On the Influence of the Nature of Non-Bridging Donor Atoms on the Structure and Magnetic Properties of Binuclear Cu(II) Complexes with Heterocyclic Azomethine Ligands

Binuclear complex [Cu₂L(μ₂-pz)] (pz = pyrazolate anion) of copper(II) with the condensation product of 1,3-diamino-2-propanol (DAP) and 4-formyl-3-formylcoumarin (H₃L) is synthesized and characterized. Magnetic properties of the complex are compared with those demonstrated by a number of previously studied compounds based on bis-azomethine derivatives of DAP with the structure similar to that of studied compounds, i.e. identical exchange fragments and immediate donor environments of copper(II) ions. Antiferromagnetic exchange parameters of these complexes are calculated within the DFT method using the "broken-symmetry" approximation. It is shown for the complexes with the same structure of the exchange fragment and the nearest donor environment of metal centers that the significant variation of the exchange parameter (∼100 cm⁻¹) is determined by the electronic nature of non-bridging donor oxygen atoms of the carbonyl fragment of the bis-azomethine ligand.