METAL-COMPLEXES OF MACROCYCLIC LIGANDS - PART XLVII - COPPER(II) AND NICKEL(II) COMPLEXES OF TRANS-DIFUNCTIONALIZED TETRAAZA MACROCYCLES

Reductive cleavage of the bis-aminal 1 of 1,4,8,11-tetraazacyclotetrad ecane allows a new synthesis of 1,8-dimethyl-1,4,8,11-tetraazacyclotet radecane (3), which is an ideal starting compound for preparing 'trans '-difunctionalized derivatives. Thus, 3 was reacted to give the macroc yclic diacetonitrile 5 and dipropanenitrile 9. These were reduced with Raney-Ni and H-2 to the corresponding diamines 6 and 10, respectively . In addition, 5 was selectively hydrolysed to the diacetamide 7 and f ully hydrolysed to the diacetic acid 8. The Cu2+ and Ni2+ complexes of these new ligands were prepared and their spectral and structural pro perties studied. Whereas 3 yielded square planar species, the function alized derivatives gave penta- or hexacoordinate complexes The ligands with amino groups in their side chains (6 and 10) formed square plana r species at acidic pH (amino groups protonated), but pentacoordinate geometries resulted at alkaline pH, where one amino group underwent co ordination. In contrast, the diacetic acid 8 gave distorted octahedral Cu2+ and Ni2+ complexes.