A binuclear antiferromagnetically coupled hydroxo-bridged copper(II) complex which undergoes two-electron oxidation to from a binuclear copper(III) derivative and exhibits an unusually intense visible absorption

Abstract

The binuclear, hydroxo-bridged, five-co-ordinate copper(II) complex of a hexadentate (N₆) phthalazine ligand, the crystal structure of which has been determined, exhibits very strong antiferromagnetic exchange (–2J= 990 ± 50 cm^–1) and very intense visible absorption (610 nm, ε 18 400 I mol^–1 cm^–1) and unlike comparable (N₄) diazine complexes undergoes two-electron oxidation at 0.50 V (vs. standard calomel electrode) to produce a stable binuclear copper(III) derivative.