Nickel(II) complexes of some o-hydroxyarylcarbonyl compounds. II. Some 5-substituted 2-hydroxyaryl ketones

Abstract

Nickel(11) complexes of the type NiL₂B_n have been prepared where L = 2-hydroxy-5-methylacetophenone, 2-hydroxy-5-methylbenzophenone, or 5-chloro-2-hydroxybenzophenone; B = H₂O or 4-methylpyridine; n = 2 or 0. The properties of these compounds closely resemble those of the unsubstituted compounds described in Part I. Molecular weights of the anhydrous compounds NiL, indicate a monomer-polymer equilibrium in non-donor solvents, the solute being almost wholly monomeric at concentrations below 10^-2M. Equilibrium studies in 2.5M 10^-8M solution show that NiL₂ reacts with 4-methylpyridine in two stages with a five-coordinate intermediate NiL₂B, analogous to corresponding copper(11) complexes. The properties of the monomeric form of NiL, are consistent with a high-spin square-planar structure.