Poly[diaqua­(μ5-pyridine-3,5-dicarboxyl­ato)strontium]

Li, D.; Duan, C.

doi:10.1107/S1600536812023379

metal-organic compounds

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ISSN: 2056-9890

Volume 68| Part 6| June 2012| Page m835

doi:10.1107/S1600536812023379

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Poly[diaqua(μ₅-pyridine-3,5-dicarboxylato)strontium]

Dan Li ^a ^* and Chaowen Duan ^b

^aSchool of Media Communications, Linyi University, Linyi 276000, People's Republic of China, and ^bSchool of Chemistry and Chemical Engineering, Linyi University, Linyi 276000, People's Republic of China
^*Correspondence e-mail: lidan@lyu.edu.cn

(Received 7 May 2012; accepted 22 May 2012; online 31 May 2012)

In the structure of the title compound, [Sr(C₇H₃NO₄)(H₂O)₂]_n, the Sr^II cation is eight-coordinated in form of a distorted dodecahedron by two water O atoms and by five O atoms and one N atom from five pyridine-3,5-dicarboxylate anions. The bridging mode of the anions leads to the formation of a layered network parallel to (100). O—H⋯O hydrogen bonding between the coordinating water molecules and the carboxylate groups of adjacent layers consolidates the crystal packing. Weak C—H⋯O interactions are also observed.

Related literature

For related structures with pyridine-3,5-dicarboxylato ligands, see: Aghabozorg et al. (2008 ); Dang et al. (2010 ); Du et al. (2009 ); Lv et al. (2010 ); Wu et al. (2008 ); Yao et al. (2010 ).

Experimental

Crystal data

[Sr(C₇H₃NO₄)(H₂O)₂]
M_r = 288.76
Triclinic, $[P \overline 1]$
a = 7.9098 (4) Å
b = 8.0028 (4) Å
c = 8.0864 (5) Å
α = 88.620 (2)°
β = 71.270 (2)°
γ = 72.030 (2)°
V = 459.52 (4) Å³
Z = 2
Mo Kα radiation
μ = 5.88 mm⁻¹
T = 293 K
0.30 × 0.17 × 0.16 mm

Data collection

Bruker APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2005 ) T_min = 0.272, T_max = 0.453
8322 measured reflections
2305 independent reflections
2226 reflections with I > 2σ(I)
R_int = 0.022

Refinement

R[F² > 2σ(F²)] = 0.017
wR(F²) = 0.046
S = 1.08
2305 reflections
136 parameters
H-atom parameters constrained
Δρ_max = 0.38 e Å⁻³
Δρ_min = −0.51 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O5—H5A⋯O4ⁱ	0.85	2.01	2.8046 (17)	155
O5—H5B⋯O3ⁱⁱ	0.85	2.05	2.8718 (18)	163
O6—H6A⋯O2ⁱⁱⁱ	0.85	1.87	2.7135 (17)	172
O6—H6B⋯O5^iv	0.86	2.03	2.848 (2)	160
C1—H1⋯O3ⁱⁱ	0.93	2.37	3.286 (2)	169
Symmetry codes: (i) -x+2, -y, -z; (ii) x, y, z+1; (iii) -x+2, -y+1, -z; (iv) -x+2, -y+1, -z+1.

Data collection: APEX2 (Bruker, 2005); cell refinement: SAINT (Bruker, 2005); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: XP in SHELXTL (Sheldrick, 2008) and DIAMOND (Brandenburg, 2012 ); software used to prepare material for publication: SHELXTL.

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536812023379/wm2630sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536812023379/wm2630Isup2.hkl

checkCIF report

Comment top

Pyridine-3,5-dicarboxylic acid (py-3,5-dc) is an interesting ligand because it can act in a multidentate fashion and also can participate in hydrogen bonding interactions with its N and O acceptors. Some polymeric complexes of this ligand with 3d metals (Dang et al., 2010; Lv et al., 2010; Du et al., 2009) and with mixed 3d-4f metals (Yao et al., 2010; Wu et al., 2008) have been published. A related strontium complex with a chain-structure has been reported by Aghabozorg et al. (2008). Here we report the layered structure of another polymeric strontium complex, [Sr(C₇H₃NO₄)(H₂O)₂]_n, (I).

