Synthesis and molecular structure of the cobalt(ii) chloride complex with bis(α-pyridyl)-substituted bispidinoaza-14-crown-4

The reaction of cobalt(ii) chloride with bis(benzo)bispidinoaza-14-crown-4 (L) containing two α-pyridyl substituents affords complex [Co(L)(H2O)][CoCl4] (1). The structure of complex 1 was determined by X-ray diffraction analysis. In structure 1, molecule L is coordinated to the neutral Co(1) atoms as an N, N, N, N-tetradentate-chelating ligand. The tetrachlorocobaltate dianion acts as a counterion. The coordination polyhedron of the Co atom in complex 1 is an octahedron, and that of the Co(2) atom in the anion is a tetrahedron. The coordination polyhedra of the Co atoms in complex 1 are linked by the bridging chlorine atom. In the octahedron of the Co(1) atom, two five-membered and two six-membered nonplanar chelate metallocycles, which are conjugated with each other along the Co(1)-N(1) and Co(1)-N(2) bonds, undergo ring closure. All bond lengths of the Co(1) atom with the N atoms range from 2.098(4) to 2.228(5) Å, and the Co(2)-Cl bond lengths change from 2.233(2) to 2.331(2) Å. The longest Co(1)-Cl(4) bond (2.558(2) Å) is that with the metal ion. A molecule of complex 1 is stabilized by strong intramolecular hydrogen bonds involving the crown ether fragment.