Poly[diaqua(μ2-3-carboxypyrazine-2-carboxylato)(μ2-pyrazine-2,3-dicarboxylic acid)potassium(I)]

Tombul, M.; Güven, K.; Svoboda, I.

doi:10.1107/S1600536807066202

metal-organic compounds

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ISSN: 2056-9890

Volume 64| Part 1| January 2008| Pages m246-m247

https://doi.org/10.1107/S1600536807066202

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Poly[diaqua(μ₂-3-carboxypyrazine-2-carboxylato)(μ₂-pyrazine-2,3-dicarboxylic acid)potassium(I)]

Mustafa Tombul,^a ^* Kutalmis Güven ^b and Ingrid Svoboda ^c

^aDepartment of Chemistry, Faculty of Arts and Science, University of Kirikkale, Campus Yahsihan, 71450 Kirikkale, Turkey, ^bDepartment of Physics, Faculty of Arts and Science, University of Kirikkale, Campus Yahsihan, 71450 Kirikkale, Turkey, and ^cStructural Research, Materials Science, Darmstadt University of Technology, Petersen Strasse 23, D-64287 Darmstadt, Germany
^*Correspondence e-mail: mustafatombul38@gmail.com

(Received 17 October 2007; accepted 8 December 2007; online 15 December 2007)

The structural unit of the title compound, [K(C₆H₃N₂O₄)(C₆H₄N₂O₄)(H₂O)₂]_n, consists of one potassium cation, one hydrogen pyrazine-2,3-dicarboxylate anion, one pyrazine-2,3-dicarboxylic acid molecule and two water molecules; this is twice the asymmetric unit, since the potassium cation lies on an inversion centre. Each anion or acid molecule is linked to two potassium cations, while the potassium cation has contacts to four symmetry-equivalent organic ligands, with two different coordination modes towards this cation. In addition, each potassium cation is coordinated by two water O atoms, raising the coordination number to eight. One of the carboxyl groups of the acid retains its H atom, which forms a hydrogen bond to a coordinated water molecule. The other carboxyl group is deprotonated in half of the ligands and protonated in the other half, taking part in a strong O—H⋯O hydrogen bond disordered over an inversion centre. The stabilization of the crystal structure is further assisted by O—H⋯O and O—H⋯N hydrogen bonds in which water acts as the donor.

Related literature

For related literature, see: Clegg & Liddle (2004 ); Cuesta et al. (2003 ); Ptasiewicz-Bak & Leciejewicz (1997a ,b ); Starosta & Leciejewicz (2005 ); Takusagawa & Shimada (1973 ); Tombul et al. (2006 , 2007 ). Richard et al. (1973 ). Nepveu et al. (1993 ).

Experimental

Crystal data

[K(C₆H₃N₂O₄)(C₆H₄N₂O₄)(H₂O)₂]
M_r = 410.35
Triclinic, $[P \overline 1]$
a = 7.4171 (11) Å
b = 8.0252 (12) Å
c = 8.1153 (13) Å
α = 68.39 (2)°
β = 81.18 (1)°
γ = 64.24 (2)°
V = 404.43 (13) Å³
Z = 1
Mo Kα radiation
μ = 0.40 mm⁻¹
T = 303 (2) K
0.40 × 0.36 × 0.14 mm

Data collection

Oxford Diffraction Xcalibur diffractometer with Sapphire CCD detector
Absorption correction: numerical [using a multifaceted crystal model based on expressions derived by Clark & Reid (1995 )] T_min = 0.858, T_max = 0.947
4541 measured reflections
1639 independent reflections
1357 reflections with I > 2σ(I)
R_int = 0.017

Refinement

R[F² > 2σ(F²)] = 0.029
wR(F²) = 0.089
S = 0.82
1639 reflections
141 parameters
3 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.30 e Å⁻³
Δρ_min = −0.24 e Å⁻³

Table 1
Selected bond lengths (Å)

N1—K1	2.8655 (15)
O1—K1	2.8995 (12)
O3—K1	2.8771 (15)
K1—N1ⁱ	2.8655 (15)
K1—O3ⁱ	2.8771 (15)
K1—O1ⁱ	2.8995 (12)
K1—O2ⁱⁱ	3.0897 (13)
K1—O2ⁱⁱⁱ	3.0897 (13)
Symmetry codes: (i) -x, -y+1, -z+1; (ii) -x+1, -y, -z+1; (iii) x-1, y+1, z.

