Poly[[μ₁₀-2,3-bis(carboxymethyl)butanedioato]disodium]

Abstract

The asymmetric unit of the title compound, [Na₂(C₈H₈O₈)]_n, contains one Na⁺ ion and half of a 2,3-bis(carboxymethyl)butanedioate (H₂BTC²⁻) dianion, which lies on a center of symmetry. The dianion exhibits a μ₁₀-bridging mode. Each Na atom lies in a NaO₆ octa­hedron defined by six O atoms from five dianions. Adjacent NaO₆ octa­hedra share a common O—O edge, generating a biocta­hedron; adjacent biocta­hedra are O—O edge-connected to one another, building up a chain along [001]. The chains are connected by adjacent H₂BTC²⁻ anions into a three-dimensional framework. The structure is further stabilized by O—H⋯O hydrogen bonds.

Related literature

For related structures, see: Delgado et al. (2007 ▶); Liu et al. (2008 ▶); Wang et al. (2005 ▶); Zheng et al. (2004 ▶); Zhu & Zheng (2010 ▶).

Experimental

Crystal data

• [Na₂(C₈H₈O₈)]

• M _r = 278.12

• Orthorhombic,

• a = 8.9053 (18) Å

• b = 8.6395 (17) Å

• c = 12.527 (3) Å

• V = 963.8 (3) ų

• Z = 4

• Mo Kα radiation

• μ = 0.24 mm⁻¹

• T = 293 K

• 0.44 × 0.36 × 0.32 mm

Data collection

• Rigaku R-AXIS RAPID diffractometer

• Absorption correction: multi-scan (ABSCOR; Higashi, 1995 ▶) T _min = 0.900, T _max = 0.925

• 8610 measured reflections

• 1097 independent reflections

• 1000 reflections with I > 2σ(I)

• R _int = 0.021

Refinement

• R[F ² > 2σ(F ²)] = 0.038

• wR(F ²) = 0.111

• S = 1.10

• 1097 reflections

• 86 parameters

• 1 restraint

• H atoms treated by a mixture of independent and constrained refinement

• Δρ_max = 0.43 e Å⁻³

• Δρ_min = −0.22 e Å⁻³

Data collection: RAPID-AUTO (Rigaku, 1998 ▶); cell refinement: RAPID-AUTO; data reduction: CrystalStructure (Rigaku/MSC, 2004 ▶); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

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
O2—H2C⋯O4i	0.85 (2)	1.67 (3)	2.5097 (18)	177 (2)

Symmetry code: (i) .

supplementary crystallographic information

Comment

Recently, the aliphatic multi-carboxylic acids have attractived considerable attention due to both its conformational flexibility and a variety of coordination fashions (Wang et al., 2005; Zheng et al., 2004).The butane-1,2,3,4-tetracarboxylic acid (H₄BTC) ligand possesses four ionizable protons that can be removed gradually to form a series of deprotonated anions such as H₃BTC^-, H₂BTC^2-, HBTC^3-, BTC^4-, which have allowed the preparation of a variety of complexes with differents metals (Delgado et al., 2007; Liu et al., 2008; Zhu et al., 2010). In this contribution, we report the synthesis and crystal structure of the title compound.

The asymmetric unit of the title compound contains one Na⁺ ion and half a H₂BTC^2- anion(Figure 1). The H₂BTC^2-ligand is diprotonated, which is crystallographically imposed by symmetry of center with inversion centers at the midpoints of the central C3—C3ⁱ bond with the Wyckoff 4b site. Each H₂BTC^2- anions coordinate ten sodium ions through eight carboxyl oxygen atoms. The carboxylate group and carboxylic group all coordinates to two metal atoms in a syn/anti µ₂η² bridging fashion, and two seven-membered chelating rings are concomitantly formed. Each Na atom is in a distorted octahedra NaO₆ gemetry defined by six O atoms from five H₂BTC^2- ligands, the Na—O contact distances are all within the normal ranges. The adjacent two NaO₆ octahedra are fused via common edge O1—O1 and O3—O3, generating a one-dimensional sodium-oxide chains (Figure 2), and the resulting chains are further interlinked by H₂BTC^2- anions into three-dimensional frameworks (Figure 3).

Experimental

All chemicals were obtained from commerical sources and were used as obtained. NaOH (0.079 g, 1.98 mmol) was added to a stirred mixture solution of butane-1,2,3,4-tetracarboxylic acid (0.1173 g, 0.50 mmol) in 10 ml H₂O and 10 ml me thanol, and the resulting mixture was stirred for 5 min. Colorless crystals were obtained from the solution (pH = 7.13) after standing at room temperature for five weeks.

