catena-Poly[[diaqua­strontium]-bis­(μ-2-bromo­benzoato)-κ² O,O′:O′;κ³ O:O,O′]

Abstract

The hydro­thermal reaction of SrCO₃ and 2-bromo­benzoic acid in CH₃OH–H₂O afforded the Sr^II title polymeric complex, [Sr(C₇H₄BrO₂)₂(H₂O)₂]_n. Within the coordination sphere, the Sr^II ion is located on a crystallographic twofold axis, and is coordinated by eight O atoms from two water mol­ecules and four carboxyl­ate groups of 2-bromo­benzoate ligands in an irregular coordination geometry. Two μ₃-carboxyl­ate groups of the 2-bromo­benzoate anions bridge two symmetry-related Sr^II atoms, giving rise to a chain structure extending along [001]. The polymeric chains are connected via O—H⋯O and O—H⋯Br hydrogen bonds inter­actions into a three-dimensional supra­molecular network.

Related literature

For other metal complexes with the 2-bromo­benzoato ligand, see: Zhang et al. (2005 ▶, 2008 ▶); Zhang (2006 ▶); Wang et al. (2003 ▶). For related structures, see: Zhang (2008 ▶); Karipides et al. (1988 ▶).

Experimental

Crystal data

• [Sr(C₇H₄BrO₂)₂(H₂O)₂]

• M _r = 523.68

• Orthorhombic,

• a = 18.740 (4) Å

• b = 11.669 (2) Å

• c = 8.0529 (16) Å

• V = 1760.9 (6) ų

• Z = 4

• Mo Kα radiation

• μ = 7.62 mm⁻¹

• T = 290 K

• 0.36 × 0.20 × 0.16 mm

Data collection

• Rigaku R-AXIS RAPID diffractometer

• Absorption correction: multi-scan (ABSCOR; Higashi, 1995 ▶) T _min = 0.170, T _max = 0.309

• 12747 measured reflections

• 1550 independent reflections

• 1273 reflections with I > 2σ(I)

• R _int = 0.090

Refinement

• R[F ² > 2σ(F ²)] = 0.042

• wR(F ²) = 0.130

• S = 1.14

• 1550 reflections

• 106 parameters

• H-atom parameters constrained

• Δρ_max = 0.84 e Å⁻³

• Δρ_min = −0.78 e Å⁻³

Data collection: RAPID-AUTO (Rigaku, 1998 ▶); cell refinement: RAPID-AUTO; data reduction: CrystalStructure (Rigaku, 1998 ▶); 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
O1—H1A⋯O2i	0.82	1.98	2.753 (5)	156
O1—H1B⋯Br1ii	0.82	2.81	3.603 (2)	164

Symmetry codes: (i) ; (ii) .

supplementary crystallographic information

Comment

Metal ions with 2-bromobenzoato ligands can form, among others, mononuclear, dinuclear complexes (Zhang et al., 2005, 2008; Zhang, 2006; Wang et al., 2003) but very few reports on one-dimensional chain structures complexes including 2-bromobenzoato ligands have been published.

In this paper, we would like to report the synthesis and crystal structure of a one-dimensional chain complex including 2-bromobenzoato and Strontium(II). The crystal structure of the title compound is similar to previously published structures (Zhang, 2008; Karipides et al., 1988). Within the title compound, each Sr^II ion is located on a crystallographic two-fold axis and is coordinated by eight O atoms from two water molecules and four carboxyl groups of 2-bromobenzoic acid anions in an irregular coordination geometry. Two µ₃-carboxyl groups of the 2-bromobenzoic anions bridge two symmetry related Strontium atoms, giving rise to a one-dimensional chain structure extending along the [001] direction, with Sr—O bond lengths in the range of 2.498 (3) to 2.753 (4) Å. Separation between Sr and Sr^iv (symmetry code iv: -x+1, -y+2, -z+1) is 4.1703 (8) Å (Fig. 1). The polymeric chains are connected via O—H···O and O—H···Br hydrogen bonds interactions in a three-dimensional supramolecular structure (Fig. 2). The O1—H1A···O3 and O1—H1A···Br1 separations are 2.753 Å and 3.603 Å. The O—H···O and O1—H1A···Br1 bond angles are 156 ° and 164°, Table 2.

