The dinucleating macrocyclic ligands (L2a)2 and (L2b)2 were prepared by [1 : 1] cyclic condensation of N,N0-dipropionitrile-N,N0-ethylene-di(5-methyl-3-formyl-2-hydroxybenzylamine or N,N0-dipropionitrile-N,N0-ethylene-di(5-bromo-3-formyl-2-hydroxybenzylamine with 1,3-diaminopropane. The ligands include dissimilar N(amine)2O2 and N(imine)2O2 coordination sites sharing two phenolic oxygen atoms and containing two propionitrile pendant arms on the amine nitrogen atoms. A series of mono- and dinuclear complexes were synthesized and characterized on the basis of elemental analysis, molar conductance measurement, X-ray crystallography, IR, NMR, and UV-Vis spectroscopies as well as cyclic voltammetric measurements. During the cyclization copper(II) migrates from the N(amine)2O2 to the N(imine)2O2 coordination site and one of the propionitrile pendant arms is removed. The heterodinuclear complexes [ZnL2Cu(OAc)]þ were prepared by a transmetallation reaction. The characterization results showed that the two metal ions are bridged by two phenolic oxygen atoms and an acetate group, providing distorted five-coordinate geometries for both metals
