools ◽  
Engineering Properties ◽  
Relaxation Rates ◽  
Nmr Studies ◽  
Wide Range ◽  
Nuclear Magnetic

ABSTRACTSiloxanes have a wide variety of applications throughout the aerospace industry which take advantage of their exceptional insulating and adhesive properties and general resilience. They also offer a wide range of tailorable engineering properties with changes in composition and filler content. They are, however, subject to degradation in radiatively and thermally harsh environments. We are using solid state nuclear magnetic resonance techniques to investigate changes in network and interfacial structure in siloxane elastomers and their correlations to changes in engineering performance in a series of degraded materials. Nuclear magnetic resonance (NMR) parameters such as transverse (T2) relaxation times, cross relaxation rates, and residual dipolar coupling constants provide excellent probes of changes crosslink density and motional dynamics of the polymers caused by multi-mechanism degradation. The results of NMR studies on aged siloxanes are being used in conjunction with other mechanical tests to provide insight into component failure and degradation kinetics necessary for preliminary lifetime assessments of these materials as well as into the structure-property relationships of the polymers. NMR and magnetic resonance imaging (MRI) results obtained both from high resolution NMR spectrometers as well as low resolution benchtop NMR screening tools will be presented.

SOLID-STATE 13C AND 45Sc NMR STUDIES ON ENDOHEDRAL SCANDIUM-CARBIDE METALLOFULLERENES: A MOTIONAL DYNAMICS OF Sc ATOMS IN FULLERENES

NANO ◽  
2008 ◽  
Vol 03 (01) ◽  
pp. 21-25 ◽  
Author(s):  
HARUYA OKIMOTO ◽  
WILHELM HEMME ◽  
YASUHIRO ITO ◽  
TOSHIKI SUGAI ◽  
RYO KITAURA ◽  
...  
Keyword(s):  
Activation Energy ◽  
Solid State ◽  
Crystal Field ◽  
Absorption Spectroscopy ◽  
Nmr Studies ◽  
Field Effects ◽  
Nir Absorption ◽  
Motional Dynamics

Sc 2 C 2@ C 82( II ) and Sc 2 C 2@ C 82( III ) have been synthesized and chromatographically isolated and characterized by using UV-Vis-NIR absorption spectroscopy. Solid-state 13 C and 45 Sc NMR on Sc 2 C 2@ C 82 metallofullerenes provide the rotational activation energy of Sc atoms encapsulated in C 82 fullerenes which is lower than that in solution due to crystal field effects on the rate of the rotation.

scholarly journals Oxygen-17 NMR spectroscopy of water molecules in solid hydrates

2016 ◽  
Vol 94 (3) ◽  
pp. 189-197 ◽  
Author(s):  
Sherif Nour ◽  
Cory M. Widdifield ◽  
Libor Kobera ◽  
Kevin M. N. Burgess ◽  
Dylan Errulat ◽  
...  
Keyword(s):  
Solid State ◽  
Chemical Shift ◽  
Density Functional ◽  
Chemical Shifts ◽  
Sodium Perchlorate ◽  
Coupling Constants ◽  
Water Molecules ◽  
Potassium Oxalate ◽  
Nmr Studies ◽  
Quadrupolar Coupling

17O solid-state NMR studies of waters of hydration in crystalline solids are presented. The 17O quadrupolar coupling and chemical shift (CS) tensors, and their relative orientations, are measured experimentally at room temperature for α-oxalic acid dihydrate, barium chlorate monohydrate, lithium sulfate monohydrate, potassium oxalate monohydrate, and sodium perchlorate monohydrate. The 17O quadrupolar coupling constants (CQ) range from 6.6 to 7.35 MHz and the isotropic chemical shifts range from –17 to 19.7 ppm. The oxygen CS tensor spans vary from 25 to 78 ppm. These represent the first complete CS and electric field gradient tensor measurements for water coordinated to metals in the solid state. Gauge-including projector-augmented wave density functional theory calculations overestimate the values of CQ, likely due to librational dynamics of the water molecules. Computed CS tensors only qualitatively match the experimental data. The lack of strong correlations between the experimental and computed data, and between these data and any single structural feature, is attributed to motion of the water molecules and to the relatively small overall range in the NMR parameters relative to their measurement precision. Nevertheless, the isotropic chemical shift, quadrupolar coupling constant, and CS tensor span clearly differentiate between the samples studied and establish a ‘fingerprint’ 17O spectral region for water coordinated to metals in solids.

