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

Danish, M.; Saleem, I.; Ahmad, N.; Starosta, W.; Leciejewicz, J.

doi:10.1107/S1600536810015400

metal-organic compounds

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ISSN: 2056-9890

Volume 66| Part 6| June 2010| Page m616

https://doi.org/10.1107/S1600536810015400

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

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

^aDepartment of Chemistry, University of Sargodha, Sargodha 40100, Pakistan, and ^bInstitute of Nuclear Chemistry and Technology, ul. Dorodna 16, 03-195 Warszawa, Poland
^*Correspondence e-mail: drdanish62@gmail.com

(Received 31 March 2010; accepted 26 April 2010; online 8 May 2010)

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, P 2₁ /c
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 $[Oxford Diffraction (2008). CrysAlis RED. Oxford Diffraction Ltd, Yarnton, England]$ ) 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[F² > 2σ(F²)] = 0.049
wR(F²) = 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

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

Data collection: KM-4 Software (Kuma, 1996 $[Kuma (1996). KM-4 Software. Kuma Diffraction Ltd, Wrocław, Poland.]$ ); cell refinement: KM-4 Software; data reduction: DATAPROC (Kuma, 2001 $[Kuma (2001). DATAPROC. Kuma Diffraction Ltd, Wrocław, Poland.]$ ); 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.

Supporting information

Crystal structure: contains datablocks I, global. DOI: https://doi.org/10.1107/S1600536810015400/ez2207sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536810015400/ez2207Isup2.hkl

checkCIF report

Comment top

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.

Related literature top

Tin complexes with organic ligandshave 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 top

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.

Structure description top

# Used for convenience to store draft or replaced versions # of the abstract, comment etc. # Its contents will not be output

#==============================================================================

Computing details top

Data collection: KM-4 Software (Kuma, 1996); cell refinement: KM-4 Software (Kuma, 1996); 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 (Sheldrick, 2008).

Figures top

	Fig. 1. A structural unit of (1) with atom labelling scheme and 50% probability displacement ellipsoids. Symmetry codes: (i) x,-y-3/2,z-1/2; (ii) x,-y+3/2,z+1/2; (iii) -x,y-1/2,-z+3/2; (iv) -x+1,-y+2,-z+1; (v) -x+1,y-1/2,-z+1/2; (vi) -x+1,y+1/2;-z+1/2; (vii) -x,y+1/2,-z+3/2.
	Fig. 2. Packing diagram of the structure.

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

Crystal data top

[K(C₈H₅N₂O₆)]	F(000) = 536
M_r = 264.24	D_x = 1.790 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 25 reflections
a = 8.1632 (16) Å	θ = 6–15°
b = 16.998 (3) Å	µ = 0.56 mm⁻¹
c = 7.0684 (14) Å	T = 293 K
β = 90.49 (3)°	Block, brown
V = 980.7 (3) Å³	0.43 × 0.32 × 0.22 mm
Z = 4

Data collection top

Kuma KM-4 four-circle diffractometer	2200 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	R_int = 0.033
Graphite monochromator	θ_max = 30.1°, θ_min = 2.4°
profile data from ω/2θ scans	h = −11→0
Absorption correction: analytical (CrysAlis RED; Oxford Diffraction, 2008)	k = 0→23
T_min = 0.889, T_max = 0.920	l = −9→9
3035 measured reflections	3 standard reflections every 200 reflections
2855 independent reflections	intensity decay: 0.7%

Refinement top

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)] = 0.049	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.148	H-atom parameters constrained
S = 1.06	w = 1/[σ²(F_o²) + (0.1144P)² + 0.0549P] where P = (F_o² + 2F_c²)/3
2855 reflections	(Δ/σ)_max = 0.001
155 parameters	Δρ_max = 0.72 e Å⁻³
0 restraints	Δρ_min = −0.72 e Å⁻³

