Preparation and crystal structures of two forms of trans-[CuCl2{N(H)SPh2}2 ]; an unusual example of square planar/pseudo-tetrahedral isomerism in a neutral copper(II) complex

At ambient temperatures, in acetonitrile, S,S-diphenylsulfimide reacted with CuCl 2 (molar ratio 2∶1) to give trans-[CuCl 2 {N(H)SPh 2 } 2 ]; depending upon the crystallisation technique this can be isolated as either blue (perfect square-planar geometry) or green (pseudo-tetrahedral) crystals which do not interconvert in the solid state.