Refinement

H atoms bonded to C atoms were palced in geometrically calculated position and were refined using a riding model, with U_iso(H) = 1.2 U_eq(C). H atoms attached to O atoms were found in a difference Fourier synthesis and refined with the O—H distance restranied to 0.83 (1) Å.

Figures

Fig. 1.

The content of asymmetric unit showing the atomic numbering and 45% probability dispalcement ellipsoids.[Symmetry codes: (i) -x + 2, -y + 1, -z + 1. (ii) -x + 2, -y, -z + 1. (iii) -x + 2, y, -z + 1.5. (iv) x - 1/2,y - 1/2, -z + 1.5. (v) x - 1/2, -y + 1/2, -z + 1.]

Fig. 2.

The one-dimensional sodium-oxide chains with the common edges O1—O1 and O3—O3.

Fig. 3.

The three-dimensional metal-organic framework in the title compound.

Crystal data

[Na2(C8H8O8)]	F(000) = 568
Mr = 278.12	Dx = 1.917 Mg m−3
Orthorhombic, Pbcn	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2n 2ab	Cell parameters from 7116 reflections
a = 8.9053 (18) Å	θ = 3.3–27.4°
b = 8.6395 (17) Å	µ = 0.24 mm−1
c = 12.527 (3) Å	T = 293 K
V = 963.8 (3) Å3	Block, colorless
Z = 4	0.44 × 0.36 × 0.32 mm

Data collection

Rigaku R-AXIS RAPID diffractometer	1097 independent reflections
Radiation source: fine-focus sealed tube	1000 reflections with I > 2σ(I)
graphite	Rint = 0.021
Detector resolution: 0 pixels mm-1	θmax = 27.4°, θmin = 3.3°
ω scan	h = −11→11
Absorption correction: multi-scan (ABSCOR; Higashi, 1995)	k = −11→11
Tmin = 0.900, Tmax = 0.925	l = −16→16
8610 measured reflections

Refinement

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)] = 0.038	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.111	H atoms treated by a mixture of independent and constrained refinement
S = 1.10	w = 1/[σ2(Fo2) + (0.0658P)2 + 0.5154P] where P = (Fo2 + 2Fc2)/3
1097 reflections	(Δ/σ)max < 0.001
86 parameters	Δρmax = 0.43 e Å−3
1 restraint	Δρmin = −0.22 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 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 (Ų)

	x	y	z	Uiso*/Ueq
Na	0.91916 (8)	0.06655 (8)	0.62976 (5)	0.0292 (2)
O1	1.12521 (17)	0.21959 (14)	0.69249 (10)	0.0391 (4)
O2	1.30500 (16)	0.37558 (13)	0.75029 (10)	0.0325 (3)
C1	1.19167 (19)	0.34236 (18)	0.68752 (12)	0.0243 (3)
C2	1.15019 (18)	0.46906 (17)	0.61037 (11)	0.0219 (3)
H2A	1.2386	0.4963	0.5692	0.026*
H2B	1.1207	0.5598	0.6508	0.026*
C3	1.02287 (16)	0.42768 (14)	0.53277 (10)	0.0161 (3)
H3A	0.9358	0.3927	0.5741	0.019*
C4	1.07185 (16)	0.29671 (16)	0.45770 (11)	0.0177 (3)
O3	1.01257 (15)	0.16760 (12)	0.46431 (9)	0.0300 (3)
O4	1.17325 (15)	0.33112 (14)	0.39020 (10)	0.0300 (3)
H2C	1.310 (4)	0.308 (3)	0.7989 (19)	0.088 (11)*

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
Na	0.0336 (4)	0.0244 (4)	0.0296 (4)	−0.0038 (3)	0.0023 (3)	−0.0031 (2)
O1	0.0481 (8)	0.0278 (7)	0.0415 (7)	−0.0062 (6)	−0.0172 (6)	0.0104 (5)
O2	0.0432 (7)	0.0262 (6)	0.0282 (6)	0.0011 (5)	−0.0177 (5)	0.0041 (5)
C1	0.0305 (8)	0.0216 (7)	0.0208 (7)	0.0046 (6)	−0.0054 (6)	−0.0007 (5)
C2	0.0278 (7)	0.0185 (7)	0.0194 (7)	0.0020 (6)	−0.0054 (6)	0.0003 (5)
C3	0.0208 (7)	0.0137 (6)	0.0138 (6)	0.0032 (5)	0.0005 (5)	0.0002 (5)
C4	0.0212 (7)	0.0160 (6)	0.0159 (6)	0.0039 (5)	−0.0012 (5)	−0.0008 (5)
O3	0.0448 (7)	0.0166 (5)	0.0286 (6)	−0.0050 (5)	0.0081 (5)	−0.0041 (4)
O4	0.0340 (6)	0.0247 (6)	0.0314 (6)	−0.0026 (5)	0.0148 (5)	−0.0082 (5)