Crystal data top

[K(C₈H₅N₂O₆)]	V = 980.7 (3) Å³
M_r = 264.24	Z = 4
Monoclinic, P2₁/c	Mo Kα radiation
a = 8.1632 (16) Å	µ = 0.56 mm⁻¹
b = 16.998 (3) Å	T = 293 K
c = 7.0684 (14) Å	0.43 × 0.32 × 0.22 mm
β = 90.49 (3)°

Data collection top

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

Refinement top

R[F² > 2σ(F²)] = 0.049	0 restraints
wR(F²) = 0.148	H-atom parameters constrained
S = 1.06	Δρ_max = 0.72 e Å⁻³
2855 reflections	Δρ_min = −0.72 e Å⁻³
155 parameters

Special details top

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 (Å²) top

	x	y	z	U_iso*/U_eq
K1	0.30646 (5)	0.70455 (2)	0.53719 (5)	0.03281 (15)
C1	0.24609 (16)	0.97819 (8)	0.52276 (19)	0.0220 (3)
C7	0.26751 (18)	0.88921 (9)	0.5373 (2)	0.0246 (3)
C2	0.30932 (17)	1.02265 (9)	0.3727 (2)	0.0233 (3)
C6	0.16004 (17)	1.01430 (9)	0.6686 (2)	0.0255 (3)
H6	0.1179	0.9844	0.7670	0.031*
C3	0.28318 (19)	1.10416 (9)	0.3816 (2)	0.0266 (3)
O1	0.25937 (19)	0.85008 (8)	0.38860 (17)	0.0395 (3)
O6	0.39480 (19)	1.22199 (8)	0.2829 (2)	0.0471 (4)
O2	0.28968 (18)	0.86252 (8)	0.69897 (17)	0.0373 (3)
N1	0.04619 (18)	1.13215 (9)	0.8188 (2)	0.0346 (3)
N2	0.34771 (18)	1.15683 (9)	0.2343 (2)	0.0334 (3)
C5	0.13803 (18)	1.09462 (9)	0.6657 (2)	0.0270 (3)
O5	0.3523 (2)	1.13326 (10)	0.0711 (2)	0.0526 (4)
C8	0.4096 (2)	0.98522 (10)	0.2191 (2)	0.0319 (3)
H81	0.3405	0.9739	0.1120	0.048*
H83	0.4573	0.9373	0.2656	0.048*
H82	0.4951	1.0207	0.1819	0.048*
C4	0.20004 (19)	1.14170 (10)	0.5248 (2)	0.0295 (3)
H4	0.1866	1.1960	0.5261	0.035*
O3	0.0391 (2)	1.20350 (9)	0.8230 (3)	0.0503 (4)
O4	−0.0210 (2)	1.08967 (10)	0.9335 (2)	0.0533 (4)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
K1	0.0473 (3)	0.0273 (2)	0.0239 (2)	−0.00228 (13)	0.00711 (15)	0.00005 (11)
C1	0.0202 (6)	0.0239 (6)	0.0219 (6)	0.0009 (5)	0.0005 (5)	−0.0003 (5)
C7	0.0229 (6)	0.0250 (7)	0.0259 (7)	0.0011 (5)	0.0041 (5)	0.0009 (5)
C2	0.0202 (6)	0.0269 (7)	0.0228 (6)	−0.0014 (5)	0.0016 (5)	−0.0004 (5)
C6	0.0217 (6)	0.0314 (8)	0.0234 (6)	0.0004 (5)	0.0042 (5)	0.0004 (5)
C3	0.0250 (7)	0.0270 (7)	0.0280 (7)	−0.0014 (5)	0.0026 (5)	0.0045 (5)
O1	0.0608 (9)	0.0291 (6)	0.0285 (6)	0.0017 (6)	0.0010 (5)	−0.0041 (5)
O6	0.0453 (8)	0.0310 (7)	0.0650 (10)	−0.0058 (5)	0.0100 (7)	0.0082 (6)
O2	0.0520 (8)	0.0329 (6)	0.0270 (6)	0.0053 (5)	0.0035 (5)	0.0063 (5)
N1	0.0266 (7)	0.0394 (8)	0.0381 (7)	0.0041 (5)	0.0069 (5)	−0.0106 (6)
N2	0.0282 (6)	0.0336 (7)	0.0385 (7)	−0.0012 (5)	0.0023 (6)	0.0121 (6)
C5	0.0212 (6)	0.0312 (7)	0.0288 (7)	0.0029 (5)	0.0038 (5)	−0.0050 (6)
O5	0.0650 (10)	0.0608 (10)	0.0321 (7)	−0.0112 (8)	0.0014 (7)	0.0126 (6)
C8	0.0306 (7)	0.0386 (9)	0.0268 (7)	−0.0033 (6)	0.0107 (6)	−0.0039 (6)
C4	0.0261 (7)	0.0262 (7)	0.0361 (8)	0.0022 (5)	0.0028 (6)	−0.0002 (6)
O3	0.0412 (8)	0.0410 (8)	0.0688 (10)	−0.0005 (5)	0.0146 (7)	−0.0228 (7)
O4	0.0585 (10)	0.0587 (9)	0.0432 (8)	0.0134 (7)	0.0271 (7)	0.0030 (7)

