Poly[[diaqua­hemi-μ4-oxalato-μ2-oxalato-praseodymium(III)] monohydrate]

Ting-Hai Yang; Qiang Chen; Wei Zhuang; Zhe Wang; Bang-Yi Yue

doi:10.1107/S1600536809033947

. 2009 Aug 29;65(Pt 9):m1152–m1153. doi: 10.1107/S1600536809033947

Poly[[diaquahemi-μ₄-oxalato-μ₂-oxalato-praseodymium(III)] monohydrate]

Ting-Hai Yang ^a,^*, Qiang Chen ^a, Wei Zhuang ^a, Zhe Wang ^a, Bang-Yi Yue ^a

PMCID: PMC2969896 PMID: 21577485

Abstract

In the title complex, {[Pr(C₂O₄)_1.5(H₂O)₂]·H₂O}_n, the Pr^III ion, which lies on a crystallographic inversion centre, is coordinated by seven O atoms from four oxalate ligands and two O atoms from two water ligands; further Pr—O coordination from tetradentate oxalate ligands forms a three-dimensional structure. The compound crystallized as a monohydrate, the water molecule occupying space in small voids and being secured by O—H⋯O hydrogen bonding as an acceptor from ligand water H atoms and as a donor to oxalate O-acceptor sites.

Related literature

For background to lanthanide oxalates and their preparation, see: Hansson (1970 ▶, 1972 ▶, 1973a ▶, 1973b ▶); Michaelides et al. (1988 ▶); Ollendorf & Weigel (1969 ▶); Steinfink & Brunton (1970 ▶); Trollet et al. (1998 ▶); Trombe (2003 ▶); Unaleroglu et al. (1997 ▶). For related structures, see: Trombe et al. (2004 ▶); Barrett Adams et al. (1998 ▶); Beagley et al. (1988 ▶).

Experimental

Crystal data

[Pr(C₂O₄)_1.5(H₂O)₂]·H₂O
M _r = 326.99
Triclinic,
a = 6.0367 (12) Å
b = 7.6222 (15) Å
c = 8.9353 (18) Å
α = 98.330 (4)°
β = 99.814 (3)°
γ = 96.734 (4)°
V = 396.58 (14) Å³
Z = 2
Mo Kα radiation
μ = 6.17 mm⁻¹
T = 273 K
0.18 × 0.16 × 0.10 mm

Data collection

Bruker SMART APEX CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2001 ▶) T _min = 0.341, T _max = 0.542
2140 measured reflections
1521 independent reflections
1450 reflections with I > 2σ(I)
R _int = 0.020

Refinement

R[F ² > 2σ(F ²)] = 0.029
wR(F ²) = 0.075
S = 1.00
1521 reflections
118 parameters
H-atom parameters constrained
Δρ_max = 0.80 e Å⁻³
Δρ_min = −1.50 e Å⁻³

Data collection: SMART (Bruker, 2007 ▶); cell refinement: SAINT (Bruker, 2007 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: DIAMOND (Brandenburg, 1999 ▶); software used to prepare material for publication: SHELXTL (Sheldrick, 2008 ▶).

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809033947/nk2001sup1.cif

e-65-m1152-sup1.cif^{(17.4KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809033947/nk2001Isup2.hkl

e-65-m1152-Isup2.hkl^{(75KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O2W—H2WB⋯O1W	0.84	2.55	2.858 (7)	103
O1W—H1WA⋯O2ⁱ	0.84	1.96	2.694 (6)	146
O1W—H1WA⋯O3ⁱⁱ	0.84	2.60	3.235 (6)	133
O1W—H1WB⋯O3Wⁱⁱⁱ	0.84	2.00	2.833 (6)	169
O2W—H2WA⋯O3W^iv	0.84	1.98	2.807 (7)	166
O2W—H2WB⋯O3^v	0.84	2.20	2.919 (6)	144
O3W—H3WA⋯O6^vi	0.84	2.08	2.829 (7)	149
O3W—H3WB⋯O4^vii	0.84	2.03	2.833 (6)	159

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) ; (iv) ; (v) ; (vi) ; (vii) .

Acknowledgments

The authors acknowledge the High-Tech Research Institute of Nanjing University for supporting this work.

supplementary crystallographic information

Comment

In the last decade considerable attention has been afforded to the structures and properties of lanthanide oxalates due to their ability to act as precursors of lanthanide oxides. Some single crystals of lanthanide oxalates, such as[Ln(C₂O₄)₃(H₂O)₄].(H₂O) (Ln = Sc or Yb), [Ln₂(C₂O₄)₃(H₂O)₆].4H₂O (Ln = La, Ce, Pr or Nd) and [Nd₂(C₂O₄)₃(H₂O)₆] have been obtained either in silica gel (Ollendorff & Weigel, 1969), by hydrothermal reaction (Michaelides et al., 1988) or by other methods (Hansson, 1970, 1972, 1973a,b; Unaleroglu et al., 1997; Trollet et al., 1998; Trombe, 2003). Crystals of [Ln(C₂O₄)(HC₂O₄)].4H₂O (Ln = Er or Tm) were prepared by saturating a boiling solution of oxalic acid in 3 M H₂SO₄ with the lanthanide oxide and then slowly cooling to 273 K (Steinfink & Brunton, 1970). However, a few praseodymium oxalate complex has been reported. The present paper is concerned with a new crystal structure of praseodymium oxalate complex with a three-dimensional network structure.

The asymmetric unit of the title compound, [Pr(C₂O₄)_1.5(H₂O)₂].(H₂O), (I), is shown in Fig. 1. The Pr atom lies on an inversion centre and is coordinated by seven O atoms [O1, O1^iv, O2ⁱⁱ, O3, O4ⁱⁱⁱ, O5 and O6ⁱ] from four oxlate ligands, and two O atoms from two aqua ligands, thereby forming a slightly distorted PrO₉ polyhedral coordination geometry. The Pr—O bond distances range from 2.451 (4) Å to 2.608 (3) Å, in agreement with those in compounds (Trombe et al. (2004); Barrett Adams et al. (1998)).

In the complex, the equivalent Pr atom are connected is coordinated by seven O atoms from four oxalate ligands and two O atoms from water ligands. Further Pr–O coordination from the tetradentate oxalate ligands forms a three-dimensional structure (Fig.2). The compound crystallized as a monohydrate; this water molecule occupies space in small voids and is secured by O–H···O hydrogen bonding as an acceptor from ligand water H-atoms and as a donor to oxalate O acceptor sites.

Experimental

All solvents and chemicals were of analytical grade and were used without further purification. Pr(NO₃)₃^.6H₂O (0.05 mmol, 0.023 g), Na₂C₂O₄(0.075 mmol, 0.011 g), and deionized water (10 ml) were mixed together. The mixture was sealed in a Teflon-line autoclave and then heated at 443 K for 5 d under autogenous pressure and then cooled to room temperature. Green crystals were obtained.