Poly[(μ-5,7-dihydr­oxy-4-oxo-2-phenyl-4H-chromene-8-sulfonato)potassium(I)]

Bin Liu; Bo-Lun Yang

doi:10.1107/S1600536808041779

. 2008 Dec 13;65(Pt 1):m66–m67. doi: 10.1107/S1600536808041779

Poly[(μ-5,7-dihydroxy-4-oxo-2-phenyl-4H-chromene-8-sulfonato)potassium(I)]

Bin Liu ^a,^b,^*, Bo-Lun Yang ^a

PMCID: PMC2967906 PMID: 21581534

Abstract

In the polymeric title compound, [K(C₁₅H₉O₇S)]_n, the potassium cation is five-coordinated by four sulfonate O atoms and one carbonyl O atom. Two intramolecular O—H⋯O hydrogen bonds stabilize the conformation of the anion. The polymeric three-dimensional supramolecular architecture is formed via coordination interactions and π–π stacking interactions involving centrosymmetrically related pyrone rings, with a centroid–centroid separation of 3.513 (2) Å.

Related literature

For biological activities of flavonoids, see: Aljancic et al. (1999 ▶); Habtemariam (1997 ▶); Knekt et al. (1997 ▶); Ko et al. (1998 ▶); Nkengfack et al. (1994 ▶); Sakaguchi et al. (1992 ▶). For related structures, see: Benedict et al. (2004 ▶); Li & Zhang (2008 ▶); Wang & Zhang (2005a ▶,b ▶); Zhang & Wang (2005a ▶,b ▶).

Experimental

Crystal data

[K(C₁₅H₉O₇S)]
M _r = 372.38
Orthorhombic,
a = 19.0846 (19) Å
b = 20.6555 (19) Å
c = 7.5148 (7) Å
V = 2962.3 (5) Å³
Z = 8
Mo Kα radiation
μ = 0.54 mm⁻¹
T = 296 (2) K
0.37 × 0.20 × 0.13 mm

Data collection

Bruker SMART-1000 CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 1999 ▶) T _min = 0.825, T _max = 0.933
13998 measured reflections
2637 independent reflections
1746 reflections with I > 2σ(I)
R _int = 0.049

Refinement

R[F ² > 2σ(F ²)] = 0.044
wR(F ²) = 0.152
S = 1.02
2637 reflections
220 parameters
H-atom parameters constrained
Δρ_max = 0.26 e Å⁻³
Δρ_min = −0.29 e Å⁻³

Data collection: SMART (Bruker, 1999 ▶); cell refinement: SAINT-Plus (Bruker, 1999 ▶); 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 I, global. DOI: 10.1107/S1600536808041779/rz2268sup1.cif

e-65-00m66-sup1.cif^{(22.4KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808041779/rz2268Isup2.hkl

e-65-00m66-Isup2.hkl^{(129.6KB, hkl)}

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

Table 1. Selected bond lengths (Å).

K1—O5ⁱ	2.674 (2)
K1—O6ⁱⁱ	2.754 (2)
K1—O7ⁱⁱⁱ	2.655 (3)
K1—O3^iv	2.642 (2)
K1—O6	2.756 (3)

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

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

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1—H1⋯O7	0.82	1.84	2.588 (4)	152
O2—H2⋯O3	0.82	1.87	2.604 (4)	148

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Symmetry codes: .

Acknowledgments

Financial support for this work from the Natural Science Foundation of Shaanxi Province (2005B01), the National Basic Research Program of China (973 Program, 2009CB219906), the National Natural Science Foundation of China (20776117) and the Specialized Research Fund for the Doctoralal Program of Higher Education of China (20070698037) are gratefully acknowledged.

