Donor properties of the nitrone function in copper(II) complexes of some 2-hydroxy-1-naphthylnitrones

Summary Copper(II) complexes of the type CuL₂, 2H₂O and CuL₂. Py where L=-(2-hydroxy-1-naphthyl)-N-R-nitrone (R= methyl, phenyl and variously substituted phenyls) have been isolated and characterised. They have normal magnetic moments. Their ligand field spectra indicate an octahedral geometry for the dihydrates and a five-coordinate environment for the pyridine adducts. Increased (C=N) and considerably decreased (N-O) frequencies in these complexes reveal the presence of - and -interactions of the ligand with copper through nitrone oxygen. The effect of pyridine adduct formation is to increase the Cu-O -interaction.