No abstract

A method of calculation of bond parameters is proposed for magnetic molecular orbitals which describe the 3d9 configuration in the case of complexes with a rhombic surrounding (D2h symmetry), when the experimental spin Hamiltonian is known. This treatment contains as a particular case that of Kivelson et al. for square planar structures and allows us to evaluate both the anisotropic presence of unpaired spin at the various ligands, and the mixing of the d3z2−r2 orbital in the ground state which is essentially dx2−y2. Applications of this treatment in calculating the bond parameters in the CuCl2·2H2O and CuF2·2H2O compounds allow a comparison between the covalent characters of the Cu–Cl and Cu–F bonds in a similar surrounding. The results show that there is a relevant spin density at the halide ions in both compounds and that, in CuCl2·2H2O, the anisotropy of covalence in the principal plane of coordination is strong. The reliability of the proposed criteria is considered by a comparison between the covalence values obtained following our method and those obtained directly from the extrahyperfine structure in the case of a square planar copper complex.

No abstract

No abstract

Articles you may be interested inInterpretation for the anomaly of the C=O stretching band in benzoic acid crystal J. Chem. Phys. 94, 4446 (1991); 10.1063/1.460634 14N nuclear quadrupole interaction in salicylaldoxime and in Cu(II) doped bis(salicylaldoxime) Ni(II) J. Chem. Phys. 74, 3618 (1981); 10.1063/1.441469Hartree-Fock-Slater-LCAO calculations on the Cu(II) bis(dithiocarbamate) complex; magnetic coupling parameters and optical spectrum A possible interpretation of the relevant magnetic anomalies, recently observed in Cu(II):Ni(II) bis(diselenocarbamate) mixed crystals, is presented. The Cu-Se bond is considered responsible for the large "circularization" (to the value for the free electron) of g about a twofold axis in the molecular plane. Thus it is possible that a weak C 2h distortion of the D 2h symmetry in the complex [mixing of (xz) into the (3z 2_r 2) ground state, or (y z) into the (x y) ground state] may produce both the characteristic angle of approximately 45 0 between the low values of g and the molecular plane and the appearance of a principal value of g slightly lower than the free electron value. It is also clarified why A does not exhibit an analogous rotating effect. Relevant expressions of g and A tensors are deduced in terms of a simple LCAO-MO formalism and implications on the covalent character of the magnetic bonds in the complex are finally discussed.