Poly[(μ6-2-methyl-3,5-dinitro­benzoato)potassium]

Muhammad Danish; Iram Saleem; Nazir Ahmad; Wojciech Starosta; Janusz Leciejewicz

doi:10.1107/S1600536810015400

. 2010 May 8;66(Pt 6):m616. doi: 10.1107/S1600536810015400

Poly[(μ₆-2-methyl-3,5-dinitrobenzoato)potassium]

Muhammad Danish ^a,^*, Iram Saleem ^a, Nazir Ahmad ^a, Wojciech Starosta ^b, Janusz Leciejewicz ^b

PMCID: PMC2979411 PMID: 21579275

Abstract

In the structure of the title coordination polymer, [K(C₈H₅N₂O₆)]_n, each ligand bridges six K⁺ cations. The carboxylate group coordinates both bidentately to one K⁺ ion and monodentately to two K⁺ ions, while one nitro group coordinates bidentately to a fourth K⁺ ion. The last two K⁺ ions are coordinated by the remaining nitro group, one in a bidentate fashion, the other monodentately through one O atom. This bridging mode results in a three-dimensional network. The coordination geometry of the K⁺ ion is represented by an irregular KO₉ polyhedron. Very weak C—H⋯O interactions are observed in the crystal structure.

Related literature

Tin complexes with organic ligands have attracted considerable interest due to their biological activity, see, for example: Shahzadi et al. (2007 ▶). For the structure of a sodium(I) complex with the 2-methyl-3,5-dinitro-benzoate ligand, see: Danish et al. (2010 ▶).

Experimental

Crystal data

[K(C₈H₅N₂O₆)]
M _r = 264.24
Monoclinic,
a = 8.1632 (16) Å
b = 16.998 (3) Å
c = 7.0684 (14) Å
β = 90.49 (3)°
V = 980.7 (3) Å³
Z = 4
Mo Kα radiation
μ = 0.56 mm⁻¹
T = 293 K
0.43 × 0.32 × 0.22 mm

Data collection

Kuma KM-4 four-circle diffractometer
Absorption correction: analytical (CrysAlis RED; Oxford Diffraction, 2008 ▶) T _min = 0.889, T _max = 0.920
3035 measured reflections
2855 independent reflections
2200 reflections with I > 2σ(I)
R _int = 0.033
3 standard reflections every 200 reflections intensity decay: 0.7%

Refinement

R[F ² > 2σ(F ²)] = 0.049
wR(F ²) = 0.148
S = 1.06
2855 reflections
155 parameters
H-atom parameters constrained
Δρ_max = 0.72 e Å⁻³
Δρ_min = −0.72 e Å⁻³

Data collection: KM-4 Software (Kuma, 1996 ▶); cell refinement: KM-4 Software; data reduction: DATAPROC (Kuma, 2001 ▶); 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/S1600536810015400/ez2207sup1.cif

e-66-0m616-sup1.cif^{(17.7KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810015400/ez2207Isup2.hkl

e-66-0m616-Isup2.hkl^{(140.2KB, hkl)}

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
C6—H6⋯O4ⁱ	0.93	2.59	3.518 (2)	174
C8—H81⋯O4ⁱⁱ	0.96	2.84	3.576 (3)	134
C8—H82⋯O2ⁱⁱⁱ	0.96	2.78	3.610 (2)	146

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

Acknowledgments

MD is grateful to the Australian Government for the award of Endeavour Post Doctoral Fellowships for the years 2009–2010.

supplementary crystallographic information

Comment

Methyl-benzoic acids have been studied as precursors in the synthesis of biologically active tin(IV) complexes (Shahzadi et al., 2007). The structure of compound (1) is a three-dimensional polymeric network in which K⁺ ions are bridged by carboxylate and nitro-group O atoms of the ligand (Fig. 1). The ligand's carboxylate group coordinates bidentately to K1. Its oxygen atoms also coordinate to K1⁽ⁱ⁾ and K1⁽ⁱⁱ⁾ [symmetry codes: (i) x,-y-3/2,z-1/2; (ii) x,-y+3/2,z+1/2]. The planes formed by atoms K1/O1/K1⁽ⁱ⁾/O2⁽ⁱ⁾ and K1/O2/K1⁽ⁱⁱ⁾/O1⁽ⁱⁱ⁾, each with s.u.s of 0.1326 (2) Å, make angles of 8.7 (1)° with the C7/O1/O2 plane forming a zig-zag molecular ribbon. A three-dimensional network (Fig. 2) composed of the ribbons inter-connected by nitro-groups represents the stucture of the title compound. The N1/O3/O4 nitro-group coordinates bidentately to K1^(vii); N2/O5/O6 is chelated to the K1^(vi), however, the O6 atom is also linked to K1^(iv). The carboxylic group C7/O1/O2 makes an angle of 38.0 (1)° to the methylbenzene ring, while the nitro-groups N1/O3/O4 and N2/O5/O6 are oriented at angles of 6.7 (1)° and 35.5 (1)°, respectively. K1 is nine-coordinate with a complicated geometry, while the coordination environment of a Na(I) ion in the complex with the same ligand consists of seven O atoms (Danish et al., 2010). Very weak interactions of the C—H···O type are also operating.

Experimental

50 ml of aqueous solution containing 0.008 mol of 2-methyl-3,5-dinitro benzoic acid was added dropwise to 50 ml of an aqueous solution of potassium hydroxide (0.008 mol) with constant stirring at room temperature. The mixture was refluxed for 3 hours, then brought to room temperature and concentrated under reduced pressure. A brown solid was purified by repeated crystallization from ethanol-ethyl acetate (1:1) mixture to obtain brown single crystals.