X-ray crystal structures of copper(II) nitrate complexes of two isomeric N,O-chelating ligands

X-ray crystal structures are reported for the copper(II) nitrate complexes of the two isomeric ligands 2,2'-bipyridine N-oxide (3) and 1-(2'-pyridyl)- 2-pyridone (4). This is the first reported use of 3 as a ligand and the fir st X-ray structure of a metal complex of either Ligand. Each complex contai ns two trans-oriented N,O-bidentate ligands and two tl ans monodentate nitr ate ligands, in a tetragonally distorted octahedral environment. The comple x of 3 crystallises with an acetonitrile solvate molecule (monoclinic, a=13 .6519(4). b=7.7254(2), c=22.1895(6) Angstrom, beta=93.208(1)degrees, P2(1)/ n, Z=4), while that of 4 has a crystallographic centre of inversion (tricli nic, a=7.8430(2), b=8.0397(2), c=9.7492(3) Angstrom, alpha=109.359(1), beta =93.232(1), gamma=116.187(1)degrees, P-1, Z=1). Both ligands behave as neut ral analogues of the more well-studied anionic Ligand 2-(2'pyridyl)phenolat e (2), with which they are isoelectronic. (C) 1999 Elsevier Science S.A. Al l rights reserved.