title: Orientational disorder in the one-dimensional coordination polymer catena-poly[[bis-(acetyl-acetonato-κ(2) O,O')cobalt(II)]-μ-1,4-di-aza-bicyclo-[2.2.2]octane-κ(2) N (1):N (4)].
abstract: The title compound, [Co(C5H7O2)2(C6H12N2)] n , was obtained as a one-dimensional coordination polymer from bis-(acetyl-acetonato)di-aqua-cobalt(II), [Co(acac)2(OH2)2], and 1,4-di-aza-bicyclo-[2.2.2]octane (DABCO), a di-amine with good bridging ability and rod-like spacer function. In the chain complex that extends along the c axis, the Co(II) atom is six-coordinated, the O-donor atoms of the chelating acac ligands occupying the equatorial positions and the bridging DABCO ligands being in trans-axial positions. In the crystal structure, the DABCO ligand is conformationally disordered in a 50:50 manner as a result of its location across a crystallographic mirror plane. The metal-metal distance is very close to that in a related compound exhibiting weak anti-ferromagnetic exchange between the Co(II) ions, and the title compound can thus be useful for obtaining more information about the contribution of different bridges to the magnetic coupling between paramagnetic ions.
authors.affiliation: Faculty of Applied Chemistry and Materials Science, University Politehnica of Bucharest, Polizu 1, RO-011061 Bucharest, Romania.
authors.forename: Florina
authors.initials: F
authors.lastname: Dumitru
authors.affiliation: Institute of Inorganic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany.
authors.forename: Ulli
authors.initials: U
authors.lastname: Englert
authors.affiliation: Institute of Chemistry, Humboldt University of Berlin, Brook-Taylor-Strasse 2, D-12489 Berlin, Germany.
authors.forename: Beatrice
authors.initials: B
authors.lastname: Braun
keywords: DABCO; acetyl­acetonate complexes; cobalt(II); crystal structure; magnetic behaviour; one-dimensional coordination polymer; orientational disorder