Synthesis and characterization of the 1:1 adducts of copper(I) halides with bidentate N,N′-bis(benzophenone)-1,2-diiminoethane Schiff base: Crystal structures of [Cu(bz2en)2][CuX2] (X = Br, I) complexes

1:1 adducts of N,N′-bis(benzophenone)-1,2-diiminoethane (bz₂en) with copper(I) chloride, bromide and iodide, [Cu(bz₂en)₂][CuX₂] (X = Cl, Br, and I), have been synthesized and the structures of the solid bromide and iodide adducts were determined by X-ray crystallography from single-crystal data. The solid-state structure reveals ionic complexes containing a cation of copper(I) ion coordinated to four nitrogen atoms of two bz₂en molecules (distorted tetrahedron) and a linear dibromocuprate(I) and a di-μ-iodo-diiododicuprate(I) anion for the bromo and iodo adducts, respectively. The bromo adduct structure contains CH?Br intermolecular hydrogen bonds. The complexes are very stable towards atmospheric oxygen in the solid state. The spectral properties of the above complexes are also discussed.