Poly[tetra­aqua­(5-hy­droxy­pyridin-1-ium-3-carboxyl­ato-κO3)tris­(μ-oxalato-κ4O1,O2:O1′,O2′)dieuropium(III)]

Xu, S.-S.; Mi, J.-L.; Chen, H.-J.

doi:10.1107/S1600536813011057

metal-organic compounds

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ISSN: 2056-9890

Volume 69| Part 5| May 2013| Pages m294-m295

https://doi.org/10.1107/S1600536813011057

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Poly[tetraaqua(5-hydroxypyridin-1-ium-3-carboxylato-κO³)tris(μ-oxalato-κ⁴O¹,O²:O^1′,O^2′)dieuropium(III)]

Shan-Shan Xu,^a Jun-Long Mi ^a and Hong-Ji Chen ^a ^*

^aDepartment of Materials Science and Engineering, Jinan University, Guangzhou 510632, People's Republic of China
^*Correspondence e-mail: thjchen@jnu.edu.cn

(Received 15 April 2013; accepted 23 April 2013; online 27 April 2013)

In the title compound, [Eu₂(C₆H₅NO₃)₂(C₂O₄)₃(H₂O)₄]_n, the Eu^III atom is bonded to one O atom from a monodentate 5-hydroxypyridin-1-ium-3-carboxylate ligand, six O atoms from three oxalate ligands and two water molecules, exhibiting a highly distorted tricapped trigonal geometry. Three independent oxalate ligands, each lying on an inversion center, bridge the Eu^III atoms, forming a brickwall-like layer parallel to (001), which is stabilized by intralayer O—H⋯O hydrogen bonds. The layers are further linked through interlayer O—H⋯O and N—H⋯O hydrogen bonds and π–π interactions between the pyridine rings [centroid–centroid distance = 3.5741 (14) Å] into a three-dimensional supramolecular network.

Related literature

For background to metal complexes of pyridine-carboxylic derivatives, see: Black et al. (2009 ); Cañadillas-Delgado et al. (2010 ); Hu et al. (2007 ); Sun et al. (2010 ); Wen et al. (2007 ); Xu et al. (2008 ). For structures and properties of coordination polymers derived from 5-hydroxynicotinic acid, see: Bunzli (2010 ); Decadt et al. (2012 ); Gai et al. (2012 ); Ramya et al. (2012 ); Yang et al. (2011 ); Zhang et al. (2012 ).

Experimental

Crystal data

[Eu₂(C₆H₅NO₃)₂(C₂O₄)₃(H₂O)₄]
M_r = 918.26
Triclinic, $[P \overline 1]$
a = 7.5912 (2) Å
b = 8.0973 (3) Å
c = 10.6706 (3) Å
α = 103.493 (3)°
β = 98.589 (3)°
γ = 92.240 (3)°
V = 628.78 (3) Å³
Z = 1
Mo Kα radiation
μ = 5.05 mm⁻¹
T = 153 K
0.24 × 0.17 × 0.08 mm

Data collection

Bruker APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ) T_min = 0.377, T_max = 0.688
12455 measured reflections
3135 independent reflections
2965 reflections with I > 2σ(I)
R_int = 0.037

Refinement

R[F² > 2σ(F²)] = 0.018
wR(F²) = 0.038
S = 1.09
3135 reflections
221 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.55 e Å⁻³
Δρ_min = −0.54 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1⋯O9ⁱ	0.83 (3)	1.84 (3)	2.662 (3)	172 (3)
O3—H3A⋯O2ⁱⁱ	0.82	1.73	2.543 (2)	169
O10—H7⋯O4ⁱⁱⁱ	0.76 (4)	2.26 (4)	3.016 (2)	168 (4)
O10—H8⋯O2^iv	0.92 (4)	1.85 (4)	2.759 (3)	170 (3)
O11—H9⋯O6ⁱⁱⁱ	0.88 (4)	1.90 (4)	2.771 (3)	170 (4)
O11—H10⋯O3^v	0.74 (4)	2.04 (4)	2.776 (3)	172 (4)
Symmetry codes: (i) x, y, z+1; (ii) x, y-1, z; (iii) -x+2, -y+2, -z+1; (iv) -x+2, -y+2, -z+2; (v) x, y+1, z.