Table 2
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O3—H3A⋯O4^iv	0.85 (2)	1.899 (10)	2.7334 (17)	167 (2)
O3—H3B⋯N2ⁱⁱ	0.848 (9)	2.035 (10)	2.8701 (19)	168 (2)
O5—H5⋯O3^v	0.86 (3)	1.76 (3)	2.5994 (17)	168 (2)
O1—H1⋯O1^iv	0.80 (4)	1.68 (4)	2.480 (2)	171 (5)
Symmetry codes: (ii) -x+1, -y, -z+1; (iv) -x+1, -y+1, -z+1; (v) x+1, y-1, z+1.

Data collection: CrysAlis CCD (Oxford Diffraction, 2006 $[Oxford Diffraction (2006). CrysAlis CCD and CrysAlis CCD. Versions 1.171.31.4 Oxford Diffraction Ltd, Abingdon, Oxfordshire, England.]$ ); cell refinement: CrysAlis RED (Oxford Diffraction, 2006 $[Oxford Diffraction (2006). CrysAlis CCD and CrysAlis CCD. Versions 1.171.31.4 Oxford Diffraction Ltd, Abingdon, Oxfordshire, England.]$ ); data reduction: CrysAlis RED; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: Mercury (Macrae et al., 2006 ).; software used to prepare material for publication: publCIF (Westrip, 2008 ).

Supporting information

Crystal structure: contains datablocks global, I. DOI: https://doi.org/10.1107/S1600536807066202/cf2158sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536807066202/cf2158Isup2.hkl

checkCIF report

Comment top

Pyrazine-2,3-dicarboxylic acid (Takusagawa & Shimada, 1973) and its dianion (Richard et al., 1973; Nepveu et al., 1993) have been reported to be well suited for the construction of multidimentional frameworks (nD, n = 1–3), owing to the presence of two adjacent carboxylate groups (O donor atoms) as substituents on the N-heterocyclic pyrazine ring (N donor atoms). In recent years, a variety of metal-organic compound of pyrazine-2,3-dicarboxylic acid have been characterized crystallographically due to growing interest in supramolecular chemistry. These include the calcium (Ptasiewicz-Bak- & Leciejewicz, 1997a; Starosta & Leciejewicz, 2005), magnesium (Ptasiewicz-Bak- H. & Leciejewicz, 1997b), sodium (Tombul et al., 2006) and caesium (Tombul et al., 2007) complexes. We present here the synthesis and crystal structure of the hydrated potassium complex, (I), formed with pyrazine-2,3-dicarboxylic acid.

The structural unit of the title compound, (I), contains one potassium cation, one hydrogen pyrazine-2,3-dicarboxylate anion, one pyrazine-2,3-dicarboxylic acid molecule and two water molecules; this is twice the asymmetric unit, as the potassium ion lies on an inversion centre. Pyrazine-2,3-dicarboxylic acid is, on average, only half deprotonated at one of the carboxylate groups (O1) and together with the symmetry-related oxygen atom (O1^v) which is also half deprotonated, completes the charge balance of the cation. In the crystal structure, the anion or acid molecule is linked to two potassium cations, while the K⁺ cation is surrounded by four organic ligands, two of which are coordinated by utilizing both N and O atoms and the other two are coordinated solely by O atoms. In addition, each potassium cation is coordinated by two water molecules, achieving a coordination number of eight. The primary coordination comprises six oxygen atoms, together with two nitrogen atoms. The planes of the carboxylic/carboxylate groups (O4/C5/O1) and (O2/C6/O5) form dihedral angles with the ring plane of 54.33 (14) and 53.75 (14)°, respectively. The K—O distances are in the range 2.877 (2) Å to 3.089 (2) Å, in accordance with the corresponding values reported for other potassium complexes (Clegg & Liddle, 2004; Cuesta et al., 2003).

