(μ-Oxalato-κ4 O 1,O 2:O 1′,O 2′)bis­[bis­(2,2′-bipyridine-κ2 N,N′)cobalt(II)] μ6-oxido-dodeca-μ2-oxido-hexa­oxido-hexa­tungstate(VI)

Congwen Shi; Liming Fan; Peihai Wei; Bin Li; Xiutang Zhang

doi:10.1107/S1600536810023007

. 2010 Jun 18;66(Pt 7):m822–m823. doi: 10.1107/S1600536810023007

(μ-Oxalato-κ⁴ O ¹,O ²:O ^1′,O ^2′)bis[bis(2,2′-bipyridine-κ² N,N′)cobalt(II)] μ₆-oxido-dodeca-μ₂-oxido-hexaoxido-hexatungstate(VI)

Congwen Shi ^a, Liming Fan ^a,^b, Peihai Wei ^a, Bin Li ^b, Xiutang Zhang ^a,^b,^*

PMCID: PMC3006761 PMID: 21587738

Abstract

The asymmetric unit of the title compound, [Co₂(C₂O₄)(C₁₀H₈N₂)₄][W₆O₁₉], consists of one half of the complex [Co₂(C₂O₄)(C₁₀H₈N₂)₄]²⁺ cation and one half of the Lindqvist-type [W₆O₁₉]²⁻ isopolyanion. Both constituents are completed by crystallographic inversion symmetry. In the dimeric cation, the Co^II atom is surrounded in a distorted octahedral coordination by four N atoms from two chelating 2,2′-bipyridine ligands and by two O atoms from the chelating oxalate anion. The Lindqvist-type anion exhibits the characteristic W—O bond-length distribution, with the shortest bonds being the W—O_terminal bonds and the longest being those to the central O atom.

Related literature

For general background to polyoxidometalates, see: Pope & Müller (1991 ▶). For polyoxidometalates modified with amines, see: Zhang, Dou et al. (2009 ▶); Zhang, Wei et al. (2009 ▶); Zhang et al. (2010 ▶). For another structure comprising a Lindqvist-type isopolyanion, see: Meng et al. (2006 ▶). For a related structure, see: Li & Xu (2009 ▶).

Experimental

Crystal data

[Co₂(C₂O₄)(C₁₀H₈N₂)₄][W₆O₁₉]
M _r = 2237.72
Triclinic,
a = 9.4876 (15) Å
b = 9.8548 (15) Å
c = 14.174 (2) Å
α = 90.769 (2)°
β = 91.576 (2)°
γ = 91.113 (2)°
V = 1324.3 (4) Å³
Z = 1
Mo Kα radiation
μ = 13.67 mm⁻¹
T = 293 K
0.12 × 0.10 × 0.08 mm

Data collection

Bruker APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2001 ▶) T _min = 0.291, T _max = 0.408
9331 measured reflections
4613 independent reflections
3755 reflections with I > 2σ(I)
R _int = 0.027

Refinement

R[F ² > 2σ(F ²)] = 0.031
wR(F ²) = 0.076
S = 1.00
4613 reflections
368 parameters
H-atom parameters constrained
Δρ_max = 2.41 e Å⁻³
Δρ_min = −1.10 e Å⁻³

Data collection: APEX2 (Bruker, 2004 ▶); cell refinement: SAINT-Plus (Bruker, 2001 ▶); data reduction: SAINT-Plus; 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: SHELXTL.

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536810023007/wm2358sup1.cif

e-66-0m822-sup1.cif^{(23.8KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810023007/wm2358Isup2.hkl

e-66-0m822-Isup2.hkl^{(226KB, hkl)}

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

Table 1. Selected bond lengths (Å).

