Synthesis and Characterization of Polynuclear Metal Complexes with Bridging Ketoiminato and Thioiminato Schiff Base Ligands

Abstract

Bimetallic and trimetallic complexes of stoichiometry [M(acacen)M′Y2], [M(sacacen)M′Y2], and {[M(acacen)]2M′Y2} have been prepared by reaction of the appropriate square-planar Schiff base metal complex with various secondary metal salts in toluene and/or absolute ethanol. Systems which are reported here include those where M = Cu(II); M′ = Cu(II), Ni(II), Co(II), Mn(lI) and Zn(II); Y− = Cl−, Br−, and NO3 −. Trinuclear complexes have been isolated only for {[Cu(acacen)]2M′(NO3)2} where M′ = Cu(lI) or Mn(II); binuclear complexes result from all other combinations. The geometry of the chelated Cu(II) ion is square-planar in the bimetallic complexes and possibly square-pyramidal in the trimetallic compounds, while that of the secondary metal ion depends on the coordination preference of M′, the nature of Y− and whether the bridging donor atoms are oxygen or sulfur. Probable structures of the new polynuclear complexes have been deduced from spectral, conductivity and magnetic measurements.