In the crystal structure, an asymmetric strong hydrogen bond occurs, linking carboxylate O atoms (Table 2). Atom H1 is involved in this bond and maintains the charge balance within the structure. The ordered carboxyl group forms a hydrogen bond in which water serves as acceptor. The water molecules are involved in normal, slightly bent, hydrogen bonds with hydrogen pyrazine-2,3-dicarboxylate (Table 2); the acceptors are carboxylate O atoms and N atoms of the aromatic ring.

Related literature top

For related literature, see: Clegg & Liddle (2004); Cuesta et al. (2003); Ptasiewicz-Bak & Leciejewicz (1997a,b); Starosta & Leciejewicz (2005); Takusagawa & Shimada (1973); Tombul et al. (2006, 2007). Richard et al. (1973). Nepveu et al. (1993).

Experimental top

K₂CO₃ (346 mg, 2.5 mmol) was carefully added to an aqueous solution (20 ml) of pyrazine-2,3-dicarboxylic acid (1680 mg, 10 mmol), until no further bubbles formed. The reaction mixture gave a colourless and clear solution which was stirred at 333 K for 2.5 h, until it solidified. The solid product was redissolved in water (10 ml) and allowed to stand for a week at room temperature, after which transparent fine crystals were harvested.

Structure description top

For related literature, see: Clegg & Liddle (2004); Cuesta et al. (2003); Ptasiewicz-Bak & Leciejewicz (1997a,b); Starosta & Leciejewicz (2005); Takusagawa & Shimada (1973); Tombul et al. (2006, 2007). Richard et al. (1973). Nepveu et al. (1993).

Computing details top

Data collection: CrysAlis CCD (Oxford Diffraction, 2006); cell refinement: CrysAlis RED (Oxford Diffraction, 2006); data reduction: CrysAlis RED (Oxford Diffraction, 2006); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: Mercury (Macrae et al., 2006).; software used to prepare material for publication: publCIF (Westrip, 2008).

Figures top

	Fig. 1. A segment of the structure of (I), showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 50% probability level. [Symmetry Codes: (ii) -x + 1, -y, -z + 1; (iv) -x, -y + 1, -z + 1; (v) x - 1, y + 1, z.]
	Fig. 2. A packing diagram for (I). Dashed lines indicate hydrogen bonds. (H1A and H2 are omitted for clarity). [Symmetry Codes: (i) -x + 1, -y + 1, -z + 1; (ii) -x + 1, -y, -z + 1; (iii) x + 1, y - 1, z + 1.]

Poly[diaqua(µ₂-3-carboxypyrazine-2-carboxylato)(µ₂-pyrazine- 2,3-dicarboxylic acid)potassium(I)] top

Crystal data top

[K(C₆H₃N₂O₄)(C₆H₄N₂O₄)(H₂O)₂]	Z = 1
M_r = 410.35	F(000) = 210
Triclinic, P1	D_x = 1.685 Mg m⁻³
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 7.4171 (11) Å	Cell parameters from 2574 reflections
b = 8.0252 (12) Å	θ = 2.7–27.5°
c = 8.1153 (13) Å	µ = 0.40 mm⁻¹
α = 68.39 (2)°	T = 303 K
β = 81.18 (1)°	Prism, colorless
γ = 64.24 (2)°	0.40 × 0.36 × 0.14 mm
V = 404.43 (13) Å³

