Crystal and molecular structure of the blue form of the 1 : 2 addition complex of copper(II) dichloroacetate with α-picoline

Abstract

The crystal structure of the blue form of the 1 : 2 addition complex of copper(II) dichloroacetate with α-picoline [Cu(Cl₂CHCO₂)₂(α-picoline)₂] has been determined by X-ray diffraction methods and refined by least-squares procedures. The crystals are monoclinic, space group P2₁/n, with a= 10·511, b= 16·091, c= 12·275 Å, β= 93° 24′, and Z= 4. The copper atom is surrounded by four atoms in a distorted square-planar arrangement with two short Cu–O distances of 1·999(7) and 2·017(7)Å and two Cu–N distances of 1·990(10) and 2·032(10)Å. Two longer ‘out-of-plane’ Cu–O distances [2·711(10) and 2·493(9)Å] are made with the remaining oxygen atoms of the dichloroacetate groups. The α-picoline rings are mutually trans but the α-methyl groups of the rings are cis with respect to the copper atom. The oxygen atom of the shorter of the two longer ‘out-of-plane’ Cu–O distances is trans to the α-methyl groups of the picoline rings and the direction of the Cu–O bond lies 21·4° from the normal to the mean plane of N₂O₂ square plane.