supplementary crystallographic information

Comment

The biological properties of flavonoids (2-phenylbenzo-γ-pyrone derivatives) are well known (Sakaguchi et al., 1992; Nkengfack et al., 1994; Habtemariam, 1997; Knekt et al., 1997; Ko et al., 1998; Aljancic et al., 1999). The main problem that these compounds present for their use in biological experiments is their poor solubility in water. To overcome this problem, many flavonoidsulfonate derivatives have been synthesized, for example [Ni(H₂O)₆](C₁₇H₁₃O₇S)₂.8H₂O (Zhang & Wang, 2005a), [Sr(H₂O)₇(C₁₆H₁₁O₄SO₃)][C₁₆H₁₁O₄SO₃].6H₂O (Zhang & Wang, 2005b), [Mg(H₂O)₆](C₁₉H₁₇O₄SO₃)₂].8H₂O and [Zn(H₂O)₆](C₁₉H₁₇O₄SO₃)₂].8H₂O (Wang & Zhang, 2005a) and [Co(H₂O)₆](C₁₉H₁₇O₄SO₃)₂.8H₂O (Wang & Zhang, 2005b). Against this background, we report here the solid-state characterization of the potassium salt of 5,7-dihydroxyflavone-8-sulfonate.

The asymmetric unit of title compound consists of one potassium(I) cation and one 5,7-dihydroxyflavone-8-sulfonate anion (Fig. 1). The cation has a distorted coordination geometry and is coordinated by four sulfonate O atoms (O5ⁱ, O6, O6ⁱⁱ, and O7ⁱⁱⁱ; symmetry codes: (i) x, y, z + 1; (ii) x, -y + 1/2, z + 1/2; (iii) -x + 1/2, y, z + 1/2) and one carbonyl O atom (O3^iv; symmetry code: (iv) -x, -y + 1, -z + 1). The K—O bond distances (Table 1) are in agreement with those found in K⁺.C₁₆H₁₁O₈^-.2H₂O (Benedict et al., 2004). The flavone skeleton presents the same structure of a corresponding flavonesulfonate ligand reported previously (Li & Zhang, 2008) and is stabilized by intramolecular hydrogen bonds, with O1—H1···O7 = 2.588 (4) Å and O2—H2···O3 = 2.640 (4) Å (Table 2).

As shown in Fig. 2, K1^vi (symmetry code: (vi) x, -y + 1/2, z - 1/2) and K1^vii (symmetry code: (vii) -x + 1/2, y, z - 1/2) coordinate with O6 and O7^viii (symmetry code: (viii) -x + 1/2, -y + 1/2, z) and O6^viii and O7, respectively, resulting in a centrosymmetric eight-membered chelate ring that is non-planar. Coordination bonds K1^vi–O3^ix (symmetry code: (ix) -x, y - 1/2, -z + 1/2) and K1^vii–O3^x (symmetry code: (x) x + 1/2, -y + 1, -z + 1/2) link the flavone skeletons [C1—C15/O4]^ix and [C1—C15/O4]^x and the eight-membered ring together to form a two-dimensional sheet-like structure in the ab plane. Another eight-membered chelate ring is built up by O6ⁱⁱ, S1ⁱⁱ, O7ⁱⁱ, K1^viii, O6ⁱⁱⁱ, S1ⁱⁱⁱ, O7ⁱⁱⁱ and K1. Two adjacent eight-membered rings are further linked into a one-dimensional polyion chain along the c axis by the coordination bonds K1–O6, K1^vii–O5ⁱⁱⁱ, K1^viii–O6^viii and K1^vi–O5ⁱⁱ (Fig. 3). Additionally, π···π stacking interactions (Fig. 2) between centrosymmetrically related pyrone rings may be effective in the stabilization of the three-dimensional polymeric structure, with a centroid-centroid distance of 3.513 (2) Å, a perpendicular interplanar distance of 3.342 (3) Å and a centroid···centroid offset of 1.084 (2) Å.

Experimental

5,7-dihydroxyflavone (1.0 g, 3.9 mmol) was added slowly to concentrated sulfuric acid (6 ml) with stirring. The reaction was maintained at room temperature for 12 h. Then, the mixture was poured into a KCl saturated aqueous solution (50 ml) and a yellow precipitate appeared. After 5 h, the precipitate was filtered and washed with a KCl saturated aqueous solution until the pH value of the filtrate was 7. The solid product was recrystallized from an ethanol-water (1:1 v/v) solution. Colourless plate-shaped crystals suitable for X-ray analysis were obtained by slow evaporation of the solvent for about 4 d at room temperature (yield 83%).