Data collection: APEX2 (Bruker, 2007 ); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ); program(s) used to refine structure: SHELXTL; molecular graphics: DIAMOND (Brandenburg, 1999 ); software used to prepare material for publication: SHELXTL.

Supporting information

Crystal structure: contains datablocks I, global. DOI: https://doi.org/10.1107/S1600536813011057/hy2623sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536813011057/hy2623Isup2.hkl

checkCIF report

Comment top

Pyridine-carboxylic derivatives are of resent interest in coordination polymers due to their structural diverity and unique physical properties (Black et al., 2009; Cañadillas-Delgado et al., 2010). Some transition and/or rare earth metal complexes with pyridine-2,5/6-dicarboxylic acid (Sun et al., 2010; Wen et al., 2007) or 2/6-hydroxynicotinic acid (Hu et al., 2007; Xu et al., 2008) have been prepared and documented. Recently, a few coordination polymers from 5-hydroxynicotinic acid are reported, in which the multidentate bridging ligand exhibits versatile coordination modes in constructing transition metal (Yang et al., 2011) and rare earth metal (Zhang et al., 2012) organic frameworks. The research interest in europium(III) coordination polymers with the ligands comes from their luminescent properties (Decadt et al., 2012; Gai et al., 2012; Ramya et al., 2012) and applications (Bunzli, 2010). Here, we report the crystal structure of an europium(III) complex of a pyridine-carboxylic derivative.

The title compound is isostructural with its Tb(III) and Sm(III) analogues (Zhang et al., 2012). As shown in Fig. 1, the asymmetric unit contains an Eu^III ion, a 3-H-5-hydroxynicotinate ligand, one and half oxalate ligands and two coordinated water molecules. The Eu^III ion is bonded to nine O atoms, one from the 3-H-5-hydroxynicotinate ligand, six from three oxalate ligands and two from the water molecules, exhibiting a highly distorted tricapped trigonal geometry. The Eu^III ions are linked by the oxalate ligands into a brickwall-like layer parallel to (001) (Fig. 2), with Eu···Eu distances of 6.1886 (3), 6.2845 (3) and 6.4206 (3) Å. In the compound, the three oxalate ligands are centrosymmetric and bridge metal ions in a side-by-side coordination manner. The layers are stabilized by intralayer O—H···O hydrogen bonds and further linked through interlayer O—H···O hydrogen bonds and π–π interactions between the pyridine rings [centroid–centroid distance = 3.5741 (14) Å] into a three-dimensional supramolecular network.

Related literature top

For background to metal complexes of pyridine-carboxylic derivatives, see: Black et al. (2009); Cañadillas-Delgado et al. (2010); Hu et al. (2007); Sun et al. (2010); Wen et al. (2007); Xu et al. (2008). For structures and properties of coordination polymers with 5-hydroxynicotinic acid, see: Bunzli (2010); Decadt et al. (2012); Gai et al. (2012); Ramya et al. (2012); Yang et al. (2011); Zhang et al. (2012).

Experimental top

A mixture of europium nitrate (0.4 mmol, 0.186 g), 5-hydroxynicotinic acid (0.8 mmol, 0.112 g), ammonium oxalate (0.8 mmol, 0.099 g) and 10 ml water was sealed in a 15 ml Teflon-lined autoclave. Colorless crystals suitable for X-ray analysis were obtained by heating the mixture at 443 K for 70 h and then cooled down to room temperature at a rate of 5 K/h (yield: 45%). Analysis, calculated for C₉H₉EuNO₁₁: C 23.54, H 1.98, N 3.05%; found: C 23.36, H 2.02, N 3.01%.

Structure description top

For background to metal complexes of pyridine-carboxylic derivatives, see: Black et al. (2009); Cañadillas-Delgado et al. (2010); Hu et al. (2007); Sun et al. (2010); Wen et al. (2007); Xu et al. (2008). For structures and properties of coordination polymers with 5-hydroxynicotinic acid, see: Bunzli (2010); Decadt et al. (2012); Gai et al. (2012); Ramya et al. (2012); Yang et al. (2011); Zhang et al. (2012).

