Metal complexes of macrocyclic ligands. Part XXIII. Synthesis, properties, and structures of mononuclear complexes with 12‐ and 14‐membered tetraazamacrocycle‐<i>N</i>,<i>N</i>′,<i>N</i>″,<i>N</i>‴‐tetraacetic Acids

Abstract

Abstract The two tetraazamacrocycle‐ N , N ′, N ″, N ‴‐tetraacetic acids H 4 dota and H 4 teta form with Ni 2+ , Cu 2+ , and Zn 2+ (M 2+ ) mononuclear complexes MLH 2 and M′[ML], M′ being an alkaline earth ion. The structures of Ni(H 2 dota) and Cu(H 2 dota) have been solved by X‐ray structure analysis. The metal ions are in a distorted octahedral geometry coordinated by four amino N‐atoms and two carboxylates. In the case of Cu 2+ , the distortions are more pronounced than for Ni 2+ indicating that the Jahn ‐ Teller effect is operating. Starting from these two structures, the coordination geometry of the other complexes is discussed using VIS and IR spectra.