New macrocyclic ligands having discrete metal binding sites

New macrocyclic dinucleating ligands have been easily synthesized by Schiff-base condensation reaction with the appropriate aldehyde and amine using the boric ion template method. The ligands have two N2O2 metal-binding sites which are doubly linked to each other with methylene spacers. The ligands chelate with Co2+, Cu2+ and Ni2+ to form dimetallic compounds in high yields.