Formation of the N,N-Bidentate Chelates of 2-(2-Pyridilazo)phenolic Ligands with Nickel(II) in Nonaqueous Solvents

Article abstract of DOI:10.1246/bcsj.59.795

The formatiom of N,N-bidentate 1:2 complexes of nickel(II) with various N,N,O-terdentate 2-(2-pyridylazo)-phenolic ligands was detected spectrophotometrically in ethyl acetate and was examined with respect to the influences of Broensted bases, the counter anions in the nickel(II) salts employed, solvent basicity, and the steric requirements around the donor nitrogen atoms in the ligand in the 1:2 complex.It is concluded that the stabilitiy of the N,N-bidentate complex species in solutions predominantly depends on the basicity of the counter anions X in NiX2 and of the solvent.In the case of 1-(2-pyridlyazo)-2-naphthol, owing to a high steric hindrance of the naphthalene ring, the formation of the N,N-bidentate complex was not observed even in the solvent of low basicity such as dioxane.