Intramolecular and intermolecular O-H-O hydrogen bond in some nickel(II) complexes with tridentate amino-oxime ligands

摘要

The 3-[(2-pyridyl)methylamino]-butan-2-one oxime (H-LNH-py) tridentate ligand forms with Ni(II) the pseudo-octahedral complex [Ni(II)(H-LNH-py)(LNH-py)]ClO4 where the coordination of two ligands to the metal atom leads to the formation of an equatorial chelating system containing an intramolecular hydrogen bond (O-H-O) involving the oxime oxygen atoms. In acidic medium the [Ni(II)(H-LNH-py)(2)](ClO4)(2), Complex is formed, deriving of the precedent by addition of a proton to the O-H-O bridge. A third complex, [Ni(II)(H-LNH-py)(2)(C6H2N3O7)](C6H2N3O7), was isolated, as picrate, containing a double intermolecular hydrogen bond with a picrate ion. X-ray analysis of these compounds allows defining in all three cases the geometry of the hydrogen bonding fragments. (C) 2003 Elsevier B.V. All rights reserved. [References: 35]