Computing details top

Data collection: APEX2 (Bruker, 2007); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT (Bruker, 2007); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 1999); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top

	Fig. 1. The asymmetric unit of the title compound, showing displacement ellipsoids at the 50% probability level. [Symmetry codes: (i) -x+1, -y+2, -z+1; (ii) -x+2, -y+1, -z+1; (iii) -x+1, -y+1, -z+1.]
	Fig. 2. The layer structure of the title compound parallel to (001). H atoms are omitted for clarity.

Poly[tetraaqua(5-hydroxypyridin-1-ium-3-carboxylato-κO³)tris(µ-oxalato-κ⁴O¹,O²:O^1',O^2')dieuropium(III)] top

Crystal data top

[Eu₂(C₆H₅NO₃)₂(C₂O₄)₃(H₂O)₄]	Z = 1
M_r = 918.26	F(000) = 442
Triclinic, P1	D_x = 2.425 Mg m⁻³
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 7.5912 (2) Å	Cell parameters from 3135 reflections
b = 8.0973 (3) Å	θ = 2.6–29.4°
c = 10.6706 (3) Å	µ = 5.05 mm⁻¹
α = 103.493 (3)°	T = 153 K
β = 98.589 (3)°	Block, colorless
γ = 92.240 (3)°	0.24 × 0.17 × 0.08 mm
V = 628.78 (3) Å³

Data collection top

Bruker APEXII CCD diffractometer	3135 independent reflections
Radiation source: fine-focus sealed tube	2965 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.037
φ and ω scans	θ_max = 29.5°, θ_min = 2.6°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −9→9
T_min = 0.377, T_max = 0.688	k = −11→10
12455 measured reflections	l = −13→14

Refinement top

Refinement on F²	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F² > 2σ(F²)] = 0.018	H atoms treated by a mixture of independent and constrained refinement
wR(F²) = 0.038	w = 1/[σ²(F_o²) + (0.0087P)² + 0.3669P] where P = (F_o² + 2F_c²)/3
S = 1.09	(Δ/σ)_max = 0.002
3135 reflections	Δρ_max = 0.55 e Å⁻³
221 parameters	Δρ_min = −0.54 e Å⁻³
0 restraints	Extinction correction: SHELXL, Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0094 (4)

Crystal data top

[Eu₂(C₆H₅NO₃)₂(C₂O₄)₃(H₂O)₄]	γ = 92.240 (3)°
M_r = 918.26	V = 628.78 (3) Å³
Triclinic, P1	Z = 1
a = 7.5912 (2) Å	Mo Kα radiation
b = 8.0973 (3) Å	µ = 5.05 mm⁻¹
c = 10.6706 (3) Å	T = 153 K
α = 103.493 (3)°	0.24 × 0.17 × 0.08 mm
β = 98.589 (3)°

Data collection top

Bruker APEXII CCD diffractometer	3135 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	2965 reflections with I > 2σ(I)
T_min = 0.377, T_max = 0.688	R_int = 0.037
12455 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.018	0 restraints
wR(F²) = 0.038	H atoms treated by a mixture of independent and constrained refinement
S = 1.09	Δρ_max = 0.55 e Å⁻³
3135 reflections	Δρ_min = −0.54 e Å⁻³
221 parameters

Special details top

Experimental. IR (cm^-1, KBr): 3495(s), 3380(s), 3103(m), 3076(w), 3047(w), 2929(w), 2461(m), 2146(m), 1968(w), 1893(w), 1695(s), 1655(s), 1621(s), 1602(s), 1575(s), 1379(s), 1320(s), 1256(m), 1147(w), 1114(w), 1010(w), 935(w), 880(m), 806(s), 784(s), 667(m), 620(w), 565(w), 531(w), 484(m).