The coordination number of the cation is eight, with bonds to seven O and one N atoms from five py-3,5-dc anions (Fig. 1). The corresponding geometry is distorted dodecahedral (Fig. 2). The Sr—O distances are in the range of 2.5287 (13)–2.7232 (12) Å, and the Sr—N bond is the longest of the coordination polyhedron with a length of 2.8064 (14) Å. The carboxylate O1 atom links two cations to form a rhombic binuclear Sr₂O₂ unit. These units are further connected by carboxylate groups and N atoms of symmetry-related ligands to form a two-dimensional network parallel to (100). Atoms O2, O3 and O4 from these ligands are acceptor atoms for hydrogen bonding with coordinating water molecules of adjacent ligands as donor atoms, leading to a three-dimensional set-up of the structure (Table 1 and Fig. 3). Weak C—H···O interactions are also observed.

Related literature top

For related structures with pyridine-3,5-dicarboxylato ligands, see: Aghabozorg et al. (2008); Dang et al. (2010); Du et al. (2009); Lv et al. (2010); Wu et al. (2008); Yao et al. (2010).

Experimental top

A mixture of 3,5-H₂pdc (0.0330 g, 0.2 mmol), SrCl₂^.6H₂O (0.0539 g, 0.2 mmol), imidazole (0.0320 g, 0.47 mmol), C₂H₅OH / H₂O = 1: 2 (3 ml) was placed in a Pyrex-tube (8 ml). The tube was heated for 4 days at 393 K under autogenous pressure. Colourless rod-shaped crystals were obtained. Anal. Calc. for C₇H₇NO₆Sr: C, 29.12; N, 4.85; H, 2.44. Found: C, 28.65; N, 4.60; H, 2.35%. IR (KBr, cm^-1): 3490 br, 1610 s, 1552 s, 1455 s, 1421 s, 1385 s, 1311 s, 1132 s, 1030 s, 941 s, 827 s, 782 s, 739 s, 651 s, 570 s, 439 s.

Computing details top

Data collection: APEX2 (Bruker, 2005); cell refinement: SAINT (Bruker, 2005); data reduction: SAINT (Bruker, 2005); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: XP in SHELXTL (Sheldrick, 2008) and DIAMOND (Brandenburg, 2012); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top

	Fig. 1. The molecular structure of compound (I), with displacement ellipsoids drawn at the 50% probability level [H-atoms have been omitted for clarity; symmetry codes: (A) -x + 1, -y + 1, -z + 1; (B) -x + 1, -y + 1, -z; (C) x, y + 1, z + 1; (AC) x, y + 1, z.
	Fig. 2. A view of the distorted dodecahedral environment around the Sr^II atom in (I).
	Fig. 3. A view down the b axis of the crystal packing of compound (I). Hydrogen bonds are shown as dashed lines.

Poly[diaqua(µ₅-pyridine-3,5-dicarboxylato)strontium] top

Crystal data top

[Sr(C₇H₃NO₄)(H₂O)₂]	Z = 2
M_r = 288.76	F(000) = 284
Triclinic, P1	D_x = 2.087 Mg m⁻³
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 7.9098 (4) Å	Cell parameters from 3510 reflections
b = 8.0028 (4) Å	θ = 2.7–25.3°
c = 8.0864 (5) Å	µ = 5.88 mm⁻¹
α = 88.620 (2)°	T = 293 K
β = 71.270 (2)°	Block, colourless
γ = 72.030 (2)°	0.30 × 0.17 × 0.16 mm
V = 459.52 (4) Å³