Data collection top

Oxford Diffraction Xcalibur diffractometer with Sapphire CCD detector	1639 independent reflections
Radiation source: Enhance (Mo) X-ray Source	1357 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.017
Detector resolution: 8.4012 pixels mm^-1	θ_max = 26.4°, θ_min = 2.7°
ω and φ scans	h = −9→9
Absorption correction: numerical [using a multifaceted crystal model based on expressions derived by Clark & Reid (1995)]	k = −9→9
T_min = 0.858, T_max = 0.947	l = −10→10
4541 measured reflections

Refinement top

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)] = 0.029	H atoms treated by a mixture of independent and constrained refinement
wR(F²) = 0.089	w = 1/[σ²(F_o²) + (0.0664P)² + 0.1925P] where P = (F_o² + 2F_c²)/3
S = 0.82	(Δ/σ)_max < 0.001
1639 reflections	Δρ_max = 0.30 e Å⁻³
141 parameters	Δρ_min = −0.24 e Å⁻³
3 restraints	Extinction correction: SHELXL, Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.043 (8)

Crystal data top

[K(C₆H₃N₂O₄)(C₆H₄N₂O₄)(H₂O)₂]	γ = 64.24 (2)°
M_r = 410.35	V = 404.43 (13) Å³
Triclinic, P1	Z = 1
a = 7.4171 (11) Å	Mo Kα radiation
b = 8.0252 (12) Å	µ = 0.40 mm⁻¹
c = 8.1153 (13) Å	T = 303 K
α = 68.39 (2)°	0.40 × 0.36 × 0.14 mm
β = 81.18 (1)°

Data collection top

Oxford Diffraction Xcalibur diffractometer with Sapphire CCD detector	1639 independent reflections
Absorption correction: numerical [using a multifaceted crystal model based on expressions derived by Clark & Reid (1995)]	1357 reflections with I > 2σ(I)
T_min = 0.858, T_max = 0.947	R_int = 0.017
4541 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.029	3 restraints
wR(F²) = 0.089	H atoms treated by a mixture of independent and constrained refinement
S = 0.82	Δρ_max = 0.30 e Å⁻³
1639 reflections	Δρ_min = −0.24 e Å⁻³
141 parameters

