Research Article: Poly[[diaqua­bis­[μ4-5-nitro­isophthalato-κ4O1:O1:O3:O3′]bis­[μ3-pyridine-4-carboxyl­ato-κ3O:O′:N]tricobalt(II)] tetra­hydrate]

Date Published: April 01, 2012

Publisher: International Union of Crystallography

Author(s): Xia Yin, Jun Fan, Jingling Xin, Shengrun Zheng, Weiguang Zhang.


The title compound, {[Co3(C6H4NO2)2(C8H3NO6)2(H2O)2]·4H2O}n, exhibits a two-dimensional layer-like structure in which the CoII ions exhibit two kinds of coordination geometries. One nearly octa­hedral CoII ion with crystallographic inversion symmetry is coordinated to six carboxyl­ate O atoms from four bridging 5-nitro­isophthalate (NIPH) ligands and two isonicotinate (IN) anions, while the other type of CoII ion binds with one N atom and one carboxyl­ate O atom from two IN anions, two carboxyl­ate O atoms from two different NIPH anions and one ligated water mol­ecule, displaying a distorted square-pyramidal coordination geometry. Three adjacent CoII ions are bridged by six carboxyl­ate groups from four NIPH ligands and two IN anions to form a linear trinuclear secondary building unit (SBU). Every trinuclear SBU is linked to its nearest neighbours in the ab plane, resulting in a two-dimensional layer-like structure perpendicular to the c axis. Along the a-axis direction neighbouring mol­ecules are connected through carboxyl­ate and pyridyl units of the IN anions, along the b axis through carboxyl­ate groups of the NIPH ligands. The H atoms of one free water mol­ecule are disordered in the crystal in a 1:1 ratio. Typical O—H⋯O hydrogen bonds are observed in the lattice, which include the following contacts: (a) between coordinated water mol­ecules and carboxyl­ate O atoms of the NIPH anions, (b) between lattice water mol­ecules and carboxyl­ate O atoms of the NIPH anions, and (c) between coordinated and lattice water mol­ecules. These inter­molecular hydrogen bonds connect the two-dimensional layers to form a three-dimensional supra­molecular structure.

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For general background to the design and synthesis of coordination polymers, see: Jiang et al. (2010 ▶); Ma et al. (2009 ▶); Natarajan & Mahata (2009 ▶); Zang et al. (2006 ▶). For complexes with isonicotinate, see: Amo-Ochoa et al. (2010 ▶). For complexes with 5-nitro­isophthalate, see: Chen et al. (2006 ▶, 2010 ▶); Sun et al. (2010 ▶). For related compounds, see: Du et al. (2008 ▶); Luo et al. (2003 ▶); Wang et al. (2009 ▶).