Data collection top

Bruker APEXII CCD diffractometer	2305 independent reflections
Radiation source: fine-focus sealed tube	2226 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.022
ϕ and ω scans	θ_max = 28.4°, θ_min = 2.7°
Absorption correction: multi-scan (SADABS; Bruker, 2005)	h = −10→10
T_min = 0.272, T_max = 0.453	k = −10→10
8322 measured reflections	l = −9→10

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.017	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.046	H-atom parameters constrained
S = 1.08	w = 1/[σ²(F_o²) + (0.0269P)² + 0.1887P] where P = (F_o² + 2F_c²)/3
2305 reflections	(Δ/σ)_max = 0.001
136 parameters	Δρ_max = 0.38 e Å⁻³
0 restraints	Δρ_min = −0.51 e Å⁻³

Crystal data top

[Sr(C₇H₃NO₄)(H₂O)₂]	γ = 72.030 (2)°
M_r = 288.76	V = 459.52 (4) Å³
Triclinic, P1	Z = 2
a = 7.9098 (4) Å	Mo Kα radiation
b = 8.0028 (4) Å	µ = 5.88 mm⁻¹
c = 8.0864 (5) Å	T = 293 K
α = 88.620 (2)°	0.30 × 0.17 × 0.16 mm
β = 71.270 (2)°

Data collection top

Bruker APEXII CCD diffractometer	2305 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2005)	2226 reflections with I > 2σ(I)
T_min = 0.272, T_max = 0.453	R_int = 0.022
8322 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.017	0 restraints
wR(F²) = 0.046	H-atom parameters constrained
S = 1.08	Δρ_max = 0.38 e Å⁻³
2305 reflections	Δρ_min = −0.51 e Å⁻³
136 parameters

Special details top

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
Sr1	0.685514 (18)	0.654700 (16)	0.373999 (17)	0.01302 (5)
O1	0.53412 (17)	0.40183 (16)	0.33347 (15)	0.0220 (2)
O3	0.63315 (17)	0.12206 (15)	−0.40559 (15)	0.0206 (2)
O2	0.7094 (2)	0.47815 (16)	0.09101 (16)	0.0260 (3)
O4	0.76724 (18)	−0.16816 (16)	−0.41598 (16)	0.0215 (2)
O5	0.85222 (17)	0.35498 (17)	0.47402 (19)	0.0288 (3)
O6	1.03912 (18)	0.5746 (2)	0.23839 (17)	0.0303 (3)
N1	0.7457 (2)	−0.11960 (18)	0.10565 (18)	0.0204 (3)
C7	0.7063 (2)	−0.0153 (2)	−0.34150 (19)	0.0143 (3)
C4	0.7184 (2)	0.0071 (2)	−0.16144 (19)	0.0146 (3)
C3	0.6819 (2)	0.1745 (2)	−0.0860 (2)	0.0150 (3)
H3	0.6607	0.2725	−0.1498	0.018*
C2	0.6775 (2)	0.1931 (2)	0.0855 (2)	0.0148 (3)
C5	0.7511 (2)	−0.1354 (2)	−0.0614 (2)	0.0182 (3)
H5	0.7781	−0.2475	−0.1125	0.022*
C6	0.6365 (2)	0.3698 (2)	0.1760 (2)	0.0155 (3)
C1	0.7093 (2)	0.0429 (2)	0.1755 (2)	0.0189 (3)
H1	0.7051	0.0559	0.2909	0.023*
H6A	1.1093	0.5659	0.1327	0.028*
H5A	0.9661	0.2895	0.4265	0.028*
H5B	0.7950	0.2793	0.4868	0.028*
H6B	1.0903	0.5704	0.3176	0.028*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Sr1	0.01678 (8)	0.01181 (8)	0.01109 (8)	−0.00511 (5)	−0.00483 (5)	0.00017 (5)
O1	0.0290 (6)	0.0226 (6)	0.0127 (5)	−0.0120 (5)	−0.0006 (5)	−0.0034 (4)
O3	0.0265 (6)	0.0195 (6)	0.0153 (5)	−0.0035 (5)	−0.0100 (5)	0.0024 (4)
O2	0.0417 (8)	0.0208 (6)	0.0155 (6)	−0.0187 (5)	−0.0006 (5)	−0.0019 (5)
O4	0.0266 (6)	0.0181 (6)	0.0196 (6)	−0.0042 (5)	−0.0097 (5)	−0.0059 (5)
O5	0.0194 (6)	0.0245 (6)	0.0418 (8)	−0.0066 (5)	−0.0101 (6)	0.0104 (6)
O6	0.0222 (6)	0.0457 (8)	0.0198 (6)	−0.0126 (6)	−0.0007 (5)	0.0007 (6)
N1	0.0317 (8)	0.0162 (6)	0.0153 (6)	−0.0076 (5)	−0.0104 (6)	0.0037 (5)
C7	0.0158 (7)	0.0163 (7)	0.0110 (7)	−0.0058 (5)	−0.0040 (5)	−0.0006 (5)
C4	0.0177 (7)	0.0141 (7)	0.0120 (7)	−0.0048 (5)	−0.0052 (5)	−0.0009 (5)
C3	0.0202 (7)	0.0128 (7)	0.0131 (7)	−0.0065 (5)	−0.0056 (5)	0.0013 (5)
C2	0.0195 (7)	0.0147 (7)	0.0117 (7)	−0.0077 (5)	−0.0044 (5)	−0.0016 (5)
C5	0.0268 (8)	0.0127 (7)	0.0161 (7)	−0.0060 (6)	−0.0084 (6)	−0.0004 (6)
C6	0.0201 (7)	0.0156 (7)	0.0125 (7)	−0.0070 (6)	−0.0063 (6)	−0.0014 (6)
C1	0.0273 (8)	0.0196 (8)	0.0121 (7)	−0.0093 (6)	−0.0079 (6)	0.0016 (6)