NMR-Untersuchungen an Organoelement(IVb)-phosphinen, VII [1] 119Sn-NMR-Untersuchungen an Trimethylstannylphosphin-substituierten Verbindungen der Pseudonickelcarbonylserie/NMR Studies on Organoelement(IVb)-phosphines, VII [1] 119Sn NMR Spectroscopic Investigations on Trimethylstannylphosphine Substituted Compounds of the Pseudonickelcarbonyl Series

1981 ◽  
Vol 36 (8) ◽  
pp. 904-906 ◽  
Author(s):  
Manfred Meißner ◽  
Heinz-Jürgen Kroth ◽  
Karl-Heinz Köhricht ◽  
Herbert Schumann
Keyword(s):  
Chemical Shifts ◽  
Coupling Constants ◽  
Nmr Studies ◽  
Nmr Chemical Shifts ◽  
Spectroscopic Investigations ◽  
119Sn Nmr

Abstract119Sn NMR chemical shifts as well as 1H119Sn and 31P 119Sn NMR coupling constants are reported and discussed for compounds of the type [(CH3)3Sn]n[tC4H9]3-n P (n = 1, 2, 3) and related complexes Mn(NO)3L, Fe(CO)(NO)2L, Co(CO)2(NO)L and Ni(CO)3 L (L = organotin phosphine).

scholarly journals Temperature Dependence of the 127I Quadrupole Coupling in Periodates with Alkyl- or Aryl-Substituted Cations of Main Group V

1986 ◽  
Vol 41 (1-2) ◽  
pp. 330-334 ◽  
Author(s):  
Dagmar G. Klobasa ◽  
Paul K. Burkert ◽  
Gerhard Müller
Keyword(s):  
Solid State ◽  
Solid State Nmr ◽  
Main Group ◽  
Coupling Constants ◽  
Positive Temperature ◽  
Nmr Studies ◽  
Group V ◽  
Temperature Coefficients ◽  
Quadrupole Coupling ◽  
Temperature Dependences

127I solid state NMR studies of metaperiodates with alkyl- or aryl-substituted cations of main group V revealed second order quadrupole effects with quadrupole coupling constants in the range of 2 - 7 MHz.In (C2H5)4PIO4 and (C2H5)4AsIO4 the 127I quadrupole coupling constants show normal temperature coefficients ᾱ in the order of -10-4 K-1 for 186 K < T < 300 K.For the metaperiodates with aryl-substituted cations (C6H5)4P+, (C6H5)4As+ and (C6H5)4Sb+ complicated temperature dependences of the 127I quadrupole interaction with phase transitions and anomalous positive temperature coefficients +0.2 · 10-2K-1 ≦ ᾱ ≦ +0.8 · 10-2K-1 were observed.The relevance of possible mechanisms for the anomalous temperature coefficients, like breakdown of dη - pη backbonding, negative pressure coefficients, charge transfer, orientational change of the EFG-tensor axes system and influence of reorientational motions is discussed for these compounds, including results from an X-ray investigation of (C6H5)4AsIO4 and 1H-solid state NMR measurements.

Solid-state 45Sc NMR studies of Cp*2Sc–X and Cp*2ScX(THF)

2018 ◽  
Vol 47 (37) ◽  
pp. 13063-13071 ◽  
Author(s):  
Winn Huynh ◽  
Damien B. Culver ◽  
Hosein Tafazolian ◽  
Matthew P. Conley
Keyword(s):  
Solid State ◽  
Systematic Study ◽  
Coupling Constants ◽  
Nmr Studies ◽  
Quadrupolar Coupling

A systematic study showing how the Sc–X bond affects solid-state 45Sc NMR quadrupolar coupling constants in Cp*2Sc–X.

Sign in / Sign up

Export Citation Format

Share Document