Synthesis and structural characterization of new trinuclear cobalt(II) and nickel(II) complexes possessing five- and six-coordinated geometry.

Tri-nuclear cobalt and nickel complexes ([(CoL)2(OAc)2Co] · THF (I) and [(NiL)2(OAc)2(THF)2Ni] · THF (II)) have been synthesized by reaction of a new Salen-type bisoxime chelating ligand of 2,2'-[ethylenedioxybis(nitrilomethylidyne)]dinaphthol(H2L) with cobalt(II) acetate tetrahydrate or nickel(II) acetate tetrahydrate, respectively. Complexes I and II were characterized by elemental analyses, IR, TG-DTA and 1H-NMR etc. The X-ray crystal structures of I and II reveal that two acetate ions coordinate to three cobalt or nickel ions through M-O-C-O-M (M = Co or Ni) bridges and four μ-naphthoxo oxygen atoms from two [ML] units also coordinate to cobalt(II) or nickel(II). Complex I has two distorted square-pyramidal coordination spheres and an octahedral geometry around Co1. In complex II all three nickel ions are six-coordinate. [ABSTRACT FROM AUTHOR]