Crystal structure of di-μ-chlorido-bis-{chlorido-[(-)-5,6-pinenebi-pyridine]-cobalt(II)} aqua-dichlorido[(-)-5,6-pinenebi-pyridine]cobalt(II)

Abstract

The crystal structure of [Co₂Cl₄(C₁₇H₁₈N₂)₂][CoCl₂(C₁₇H₁₈N₂)(H₂O)] or [Co(L)Cl(μ-Cl)]₂[Co(L)(Cl)₂(OH₂)], where L is the enanti-opure bidentate ligand (-)-5,6-pinenebi-pyridine (C₁₇H₁₈N₂), has been determined. Crystals suitable for X-ray structure analysis were obtained by slow evaporation of an ethano-lic solution containing equimolar amounts of L and CoCl₂·6H₂O. The Co^II cations all have a coordination number of five, and in each case the coordination polyhedron is a trigonal bipyramid. The Co-N bonds lengths range from 2.037 (7) to 2.195 (7) Å, and Co-Cl bonds lengths range from 2.284 (2) to 2.509 (2) Å. The asymmetric unit contains two discrete complexes, one dinuclear and the other mononuclear. Between the two mol-ecules, two types of inter-molecular inter-actions have been evidenced: π-π stackings involving the bi-pyridine units, and O-H⋯Cl hydrogen bonds between the hydrogen atoms of the aqua ligand coordinating to the mononuclear complex and the non-bridging chlorido ligand coordinating to the dinuclear mol-ecule. These inter-actions lead to a two-dimensional supra-molecular arrangement parallel to the ab plane.

Keywords: (−)-5,6-pinenebi­pyridine; cobalt(II) complex; crystal structure; hydrogen bonding.