Synthesis and characterization of novel macrocycles and their complexes with transition metal ions

Novel Schiff base macrocycles, 1,4,7,10-tetraazacyclododeca-5,6,11,12-tetraaminoisobutyric acid-4,6,10,12-tetraene (L-1), 1,4,7,10-tetraazacyclododeca-5,6,11,12-tetraaminopiperizine-4,6,10,12-tetraene (L-2) and 1,4,7,10-tetraazacyclodeca-5,6,11,12-tetraaminouracil-4,6,10,12-tetraene (L-3) containing pendant groups have been synthesized by reactions of oxamidediisobutyric acid, oxamidedipiperizine or oxamidediuracil, respectively, with ethylenediamine. Their first-row transition metal complexes of the types [M(L)Cl-2] and [M(L)Cl-2]Cl have been prepared. All of the compounds have been characterized on the basis of elemental analyses, IR, UV-Visible, EPR, NMR spectroscopy, magnetic moments and conductance measurements. The complex of divalent metal ions are non-ionic while those of trivalent metal ions are 1:1 electrolytes. For all of these complexes an octahedral stereochemistry has been proposed.