The crystal structures of the Hexakis(pyridine 1-oxide) complexes of copper(II), cobalt(II) and iron(II) perchlorates

Abstract

The crystal structures of the isomorphous complexes [M(pyridine 1-oxide)₆] (ClO₄)₂ M = Cu (1), Co (2) and Fe (3), have been determined from X-ray diffractometer data collected at 293 K. The complexes crystallize in the rhombohedral space group R3 with Z = 1; cell constants for (1): a 9.605(1)Ǻ, α 81.10(1)°; for (2): a 9.619(1)Ǻ, α 81.19(1)°; for (3): a 9.640(1)Ǻ, α 81.06(1)°. The structures were solved by Fourier techniques and refined by block-diagonal least squares to convergence at R, R': (1) 0.037, 0.039 for 1009 reflections; (2) 0.030, 0.038 for 812 reflections; (3) 0.032, 0.041 for 780 reflections with I ≥ 3σ(I). The cations have exact S₆ symmetry with the MO₆ moiety having almost exact O_h symmetry, which implies for (1) a lack of a static Jahn-Teller distortion. The M-O distances increase (1) 2.076(2), (2) 2.090(1), (3) 2.112(2)Ǻ in the order expected. The geometries of the pyridine 1-oxide ligand and the perchlorate ion are consistent over the three determinations and are normal.