Supramolecular interactions in 4,4′-Bipyridine cobalt(II) nitrate networks

Felloni, M., Blake, A. J., Champness, N. R., Hubberstey, P., Wilson, C. and Schröder, M. (2002) Supramolecular interactions in 4,4′-Bipyridine cobalt(II) nitrate networks. Journal of Supramolecular Chemistry, 2(1-3), pp. 163-174. (doi: 10.1016/s1472-7862(03)00006-6)

Abstract

Crystallisation of cobalt(II) nitrate from solutions containing 4,4′-bipyridine (4,4′-bipy) yields, depending on the conditions, 4,4′-bipyridine cobalt(II) nitrate networks with 4,4′-bipy:Co molar ratios of 3:2 {[{Co(O2NO)2}(μ-4,4′-bipy)1.5]·Et2O}∞, 3:1 {[{Co(ONO2)2(4,4′-bipy)2}(μ-4,4′-bipy)]·2.5MeOH}∞, 1, 4:1 {[{Co(H2O)2}(μ-4,4′-bipy)2][NO3]2·2(4,4′-bipy)·2H2O}∞, 2, or 5:1 {[{Co(H2O)2(4,4′-bipy)2}(μ-4,4′-bipy)]·1.5[NO3]·0.5OH·2(4,4′-bipy)·2.5H2O}∞, 3. Whereas the purple 3:2 product is based on a pentagonal pyramidal CoO4N3 co-ordination sphere, the other three orange products (1–3) are all based on octahedral CoO2N4 centres. Although analogues of the purple product, the extended structure of which adopts a 1-D ladder motif, have been reported previously, the orange products, the extended structures of which are based on 2-D sheets of (4,4) topology, are unprecedented. These products, however, differ in the construction of the (4,4) sheets. In 2, all four of the 4,4′-bipy molecules bridge cobalt(II) centres to generate an almost square (4,4) grid, while in 1 and 3, only two of the four 4,4′-bipy molecules bridge cobalt(II) centres to generate either a zig-zag chain (in 1) or a linear chain (in 3). The two terminal 4,4′-bipy ligands in 1 and 3 are involved in π–π stacking interactions and in hydrogen-bonding interactions, respectively, to form rhombic (4,4) grids. In 2, however, an unprecedented sequence of co-ordinate, hydrogen-bonding and π–π stacking interactions links cobalt(II) centres from parallel {[Co(μ-4,4′-bipy)2]2+}∞ square grids via two water and two 4,4′-bipy molecules to generate a doubly-interpenetrated ReO3-type network structure. 44,′-Bipyridine cobalt(III)nitrate networks with 4-4′-bipy:Co ratios of 3:1, 4:1 and 5:1, in which a wide range of co-ordinate, hydrogen-bonding and π-π stacking interactions are observed, have been synthesised and structurally characterised.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Wilson, Dr Claire
• Authors: Felloni, M., Blake, A. J., Champness, N. R., Hubberstey, P., Wilson, C., and Schröder, M.
• College/School: College of Science and Engineering > School of Chemistry
• Journal Name: Journal of Supramolecular Chemistry
• Publisher: Elsevier
• ISSN: 1472-7862
• Published Online: 15 March 2003