Geometric parameters (Å, º) top

Sr1—O6	2.5287 (13)	O5—H5A	0.8542
Sr1—O3ⁱ	2.5377 (12)	O5—H5B	0.8477
Sr1—O1ⁱⁱ	2.5715 (12)	O6—H6A	0.8468
Sr1—O4ⁱⁱⁱ	2.5881 (12)	O6—H6B	0.8563
Sr1—O5	2.6050 (13)	N1—C1	1.339 (2)
Sr1—O2	2.6423 (12)	N1—C5	1.345 (2)
Sr1—O1	2.7232 (12)	N1—Sr1^vi	2.8065 (14)
Sr1—N1^iv	2.8064 (14)	C7—C4	1.508 (2)
Sr1—C6	3.0051 (15)	C4—C5	1.390 (2)
Sr1—H6B	2.9429	C4—C3	1.391 (2)
O1—C6	1.2520 (19)	C3—C2	1.387 (2)
O1—Sr1ⁱⁱ	2.5715 (12)	C3—H3	0.9300
O3—C7	1.2590 (19)	C2—C1	1.388 (2)
O3—Sr1ⁱ	2.5377 (12)	C2—C6	1.502 (2)
O2—C6	1.258 (2)	C5—H5	0.9300
O4—C7	1.2554 (19)	C1—H1	0.9300
O4—Sr1^v	2.5881 (12)

