The coordination chemistry ofN, N′-ethylenebis(2-acetylpyridine imine) andN, N′-ethylenebis(2-benzoylpyridine imine); two potentially tetradentate ligands containing four nitrogen atoms

New complexes of the general formulae [MLA(H2O)2]-Cl2 (M=Ni or Cu), [MLAX2] (M=Co or Cu; X=Cl or Br), [NiLABr2]·H2O, [MLA] [MCl4] (M=Pd or Pt), [NiLB(H2O)2]Cl2·2H2O, [MLBCl2] (M=Co, Ni, Cu, Pd or Pt; X=Cl or Br) and [MLB] [MCl4] (M=Pd or Pt), where LA=N,N′-ethylenebis(2-acetylpyridine imine) and LB=N, N′-ethylenebis(2-benzoylpyridine imine), have been isolated. The complexes were characterized by elemental analyses, conductivity measurements, t.g./d.t.g. methods, magnetic susceptibilities and spectroscopic (i.r., far-i.r., ligand field,1Hn.m.r.) studies. Monomeric pseudo-octahedral stereochemistries for the CoII, NiII and CuII complexes andcis square planar structures for the compounds [MLBX2] (M=Pd or Pt; X=Cl or Br) are assigned in the solid state. The molecules LA and LB behave as tetradentate chelate ligands in the CoII, NiII, CuII and Magnus-type PdII and PtII complexes, bonding through both the pyridine and methine nitrogen atoms. A bidentateN-methine coordination of the Schiff base LB is assigned in the [MLBX2] complexes (M=Pd or Pt; X=Cl or Br). The anomalous magnetic moment values of the CoII complexes are discussed.