Structure and stability of carboxylate complexes. Part VI. Crystal and molecular structure of bis(methoxyacetato)tetrakis(imidazole)copper(II)

Abstract

The crystal and molecular structure of bis(methoxyacetato)tetrakis(imidazole)copper(II), monoclinic space group P2₁/a, a= 8·35, b= 9·85, c= 14·77 Å, α= 94·8°, was determined by three-dimensional X-ray methods and refined to R= 0·092. The copper atom at a symmetry centre is surrounded by the nitrogen atoms of four imidazole ligands in a square plane and two carboxylate oxygen atoms of two methoxyacetate ligands complete a distorted octahedral co-ordination sphere, Cu ⋯ O 2·825 Å. The imidazole ligands are two non-equivalent pairs. One pair, Cu–N 1·913 Å, appeared to be bonded to copper with the displacement of protons, and the other pair, Cu–N 2·045 Å, without proton displacement. The hydrogen-bond system and the location of the protons is discussed.