Macrocyclic Melamine‐Based Ligand Complexes as Building Blocks for the Metal‐Directed Synthesis of Heterometallic Di‐ and Trinuclear Compounds

Heterodi‐ and heterotrimetallic Ni II /Cu II , Ni 2 II /Cu II and Ni II /Cu 2 II complexes of bis‐ and tris‐macrocyclic ligands, linked by a 1,3,5‐triazine spacer group, are obtained as products of copper( II )‐ or nickel( II )‐assisted condensations of the open‐chain tetraamine complexes [M 2 (2,3,2‐tet)] 2+ [2,3,2‐tet= bis‐ N , N ′‐(2‐aminoethyl)propane‐1,3‐diamine, M 2 = Ni II or Cu II ] with formaldehyde and the monomacrocyclic ligand complexes [M 1 (L 1 )] 2+ , where L 1 is a cyclam‐type macrocycle with a pendent melamine group (M 1 = Cu II or Ni II ). The spectroscopic (UV/Vis and EPR) and electrochemical properties of the oligonuclear heterometallic compounds in comparison with those of the homometallic analogues indicate small, but significant, intramolecular metal‐metal interactions. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)