Two pentacoordinate copper(II) complexes that display accessible Cu(III/II) couples

2531-2535Two copper(II) complexes of the type CuL2.imidazole (1) and Cu2L4(4,4' -bpy).2H2O.C6H14 (2), where LH = 1-nitroso-2-naphthol and 4,4'-bpy = 4,4'- bipyridine, are characterised by X-ray crystallography. In 2, the two copper atoms are linked by 4,4'bpy. In both the complexes, copper is found to have a distorted square pyramidal N3O2 coordination sphere. The axial position in 1 is occupied by an oxygen atom while those in 2 by the nitrogen atoms of 4,4'-bpy. The two complexes display quasireversible Cu(III/II) couples around 0.68 Vvs. saturated calomel electrode in cyclic voltammetry in dichloromethane