Experimental

SrCl₂.6H₂O. (0.533 g, 2.00 mmol) was dissolved in the appropriate amount of water, and then 1M Na₂CO₃ solution was added. SrCO₃ was obtained by filtration, which was then washed with distilled water (5 times). The freshly prepared SrCO₃, 2-bromobenzoic acid (0.402 g, 2.00 mmol), CH₃OH/H₂O (v/v = 1:2, 15 ml) were mixed and stirred for 2.0 h. Subsequently, the resulting cream suspension was heated in a 23 ml Teflon-lined stainless steel autoclave at 433 K for 5800 minutes. After the autoclave was cooled to room temperature according to the procedure at 2600 minutes, the solid was filtered off. The resulting filtrate was allowed to stand at room temperature, and slow evaporation for 6 weeks afforded colorless block-shaped single crystals.

Refinement

C-bound H atoms were placed in calculated positions, with C—H = 0.93Å and U_iso(H) = 1.2U_eq(C), and were refined using the riding- model approximation. The H atoms of the water molecule were located in a difference Fourier map and refined with an O—H distance restraint of 0.82 (1) Å and U_iso(H) = 1.5U_eq(O).

Figures

Fig. 1.

The one-dimensional chain structure of the title compound, showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 50% probability level.

Fig. 2.

A packing diagram of the title complex, viewed along the c axis, The O—H···O and O—H···Br hydrogen bonds (dashed lines) in the title compound.

Crystal data

[Sr(C7H4BrO2)2(H2O)2]	F(000) = 1008
Mr = 523.68	Dx = 1.975 Mg m−3
Orthorhombic, Pbcn	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2n 2ab	Cell parameters from 9800 reflections
a = 18.740 (4) Å	θ = 3.3–25.0°
b = 11.669 (2) Å	µ = 7.62 mm−1
c = 8.0529 (16) Å	T = 290 K
V = 1760.9 (6) Å3	Block, colorless
Z = 4	0.36 × 0.20 × 0.16 mm

Data collection

Rigaku R-AXIS RAPID diffractometer	1550 independent reflections
Radiation source: fine-focus sealed tube	1273 reflections with I > 2σ(I)
graphite	Rint = 0.090
ω scans	θmax = 25.0°, θmin = 3.3°
Absorption correction: multi-scan (ABSCOR; Higashi, 1995)	h = −22→22
Tmin = 0.170, Tmax = 0.309	k = −13→13
12747 measured reflections	l = −9→8

Refinement

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)] = 0.042	H-atom parameters constrained
wR(F2) = 0.130	w = 1/[σ2(Fo2) + (0.0652P)2 + 1.8313P] where P = (Fo2 + 2Fc2)/3
S = 1.14	(Δ/σ)max < 0.001
1550 reflections	Δρmax = 0.84 e Å−3
106 parameters	Δρmin = −0.78 e Å−3
0 restraints	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
0 constraints	Extinction coefficient: 0.0016 (6)
Primary atom site location: structure-invariant direct methods

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Sr1	0.5000	0.95347 (6)	0.2500	0.0294 (3)
Br1	0.26073 (4)	1.23028 (6)	0.28032 (9)	0.0528 (3)
O1	0.4082 (2)	0.8205 (4)	0.1116 (5)	0.0577 (12)
H1A	0.4050	0.8178	0.0101	0.087*
H1B	0.3663	0.8112	0.1371	0.087*
O2	0.5875 (3)	1.1245 (4)	0.2207 (4)	0.0523 (13)
O3	0.4433 (2)	1.1017 (3)	0.0190 (4)	0.0395 (10)
C1	0.4152 (3)	1.1591 (4)	0.1317 (6)	0.0335 (12)
C2	0.3870 (3)	1.2758 (4)	0.0915 (6)	0.0318 (12)
C3	0.3238 (3)	1.3201 (4)	0.1490 (6)	0.0404 (14)
C4	0.3005 (4)	1.4307 (5)	0.1105 (8)	0.0475 (16)
H4	0.2569	1.4575	0.1495	0.057*
C5	0.3434 (5)	1.4993 (5)	0.0138 (8)	0.0549 (19)
H5A	0.3293	1.5739	−0.0105	0.066*
C6	0.4068 (5)	1.4582 (5)	−0.0469 (8)	0.060 (2)
H6	0.4352	1.5050	−0.1129	0.072*
C7	0.4288 (3)	1.3487 (5)	−0.0113 (7)	0.0452 (15)
H7	0.4716	1.3218	−0.0549	0.054*

