SYNTHESIS AND CHARACTERIZATION OF BIVALENT-METAL COMPLEXES OF A TETRADENTATE N-6 MACROCYCLIC LIGAND

Bivalent cobalt, nickel and copper salts react in situ with 2,6-diacet ylpyridine and 1,2-diaminobenzene to form complexes containing a 18-me mbered N-6 tetradentate macrocyclic ligand. The complexes were charact erized as distorted octahedral of the type [M(TML)X-2; where M = Co-II , Ni-II or Cu-II; X = Cl, Br, NO3 or NCS; TML = tetradentate macrocycl ic ligand. The ligand coordinates through all the six nitrogen atoms. The molar conductance measured in DMF show that these chelates are 1:2 electrolytes. The test for anions are positive directly without decom posing the chelates, showing their presence outside the coordination s phere. The magnetic, electronic, IR and far-IR spectral studies are al so discussed. (C) 1997 Elsevier Science Ltd.