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 F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
C1	0.7687 (3)	0.8846 (3)	0.9610 (2)	0.0095 (5)
C2	0.7420 (3)	0.7295 (3)	1.0146 (2)	0.0094 (5)
C3	0.7733 (3)	0.5691 (3)	0.9454 (2)	0.0116 (5)
H3	0.8082	0.5552	0.8639	0.014*
C4	0.7525 (4)	0.4283 (3)	0.9978 (2)	0.0127 (5)
C5	0.7046 (4)	0.4541 (3)	1.1205 (2)	0.0132 (5)
H5	0.6934	0.3631	1.1590	0.016*
C6	0.6887 (3)	0.7479 (3)	1.1353 (2)	0.0110 (5)
H6	0.6631	0.8540	1.1818	0.013*
C7	0.5536 (3)	1.0035 (3)	0.4431 (2)	0.0099 (5)
C8	1.0255 (3)	0.5479 (3)	0.4489 (2)	0.0084 (5)
C9	0.4854 (3)	0.4971 (3)	0.5697 (2)	0.0101 (5)
Eu1	0.797021 (16)	0.810935 (14)	0.626500 (11)	0.00700 (5)
N1	0.6745 (3)	0.6119 (3)	1.1836 (2)	0.0112 (4)
O1	0.8197 (2)	0.8624 (2)	0.85299 (16)	0.0118 (4)
O2	0.7395 (3)	1.0258 (2)	1.03073 (16)	0.0141 (4)
O3	0.7803 (3)	0.2743 (2)	0.92694 (18)	0.0225 (5)
H3A	0.7713	0.2035	0.9698	0.034*
O4	0.7120 (2)	0.9644 (2)	0.45635 (16)	0.0117 (4)
O5	0.5274 (2)	0.9519 (2)	0.65247 (17)	0.0138 (4)
O6	0.9752 (2)	0.6961 (2)	0.45804 (16)	0.0103 (3)
O7	0.8889 (2)	0.5283 (2)	0.63432 (17)	0.0120 (4)
O8	0.5549 (2)	0.6147 (2)	0.66268 (16)	0.0117 (4)
O9	0.6111 (2)	0.6314 (2)	0.42511 (16)	0.0138 (4)
O10	1.1269 (2)	0.8348 (2)	0.70926 (19)	0.0138 (4)
O11	0.9123 (3)	1.1139 (2)	0.7043 (2)	0.0161 (4)
H1	0.645 (4)	0.622 (4)	1.257 (3)	0.025 (9)*
H7	1.179 (5)	0.876 (4)	0.667 (4)	0.032 (11)*
H8	1.168 (5)	0.893 (4)	0.794 (4)	0.038 (10)*
H9	0.937 (5)	1.181 (5)	0.654 (4)	0.050 (12)*
H10	0.874 (5)	1.164 (4)	0.760 (4)	0.027 (10)*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C1	0.0109 (12)	0.0101 (11)	0.0078 (12)	−0.0005 (9)	0.0008 (9)	0.0036 (9)
C2	0.0096 (12)	0.0113 (11)	0.0076 (12)	−0.0008 (9)	0.0007 (9)	0.0037 (9)
C3	0.0162 (13)	0.0124 (12)	0.0073 (12)	0.0010 (10)	0.0041 (9)	0.0035 (9)
C4	0.0177 (13)	0.0096 (12)	0.0118 (13)	0.0024 (10)	0.0037 (10)	0.0034 (9)
C5	0.0191 (14)	0.0104 (12)	0.0127 (13)	0.0025 (10)	0.0051 (10)	0.0060 (9)
C6	0.0151 (13)	0.0080 (11)	0.0101 (12)	−0.0007 (10)	0.0036 (9)	0.0015 (9)
C7	0.0127 (12)	0.0076 (11)	0.0106 (12)	0.0009 (9)	0.0053 (9)	0.0025 (9)
C8	0.0074 (12)	0.0105 (11)	0.0078 (11)	0.0007 (9)	0.0009 (9)	0.0030 (9)
C9	0.0080 (12)	0.0138 (12)	0.0103 (13)	0.0028 (10)	0.0037 (9)	0.0045 (9)
Eu1	0.00918 (8)	0.00665 (7)	0.00609 (7)	0.00141 (4)	0.00295 (4)	0.00217 (4)
N1	0.0159 (11)	0.0124 (10)	0.0056 (10)	−0.0002 (9)	0.0039 (8)	0.0014 (8)
O1	0.0162 (9)	0.0119 (8)	0.0077 (9)	−0.0008 (7)	0.0031 (7)	0.0027 (6)
O2	0.0256 (10)	0.0077 (8)	0.0102 (9)	0.0014 (7)	0.0067 (7)	0.0019 (7)
O3	0.0487 (14)	0.0073 (9)	0.0173 (10)	0.0068 (9)	0.0196 (9)	0.0049 (7)
O4	0.0101 (9)	0.0144 (9)	0.0126 (9)	0.0033 (7)	0.0047 (7)	0.0052 (7)
O5	0.0154 (9)	0.0194 (9)	0.0107 (9)	0.0078 (7)	0.0051 (7)	0.0088 (7)
O6	0.0128 (9)	0.0080 (8)	0.0129 (9)	0.0032 (7)	0.0067 (7)	0.0049 (6)
O7	0.0170 (9)	0.0095 (8)	0.0131 (9)	0.0045 (7)	0.0096 (7)	0.0047 (7)
O8	0.0125 (9)	0.0142 (9)	0.0082 (9)	−0.0020 (7)	0.0027 (7)	0.0020 (7)
O9	0.0173 (10)	0.0148 (9)	0.0098 (9)	−0.0066 (7)	0.0049 (7)	0.0038 (7)
O10	0.0118 (9)	0.0165 (9)	0.0123 (10)	−0.0015 (8)	0.0031 (7)	0.0016 (8)
O11	0.0274 (12)	0.0109 (9)	0.0122 (10)	0.0002 (8)	0.0090 (8)	0.0035 (8)