Geometric parameters (Å, °)

Na—O4i	2.3748 (15)	O2—H2C	0.843 (10)
Na—O1	2.3943 (15)	C1—C2	1.506 (2)
Na—O3	2.3978 (13)	C2—C3	1.536 (2)
Na—O3ii	2.4188 (13)	C2—H2A	0.9700
Na—O2iii	2.4522 (14)	C2—H2B	0.9700
Na—O1iv	2.6196 (15)	C3—C4	1.5346 (18)
Na—Naiv	3.3388 (14)	C3—C3vi	1.550 (2)
Na—Naii	3.7369 (14)	C3—H3A	0.9800
O1—C1	1.216 (2)	C4—O3	1.2368 (18)
O1—Naiv	2.6196 (15)	C4—O4	1.2723 (19)
O2—C1	1.311 (2)	O3—Naii	2.4188 (13)
O2—Nav	2.4522 (14)	O4—Navii	2.3748 (15)
O4i—Na—O1	122.39 (5)	C1—O1—Na	146.90 (11)
O4i—Na—O3	95.36 (5)	C1—O1—Naiv	123.86 (11)
O1—Na—O3	79.44 (5)	Na—O1—Naiv	83.38 (5)
O4i—Na—O3ii	119.46 (5)	C1—O2—Nav	146.49 (11)
O1—Na—O3ii	115.41 (6)	C1—O2—H2C	109 (2)
O3—Na—O3ii	78.24 (5)	Nav—O2—H2C	90 (2)
O4i—Na—O2iii	86.14 (5)	O1—C1—O2	122.32 (14)
O1—Na—O2iii	119.22 (5)	O1—C1—C2	123.18 (14)
O3—Na—O2iii	156.69 (5)	O2—C1—C2	114.49 (14)
O3ii—Na—O2iii	80.80 (5)	C1—C2—C3	114.71 (13)
O4i—Na—O1iv	76.26 (5)	C1—C2—H2A	108.6
O1—Na—O1iv	63.76 (7)	C3—C2—H2A	108.6
O3—Na—O1iv	127.10 (5)	C1—C2—H2B	108.6
O3ii—Na—O1iv	150.95 (5)	C3—C2—H2B	108.6
O2iii—Na—O1iv	75.89 (5)	H2A—C2—H2B	107.6
O4i—Na—Naiv	119.52 (4)	C4—C3—C2	110.47 (11)
O1—Na—Naiv	51.20 (4)	C4—C3—C3vi	110.16 (13)
O3—Na—Naiv	129.07 (5)	C2—C3—C3vi	109.98 (14)
O3ii—Na—Naiv	109.34 (4)	C4—C3—H3A	108.7
O2iii—Na—Naiv	68.03 (4)	C2—C3—H3A	108.7
O1iv—Na—Naiv	45.42 (3)	C3vi—C3—H3A	108.7
O4i—Na—Naii	112.22 (4)	O3—C4—O4	123.93 (13)
O1—Na—Naii	99.22 (5)	O3—C4—C3	120.17 (12)
O3—Na—Naii	39.32 (3)	O4—C4—C3	115.89 (12)
O3ii—Na—Naii	38.92 (3)	C4—O3—Na	122.30 (9)
O2iii—Na—Naii	119.06 (4)	C4—O3—Naii	127.90 (10)
O1iv—Na—Naii	162.35 (5)	Na—O3—Naii	101.76 (5)
Naiv—Na—Naii	128.23 (4)	C4—O4—Navii	144.24 (11)

Symmetry codes: (i) x−1/2, −y+1/2, −z+1; (ii) −x+2, −y, −z+1; (iii) x−1/2, y−1/2, −z+3/2; (iv) −x+2, y, −z+3/2; (v) x+1/2, y+1/2, −z+3/2; (vi) −x+2, −y+1, −z+1; (vii) x+1/2, −y+1/2, −z+1.

Hydrogen-bond geometry (Å, °)

D—H···A	D—H	H···A	D···A	D—H···A
O2—H2C···O4viii	0.85 (2)	1.67 (3)	2.5097 (18)	177 (2)

Symmetry codes: (viii) −x+5/2, −y+1/2, z+1/2.