Grid-corner analogues: Synthesis, characterisation and spectroscopic properties of meridional complexes of tridentate NNO Schiff-base ligands

Reactions of the tridentate Schiff-base ligands HL1, HL2 and HL3 formed from pyridine-2-aldehyde and 2-aminophenol plus two of its methoxycarbonyl derivatives, with AgNO3, [Cu(CH3CN)(4)]PF6, Cu(NO3)(2), Co(NO3)(2) and Zn(NO3)(2) give complexes of the following types: [Ag(HL)(2)]NO3 (1a, 2a, 3a); [Cu-II(HL)L]PF6 (1b, 2b, 3b): [Cu-II(HL)L]NO3 (1c, 2c, 3c); and [M(HL)L](2)[M(NO3)(4)] where M=Co(II) (1d, 2d, 3d): or Zn(II) (1e, 2e, 3e), which in principle define the basic characteristics of the metal sites in certain metallogrids. The complexes have been characterized by spectroscopic techniques and elemental analysis. The solid state structures of complexes 2b and 2e have been established by X-ray crystallography. (C) 2009 Elsevier Ltd. All rights reserved.