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
Sr1	0.0387 (5)	0.0285 (4)	0.0210 (4)	0.000	0.0023 (3)	0.000
Br1	0.0460 (5)	0.0583 (5)	0.0542 (5)	0.0021 (3)	0.0062 (3)	0.0062 (3)
O1	0.058 (3)	0.077 (3)	0.038 (2)	−0.029 (2)	−0.002 (2)	0.003 (2)
O2	0.076 (4)	0.053 (3)	0.028 (2)	−0.026 (2)	0.007 (2)	−0.0068 (18)
O3	0.052 (3)	0.041 (2)	0.0251 (19)	0.0051 (18)	0.0075 (17)	−0.0051 (16)
C1	0.034 (3)	0.039 (3)	0.028 (3)	0.007 (2)	0.000 (2)	−0.001 (2)
C2	0.037 (3)	0.031 (3)	0.027 (3)	0.008 (2)	−0.003 (2)	−0.006 (2)
C3	0.060 (4)	0.035 (3)	0.026 (3)	0.008 (3)	−0.010 (3)	0.000 (2)
C4	0.053 (4)	0.043 (3)	0.047 (4)	0.011 (3)	−0.009 (3)	−0.006 (3)
C5	0.080 (6)	0.034 (3)	0.052 (4)	0.010 (3)	−0.011 (4)	0.001 (3)
C6	0.087 (6)	0.046 (4)	0.047 (4)	−0.014 (4)	−0.006 (4)	0.012 (3)
C7	0.047 (4)	0.044 (3)	0.045 (3)	−0.005 (3)	0.004 (3)	0.000 (3)

Geometric parameters (Å, °)

