Poly[dimethylammonium [aquadi-μ2-oxalato-yttriate(III)] trihydrate]

The title complex, {(C2H8N)[Y(C2O4)2(H2O)]·3H2O}n, was obtained accidentally under hydrothermal conditions. The YIII atom is chelated by four oxalate ligands and one water molecule resulting in a distorted tricapped trigonal–prismatic geometry. Each oxalate ligand bridges two YIII atoms, thus generating a three-dimensional network with cavities in which the ammonium cations and lattice water molecules reside. Various O—H⋯O and N—H⋯O hydrogen-bonding interactions stabilize the crystal structure. The title complex is isotypic with the Eu and Dy analogues.

The title complex, {(C 2 H 8 N)[Y(C 2 O 4 ) 2 (H 2 O)]Á3H 2 O} n , was obtained accidentally under hydrothermal conditions. The Y III atom is chelated by four oxalate ligands and one water molecule resulting in a distorted tricapped trigonal-prismatic geometry. Each oxalate ligand bridges two Y III atoms, thus generating a three-dimensional network with cavities in which the ammonium cations and lattice water molecules reside. Various O-HÁ Á ÁO and N-HÁ Á ÁO hydrogen-bonding interactions stabilize the crystal structure. The title complex is isotypic with the Eu and Dy analogues.

Related literature
For general background to the rational design and synthesis of metal-organic polymers, see: Lv et al. (2010Lv et al. ( , 2011. For related structures, see: Platel et al. (2009) ;Gao & Cui (2008); Deguenon et al. (1990). The structure of the isotypic Eu III compound was reported by Yang et al. (2005), and that of the Dy III compound by Ye & Lin (2010). For decomposition products obtained under hydrothermal conditions, see: Song et al. (2004).

Poly[dimethylammonium [aquadi-µ 2 -oxalato-yttriate(III)] trihydrate]
Yao-Kang Lv, Li-Hua Gan, Liang Xu, Hao-Wen Zheng and Cao Liu S1. Comment Rational design and synthesis of metal-organic polymers have attracted much attention in the field of supramolecular chemistry and crystal engineering (Lv et al., 2010;. Oxalate, which usually represent one of the products of the degradation of some organic compounds, is one of the simplest multidentate organic ligands potentially able to bridge metal ions in a bidentate chelating manner (Deguenon et al., 1990). Herein, we report the synthesis and structure of a novel yttrium(III) complex, (C 2 Complex (I) is isotypic with its Eu(III) (Yang et al., 2005) and Dy(III) (Ye & Lin, 2010) analogues. As shown in Fig. 1, the Y III atom is chelated by four oxalate ligands and one water molecule resulting in a distorted tricapped trigonalprismatic coordination environment. The Y-O bond lengths fall in the range of 2.374 (2)-2.459 (2) Å, which is in agreement with comparable values reported elsewhere (Platel et al., 2009;Gao & Cui, 2008). Each oxalate ligand bridges two Y III atoms, thus generating a three-dimensional network with cavities where the ammonium cations and lattice water molecules reside (Fig. 2). Furthermore, there are various hydrogen-bonding interactions (N-H···O and O-H···O), involving the lattice water molecules and the cations, which give rise to a tightly held network structure.
Colorless block-shaped crystals of the title compound suitable for X-ray crystallographic study were obtained via slow evaporation within 2 weeks.
It is most likely that the oxalate ligands in this complex originates from the decomposition of the potassium salt of Dsaccharic acid, and the protonated dimethylamine cations compensating the negative charge of the anionic network are believed to result from decomposition of the N,N-dimethylformamide solvent (Song et al., 2004;Ye & Lin, 2010).

S3. Refinement
The hydrogen atoms attached to carbon and nitrogen atoms were positioned geometrically, while those attached to oxygen atom were located from difference Fourier maps. H atoms attached to C atoms were refined using a riding model with C-H = 0.96 Å and U iso (H) = 1.2U eq (C); H atoms attached to N atoms were refined with N-H = 0.90 Å and U iso (H) = 1.2U eq (N); H atoms attached to O atoms were refined without distance restraints and with U iso (H) = 1.2U eq (O).  An expanded vioew of the asymmetric unit of (I), showing the coordination of the Y III atom, and the presence of the lattice water molecules and the ammonium cation. All hydrogen atoms were omitted for clarity. [Symmetry codes: (i) -x + 1, y + 1/2, -z + 1/2; (ii) -x + 1, -y + 2, -z + 1; (iii) -x + 2, -y + 2, -z + 1.]

Figure 2
View of the three-dimensional framework of (I). All hydrogen atoms are omitted for clarity. Hydrogen bonding between donator and acceptor atoms is indicated by dashed lines. where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max = 0.001 Δρ max = 0.70 e Å −3 Δρ min = −0.58 e Å −3 Special details Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes. Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.