Poly[[diaqua-μ4-pyrazine-2,3-dicarboxyl­ato-κ6 N,O 2:O 2′:O 3,O 3′:O 3-strontium(II)] monohydrate]

Anita Abedi; Maryam Mousavi Mirkolaei; Vahid Amani

doi:10.1107/S1600536808015316

. 2008 Jun 7;64(Pt 7):m888–m889. doi: 10.1107/S1600536808015316

Poly[[diaqua-μ₄-pyrazine-2,3-dicarboxylato-κ⁶ N,O ²:O ^2′:O ³,O ^3′:O ³-strontium(II)] monohydrate]

Anita Abedi ^a, Maryam Mousavi Mirkolaei ^a, Vahid Amani ^b,^*

PMCID: PMC2961772 PMID: 21202756

Abstract

In the title compound, {[Sr(C₆H₂N₂O₄)(H₂O)₂]·H₂O}_n, the Sr^II ions are bridged by the pyrazine-2,3-dicarboxylate ligands with the formation of two-dimensional polymeric layers parallel to the ac plane. Each Sr^II ion is eight-coordinated by one N and five O atoms from the four ligands and two water molecules. The coordination polyhedron is derived from a pentagonal bipyramid with an O atom at the apex on one side of the equatorial plane and two O atoms sharing the apical site on the other side. The coordinated and uncoordinated water molecules are involved in O—H⋯O and O—H⋯N hydrogen bonds, which consolidate the crystal structure.

Related literature

For related literature, see: Takusagawa & Shimada (1973 ▶); Richard et al. (1973 ▶); Zou et al. (1999 ▶); Konar et al. (2004 ▶); Li et al. (2003 ▶); Xu et al. (2008 ▶); Ma et al. (2006 ▶); Ptasiewicz-Bak & Leciejewicz (1997a ▶,b ▶); Starosta & Leciejewicz (2005 ▶); Tombul et al. (2006 ▶).

Experimental

Crystal data

[Sr(C₆H₂N₂O₄)(H₂O)₂]·H₂O
M _r = 307.76
Monoclinic,
a = 10.4931 (7) Å
b = 6.9839 (4) Å
c = 13.5208 (8) Å
β = 94.2670 (10)°
V = 988.10 (10) Å³
Z = 4
Mo Kα radiation
μ = 5.48 mm⁻¹
T = 120 (2) K
0.28 × 0.25 × 0.10 mm

Data collection

Bruker SMART 1000 CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 1998 ▶) T _min = 0.240, T _max = 0.568
8338 measured reflections
1934 independent reflections
1595 reflections with I > 2σ(I)
R _int = 0.040

Refinement

R[F ² > 2σ(F ²)] = 0.024
wR(F ²) = 0.054
S = 1.00
1934 reflections
145 parameters
H-atom parameters constrained
Δρ_max = 0.92 e Å⁻³
Δρ_min = −0.45 e Å⁻³

Data collection: SMART (Bruker, 1998 ▶); cell refinement: SAINT-Plus (Bruker, 1998 ▶); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536808015316/cv2408sup1.cif

e-64-0m888-sup1.cif^{(20.1KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808015316/cv2408Isup2.hkl

e-64-0m888-Isup2.hkl^{(95.2KB, hkl)}

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

Table 1. Selected bond lengths (Å).

Sr1—O2ⁱ	2.4887 (18)
Sr1—O2W	2.5106 (18)
Sr1—O4ⁱⁱ	2.5533 (18)
Sr1—O1W	2.5937 (19)
Sr1—O3	2.6145 (18)
Sr1—O1ⁱⁱⁱ	2.6155 (18)
Sr1—N1	2.714 (2)
Sr1—O2ⁱⁱⁱ	2.8517 (18)

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) .

Table 2. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1W—H1W1⋯O3Wⁱ	0.85	1.87	2.713 (3)	170
O1W—H2W1⋯O3W^iv	0.85	1.90	2.744 (3)	171
O2W—H1W2⋯O1ⁱⁱ	0.85	1.85	2.696 (3)	174
O2W—H2W2⋯O1W^v	0.85	2.01	2.857 (3)	178
O3W—H1W3⋯O4	0.85	1.94	2.781 (3)	170
O3W—H2W3⋯N2^vi	0.85	1.96	2.792 (3)	168

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

Acknowledgments

We are grateful to the Islamic Azad University, North Tehran Branch, for financial support.

supplementary crystallographic information

Comment

Takusagawa & Shimada (1973) first determined the structure of pyrazine-2,3-dicarboxlic acid by single-crystal X-ray analysis. Almost at the same time, the first metal-organic compound of pyrazine-2,3-dicarboxylic acid was reported (Richard et al., 1973). Among many reported compounds containing pyrazine-2,3-dicarboxylic acid, most are complexes of transition metal ions, including manganese (Zou et al., 1999), copper (Konar et al., 2004), zinc (Li et al., 2003), iron (Xu et al., 2008) and cadmium (Ma et al., 2006). Also, there are many reported compounds of pyrazine-2,3-dicarboxylic acid with main group metals such as calcium (Ptasiewicz-Bak & Leciejewicz, 1997a; Starosta & Leciejewicz, 2005), magnesium (Ptasiewicz-Bak & Leciejewicz, 1997b) and sodium (Tombul et al., 2006) complexes. For further investigation of pyrazine-2,3-dicarboxylic acid, we synthesized the title compound, (I).

The asymmetric unit of the title compound, (Fig. 1), contains molecular sheets in which Sr^II ions are bridged by the carboxylate groups of the ligand molecules. Two bridging paths are evident. In the first, an N,O-bonding moiety formed by a hetero-ring nitrogen atom and the carboxylate oxygen atom nearest to it and both oxygen atoms of the second carboxylic group are active. The second path is formed by the other oxygen atom from the carboxylic group involved in the N,O-bonding moiety and an oxygen atom from the second carboxylic group. The latter atom is bidentate. A two-dimensional molecular pattern is formed. Each Sr^II ion is also coordinated by two water oxygen atoms, making the number of coordinated atoms eight. The coordination polyhedron is a distorted pentagonal bipyramid with an oxygen atom at the apex on one side of the equatorial plane and two oxygen atoms forming the apices on the other side. There is also one non-coordinated water molecule in the asymmetric unit. The Sr—O and Sr—N bond lengths are collected in Table 1.

Intermolecular O—H···O and O—H···N hydrogen bonds (Table 2) help to consolidate the crystal packing (Fig. 2).

Experimental

A solution of pyrazine-2,3-dicarboxlic acid (0.5 g, 2.91 mmol) in methanol (40 ml) was added to a solution of Sr(NO₃)₂ (0.31 g, 1.46 mmol) in water (10 ml) and the resulting colourless solution was stirred for 10 min at room temperature. This solution was left to evaporate slowly at room temperature. After one week, colourless plate crystals of the title compound were isolated (yield 0.35 g, 78.03%).