Sr1—O3i	2.498 (3)	O3—C1	1.244 (6)
Sr1—O3ii	2.498 (3)	O3—Sr1i	2.498 (3)
Sr1—O1	2.570 (4)	C1—O2iii	1.257 (6)
Sr1—O1iii	2.570 (4)	C1—C2	1.496 (7)
Sr1—O2	2.594 (4)	C2—C3	1.373 (8)
Sr1—O2iii	2.594 (4)	C2—C7	1.422 (8)
Sr1—O3iii	2.753 (4)	C3—C4	1.397 (8)
Sr1—O3	2.753 (4)	C4—C5	1.376 (10)
Sr1—C1iii	3.031 (5)	C4—H4	0.9300
Sr1—C1	3.031 (5)	C5—C6	1.371 (11)
Br1—C3	1.901 (6)	C5—H5A	0.9300
O1—H1A	0.8200	C6—C7	1.373 (9)
O1—H1B	0.8200	C6—H6	0.9300
O2—C1iii	1.257 (6)	C7—H7	0.9300
O3i—Sr1—O3ii	150.14 (16)	O2—Sr1—Sr1iv	83.55 (8)
O3i—Sr1—O1	75.71 (13)	O2iii—Sr1—Sr1iv	73.25 (8)
O3ii—Sr1—O1	86.32 (12)	O3iii—Sr1—Sr1iv	35.34 (7)
O3i—Sr1—O1iii	86.32 (12)	O3—Sr1—Sr1iv	119.25 (7)
O3ii—Sr1—O1iii	75.71 (13)	C1iii—Sr1—Sr1iv	59.36 (10)
O1—Sr1—O1iii	105.7 (2)	C1—Sr1—Sr1iv	95.59 (10)
O3i—Sr1—O2	81.37 (12)	O3i—Sr1—Sr1i	39.61 (8)
O3ii—Sr1—O2	123.12 (11)	O3ii—Sr1—Sr1i	154.76 (9)
O1—Sr1—O2	147.99 (12)	O1—Sr1—Sr1i	74.84 (9)
O1iii—Sr1—O2	94.65 (16)	O1iii—Sr1—Sr1i	125.16 (9)
O3i—Sr1—O2iii	123.12 (11)	O2—Sr1—Sr1i	73.25 (8)
O3ii—Sr1—O2iii	81.37 (12)	O2iii—Sr1—Sr1i	83.55 (8)
O1—Sr1—O2iii	94.65 (16)	O3iii—Sr1—Sr1i	119.25 (7)
O1iii—Sr1—O2iii	147.99 (12)	O3—Sr1—Sr1i	35.34 (7)
O2—Sr1—O2iii	79.4 (2)	C1iii—Sr1—Sr1i	95.59 (10)
O3i—Sr1—O3iii	125.68 (15)	C1—Sr1—Sr1i	59.36 (9)
O3ii—Sr1—O3iii	74.95 (13)	Sr1iv—Sr1—Sr1i	149.82 (4)
O1—Sr1—O3iii	158.51 (13)	Sr1—O1—H1A	120.4
O1iii—Sr1—O3iii	80.09 (12)	Sr1—O1—H1B	127.8
O2—Sr1—O3iii	48.25 (10)	H1A—O1—H1B	99.9
O2iii—Sr1—O3iii	72.51 (13)	C1iii—O2—Sr1	97.8 (3)
O3i—Sr1—O3	74.95 (13)	C1—O3—Sr1i	162.0 (3)
O3ii—Sr1—O3	125.68 (15)	C1—O3—Sr1	90.5 (3)
O1—Sr1—O3	80.09 (12)	Sr1i—O3—Sr1	105.05 (13)
O1iii—Sr1—O3	158.51 (13)	O3—C1—O2iii	122.3 (5)
O2—Sr1—O3	72.51 (13)	O3—C1—C2	118.8 (4)
O2iii—Sr1—O3	48.25 (10)	O2iii—C1—C2	118.9 (4)
O3iii—Sr1—O3	102.18 (15)	O3—C1—Sr1	65.3 (3)
O3i—Sr1—C1iii	104.69 (13)	O2iii—C1—Sr1	58.0 (3)
O3ii—Sr1—C1iii	98.88 (13)	C2—C1—Sr1	166.8 (4)
O1—Sr1—C1iii	164.74 (14)	C3—C2—C7	116.5 (5)
O1iii—Sr1—C1iii	89.49 (15)	C3—C2—C1	125.1 (5)
O2—Sr1—C1iii	24.26 (12)	C7—C2—C1	118.4 (5)
O2iii—Sr1—C1iii	72.16 (16)	C2—C3—C4	122.8 (6)
O3iii—Sr1—C1iii	24.23 (11)	C2—C3—Br1	121.1 (4)
O3—Sr1—C1iii	85.27 (13)	C4—C3—Br1	116.0 (5)
O3i—Sr1—C1	98.88 (13)	C5—C4—C3	118.7 (6)
O3ii—Sr1—C1	104.69 (13)	C5—C4—H4	120.6
O1—Sr1—C1	89.49 (15)	C3—C4—H4	120.6
O1iii—Sr1—C1	164.74 (14)	C6—C5—C4	120.2 (6)
O2—Sr1—C1	72.16 (16)	C6—C5—H5A	119.9
O2iii—Sr1—C1	24.26 (12)	C4—C5—H5A	119.9
O3iii—Sr1—C1	85.27 (13)	C5—C6—C7	120.8 (7)
O3—Sr1—C1	24.23 (11)	C5—C6—H6	119.6
C1iii—Sr1—C1	75.3 (2)	C7—C6—H6	119.6
O3i—Sr1—Sr1iv	154.76 (9)	C6—C7—C2	120.8 (6)
O3ii—Sr1—Sr1iv	39.61 (8)	C6—C7—H7	119.6
O1—Sr1—Sr1iv	125.16 (9)	C2—C7—H7	119.6
O1iii—Sr1—Sr1iv	74.84 (9)

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

Hydrogen-bond geometry (Å, °)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1A···O2i	0.82	1.98	2.753 (5)	156
O1—H1B···Br1v	0.82	2.81	3.603 (2)	164

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