Special details top

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s 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	Occ. (<1)
C1	0.2243 (2)	−0.0442 (2)	0.6857 (2)	0.0317 (4)
H1A	0.0951	−0.0140	0.6552	0.038*
C2	0.3500 (2)	−0.2386 (2)	0.7694 (2)	0.0335 (4)
H2	0.3046	−0.3358	0.7905	0.040*
C3	0.5925 (2)	−0.1443 (2)	0.78702 (18)	0.0249 (3)
C4	0.4681 (2)	0.0507 (2)	0.69820 (18)	0.0236 (3)
C5	0.5421 (2)	0.2104 (2)	0.6487 (2)	0.0289 (3)
C6	0.8033 (2)	−0.2156 (2)	0.8493 (2)	0.0277 (3)
N1	0.28268 (17)	0.10040 (18)	0.64756 (16)	0.0281 (3)
N2	0.53451 (18)	−0.28984 (18)	0.82048 (17)	0.0310 (3)
O1	0.41860 (17)	0.38402 (16)	0.56448 (17)	0.0394 (3)
H1	0.476 (7)	0.455 (6)	0.533 (5)	0.039 (11)*	0.50
O2	0.94651 (16)	−0.29530 (18)	0.77161 (16)	0.0392 (3)
O3	0.14687 (17)	0.66521 (18)	0.15762 (17)	0.0407 (3)
H3A	0.195 (3)	0.727 (3)	0.190 (3)	0.057 (6)*
H3B	0.245 (2)	0.563 (2)	0.149 (3)	0.057 (6)*
O4	0.71570 (17)	0.16296 (17)	0.68558 (19)	0.0476 (4)
O5	0.80518 (19)	−0.1943 (2)	1.00104 (17)	0.0504 (4)
H5	0.925 (4)	−0.241 (4)	1.038 (3)	0.065 (7)*
K1	0.0000	0.5000	0.5000	0.0471 (2)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C1	0.0200 (7)	0.0376 (8)	0.0396 (8)	−0.0125 (6)	−0.0024 (6)	−0.0137 (7)
C2	0.0279 (8)	0.0336 (8)	0.0424 (9)	−0.0165 (6)	0.0010 (6)	−0.0120 (7)
C3	0.0220 (7)	0.0276 (7)	0.0250 (7)	−0.0091 (6)	−0.0002 (5)	−0.0101 (5)
C4	0.0213 (7)	0.0259 (7)	0.0239 (7)	−0.0076 (6)	−0.0016 (5)	−0.0107 (5)
C5	0.0255 (7)	0.0271 (7)	0.0356 (8)	−0.0088 (6)	−0.0030 (6)	−0.0134 (6)
C6	0.0236 (7)	0.0241 (7)	0.0329 (8)	−0.0082 (6)	−0.0042 (6)	−0.0075 (6)
N1	0.0210 (6)	0.0293 (6)	0.0322 (7)	−0.0067 (5)	−0.0031 (5)	−0.0116 (5)
N2	0.0253 (6)	0.0274 (6)	0.0377 (7)	−0.0107 (5)	−0.0017 (5)	−0.0079 (5)
O1	0.0301 (6)	0.0261 (6)	0.0558 (8)	−0.0121 (5)	−0.0066 (5)	−0.0039 (5)
O2	0.0221 (5)	0.0465 (7)	0.0535 (7)	−0.0108 (5)	0.0004 (5)	−0.0257 (6)
O3	0.0316 (6)	0.0372 (7)	0.0555 (8)	−0.0072 (5)	−0.0149 (5)	−0.0206 (6)
O4	0.0308 (6)	0.0333 (6)	0.0824 (10)	−0.0118 (5)	−0.0192 (6)	−0.0174 (6)
O5	0.0297 (6)	0.0743 (9)	0.0417 (7)	−0.0057 (6)	−0.0116 (5)	−0.0282 (6)
K1	0.0338 (3)	0.0339 (3)	0.0456 (3)	−0.0005 (2)	−0.0012 (2)	0.0006 (2)

Geometric parameters (Å, º) top

C1—N1	1.327 (2)	N1—K1	2.8655 (15)
C1—C2	1.383 (2)	O1—K1	2.8995 (12)
C1—H1A	0.9300	O1—H1	0.80 (4)
C2—N2	1.331 (2)	O3—K1	2.8771 (15)
C2—H2	0.9300	O3—H3A	0.85 (2)
C3—N2	1.3381 (19)	O3—H3B	0.848 (9)
C3—C4	1.392 (2)	O5—H5	0.86 (3)
C3—C6	1.5097 (19)	K1—N1ⁱ	2.8655 (15)
C4—N1	1.3397 (18)	K1—O3ⁱ	2.8771 (15)
C4—C5	1.507 (2)	K1—O1ⁱ	2.8995 (12)
C5—O4	1.2248 (18)	K1—O2ⁱⁱ	3.0897 (13)
C5—O1	1.2760 (19)	K1—O2ⁱⁱⁱ	3.0897 (13)
C6—O2	1.1983 (19)	K1—H3A	3.09 (2)
C6—O5	1.3073 (19)

