Abstract: | Mono- and binuclear copper(II) complexes derived from substituted aroylhydrazoneoximes of the general formulae Cu(H2LR)Cl2]·nH2O, Cu(HLR)Cl], {Cu(HLR)}2]·2NO3·nH2O and {Cu(LR)}2]·nH2O have been prepared and characterized, where H2LR, HLR and LR refer, respectively, to the neutral, monoanionic and dianionic ONN tridentate aroylhydrazoneoxime ligands. Electrospray ionization (ESI) mass spectra revealed the formation of tri- and tetranuclear copper(II) complexes in dimethylformamide (DMF) or dimethysulphoxide (DMSO) solutions. The effect of substitution in the aroylhydrazone residue on the degree of deprotonation of the ligand and the energies of d–d transitions of the copper(II) complexes have been studied. Tuning of the antiferromagnetic exchange coupling by different substituents in {Cu(HLR)}2]·2NO3·nH2O and {Cu(LR)}2]·nH2O complexes have been discussed. |