Magnetism and structure of copper(II) co-ordination compounds. X-Ray structure determination of trans-dichlorobis(N-methylimidazole)copper(II)

Abstract

Two modifications of the title compound have been synthesized and the crystal and molecular structure of one has been determined by a single-crystal analysis using three-dimensional X-ray data. The compound crystallizes in the triclinic space group P with two formula units in a unit cell of dimensions a= 7.632(3), b= 8.166(9), c= 10.232(3)Å, α= 87.84(5), β= 82.77(2), and γ= 76.12(5)°. The structure has been determined by direct methods and refined by least-squares techniques to R= 0.041 and R′= 0.049 for 2 307 reflections. It consists of discrete monomeric CuCl₂(mim)₂ units with tetrahedrally distorted trans-square-planar geometries around copper(II). The Cu–Cl distances [2.260(3) and 2.256(2)Å] are normal for terminal Cu–Cl bonds. The Cu–N distances [1.962(4) and 1.975(5)Å] are in the range expected for this type of compound. The two different crystal forms appear to have only slightly different spectroscopic and magnetic properties but totally different X-ray powder patterns.