N1—C1—C2	121.91 (13)	N1ⁱ—K1—O3	72.84 (4)
N1—C1—H1A	119.0	N1—K1—O3	107.16 (4)
C2—C1—H1A	119.0	O3ⁱ—K1—O3	180.0
N2—C2—C1	121.64 (14)	N1ⁱ—K1—O1ⁱ	55.92 (4)
N2—C2—H2	119.2	N1—K1—O1ⁱ	124.08 (4)
C1—C2—H2	119.2	O3ⁱ—K1—O1ⁱ	76.02 (4)
N2—C3—C4	121.58 (13)	O3—K1—O1ⁱ	103.98 (4)
N2—C3—C6	113.19 (12)	N1ⁱ—K1—O1	124.08 (4)
C4—C3—C6	125.20 (13)	N1—K1—O1	55.92 (4)
N1—C4—C3	121.03 (13)	O3ⁱ—K1—O1	103.98 (4)
N1—C4—C5	118.15 (13)	O3—K1—O1	76.02 (4)
C3—C4—C5	120.76 (13)	O1ⁱ—K1—O1	180.000 (1)
O4—C5—O1	125.67 (14)	N1ⁱ—K1—O2ⁱⁱ	107.44 (4)
O4—C5—C4	118.05 (13)	N1—K1—O2ⁱⁱ	72.56 (4)
O1—C5—C4	116.21 (13)	O3ⁱ—K1—O2ⁱⁱ	116.00 (3)
O2—C6—O5	126.25 (14)	O3—K1—O2ⁱⁱ	64.00 (3)
O2—C6—C3	121.86 (13)	O1ⁱ—K1—O2ⁱⁱ	81.35 (3)
O5—C6—C3	111.63 (13)	O1—K1—O2ⁱⁱ	98.65 (4)
C1—N1—C4	117.01 (13)	N1ⁱ—K1—O2ⁱⁱⁱ	72.56 (4)
C1—N1—K1	119.50 (9)	N1—K1—O2ⁱⁱⁱ	107.44 (4)
C4—N1—K1	123.12 (9)	O3ⁱ—K1—O2ⁱⁱⁱ	64.00 (3)
C2—N2—C3	116.78 (13)	O3—K1—O2ⁱⁱⁱ	116.00 (3)
C5—O1—K1	125.42 (10)	O1ⁱ—K1—O2ⁱⁱⁱ	98.65 (4)
C5—O1—H1	109 (3)	O1—K1—O2ⁱⁱⁱ	81.35 (4)
K1—O1—H1	126 (3)	O2ⁱⁱ—K1—O2ⁱⁱⁱ	180.00 (2)
C6—O2—K1^iv	132.38 (10)	N1ⁱ—K1—H3A	70.6 (3)
K1—O3—H3A	96.3 (15)	N1—K1—H3A	109.4 (3)
K1—O3—H3B	99.8 (15)	O3ⁱ—K1—H3A	164.1 (2)
H3A—O3—H3B	106.6 (13)	O3—K1—H3A	15.9 (2)
C6—O5—H5	111.0 (16)	O1ⁱ—K1—H3A	112.9 (3)
N1ⁱ—K1—N1	180.0	O1—K1—H3A	67.1 (3)
N1ⁱ—K1—O3ⁱ	107.16 (4)	O2ⁱⁱ—K1—H3A	79.1 (2)
N1—K1—O3ⁱ	72.84 (4)	O2ⁱⁱⁱ—K1—H3A	100.9 (2)

