Hyperfine coupling super

Although the complexes (Et2NCS2)Mo(SN(H)C H4)2 in no way represent models for the active site of enzymes, their e.s.r. spectra serve to illustrate that Mo complexes with co-ordinated N—H groups display hydrogen super hyperfine coupling of the same order of magnitude as found in the molybdenum oxides. ... 

Rh°(CN)6] reveals (super)hyperfine couplings with Rh and 2 equiv N atoms. [Rh (Cl)2(CN)4]" reveals (super)hyperfine couplings with Rh and 2 equiv Cl atoms (albeit in a complex patterns due from the presence of Cl— Cl, C1— Cl, and Cl— Cl species according to the natural abundances of the Cl isotopes). These data suggest that in both cases the SOMO mainly consists of an Rh d 2 orbital with antibonding contributions from orbitals of the axial CN and CP ligands (Fig. 15). The reported spin populations estimated from the EPR data and semiempirical calculations are listed in Table VII. 

Titaniumfiii).—Halides and Oxyhalides. Semi-empirical MO calculations on [TiF ] using a new parameter-free method have been published, and the calculated and experimental values of the ligand-field splitting, super-hyperfine coupling constants, and spin densities were in excellent agreement." ... 

CUCI2 starting salts respectively. The difference between the spin Hamiltonian parameters for the two complexes was accounted for by the presence of the counterion in the coordination sphere of the Cu(BOX) complex, as proven by the observation of couplings in the ENDOR spectrum. The resolved copper hyperfine couplings were further split due to super-hyperfine interaction with two equivalent n nuclei. 

These results were eonsistent with the presence of the heteroleptic complexes labelled [Cu°(BOX)](OTf)2 and [Cu (BOX)]Cl2 in solution. As the Cu BOX ratio was further increased (1 6), additional changes in the profile of the EPR spectra were observed, notably an increase in the multiplicity of the nitrogen super-hyperfine coupling, subsequently simulated based on four-equivalent N nuclei. Hence, at the higher Cu BOX ratios, the resulting species in solution were assigned to the homoleptic complex [Cu (BOX)2]. Notably, the homoleptic complex could only be formed from the Cu(OTf)2 starting salt. ... 

Combines sensitivity of EPR and high resolution of NMR to probe ligand super-hyperfine interactions For paramagnetic proteins enhanced chemical shift resolution, contact and dipolar shifts, spin delocalization, magnetic coupling from temperature dependence of shifts Identification of ligands coordinated to a metal centre... 

All of the [Ga(Por)FIJn materials exhibit EPR spectra (Fig.4), which show a single, narrow, nearly symmetric absorption, with g values very close to the free-electron value, and to g values for related materials [3]. We can observe, for Por = OMP, a isotopic hyperfine structure (Fig. 4a). This coupling, due to the super-hyperfine interaction of the free electron with the four N-atoms, is about 17 Gauss, and has been observed for other porphyrin series [25]. 

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