Quantum chemical interpretation of different types of exchange magnetic interactions in dinuclear copper azomethine chelates

B3LYP/LANL2DZ calculations of two series of isomeric dinuclear copper chelates based on the tridentate dibasic salicylaldimines from aromatic and heterocyclic amines were performed. According to calculations, the complexes with N,N-or S,S-donor atoms in the exchange fragment are mainly characterized by ferromagnetic exchange, whereas the formation of O, O-bridging fragments leads to antiferromagnetic spin-spin interaction.