O6—Sr1—O3ⁱ	146.80 (4)	O1ⁱⁱ—Sr1—H6B	119.9
O6—Sr1—O1ⁱⁱ	133.77 (4)	O4ⁱⁱⁱ—Sr1—H6B	65.0
O3ⁱ—Sr1—O1ⁱⁱ	75.71 (4)	O5—Sr1—H6B	63.0
O6—Sr1—O4ⁱⁱⁱ	77.95 (4)	O2—Sr1—H6B	98.6
O3ⁱ—Sr1—O4ⁱⁱⁱ	95.67 (4)	O1—Sr1—H6B	121.6
O1ⁱⁱ—Sr1—O4ⁱⁱⁱ	81.28 (4)	N1^iv—Sr1—H6B	85.2
O6—Sr1—O5	69.37 (4)	C6—Sr1—H6B	107.7
O3ⁱ—Sr1—O5	143.83 (4)	Sr1ⁱⁱ—Sr1—H6B	128.1
O1ⁱⁱ—Sr1—O5	70.70 (4)	C6—O1—Sr1ⁱⁱ	156.53 (11)
O4ⁱⁱⁱ—Sr1—O5	92.21 (4)	C6—O1—Sr1	90.40 (9)
O6—Sr1—O2	84.52 (4)	Sr1ⁱⁱ—O1—Sr1	112.09 (4)
O3ⁱ—Sr1—O2	95.32 (4)	C7—O3—Sr1ⁱ	140.72 (10)
O1ⁱⁱ—Sr1—O2	116.27 (4)	C6—O2—Sr1	94.03 (9)
O4ⁱⁱⁱ—Sr1—O2	161.21 (4)	C7—O4—Sr1^v	137.91 (10)
O5—Sr1—O2	87.86 (4)	Sr1—O5—H5A	127.0
O6—Sr1—O1	115.98 (4)	Sr1—O5—H5B	115.1
O3ⁱ—Sr1—O1	86.90 (4)	H5A—O5—H5B	100.7
O1ⁱⁱ—Sr1—O1	67.91 (4)	Sr1—O6—H6A	131.4
O4ⁱⁱⁱ—Sr1—O1	147.46 (4)	Sr1—O6—H6B	110.7
O5—Sr1—O1	68.48 (4)	H6A—O6—H6B	117.3
O2—Sr1—O1	48.48 (4)	C1—N1—C5	117.16 (14)
O6—Sr1—N1^iv	74.58 (5)	C1—N1—Sr1^vi	109.60 (10)
O3ⁱ—Sr1—N1^iv	73.32 (4)	C5—N1—Sr1^vi	130.26 (11)
O1ⁱⁱ—Sr1—N1^iv	147.89 (4)	O4—C7—O3	124.65 (14)
O4ⁱⁱⁱ—Sr1—N1^iv	93.47 (4)	O4—C7—C4	118.35 (14)
O5—Sr1—N1^iv	141.38 (4)	O3—C7—C4	117.00 (13)
O2—Sr1—N1^iv	75.20 (4)	C5—C4—C3	118.26 (14)
O1—Sr1—N1^iv	118.12 (4)	C5—C4—C7	121.27 (14)
O6—Sr1—C6	97.37 (4)	C3—C4—C7	120.27 (13)
O3ⁱ—Sr1—C6	95.75 (4)	C2—C3—C4	119.12 (14)
O1ⁱⁱ—Sr1—C6	92.37 (4)	C2—C3—H3	120.4
O4ⁱⁱⁱ—Sr1—C6	165.14 (4)	C4—C3—H3	120.4
O5—Sr1—C6	72.98 (4)	C3—C2—C1	118.28 (14)
O2—Sr1—C6	24.68 (4)	C3—C2—C6	122.02 (14)
O1—Sr1—C6	24.62 (4)	C1—C2—C6	119.69 (13)
N1^iv—Sr1—C6	98.90 (4)	N1—C5—C4	123.41 (14)
O6—Sr1—Sr1ⁱⁱ	132.57 (3)	N1—C5—H5	118.3
O3ⁱ—Sr1—Sr1ⁱⁱ	79.75 (3)	C4—C5—H5	118.3
O1ⁱⁱ—Sr1—Sr1ⁱⁱ	35.06 (3)	O1—C6—O2	122.85 (14)
O4ⁱⁱⁱ—Sr1—Sr1ⁱⁱ	115.72 (3)	O1—C6—C2	118.69 (14)
O5—Sr1—Sr1ⁱⁱ	65.11 (3)	O2—C6—C2	118.45 (14)
O2—Sr1—Sr1ⁱⁱ	81.27 (3)	O1—C6—Sr1	64.98 (8)
O1—Sr1—Sr1ⁱⁱ	32.85 (2)	O2—C6—Sr1	61.29 (8)
N1^iv—Sr1—Sr1ⁱⁱ	142.01 (3)	C2—C6—Sr1	159.61 (11)
C6—Sr1—Sr1ⁱⁱ	57.36 (3)	N1—C1—C2	123.75 (14)
O6—Sr1—H6B	15.8	N1—C1—H1	118.1
O3ⁱ—Sr1—H6B	150.4	C2—C1—H1	118.1

