Low-dimensional compounds containing cyano groups. IV. Bis(2,2'-bipyridine-kappa(2)N,N1)(dicyanamido-kappaN')copper(II) perchlorate and mu-dicyanamido-kappa(2)N1:N5-bis[bis(2,2'-bipyridine-kappa(2)N,N')copper(II)] triperchlorate ethanol hemisolvate, complexes with unusual dicyanamide coordination.
From reaction mixtures containing the same reagents, the two novel title complexes, with unusual coordination modes of the dicyanamide (dca) ligand, have been prepared. The first compound, [Cu(C(2)N(3))(C(10)H(8)N(2))(2)]ClO(4), represents a relatively rare class of compounds, with the dca ligand coordinated in a monodentate manner. Its structure is formed by the [Cu(bpy)(2)N(CN)(2)](+) complex cation (bpy is 2,2'-bipyridine) and a ClO(4)(-) anion, which does not enter the inner coordination sphere. The Cu centre is five-coordinate within a strongly distorted trigonal bipyramid to two bpy molecules and one dca ligand, which is coordinated through one nitrile N atom in the equatorial plane. The second compound, [Cu(2)(C(2)N(3))(C(10)H(8)N(2))(4)](ClO(4))(3).0.5C(2)H(6)O, contains dca coordinated in the more common bidentate manner, but instead of a chain structure, a unique binuclear complex is formed. The asymmetric unit consists of the [Cu(bpy)(2)N(CN)(2)(bpy)(2)Cu](3+) binuclear complex cation, the charge of which is neutralized by three uncoordinated perchlorate anions, and a half-molecule of ethanol. Both Cu centres in the cation are five-coordinate, adopting a slightly distorted trigonal-bipyramidal environment.