Geometric parameters (Å, º) top

C1—O1	1.246 (3)	C9—O9ⁱⁱⁱ	1.266 (3)
C1—O2	1.258 (3)	C9—C9ⁱⁱⁱ	1.546 (5)
C1—C2	1.515 (3)	Eu1—O1	2.3333 (16)
C2—C6	1.384 (3)	Eu1—O5	2.4025 (18)
C2—C3	1.385 (3)	Eu1—O7	2.4348 (16)
C3—C4	1.395 (3)	Eu1—O6	2.4433 (17)
C3—H3	0.9300	Eu1—O4	2.4539 (17)
C4—O3	1.341 (3)	Eu1—O11	2.4776 (18)
C4—C5	1.383 (3)	Eu1—O9	2.4899 (17)
C5—N1	1.344 (3)	Eu1—O10	2.5118 (19)
C5—H5	0.9300	Eu1—O8	2.5142 (16)
C6—N1	1.328 (3)	N1—H1	0.83 (3)
C6—H6	0.9300	O3—H3A	0.8200
C7—O5ⁱ	1.246 (3)	O5—C7ⁱ	1.246 (3)
C7—O4	1.252 (3)	O7—C8ⁱⁱ	1.241 (3)
C7—C7ⁱ	1.569 (5)	O9—C9ⁱⁱⁱ	1.266 (3)
C8—O7ⁱⁱ	1.241 (3)	O10—H7	0.76 (4)
C8—O6	1.260 (3)	O10—H8	0.92 (4)
C8—C8ⁱⁱ	1.562 (5)	O11—H9	0.89 (4)
C9—O8	1.238 (3)	O11—H10	0.74 (4)

