PREPARATION AND SPECTRAL PROPERTIES OF COBALT(II), NICKEL(II), COPPER(II), ZINC(II), AND PALLADIUM(II) COMPLEXES WITH TETRAAZA[14]ANNULENE-TETRACARBONITRILE

The cobalt(II), nickel(II), copper(II), zinc(II), and palladium(II) complexes of 6, 13-diethyl-1,8-dihydro-1,4,8,11-tetraazacyclotetradeca-2,4,6,9,11,13-hexaene-2,3,9,10-tetracarbonitrile have been prepared and studied by mass, vibrational, and electronic spectroscopy. Strong bands appearing at 1630 and 1582 cm-1 were assigned to the C = N and C = C stretching mode, respectively, and these bands were shifted to lower frequency upon complex formation. The absorption bands above 19000 cm-1 range were attributable to pi --> pi* transitions within a ligand molecule and CT transitions from metal to ligand. The metal complexes assume the square-planar configurations, because significant ligand-field bands were not detected in the range below 19000 cm-1.