O6—Sr1—O1—C6	−43.90 (11)	Sr1—O1—C6—O2	−21.19 (17)
O3ⁱ—Sr1—O1—C6	111.03 (10)	Sr1ⁱⁱ—O1—C6—C2	−6.4 (4)
O1ⁱⁱ—Sr1—O1—C6	−173.14 (12)	Sr1—O1—C6—C2	157.48 (13)
O4ⁱⁱⁱ—Sr1—O1—C6	−153.28 (9)	Sr1ⁱⁱ—O1—C6—Sr1	−163.9 (3)
O5—Sr1—O1—C6	−96.05 (10)	Sr1—O2—C6—O1	21.92 (17)
O2—Sr1—O1—C6	11.13 (9)	Sr1—O2—C6—C2	−156.75 (12)
N1^iv—Sr1—O1—C6	41.81 (11)	C3—C2—C6—O1	139.97 (16)
Sr1ⁱⁱ—Sr1—O1—C6	−173.14 (12)	C1—C2—C6—O1	−39.0 (2)
O6—Sr1—O1—Sr1ⁱⁱ	129.25 (5)	C3—C2—C6—O2	−41.3 (2)
O3ⁱ—Sr1—O1—Sr1ⁱⁱ	−75.83 (5)	C1—C2—C6—O2	139.73 (16)
O1ⁱⁱ—Sr1—O1—Sr1ⁱⁱ	0.0	C3—C2—C6—Sr1	−125.0 (3)
O4ⁱⁱⁱ—Sr1—O1—Sr1ⁱⁱ	19.86 (10)	C1—C2—C6—Sr1	56.1 (4)
O5—Sr1—O1—Sr1ⁱⁱ	77.09 (5)	O6—Sr1—C6—O1	141.06 (10)
O2—Sr1—O1—Sr1ⁱⁱ	−175.73 (8)	O3ⁱ—Sr1—C6—O1	−69.51 (10)
N1^iv—Sr1—O1—Sr1ⁱⁱ	−145.05 (5)	O1ⁱⁱ—Sr1—C6—O1	6.36 (11)
C6—Sr1—O1—Sr1ⁱⁱ	173.14 (12)	O4ⁱⁱⁱ—Sr1—C6—O1	70.52 (19)
O6—Sr1—O2—C6	121.16 (11)	O5—Sr1—C6—O1	75.34 (10)
O3ⁱ—Sr1—O2—C6	−92.19 (10)	O2—Sr1—C6—O1	−159.75 (16)
O1ⁱⁱ—Sr1—O2—C6	−15.52 (11)	N1^iv—Sr1—C6—O1	−143.48 (9)
O4ⁱⁱⁱ—Sr1—O2—C6	142.24 (12)	Sr1ⁱⁱ—Sr1—C6—O1	4.41 (8)
O5—Sr1—O2—C6	51.69 (10)	O6—Sr1—C6—O2	−59.19 (11)
O1—Sr1—O2—C6	−11.10 (9)	O3ⁱ—Sr1—C6—O2	90.24 (10)
N1^iv—Sr1—O2—C6	−163.36 (11)	O1ⁱⁱ—Sr1—C6—O2	166.11 (10)
Sr1ⁱⁱ—Sr1—O2—C6	−13.45 (10)	O4ⁱⁱⁱ—Sr1—C6—O2	−129.73 (16)
Sr1^v—O4—C7—O3	−33.4 (3)	O5—Sr1—C6—O2	−124.91 (11)
Sr1^v—O4—C7—C4	145.77 (12)	O1—Sr1—C6—O2	159.75 (16)
Sr1ⁱ—O3—C7—O4	105.41 (18)	N1^iv—Sr1—C6—O2	16.27 (11)
Sr1ⁱ—O3—C7—C4	−73.8 (2)	Sr1ⁱⁱ—Sr1—C6—O2	164.16 (11)
O4—C7—C4—C5	−15.8 (2)	O6—Sr1—C6—C2	35.7 (3)
O3—C7—C4—C5	163.49 (15)	O3ⁱ—Sr1—C6—C2	−174.9 (3)
O4—C7—C4—C3	169.42 (14)	O1ⁱⁱ—Sr1—C6—C2	−99.0 (3)
O3—C7—C4—C3	−11.3 (2)	O4ⁱⁱⁱ—Sr1—C6—C2	−34.8 (4)
C5—C4—C3—C2	−0.7 (2)	O5—Sr1—C6—C2	−30.0 (3)
C7—C4—C3—C2	174.30 (14)	O2—Sr1—C6—C2	94.9 (3)
C4—C3—C2—C1	−0.2 (2)	O1—Sr1—C6—C2	−105.4 (3)
C4—C3—C2—C6	−179.19 (14)	N1^iv—Sr1—C6—C2	111.2 (3)
C1—N1—C5—C4	−1.0 (3)	Sr1ⁱⁱ—Sr1—C6—C2	−100.9 (3)
Sr1^vi—N1—C5—C4	157.24 (12)	C5—N1—C1—C2	0.0 (3)
C3—C4—C5—N1	1.3 (2)	Sr1^vi—N1—C1—C2	−162.51 (13)
C7—C4—C5—N1	−173.61 (15)	C3—C2—C1—N1	0.6 (2)
Sr1ⁱⁱ—O1—C6—O2	174.94 (19)	C6—C2—C1—N1	179.60 (15)