Co1—O1	2.104 (6)
Co1—N1	2.101 (7)
Co1—N4	2.105 (6)
Co1—N2	2.114 (6)
Co1—N3	2.119 (7)
Co1—O2	2.134 (6)
O3—W2	1.690 (6)
O4—W2	1.919 (6)
O4—W3	1.926 (6)
O5—W3	1.904 (5)
O5—W2ⁱ	1.935 (5)
O6—W3	1.698 (6)
O7—W3	1.915 (6)
O7—W1	1.931 (6)
O8—W3ⁱ	2.3185 (4)
O8—W3	2.3185 (4)
O8—W1	2.3240 (4)
O8—W1ⁱ	2.3240 (4)
O8—W2ⁱ	2.3252 (5)
O8—W2	2.3252 (5)
O9—W2	1.912 (6)
O9—W1	1.915 (5)
O10—W1	1.914 (6)
O10—W3ⁱ	1.914 (6)
O11—W1	1.696 (6)
O12—W1	1.922 (5)
O12—W2ⁱ	1.920 (6)

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Symmetry code: (i) Inline graphic .

Acknowledgments

Financial support from the 973 Key Program of the MOST (2006CB932905 and 2007CB81532), the National Natural Science Foundation of China (20873160), the Chinese Academy of Sciences (KJCX2-YW—M02), Shandong Provincial Education Department and Shandong Institute of Education is gratefully acknowledged.

supplementary crystallographic information

Comment

There has been extensive interest in polyoxidometalates, owing to their fascinating properties and great potential applications in many fields such in catalysis, material science, medicine and magnetochemistry (Pope & Müller, 1991). Organic amines, such as 3-(2-pyridyl)pyrazole and pyrazine, are used to effectively modify polyoxidomolybdates or heteropolyoxidomolybdates under hydrothermal condictions (Zhang, Dou et al., 2009; Zhang, Wei et al., 2009; Zhang et al., 2010). Here, we describe the synthesis and structural characterization of the title compound.

As shown in Figure 1, the title compound consists of two subunits, viz. of a binuclear complex [Co₂(C₂O₄)(C₁₀H₈N₂)₄]²⁺ cation, and one Lindqvist-type [W₆O₁₉]^2- isopolyanion. Both constituents exhibit 1 symmetry. The Co²⁺ cation is surrounded in a distorted octahedral coordination by four N atoms from two chelating 2,2'-bipyridine ligands and two O atoms from a chelating oxalate anion. The Co—N and Co—O bond lengths are in the range of 2.101 (7)—2.119 (7) and 2.104 (6)—2.134 (6) Å, respectively, and are in good agreement with the bond lenghts observed for catena-poly[[(2,2'-bipyridine-κN,N')cobalt(II)]-µ-oxalato- κ⁴O¹,O²:O^1',O^2'] (Li & Xu, 2009).

The [W₆O₁₉]^2- polyoxidoanion, possessing the well known Lindquist structure, is formed by six WO₆ octahedra connected with each other through edge-sharing oxygen atoms. This anion approaches an approximate O_h symmetry, but actually has 1 symmetry. Three different kinds of oxygen atoms exist in the cluster, viz. terminal Oa, double-bridging Ob, and central Oc oxygen atoms. Therefore, W—O bond lengths can be grouped into three sets: W—Oa: 1.690 (6)—1.698 (6) Å; W—Ob: 1.904 (5)—1.935 (5) Å; W—Oc: 2.3185 (4)—2.3252 (5) Å; these bond lengths strictly follow the rule W—Oa < W—Ob < W—Oc, which is in agreement with the Lindqvist-type polyoxidotungstate reported by Meng et al. (2006).

Experimental

2,2'-bipyridine (0.5 mmoL 0.07 g) and p-carboxyphenylboronic acid were purchased from Jinan Henghua Science & Technology Co. Ltd. A mixture of 2,2'-bipyridine (0.5 mmol 0.07 g), tungstic acid (0.4 mmoL, 0.10 g), oxalic aicd (10 mmol, 0.09), p-carboxyphenylboronic acid (0.3 mmol, 0.05 g), and cobalt(II) sulfate heptahydrate (0.2 mmol, 0.05 g) in 14 ml distilled water was sealed in a 25 ml Teflon-lined stainless steel autoclave and was kept at 433 K for three days. Red crystals suitable for the X-ray experiment were obtained. Anal. Calc. for C₄₂H₃₂Co₂N₈O₂₃W₆: C, 22.53; H, 1.43; N, 5.01. Found: C, 22.26; H, 1.33; N, 4.85%.