Face-to-Face Dinuclear Scaffolds Composed of Tetraazamacrocyclic Charged and Neutral Complexes

A new family of bismacrocyclic homo- and heteronuclear Ni and Cu complexes has been synthesized and characterized. The ligand scaffold is comprised of two 14-membered tetraazamacrocyclic sites held in cofacial orientation. The dinuclear complexes are unique in that one macrocyclic center is neutral while the other one is charged, although the ligand backbones are nearly identical. This leads to a binuclear system of two structurally similar components, differing in their electron-donor abilities. The crystallographically characterized structures in the solid state revealed similarity of the four dinuclear complexes studied. The metal−metal separations are between 4 and 5 Å. The strongest electrostatic intramolecular interactions occur in the molecules with neutral and charged components, most differing in donor abilities.