Proton and carbon-13 NMR studies of electron spin delocalization in nickel(II) bis(alkyl xanthate) complexes of nitrogenous bases and comparison with nickel-nitroxyl interactions in analogous spin-labeled complexes

1989 ◽  
Vol 28 (25) ◽  
pp. 4496-4499 ◽  
Author(s):  
Scott K. Sheppard ◽  
Gareth R. Eaton ◽  
Sandra S. Eaton
Keyword(s):  
Electron Spin ◽  
Nmr Studies ◽  
Spin Delocalization

A comparison of electron spin resonance α- and β-hyperfine coupling constants in para-substituted α-phenethyl radicals

1986 ◽  
Vol 64 (4) ◽  
pp. 769-772 ◽  
Author(s):  
Donald R. Arnold ◽  
A. Martin de P. Nicholas ◽  
Kent M. Young
Keyword(s):  
Electron Spin Resonance ◽  
Experimental Evidence ◽  
Linear Relationship ◽  
Electron Spin ◽  
Hyperfine Coupling ◽  
Coupling Constants ◽  
Hyperfine Coupling Constants ◽  
Spin Resonance ◽  
Benzyl Radicals ◽  
Spin Delocalization

The linear relationship between the electron spin resonance hyperfine coupling constants (hfc) of the α- and β-hydrogens of para-substituted α-phenethyl radicals provides experimental evidence that the magnitude of both the α- and β -hfc is determined largely by the extent of spin delocalization in these benzylic systems. The [Formula: see text] scale, developed using substituted benzyl radicals, is shown to apply to phenethyl radicals as well.

scholarly journals Optically Pumped NMR Studies of Electron Spin Polarization and Dynamics: New Constraints on the Composite Fermion Description ofν=1/2

1999 ◽  
Vol 83 (24) ◽  
pp. 5074-5077 ◽  
Author(s):  
A. E. Dementyev ◽  
N. N. Kuzma ◽  
P. Khandelwal ◽  
S. E. Barrett ◽  
L. N. Pfeiffer ◽  
...  
Keyword(s):  
Spin Polarization ◽  
Electron Spin ◽  
Electron Spin Polarization ◽  
Composite Fermion ◽  
Optically Pumped ◽  
Nmr Studies ◽  
Optically Pumped Nmr

2H and 195 Pt NMR Studies of Molecular and Electron Spin Dynamics in Paramagnetic [Cu(H2O)6][PtCl 6]

1998 ◽  
Vol 53 (6-7) ◽  
pp. 447-452
Author(s):  
Takahiro Iijima ◽  
Kengo Orii ◽  
Motohiro Mizuno ◽  
Masahiko Suhara
Keyword(s):  
Activation Energy ◽  
Electron Spin ◽  
Nmr Spectra ◽  
Chemical Shift Anisotropy ◽  
Spin Lattice Relaxation ◽  
Water Molecules ◽  
Temperature Phase ◽  
Nmr Studies ◽  
Teller Distortion ◽  
Exponential Factor

Abstract The temperature dependences of 2H and 195Pt NMR spectra and the spin-lattice relaxation time T1 were measured for [Cu(H2O)6][PtCl6]. From the simulation of 2H NMR spectra, the jump rate of 180° flips of the water molecules (k), the nuclear quadrupole interaction parameters (e2Qq/h, ƞ) and the electron-nucleon dipolar interaction parameter (vD) were obtained. By measuring 2H T1, k was estimated in the temperature range where the spectrum is insensitive to the motion of the water molecules. Above the phase transition temperature, the pre-exponential factor k0 = 8 x1011 s-1 and the activation energy Ea = 15 kJmol-1 for 180° flips of the water molecules were obtained from the spectral simulation and T1. 195Pt NMR spectra showed an axially symmetric and unsymmetric powder pattern of the chemical shift anisotropy at the high and low temperature phase, respectively. For the deuterated compound, the correlation times of the electron spin in Cu2+ were estimated from 195Pt T1 and the activation energy for jumping between the different configurations of Jahn-Teller distortion Δ = 200 K was obtained.

Electron Spin Delocalization in Feast-Type (Durham Route) Polyacetylene: Pulsed ENDOR Investigations

1987 ◽  
Vol 4 (8) ◽  
pp. 947-951 ◽  
Author(s):  
H Käss ◽  
P Höfer ◽  
A Grupp ◽  
P. K Kahol ◽  
R Weizenhöfer ◽  
...  
Keyword(s):  
Electron Spin ◽  
Spin Delocalization

Solid state high resolution nmr studies of electron spin densities in charge-transfer complex-based organic ferromagnets

1999 ◽  
Vol 103 (1-3) ◽  
pp. 2333-2334 ◽  
Author(s):  
Goro Maruta ◽  
Sadamu Takeda ◽  
Kizashi Yamaguchi ◽  
Kazumasa Ueda ◽  
Toyonari Sugimoto
Keyword(s):  
Charge Transfer ◽  
Solid State ◽  
High Resolution ◽  
Electron Spin ◽  
Charge Transfer Complex ◽  
Nmr Studies ◽  
High Resolution Nmr ◽  
Organic Ferromagnets ◽  
Spin Densities

Nuclear magnetic resonance studies of Lewis acid-base interaction. I. Base adducts of Bis(ethylxanthato)nickel(II)

1974 ◽  
Vol 27 (1) ◽  
pp. 213 ◽  
Author(s):  
Yau Yan. Lim
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Lewis Acid ◽  
Electron Spin ◽  
Equilibrium Constants ◽  
Acid Base ◽  
Base Interaction ◽  
Magnetic Resonance Studies ◽  
Spin Delocalization ◽  
Acid Base Interaction

The interaction between bis(ethylxanthato)nickel(11) and pyridine and 4-picoline in nitrobenzene was studied by N.M.R. spectroscopy at 34�C. The 1 : 2 equilibrium constants and proton n.m.r, isotropic contact shifts were obtained. The electron spin delocalization mechanism in the 1 : 2 adduct was discussed.

Substituent effects on benzyl radical hydrogen hyperfine coupling constants (hfc's).: Part 5. The comparison of electron spin resonance hfc's and the stabilization energy of π-radicals due to spin delocalization

1986 ◽  
Vol 64 (2) ◽  
pp. 270-276 ◽  
Author(s):  
A. Martin de P. Nicholas ◽  
Donald R. Arnold
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Substituent Effects ◽  
Energy Scale ◽  
Spin Systems ◽  
Stabilization Energy ◽  
Coupling Constants ◽  
Spin Resonance ◽  
Benzyl Radicals ◽  
Spin Delocalization

Electron spin resonance (esr) hfc values of π-radicals are found to be linearly related to the stabilization energy due to spin delocalization. Application of this relationship to benzyl radicals permits the representation of σ•α values on an energy scale. Mulliken charges in the α- and β-spin systems are found to provide valuable information about factors governing the effects of substituents on spin delocalization in benzyl radicals. These effects can be rationalized by considering four types of spin–spin interactions involving σ- and π-electrons in the α- and β-spin systems. The Mulliken analysis shows that all substituents are stronger π α-acceptors (or weaker π α-donors) at the para position relative to the meta position. Similarly, in the 3 system the meta derivatives are the better acceptors. This may be understood in terms of the excess of π α-spin at the para-carbon and the excess of π β-spin at the meta-carbon. Similar effects are observed in the a framework.

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