Geometric parameters (Å, º) top

K1—O2ⁱ	2.6511 (13)	C3—C4	1.380 (2)
K1—O1ⁱⁱ	2.6826 (13)	C3—N2	1.473 (2)
K1—O1	2.7133 (14)	O1—K1ⁱ	2.6826 (13)
K1—O2	2.9221 (14)	O6—N2	1.221 (2)
K1—O3ⁱⁱⁱ	2.9974 (18)	O6—K1^iv	3.0116 (18)
K1—O6^iv	3.0115 (18)	O6—K1^vi	3.3541 (19)
K1—O4ⁱⁱⁱ	3.0485 (18)	O2—K1ⁱⁱ	2.6511 (13)
K1—O5^v	3.1388 (19)	N1—O3	1.214 (2)
K1—C7	3.1548 (17)	N1—O4	1.220 (2)
K1—N1ⁱⁱⁱ	3.2998 (16)	N1—C5	1.468 (2)
K1—O6^v	3.3541 (19)	N1—K1^vii	3.2997 (16)
K1—K1ⁱ	3.8572 (7)	N2—O5	1.222 (2)
C1—C6	1.395 (2)	C5—C4	1.377 (2)
C1—C2	1.4042 (19)	O5—K1^vi	3.1388 (19)
C1—C7	1.526 (2)	C8—H81	0.9600
C7—O2	1.2414 (19)	C8—H83	0.9600
C7—O1	1.2450 (19)	C8—H82	0.9600
C2—C3	1.403 (2)	C4—H4	0.9300
C2—C8	1.506 (2)	O3—K1^vii	2.9973 (18)
C6—C5	1.377 (2)	O4—K1^vii	3.0485 (17)
C6—H6	0.9300

