Research Article: Bis(hydrazin-1-ium) bis­(μ2-pyridazine-3,6-dicarboxyl­ato)bis­(aqua­lithiate) octa­aqua­bis­(μ3-pyridazine-3,6-dicarboxyl­ato)tetra­lithium

Date Published: March 01, 2012

Publisher: International Union of Crystallography

Author(s): Wojciech Starosta, Janusz Leciejewicz.


The unit cell of the title compound, (N2H5)2[Li2(C6H2N2O4)2(H2O)2]·[Li4(C6H2N2O4)2(H2O)8], comprises two centrosymmetric complexes, one double negatively charged and one neutral, and two mono-protonated hydrazine cations. The anionic complex molecule is a dimer, built of a pair of symmetry-related pyridazine-3,6-dicarboxyl­ate ligands and a pair of LiI ions, each coordinated by two N,O-chelating sites donated by a ligand mol­ecule and an aqua O atom at the apical position. The penta­coordination around the LiI ions is partway between a trigonal–bipyramidal and a square-pyramidal arrangement. The two carb­oxy­lic acid groups of the ligand are deprotonated and one carboxyl­ate O atom of each group is not involved in the coordination, and this applies to both the anionic and the neutral complex. The neutral complex molecule is also composed of a pair of LiI ions and a pair of ligand mol­ecules related by a centre of symmetry. They form a dimeric core in which the penta­coordination of the LiI ions includes two N,O-bonding groups donated by two ligands and an aqua O atom. The penta­coordination is described as partway between a trigonal–bipyramidal and a square-pyramidal arrangement. The coordinated carboxyl­ate group is bidentate–bridging, forming with an Li(H2O)3 unit a neutral tetra­meric mol­ecule. The coordination of the tetra­coordinated LiI ion shows a slightly distorted tetra­hedral geometry. An extended system of O—H⋯O and N—H⋯O hydrogen bonds contributes to the stability of the crystal structure.

Partial Text

For the crystal structures of LiI complexes with pyridazine-3,6-dicarboxyl­ate and water ligands, see: Starosta & Leciejewicz (2010 ▶, 2011 ▶). The structure of a hydrazine adduct of pyridazine-3,6-dicarb­oxy­lic acid was reported by Starosta & Leciejewicz (2008 ▶).