O1—C1—O2	125.5 (2)	O1—Eu1—O8	75.12 (6)
O1—C1—C2	117.7 (2)	O5—Eu1—O8	68.60 (6)
O2—C1—C2	116.8 (2)	O7—Eu1—O8	66.05 (6)
C6—C2—C3	119.3 (2)	O6—Eu1—O8	117.53 (5)
C6—C2—C1	119.8 (2)	O4—Eu1—O8	115.81 (6)
C3—C2—C1	120.9 (2)	O11—Eu1—O8	138.86 (6)
C2—C3—C4	120.1 (2)	O9—Eu1—O8	64.36 (5)
C2—C3—H3	119.9	O10—Eu1—O8	129.19 (6)
C4—C3—H3	119.9	O1—Eu1—C7ⁱ	100.78 (6)
O3—C4—C5	123.0 (2)	O5—Eu1—C7ⁱ	20.20 (6)
O3—C4—C3	118.5 (2)	O7—Eu1—C7ⁱ	140.16 (6)
C5—C4—C3	118.5 (2)	O6—Eu1—C7ⁱ	120.37 (6)
N1—C5—C4	119.3 (2)	O4—Eu1—C7ⁱ	48.67 (6)
N1—C5—H5	120.4	O11—Eu1—C7ⁱ	78.99 (6)
C4—C5—H5	120.4	O9—Eu1—C7ⁱ	70.91 (6)
N1—C6—C2	119.0 (2)	O10—Eu1—C7ⁱ	148.31 (6)
N1—C6—H6	120.5	O8—Eu1—C7ⁱ	77.75 (6)
C2—C6—H6	120.5	O1—Eu1—C7	125.61 (6)
O5ⁱ—C7—O4	125.9 (2)	O5—Eu1—C7	48.20 (6)
O5ⁱ—C7—C7ⁱ	116.6 (3)	O7—Eu1—C7	141.25 (6)
O4—C7—C7ⁱ	117.5 (3)	O6—Eu1—C7	93.32 (6)
O7ⁱⁱ—C8—O6	125.7 (2)	O4—Eu1—C7	20.65 (6)
O7ⁱⁱ—C8—C8ⁱⁱ	117.4 (3)	O11—Eu1—C7	75.30 (6)
O6—C8—C8ⁱⁱ	116.9 (3)	O9—Eu1—C7	62.82 (6)
O8—C9—O9ⁱⁱⁱ	126.9 (2)	O10—Eu1—C7	132.68 (6)
O8—C9—C9ⁱⁱⁱ	118.7 (3)	O8—Eu1—C7	98.11 (6)
O9ⁱⁱⁱ—C9—C9ⁱⁱⁱ	114.4 (3)	C7ⁱ—Eu1—C7	28.45 (8)
O1—Eu1—O5	80.96 (6)	O1—Eu1—C8ⁱⁱ	102.84 (6)
O1—Eu1—O7	85.97 (6)	O5—Eu1—C8ⁱⁱ	146.68 (6)
O5—Eu1—O7	134.62 (6)	O7—Eu1—C8ⁱⁱ	19.51 (6)
O1—Eu1—O6	138.32 (6)	O6—Eu1—C8ⁱⁱ	47.81 (6)
O5—Eu1—O6	140.49 (6)	O4—Eu1—C8ⁱⁱ	119.19 (6)
O7—Eu1—O6	67.29 (5)	O11—Eu1—C8ⁱⁱ	135.25 (6)
O1—Eu1—O4	137.52 (6)	O9—Eu1—C8ⁱⁱ	71.90 (6)
O5—Eu1—O4	67.69 (6)	O10—Eu1—C8ⁱⁱ	67.29 (6)
O7—Eu1—O4	136.49 (6)	O8—Eu1—C8ⁱⁱ	80.29 (6)
O6—Eu1—O4	75.83 (6)	C7ⁱ—Eu1—C8ⁱⁱ	142.17 (6)
O1—Eu1—O11	76.53 (6)	C7—Eu1—C8ⁱⁱ	129.65 (6)
O5—Eu1—O11	78.03 (7)	C6—N1—C5	123.8 (2)
O7—Eu1—O11	140.07 (7)	C6—N1—H1	120 (2)
O6—Eu1—O11	103.48 (6)	C5—N1—H1	116 (2)
O4—Eu1—O11	69.67 (6)	C1—O1—Eu1	158.00 (17)
O1—Eu1—O9	139.48 (6)	C4—O3—H3A	109.5
O5—Eu1—O9	83.77 (6)	C7—O4—Eu1	115.60 (15)
O7—Eu1—O9	78.60 (6)	C7ⁱ—O5—Eu1	118.04 (15)
O6—Eu1—O9	67.69 (6)	C8—O6—Eu1	118.79 (14)
O4—Eu1—O9	66.30 (6)	C8ⁱⁱ—O7—Eu1	119.54 (15)
O11—Eu1—O9	135.93 (6)	C9—O8—Eu1	118.26 (15)
O1—Eu1—O10	75.35 (6)	C9ⁱⁱⁱ—O9—Eu1	120.53 (15)
O5—Eu1—O10	143.27 (6)	Eu1—O10—H7	111 (3)
O7—Eu1—O10	71.49 (6)	Eu1—O10—H8	119 (2)
O6—Eu1—O10	66.30 (6)	H7—O10—H8	105 (3)
O4—Eu1—O10	113.98 (6)	Eu1—O11—H9	125 (3)
O11—Eu1—O10	69.47 (7)	Eu1—O11—H10	116 (3)
O9—Eu1—O10	131.87 (6)	H9—O11—H10	109 (4)

