SYNTHESIS AND CHARACTERIZATION OF COBALT(II), NICKEL(II), COPPER(II) AND ZINC(II) COMPLEXES OF N-5, 17,18-MEMBERED PENTAAZAMACRO-CYCLES WITH N-5 DONOR SETS

A series of cobalt(II), nickel(Il), copper(II)and zinc(II) complexes i ncorporating N-5 donor sets have been prepared via the template conden sation of o-aminobenzoic acid with 1,2-dibromoerbane or 1,3-dibromopro pane in the presence of diethylenetriamine resulting in the formation of pentaazamacrocyclic complexes. The overall geometry and mode of bon ding have been confirmed by elemental analysis, IR, H-1 NMR, EPR, elec tronic spectral studies, conductivity and magnetic susceptibility meas urements. An octahedral geometry is proposed for all the complexes, wh ere five coordination sites are occupied by the five amine nitrogens a nd the sixth by an anion.