Magnetic coupling and EPR spectra of catena-bis(.mu.-perchlorato)[bis(.mu.-imidazolato)bis(perchlorato)octakis(imidazole)tricopper(II)]

A trinuclear cyanamidonitrate–copper(II) complex bridged by imidazolato ligands

“…Also other imidazolato-bridged Cu(II) complexes (dinuclear, tetranuclear, katena-polymeric) show negative values of J. In an agreement with the discussion offered in [30], the relevant exchange pathway through the imidazolato bridge is of the r-type.…”

“…The negative isotropic exchange coupling constant found for 1 (À115 cm À1 ) matches the data on similar tri-copper complexes: the triangulo-shaped (À75 cm À1 ) [11], the V-shaped (À61 cm À1 ) [29], and the linear one (À118 cm À1 ) [30]; the J-values are given in conformity with Eq. (3).…”

pH‐Dependent Imidazolato Bridge Formation in Dicopper Complexes: Magnetic, Electrochemical, and Catalytic Repercussions

“…Several attempts have been made7a,7b,7d to correlate the magnitude of the coupling constant with diverse structural factors such as the Cu–N bond length and two angles: α , the Cu–N–N angle and θ , the dihedral angle between the imidazolate plane and the copper coordination plane, considering a square or square‐pyramidal coordination geometry. A stronger coupling is expected when α approaches 180° since this maximizes a σ interaction, while θ is expected to be relevant only in the hypothesis of a π Cu–imidazolate interaction; in which case a value of 90° would be optimal.…”

Synthesis and magnetic studies of μ-oxalato-bridged copper(II)-M(III)-copper(II) (M=Cr and Fe) heterotrinuclear complexes

“…Because the two copper(II) ions in the copper (II)-iron(III)-copper(II) heterotrinuclear clusters are far apart, the quality of the fit does not depend on J 0 and hence the fit with J 0 = 0 has been accepted to be more plausible [30][31][32]. Assuming that the exchange integral between the terminal copper(II) ions is zero (J 0 =0), the molar susceptibility of copper(II)-iron(III)-copper(II) ðS 1 ¼ S 3 ¼ 1 2 ; S 2 ¼ 5 2 Þ system is given by Eq.…”