NMR investigation of spin transfer to H in K2CuCl4∙2H2O

1983 ◽  
Vol 61 (12) ◽  
pp. 1627-1632 ◽  
Author(s):  
Tae Jong Han ◽  
Sung Ho Choh
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Hyperfine Interaction ◽  
Temperature Dependence ◽  
Exchange Interaction ◽  
Room Temperature ◽  
Copper Ion ◽  
Spin Transfer ◽  
Temperature Dependent ◽  
Super Exchange Interaction

Nuclear magnetic resonance of 1H in K2CuCl4∙2H2O has been measured with frequencies of 3 to 35 MHz at room temperature, 163, and 77 K. The fractional spin transfer from the copper ion to hydrogen due to the transferred hyperfine interaction is analyzed: 0.19 ± 0.03% at 300 K, 0.23 ± 0.02% at 163 K, and 0.27 ± 0.02% at 77 K, showing that the spin transfer is temperature dependent. This temperature dependence is closely associated with the unusually strong temperature dependent super-exchange interaction between Cu2+ ions in this crystal.

Nuclear-magnetic-resonance study of spin transfer to H in Rb2CuCl4∙2H2O and Rb2CuBr4∙2H2O

1985 ◽  
Vol 63 (7) ◽  
pp. 946-950 ◽  
Author(s):  
Nam Doo Moon ◽  
Kyunghee Lee ◽  
Sung Ho Choh
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Bond Strength ◽  
Room Temperature ◽  
Copper Ion ◽  
Nuclear Magnetic Resonance Study ◽  
Spin Transfer ◽  
Magnetic Resonance Study ◽  
Temperature Dependent ◽  
Nuclear Magnetic

The nuclear magnetic resonance of 1H in Rb2CuCl4∙2H2O and isomorphic Rb2CuBr4∙2H2O has been measured at room temperature, near 165, and 77 K. The fractional spin transfer from the copper ion to hydrogen due to the transferred hyperfine interaction is analyzed: 0.22 ± 0.03% at 300 K, 0.25 ± 0.02% at 168 K, and 0.29 ± 0.02% at 77 K in Rb2CuCl4∙2H2O; and 0.22 ± 0.03% at 300 K, 0.28 ± 0.02% at 163 K, and 0.32 ± 0.02% at 77 K in Rb2CuBr4∙2H2O. The temperature-dependent spin transfers are discussed in terms of the molecular mass and the bond strength of the two compounds.

Nuclear Magnetic Resonance Studies of K2CuCl4·2H2O

1971 ◽  
Vol 49 (1) ◽  
pp. 144-154 ◽  
Author(s):  
Sung Ho Choh ◽  
C. V. Stager
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Temperature Dependence ◽  
Room Temperature ◽  
Zeeman Splitting ◽  
Torsional Motion ◽  
Model Calculations ◽  
Quadrupole Coupling ◽  
Quadrupole Parameters ◽  
Nuclear Magnetic

Nuclear magnetic resonance of 35Cl in paramagnetic K2CuCl4∙2H2O has been investigated in single crystal samples at several different temperatures from 340 °K down to 4.2 °K. Zeeman splitting studies yield the two quadrupole coupling and transferred hyperfine tensors which correspond to the two inequivalent Cl ions. The quadrupole parameters at room temperature are (e2qQ/h)I = 19.05 ± 0.02 MHz, ηI = 0.183 ± 0.001 and (e2qQ/h)II = 3.262 ± 0.006 MHz, ηII = 0.945 ± 0.003. The nuclear magnetic resonance of 39K has also been investigated at room temperature. The quadrupole parameters are e2qQ/h = 0.1032 ± 0.0004 MHz and η = 0.00. The quadrupole coupling tensors for 35Cl and 39K are compared with various model calculations. The temperature dependence of the quadrupole parameters for both Cl(I) and Cl (II) can be explained by introducing a single molecular torsional motion of the rigid (CuCl4∙2H2O)2− anion. The torsional motion has an angular frequency of ~3 × 1012 rad/s around the Cu—Cl(I) bond axis. This low frequency vibration might also be involved with the anomalous temperature dependence of Cu2+ electron spin resonance previously observed in this salt.

Stereochemistry of Hexahydrocarbazoles; the Temperature-dependent Nuclear Magnetic Resonance Spectra of N-Acetyl Derivatives

1971 ◽  
Vol 49 (10) ◽  
pp. 1638-1643 ◽  
Author(s):  
Stewart McLean ◽  
U. O. Trotz ◽  
C. J. MacDonald ◽  
W. F. Reynolds ◽  
D. J. Wood
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Temperature Dependence ◽  
Ring System ◽  
Rotational Isomerism ◽  
Conformational Mobility ◽  
Temperature Dependent ◽  
Nuclear Magnetic Resonance Spectra ◽  
Acetyl Group ◽  
Cis And Trans

The configuration of certain substituted hexahydrocarbazoles 2, of significance in connection with earlier work, has been established. A study of the temperature dependence of the n.m.r. spectra of N-acetyl derivatives, initiated with the intention of distinguishing between cis- and trans-fused isomers, has led to the conclusion that the distinction could not be made on this basis since all of the temperature-dependent phenomena, even in cases where the cis-fusion had been established by other means, could be associated with rotational isomerism of the N-acetyl group and no observable effects in the temperature range studied could be related to conformational mobility of the ring system. Nevertheless, the results obtained provide information of value and interest regarding the stereochemistry of hexahydrocarbazoles.

ChemInform Abstract: Quantum Discord in Nuclear Magnetic Resonance Systems at Room Temperature

ChemInform ◽  
2013 ◽  
Vol 44 (9) ◽  
pp. no-no
Author(s):  
J. Maziero ◽  
R. Auccaise ◽  
L. C. Celeri ◽  
D. O. Soares-Pinto ◽  
E. R. deAzevedo ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Quantum Discord ◽  
Room Temperature ◽  
Nuclear Magnetic

Nuclear magnetic resonance studies. III. Rotational isomerism of some C-glucosylflavonoid acetates

1965 ◽  
Vol 18 (5) ◽  
pp. 715 ◽  
Author(s):  
RA Eade ◽  
WE Hillis ◽  
DHS Horn ◽  
JJH Simes
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Steric Hindrance ◽  
Chemical Shifts ◽  
Rotational Isomerism ◽  
Bulky Substituent ◽  
Temperature Dependent ◽  
Magnetic Resonance Studies ◽  
Rotational Isomers ◽  
Nuclear Magnetic

The temperature-dependent variations in the spectra of certain C-glucosyl-flavonoid acetates are attributed to the effect of steric hindrance of bulky substituent groups of the sugar and aromatic moieties on the rate of interconversion of the two rotational isomers present. The differences in the chemical shifts of the protons of the two isomers are attributed to differences in the orientation and position of the acetyl and phenyl groups.

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