Starosta Wojciech, Leciejewicz Janusz
Institute of Nuclear Chemistry and Technology, ul.Dorodna 16, 03-195 Warszawa, Poland.
Acta Crystallogr Sect E Struct Rep Online. 2014 May 24;70(Pt 6):m234-5. doi: 10.1107/S160053681401174X. eCollection 2014 Jun 1.
The title coordination polymer, {[Li2(C8H2N2O8)(H2O)2]·2.5H2O} n , is built up from mol-ecular ribbons propagating in the c-axis direction of the ortho-rhom-bic 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 mol-ecules. The coordination geometry of the metal ion is distorted trigonal bipyramidal, with the ligand O atoms in the axial sites. Two of the carboxyl-ate groups of the ligand remain protonated and form short symmetric O-H⋯O hydrogen bonds. In the crystal, the ribbons inter-act via a network of O-H⋯O hydrogen bonds in which coordinating water mol-ecules act as donors and carboxyl-ate O atoms within adjacent ribbons act as acceptors, giving rise to a three-dimensional framework. O-H⋯N inter-actions 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 mol-ecules have m2m site symmetry and both lattice water mol-ecules have m.. site symmetry; one of the latter was modelled with a site occupancy of 0.25.
标题配位聚合物{[Li₂(C₈H₂N₂O₈)(H₂O)₂]·2.5H₂O}ₙ由在正交晶胞c轴方向上延伸的分子带构成；配体利用其N、O、O'键合位点桥连两个Li⁺离子，相邻的Li⁺离子由成对的水分子桥连。金属离子的配位几何构型为扭曲的三角双锥，配体的O原子位于轴向位置。配体的两个羧酸根基团保持质子化并形成短的对称O—H⋯O氢键。在晶体中，分子带通过O—H⋯O氢键网络相互作用，其中配位水分子作为供体，相邻分子带内的羧酸根O原子作为受体，形成三维框架。还观察到O—H⋯N相互作用。不对称单元包含四分之一的配体，完整的配体具有2/m对称性；Li⁺离子位于具有m.. 点对称性的特殊位置。两个桥连水分子都具有m2m点对称性，两个晶格水分子都具有m.. 点对称性；后者中的一个占有率建模为0.25。