Symmetry codes: (i) −x+1, −y+2, −z+1; (ii) −x+2, −y+1, −z+1; (iii) −x+1, −y+1, −z+1.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O9^iv	0.83 (3)	1.84 (3)	2.662 (3)	172 (3)
O3—H3A···O2^v	0.82	1.73	2.543 (2)	169
O10—H7···O4^vi	0.76 (4)	2.26 (4)	3.016 (2)	168 (4)
O10—H8···O2^vii	0.92 (4)	1.85 (4)	2.759 (3)	170 (3)
O11—H9···O6^vi	0.88 (4)	1.90 (4)	2.771 (3)	170 (4)
O11—H10···O3^viii	0.74 (4)	2.04 (4)	2.776 (3)	172 (4)

Symmetry codes: (iv) x, y, z+1; (v) x, y−1, z; (vi) −x+2, −y+2, −z+1; (vii) −x+2, −y+2, −z+2; (viii) x, y+1, z.

Experimental details

Crystal data
Chemical formula	[Eu₂(C₆H₅NO₃)₂(C₂O₄)₃(H₂O)₄]
M_r	918.26
Crystal system, space group	Triclinic, P1
Temperature (K)	153
a, b, c (Å)	7.5912 (2), 8.0973 (3), 10.6706 (3)
α, β, γ (°)	103.493 (3), 98.589 (3), 92.240 (3)
V (Å³)	628.78 (3)
Z	1
Radiation type	Mo Kα
µ (mm⁻¹)	5.05
Crystal size (mm)	0.24 × 0.17 × 0.08

Data collection
Diffractometer	Bruker APEXII CCD
Absorption correction	Multi-scan (SADABS; Sheldrick, 1996)
T_min, T_max	0.377, 0.688
No. of measured, independent and observed [I > 2σ(I)] reflections	12455, 3135, 2965
R_int	0.037
(sin θ/λ)_max (Å⁻¹)	0.692

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.018, 0.038, 1.09
No. of reflections	3135
No. of parameters	221
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.55, −0.54

Computer programs: APEX2 (Bruker, 2007), SAINT (Bruker, 2007), SHELXTL (Sheldrick, 2008), DIAMOND (Brandenburg, 1999).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O9ⁱ	0.83 (3)	1.84 (3)	2.662 (3)	172 (3)
O3—H3A···O2ⁱⁱ	0.82	1.73	2.543 (2)	169
O10—H7···O4ⁱⁱⁱ	0.76 (4)	2.26 (4)	3.016 (2)	168 (4)
O10—H8···O2^iv	0.92 (4)	1.85 (4)	2.759 (3)	170 (3)
O11—H9···O6ⁱⁱⁱ	0.88 (4)	1.90 (4)	2.771 (3)	170 (4)
O11—H10···O3^v	0.74 (4)	2.04 (4)	2.776 (3)	172 (4)

Symmetry codes: (i) x, y, z+1; (ii) x, y−1, z; (iii) −x+2, −y+2, −z+1; (iv) −x+2, −y+2, −z+2; (v) x, y+1, z.

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