Low-dimensional Compounds Containing Cyano Groups. XI. Preparation, Crystal Structure and Properties of Two Copper(II) Dicyanamide Complexes with PF 6 − Anions

Abstract

From the reaction mixtures containing Cu(NO3)2, Na[N(CN)2], KPF6 and 2,2′-bipyridine (bpy) or 1,10- phenanthroline (phen) in 1:1:1:2 molar ratios, [Cu(bpy)2N(CN)2][Cu(bpy)2(H2O)](PF6)3 (1b) and [Cu (phen)2N(CN)2]PF6 (1p) complexes were isolated. Measured i.r. spectra confirm the presence of all functional groups in both complexes and, moreover, they indicate monodentate coordination of dicyanamide through the cyano nitrogen atom in (1p). The structure of (1b) contains two crystallographically independent complex cations. In both, Cu is coordinated by two chelating bpy molecules, and either dicyanamide anion or water molecule fills the fifth position, completing the basal plane. The CuII atoms in (1p) are coordinated by two chelating phen ligands and by one dicyanamide anion in the equatorial plane. Hexafluorophosphate anions in (1b) and (1p) remain uncoordinated. Besides the ionic forces in both structures, the structure of (1b) is stabilized by strong O—H………F and O—H………N hydrogen bonds and, moreover, both structures are stabilized by weak C—H………F hydrogen bonds and possible π-π interactions between pyridine rings of bpy or phen molecules.