STRUCTURAL COMPARISONS BETWEEN CU(II) AND NI(II) DIAZA-COUPLED QUASI-AROMATIC ALPHA-AMINEOXIME COMPLEXES

Reaction of NioylH and CuoylH with the diazonium salt of sulfanilic ac id quantitatively produces diaza complexes by coupling at the C-12 pos ition. X-ray structural study: [Nioyl -N=N-C6H4SO3H] . H2O; C19H28O6N6 S1Ni1, M-r = 527.23, monoclinic P2(1)/c, a = 12.752(3), b = 10.795(3), c = 16.609(3) Angstrom, beta = 92.46(3)degrees, V = 2284.2(9) Angstro m(3), Z = 4, D-x = 1.533(2) mg m(-3). [Cuoyl-N=N-C6H4SO3H] . HCl . 3H( 2)O; C19H33O8N6S1Cu1Cl1, M-r = 604.56, triclinic, P (1) over bar, a = 8.4019(8), b = 11.2266(99), c = 14.9370(20) Angstrom, alpha = 84.264(7 ), beta = 75.309(8), gamma = 73.024(8)degrees, V = 1303.0(2) Angstrom( 3), Z = 2, D-x = 1.541(2) mg m(-3). The complexes were isolated from a bout 0.2 M HCl and had different formulas due to differing protonation . The sulfonic acid proton resides on the diaza nitrogen attached to t he C6H4 ring and with the copper(II) analogue, protonation also occurs on the intramolecular hydrogen-bond oxygen. Bond distance and angle c omparisons are made and related to potential electron delocalization b etween aromatic rings.