Catena-Poly[[lithium-μ2-(di-hydrogen pyrazine-2,3,5,6-tetra-carboxyl-ato)-κ(6) O (2),N (1),O (6);O (3),N (4),O (5)-lithium-di-μ-aqua-κ(4) O:O] 2.5-hydrate

Wojciech Starosta,Janusz Leciejewicz

doi:10.1107/s160053681401174x

Wojciech Starosta, Janusz Leciejewicz

Open Access

https://doi.org/10.1107/s160053681401174x

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Abstract

The title coordination polymer, {[Li2(C8H2N2O8)(H2O)2]·2.5H2O}n, is built up from molecular ribbons propagating in the c-axis direction of the orthorhombic unit cell; the ligand bridges two Li+ ions using both its N,O,O′-bonding sites and adjacent Li+ ions are bridged by pairs of water molecules. The coordination geometry of the metal ion is distorted trigonal bipyramidal, with the ligand O atoms in the axial sites. Two of the carboxylate groups of the ligand remain protonated and form short symmetric O—H⋯O hydrogen bonds. In the crystal, the ribbons interact via a network of O—H⋯O hydrogen bonds in which coordinating water molecules act as donors and carboxylate O atoms within adjacent ribbons act as acceptors, giving rise to a three-dimensional framework. O—H⋯N interactions are also observed. The asymmetric unit contains quarter of the ligand and the complete ligand has 2/m symmetry; the Li+ ion lies on a special position with m.. site symmetry. Both bridging water molecules have m2m site symmetry and both lattice water molecules have m.. site symmetry; one of the latter was modelled with a site occupancy of 0.25.

Highlights

The title coordination polymer, {[Li2(C8H2N2O8)(H2O)2]2.5H2O}n, is built up from molecular ribbons propagating in the c-axis direction of the orthorhombic unit cell; the ligand bridges two Li+ ions using both its N,O,O0 -bonding sites and adjacent Li+ ions are bridged by pairs of water molecules
The asymmetric unit contains quarter of the ligand and the complete ligand has 2/m symmetry; the Li+ ion lies on a special position with m.. site symmetry
Both bridging water molecules have m2m site symmetry and both lattice water molecules have m.. site symmetry; one of the latter was modelled with a site occupancy of 0.25

Summary

Wojciech Starosta and Janusz Leciejewicz*

The title coordination polymer, {[Li2(C8H2N2O8)(H2O)2]2.5H2O}n, is built up from molecular ribbons propagating in the c-axis direction of the orthorhombic unit cell; the ligand bridges two Li+ ions using both its N,O,O0 -bonding sites and adjacent Li+ ions are bridged by pairs of water molecules. The coordination geometry of the metal ion is distorted trigonal bipyramidal, with the ligand O atoms in the axial sites. Two of the carboxylate groups of the ligand remain protonated and form short symmetric O—H O hydrogen bonds. The ribbons interact via a network of O—H O hydrogen bonds in which coordinating water molecules act as donors and carboxylate O atoms within adjacent ribbons act as acceptors, giving rise to a three-dimensional framework. Site symmetry; one of the latter was modelled with a site occupancy of 0.25

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Wojciech Starosta and Janusz Leciejewicz

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