Stereochemistry of rigid chelate–metal complexes. Part III. Crystal structure of dichloroaquo-(2,9-dimethyl-1,10-phenanthroline)copper(II)

Abstract

The crystal structure of dichloroaquo(2,9-dimethyl-1,10-phenanthroline)copper(II) has been determined from three-dimensional equi-inclination Weissenberg X-ray diffraction data with 1430 visually estimated reflections. Z= 2 in the monoclinic unit cell, space group P2₁, with dimensions, a= 9·886(6), b= 8·159(8), c= 9·517(6)Å, and β= 105·55(10)°. The structure was refined by least-squares methods to a conventional R of 0·099. Each molecule consists of a copper atom in a ‘triangular bipyramidal’ co-ordination, surrounded in the triangular plane by two chlorine atoms [Cl–Cu–Cl 155·6(2)°], and one nitrogen atom from the bidentate ligand. The bipyramid is completed by the other nitrogen atom [Cu–N, 1·98(1)Å], and an oxygen atom from a water molecule [Cu–O, 1·98(1)Å]. The most unusual feature is the difference between the equatorial 2·24(1)Å and axial 1·98(1)Å Cu–N bonds. This elongation of the equatorial bond is probably caused by the interaction (3·32 Å) of the methyl group of the bidentate ligand with the water molecule, [N–Cu–N, 79·7(4), bipyramid axis O–Cu–N, 171·1(5)°].