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

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O5—H5A···O4^vii	0.85	2.01	2.8046 (17)	155
O5—H5B···O3^viii	0.85	2.05	2.8718 (18)	163
O6—H6A···O2^ix	0.85	1.87	2.7135 (17)	172
O6—H6B···O5^x	0.86	2.03	2.848 (2)	160
C1—H1···O3^viii	0.93	2.37	3.286 (2)	169

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

Experimental details

Crystal data
Chemical formula	[Sr(C₇H₃NO₄)(H₂O)₂]
M_r	288.76
Crystal system, space group	Triclinic, P1
Temperature (K)	293
a, b, c (Å)	7.9098 (4), 8.0028 (4), 8.0864 (5)
α, β, γ (°)	88.620 (2), 71.270 (2), 72.030 (2)
V (Å³)	459.52 (4)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	5.88
Crystal size (mm)	0.30 × 0.17 × 0.16

Data collection
Diffractometer	Bruker APEXII CCD diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 2005)
T_min, T_max	0.272, 0.453
No. of measured, independent and observed [I > 2σ(I)] reflections	8322, 2305, 2226
R_int	0.022
(sin θ/λ)_max (Å⁻¹)	0.669

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.017, 0.046, 1.08
No. of reflections	2305
No. of parameters	136
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.38, −0.51

Computer programs: APEX2 (Bruker, 2005), SAINT (Bruker, 2005), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), XP in SHELXTL (Sheldrick, 2008) and DIAMOND (Brandenburg, 2012), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O5—H5A···O4ⁱ	0.85	2.01	2.8046 (17)	155.2
O5—H5B···O3ⁱⁱ	0.85	2.05	2.8718 (18)	163.0
O6—H6A···O2ⁱⁱⁱ	0.85	1.87	2.7135 (17)	171.7
O6—H6B···O5^iv	0.86	2.03	2.848 (2)	160.3
C1—H1···O3ⁱⁱ	0.93	2.37	3.286 (2)	168.9

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

Acknowledgements

Financial support from the Science Foundation of Linyi University (grant BS201005) is greatly acknowledged.

References

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