O2ⁱ—K1—O1ⁱⁱ	132.80 (4)	O3ⁱⁱⁱ—K1—K1ⁱ	108.17 (4)
O2ⁱ—K1—O1	92.12 (4)	O6^iv—K1—K1ⁱ	102.38 (4)
O1ⁱⁱ—K1—O1	130.77 (4)	O4ⁱⁱⁱ—K1—K1ⁱ	108.96 (4)
O2ⁱ—K1—O2	138.23 (4)	O5^v—K1—K1ⁱ	85.65 (4)
O1ⁱⁱ—K1—O2	87.03 (4)	C7—K1—K1ⁱ	66.58 (3)
O1—K1—O2	46.12 (4)	N1ⁱⁱⁱ—K1—K1ⁱ	116.03 (4)
O2ⁱ—K1—O3ⁱⁱⁱ	104.67 (6)	O6^v—K1—K1ⁱ	48.76 (3)
O1ⁱⁱ—K1—O3ⁱⁱⁱ	63.25 (5)	C6—C1—C2	120.82 (14)
O1—K1—O3ⁱⁱⁱ	90.14 (4)	C6—C1—C7	116.39 (13)
O2—K1—O3ⁱⁱⁱ	80.16 (5)	C2—C1—C7	122.79 (12)
O2ⁱ—K1—O6^iv	126.47 (5)	O2—C7—O1	126.02 (16)
O1ⁱⁱ—K1—O6^iv	82.79 (5)	O2—C7—C1	116.09 (13)
O1—K1—O6^iv	84.09 (5)	O1—C7—C1	117.88 (14)
O2—K1—O6^iv	59.62 (4)	O2—C7—K1	67.84 (9)
O3ⁱⁱⁱ—K1—O6^iv	128.64 (5)	O1—C7—K1	58.19 (9)
O2ⁱ—K1—O4ⁱⁱⁱ	75.65 (5)	C1—C7—K1	176.06 (10)
O1ⁱⁱ—K1—O4ⁱⁱⁱ	66.40 (5)	C3—C2—C1	116.14 (13)
O1—K1—O4ⁱⁱⁱ	120.29 (5)	C3—C2—C8	122.20 (13)
O2—K1—O4ⁱⁱⁱ	121.57 (5)	C1—C2—C8	121.51 (14)
O3ⁱⁱⁱ—K1—O4ⁱⁱⁱ	41.55 (5)	C5—C6—C1	119.43 (14)
O6^iv—K1—O4ⁱⁱⁱ	148.60 (5)	C5—C6—H6	120.3
O2ⁱ—K1—O5^v	69.70 (5)	C1—C6—H6	120.3
O1ⁱⁱ—K1—O5^v	103.11 (5)	C4—C3—C2	124.41 (14)
O1—K1—O5^v	112.37 (5)	C4—C3—N2	114.73 (15)
O2—K1—O5^v	119.66 (5)	C2—C3—N2	120.86 (14)
O3ⁱⁱⁱ—K1—O5^v	156.64 (5)	C7—O1—K1ⁱ	163.63 (12)
O6^iv—K1—O5^v	62.99 (5)	C7—O1—K1	98.86 (10)
O4ⁱⁱⁱ—K1—O5^v	116.73 (5)	K1ⁱ—O1—K1	91.26 (4)
O2ⁱ—K1—C7	115.06 (4)	N2—O6—K1^iv	138.32 (12)
O1ⁱⁱ—K1—C7	109.20 (4)	N2—O6—K1^vi	87.65 (10)
O1—K1—C7	22.95 (4)	K1^iv—O6—K1^vi	74.37 (4)
O2—K1—C7	23.17 (4)	C7—O2—K1ⁱⁱ	173.37 (12)
O3ⁱⁱⁱ—K1—C7	84.88 (4)	C7—O2—K1	89.00 (10)
O6^iv—K1—C7	70.65 (4)	K1ⁱⁱ—O2—K1	87.45 (4)
O4ⁱⁱⁱ—K1—C7	124.07 (5)	O3—N1—O4	123.59 (16)
O5^v—K1—C7	118.28 (5)	O3—N1—C5	118.47 (16)
O2ⁱ—K1—N1ⁱⁱⁱ	94.55 (5)	O4—N1—C5	117.93 (16)
O1ⁱⁱ—K1—N1ⁱⁱⁱ	56.83 (5)	O3—N1—K1^vii	65.06 (9)
O1—K1—N1ⁱⁱⁱ	109.77 (5)	O4—N1—K1^vii	67.48 (10)
O2—K1—N1ⁱⁱⁱ	100.25 (4)	C5—N1—K1^vii	147.35 (11)
O3ⁱⁱⁱ—K1—N1ⁱⁱⁱ	21.56 (4)	O6—N2—O5	123.42 (15)
O6^iv—K1—N1ⁱⁱⁱ	136.87 (4)	O6—N2—C3	117.79 (15)
O4ⁱⁱⁱ—K1—N1ⁱⁱⁱ	21.69 (4)	O5—N2—C3	118.79 (15)
O5^v—K1—N1ⁱⁱⁱ	135.22 (5)	C6—C5—C4	122.57 (14)
C7—K1—N1ⁱⁱⁱ	106.43 (4)	C6—C5—N1	119.15 (14)
O2ⁱ—K1—O6^v	57.45 (4)	C4—C5—N1	118.28 (15)
O1ⁱⁱ—K1—O6^v	140.00 (5)	N2—O5—K1^vi	97.94 (12)
O1—K1—O6^v	76.10 (4)	C2—C8—H81	109.5
O2—K1—O6^v	102.69 (4)	C2—C8—H83	109.5
O3ⁱⁱⁱ—K1—O6^v	156.18 (5)	H81—C8—H83	109.5
O6^iv—K1—O6^v	69.96 (4)	C2—C8—H82	109.5
O4ⁱⁱⁱ—K1—O6^v	131.53 (4)	H81—C8—H82	109.5
O5^v—K1—O6^v	38.52 (4)	H83—C8—H82	109.5
C7—K1—O6^v	89.20 (4)	C5—C4—C3	116.61 (15)
N1ⁱⁱⁱ—K1—O6^v	151.93 (4)	C5—C4—H4	121.7
O2ⁱ—K1—K1ⁱ	49.19 (3)	C3—C4—H4	121.7
O1ⁱⁱ—K1—K1ⁱ	171.19 (3)	N1—O3—K1^vii	93.38 (10)
O1—K1—K1ⁱ	44.05 (3)	N1—O4—K1^vii	90.82 (11)
O2—K1—K1ⁱ	89.48 (3)

