The Crystal Structure of Perchlorato-bis(2,2′-bipyridine)copper(II) Perchlorate, [Cu(ClO4)(bipy)2]ClO4

Abstract The structure of bis(2,2′-bipyridine)copper(II) perchlorate, Cu(bipy)2(ClO4)2, has been determined from three-dimensional X-ray data collected by the photographic method. The compound forms triclinic crystals with a=7.44(1), b=14.93(1), c=15.32(1) Å, α=136.3(0.1), β=103.7(0.1), γ=83.2(0.1)°, and Z=2 in the space group P\bar1. The structure was solved by the usual Patterson and Fourier techniques and was refined by the least-squares method to an R value of 0.134. The crystal is composed of an infinite chain of [Cu(ClO4)(bipy)2+]∞ and ClO4−; a perchlorate ion in the chain bridges two adjacent copper atoms through its two oxygen atoms. Roughly speaking, the coordination polyhedron around the copper atom is a tetragonally-distorted octahedron; the four nitrogen atoms of bipyridine molecules are arranged in a flattened tetrahedral manner (average Cu–N=1.99 Å), the least-squares plane of these atoms making an equatorial plane, while the polar positions are occupied by the two oxygen atoms of perchlorate anions, the Cu–O distances being 2.45 and 2.73 Å. The two pyridine rings are twisted slightly to each other in both of the bipyridine molecules; the dihedral angle between the pyridine planes is 13° in one bipyridine ligand and 4° in the other.