Four crowned mono- and bis-Schiff bases, 4'-(2- hydroxyphenylmethylideneimino) benzo-15-crown-5 (L^1H) and 4', 5'-bis (2-hydroxyphenylmethylideneimino) benzo-15-crown-5 (L^4H~2) as well as their substituted derivatives L^2H, L^5H~2 were prepared from benzo- 15-crown-5 via nitration, reduction, and condensation. Equilibrium constants and thermodynamic constants ΔHⅲ, ΔSⅲ for oxygenation of these crowned cobalt(II) Schiff base compleses were measured. The influence of ligand structure and basicity of axial ligand on the affinities of the complexes for dioxygen was discussed in comparison with uncrowned analoques.

Key words: CROWN ETHER, SCHIFF BASE, COBALT COMPLEX, NITRATION, REDUCTION, CONDENSATION