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

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C6—H6···O4^viii	0.93	2.59	3.518 (2)	174
C8—H81···O4^ix	0.96	2.84	3.576 (3)	134
C8—H82···O2^iv	0.96	2.78	3.610 (2)	146

Symmetry codes: (iv) −x+1, −y+2, −z+1; (viii) −x, −y+2, −z+2; (ix) −x, −y+2, −z+1.

Experimental details

Crystal data
Chemical formula	[K(C₈H₅N₂O₆)]
M_r	264.24
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	293
a, b, c (Å)	8.1632 (16), 16.998 (3), 7.0684 (14)
β (°)	90.49 (3)
V (Å³)	980.7 (3)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.56
Crystal size (mm)	0.43 × 0.32 × 0.22

Data collection
Diffractometer	Kuma KM-4 four-circle diffractometer
Absorption correction	Analytical (CrysAlis RED; Oxford Diffraction, 2008)
T_min, T_max	0.889, 0.920
No. of measured, independent and observed [I > 2σ(I)] reflections	3035, 2855, 2200
R_int	0.033
(sin θ/λ)_max (Å⁻¹)	0.705

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.049, 0.148, 1.06
No. of reflections	2855
No. of parameters	155
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.72, −0.72

Computer programs: KM-4 Software (Kuma, 1996), DATAPROC (Kuma, 2001), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C6—H6···O4ⁱ	0.93	2.59	3.518 (2)	173.6
C8—H81···O4ⁱⁱ	0.96	2.84	3.576 (3)	134.4
C8—H82···O2ⁱⁱⁱ	0.96	2.78	3.610 (2)	145.6

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

Acknowledgements

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

References

Danish, M., Saleem, I., Ahmad, N., Raza, A. R., Starosta, W. & Leciejewicz, J. (2010). Acta Cryst. E66, m137. Web of Science CSD CrossRef IUCr Journals Google Scholar
Kuma (1996). KM-4 Software. Kuma Diffraction Ltd, Wrocław, Poland. Google Scholar
Kuma (2001). DATAPROC. Kuma Diffraction Ltd, Wrocław, Poland. Google Scholar
Oxford Diffraction (2008). CrysAlis RED. Oxford Diffraction Ltd, Yarnton, England Google Scholar
Shahzadi, S., Shahid, K. & Ali, S. (2007). Russ. J. Coord. Chem. 33, 403–411. Web of Science CrossRef CAS Google Scholar
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