Nickel(II) complexes of some o-hydroxyarylcarbonyl compounds

Abstract

Nickel complexes of o-hydroxyarylcarbonyl compounds, (RCOC₆H₄O)₂Ni (R = H, CH₃, C₂H₅, C₆H₅, OCH₃, OC₂H₅), have been studied in the solid state and in solution. Their six-coordinate adducts (RCOC₆H₄O)₂NiB₂ (B = H₂O or 4- methylpyridine) are unstable in solution in hydrocarbon solvents and break down to (RCOC₆H₄O)₂Ni. In solution these anhydrous compounds are monomeric, paramagnetic (μ_eff 3.0-3.5), and have absorption spectra characteristic of octahedral nickel(II). It is concluded that they are probably examples of high-spin, square-planar complexes of nickel(II), though possibly polymeric and octahedral in the solid state.