Synthesis and crystal structure of a copper(II) complex with a tetradentate dithiadioxime ligand

A neutral five-coordinate dithiadioxime complex of copper(II), chloro[3,3′-(1,3-propanedithia)bis(3-methyl-2-butanone oximato)(1-)-S,S′, N,N′]copper(II) (Cu(LH)Cl), was prepared by reaction of CuCl₂ with the [3,3′-(1,3-propanedithia)bis(3-methyl-2-butanone oxime)] ligand (LH₂) in methanol-acetone. The crystal structure of the Cu(LH)Cl monohydrate, [CuCl(C₁₃H₂₅N₂S₂O₂)]·H₂O, reveals a square pyramidal geometry about the metal centre. The copper(II) ion is coordinated in an approximate square plane by the two oxime nitrogen atoms and two thioether sulphur atoms of the tetradentate dithiadioxime ligand, with the chlorine occupying an axial coordination site at a CuCl distance of 2.3931(8) Å. The copper-to-nitrogen distances average 1.997 Å, while the copper-to-sulphur distances average 2.3279 Å. The least-squares S₂N₂ plane is situated 0.467(1) Å below the copper centre. A proton bridges the two oxime oxygen atoms of the complex in the fashion typical of metal complexes containing cis-oxime functions.