Spin Densities and Spin Coupling in Iron-Sulfur Clusters: A New Analysis of Hyperfine Coupling Constants

1995 ◽  
Vol 34 (17) ◽  
pp. 4347-4359 ◽  
Author(s):  
J.-M. Mouesca ◽  
L. Noodleman ◽  
D. A. Case ◽  
B. Lamotte
Keyword(s):  
Hyperfine Coupling ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Hyperfine Coupling Constants ◽  
Iron Sulfur Clusters ◽  
Iron Sulfur ◽  
Spin Densities

Spectroscopiċ investigations of hydrogen bonding interactions in the gas phase. X. Properties of the hydrogen-bonded heterodimer HCN∙ ∙ ∙HF determined from hyperfine coupling and centrifugal distortion effects in its ground-state rotational spectrum

1985 ◽  
Vol 401 (1821) ◽  
pp. 327-347 ◽  
Keyword(s):  
Nuclear Spin ◽  
Hyperfine Coupling ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Rotational Spectrum ◽  
Centrifugal Distortion ◽  
Hyperfine Coupling Constants ◽  
Rotational Spectra ◽  
Isotopic Species ◽  
Centrifugal Distortion Constants

The rotational spectra of six isotopic species of HCN∙ ∙ ∙HF in their vibrational ground states have been observed by pulsed-nozzle, Fourier-transform, microwave spectroscopy and have been analysed to yield the rotational constants B 0 , centrifugal distortion constants D J and various hyperfine coupling constants X i (D), X 3 ( 14 N) and D 4, 5 as follows (subscripts refer to the numbering scheme H (1) C (2) N (3) ∙ ∙ ∙H (4) F (5) ). isotopic species B 0 / MH Z D J /kH Z X i (D)/kH Z X 3 ( 14 N)/MH Z D 4, 5 (H, F)/kH Z HC 15 N∙ ∙ ∙HF 3573 5874(2) 6.97(2) ─ ─ –242(6) HC 15 N∙ ∙ ∙DF 3551.5110 6.83 269(4)( i = 4) ─ ─ HC 14 N∙ ∙ ∙HF 3591.1552 6.99 ─ –4.098(4) –218(6) HC 14 N∙ ∙ ∙DF 3569.6576 6.86 259(2)( i = 4) –4.096(1) ─ DC 15 N∙ ∙ ∙HF 3360.3549 5.85 186(5)( i = 1) ─ –244(4) DC 15 N∙ ∙ ∙DF 3338.0824 5.81 { 181(10) ( i = 1) ─ ─ 283(7) ( i = 4) The B 0 values lead to conclusions about the dimer geometry, the D J values allow the hydrogen bond stretching force constant k σ to be determined and the hyperfine coupling constants provide information about the internal dynamics of the subunits. An analysis of the D nuclear quadrupole coupling and H, F nuclear spin nuclear-spin coupling constants demonstrates that the H—F bond lengthens by 0.14 Å when the heterodimer HCN∙ ∙ ∙HF is formed. (1 Å = 10 –10 m = 10 –1 nm.)

On the d-Orbital Influence in INDO Calculations of NMR and ESR Parameters of Sulphur Heterocyclics

1973 ◽  
Vol 28 (12) ◽  
pp. 1951-1953 ◽  
Author(s):  
V. Galasso
Keyword(s):  
Nuclear Spin ◽  
Hyperfine Coupling ◽  
The Self ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Indo Method ◽  
Hyperfine Coupling Constants ◽  
Self Consistent ◽  
Indo Calculations ◽  
Spin Coupling Constants

Comparative calculations by the self-consistent perturbed INDO method on thiophene and by the unrestricted HF INDO method on the 2-thenyl radical show that satisfactory reproduction of nuclear spin coupling constants and hyperfine coupling constants for sulphur heterocyclics can be obtained by considering the sp interaction only.

scholarly journals ESR-Parameter und Bindungseigenschaften der Liganden in [Fe(NO)2(EZ3)X]-Komplexen/ESR Parameter and Bonding Properties of Ligands in [Fe (NO)2 (EZ3) X] Complexes

1972 ◽  
Vol 27 (6) ◽  
pp. 600-607 ◽  
Author(s):  
Jörn Schmidt
Keyword(s):  
Hyperfine Coupling ◽  
Coupling Constants ◽  
Considerable Influence ◽  
Hyperfine Coupling Constants ◽  
Donor And Acceptor ◽  
Bonding Properties ◽  
Spin Densities ◽  
G Factors

Isotropic g factors and hyperfine coupling constants of a series of complexes [Fe (NO) 2 (EZ3) X] are reported. In accord with theoretical suggestions, the g factors arrange the ligands EZ3 corresponding to their π acceptor abilities. Both donor and acceptor properties of the ligands exhibit considerable influence on the spin densities.

Theory of hyperfine coupling constants of solvated molecules: Applications involving methyl and ClO2 radicals in different solvents

1996 ◽  
Vol 104 (2) ◽  
pp. 629-635 ◽  
Author(s):  
Berta Fernández ◽  
Ove Christiansen ◽  
Ota Bludsky ◽  
Poul Jo/rgensen ◽  
Kurt V. Mikkelsen
Keyword(s):  
Hyperfine Coupling ◽  
Coupling Constants ◽  
Hyperfine Coupling Constants ◽  
Solvated Molecules
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