N1—C1—C2—N2	1.9 (2)	O4—C5—O1—K1	−175.29 (12)
N2—C3—C4—N1	2.1 (2)	C4—C5—O1—K1	7.78 (19)
C6—C3—C4—N1	179.87 (13)	O5—C6—O2—K1^iv	154.68 (13)
N2—C3—C4—C5	−174.99 (13)	C3—C6—O2—K1^iv	−19.1 (2)
C6—C3—C4—C5	2.8 (2)	C1—N1—K1—O3ⁱ	61.01 (11)
N1—C4—C5—O4	−175.63 (14)	C4—N1—K1—O3ⁱ	−111.76 (11)
C3—C4—C5—O4	1.5 (2)	C1—N1—K1—O3	−118.99 (11)
N1—C4—C5—O1	1.5 (2)	C4—N1—K1—O3	68.24 (11)
C3—C4—C5—O1	178.67 (13)	C1—N1—K1—O1ⁱ	1.94 (12)
N2—C3—C6—O2	74.92 (18)	C4—N1—K1—O1ⁱ	−170.83 (10)
C4—C3—C6—O2	−103.06 (18)	C1—N1—K1—O1	−178.06 (12)
N2—C3—C6—O5	−99.65 (16)	C4—N1—K1—O1	9.17 (10)
C4—C3—C6—O5	82.37 (18)	C1—N1—K1—O2ⁱⁱ	−64.29 (11)
C2—C1—N1—C4	−1.8 (2)	C4—N1—K1—O2ⁱⁱ	122.94 (11)
C2—C1—N1—K1	−174.99 (12)	C1—N1—K1—O2ⁱⁱⁱ	115.71 (11)
C3—C4—N1—C1	−0.1 (2)	C4—N1—K1—O2ⁱⁱⁱ	−57.06 (11)
C5—C4—N1—C1	177.00 (12)	C5—O1—K1—N1ⁱ	171.23 (11)
C3—C4—N1—K1	172.82 (10)	C5—O1—K1—N1	−8.77 (11)
C5—C4—N1—K1	−10.06 (17)	C5—O1—K1—O3ⁱ	48.85 (13)
C1—C2—N2—C3	0.0 (2)	C5—O1—K1—O3	−131.15 (13)
C4—C3—N2—C2	−1.9 (2)	C5—O1—K1—O2ⁱⁱ	−70.80 (13)
C6—C3—N2—C2	−179.99 (12)	C5—O1—K1—O2ⁱⁱⁱ	109.20 (13)

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

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O3—H3A···O4^v	0.85 (2)	1.90 (1)	2.7334 (17)	167 (2)
O3—H3B···N2ⁱⁱ	0.85 (1)	2.04 (1)	2.8701 (19)	168 (2)
O5—H5···O3^vi	0.86 (3)	1.76 (3)	2.5994 (17)	168 (2)
O1—H1···O1^v	0.80 (4)	1.68 (4)	2.480 (2)	171 (5)

Symmetry codes: (ii) −x+1, −y, −z+1; (v) −x+1, −y+1, −z+1; (vi) x+1, y−1, z+1.

Experimental details

Crystal data
Chemical formula	[K(C₆H₃N₂O₄)(C₆H₄N₂O₄)(H₂O)₂]
M_r	410.35
Crystal system, space group	Triclinic, P1
Temperature (K)	303
a, b, c (Å)	7.4171 (11), 8.0252 (12), 8.1153 (13)
α, β, γ (°)	68.39 (2), 81.18 (1), 64.24 (2)
V (Å³)	404.43 (13)
Z	1
Radiation type	Mo Kα
µ (mm⁻¹)	0.40
Crystal size (mm)	0.40 × 0.36 × 0.14

Data collection
Diffractometer	Oxford Diffraction Xcalibur diffractometer with Sapphire CCD detector
Absorption correction	Numerical [using a multifaceted crystal model based on expressions derived by Clark & Reid (1995)]
T_min, T_max	0.858, 0.947
No. of measured, independent and observed [I > 2σ(I)] reflections	4541, 1639, 1357
R_int	0.017
(sin θ/λ)_max (Å⁻¹)	0.625

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.029, 0.089, 0.82
No. of reflections	1639
No. of parameters	141
No. of restraints	3
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.30, −0.24

Computer programs: CrysAlis CCD (Oxford Diffraction, 2006), CrysAlis RED (Oxford Diffraction, 2006), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), Mercury (Macrae et al., 2006)., publCIF (Westrip, 2008).

Selected bond lengths (Å) top

N1—K1	2.8655 (15)	K1—O3ⁱ	2.8771 (15)
O1—K1	2.8995 (12)	K1—O1ⁱ	2.8995 (12)
O3—K1	2.8771 (15)	K1—O2ⁱⁱ	3.0897 (13)
K1—N1ⁱ	2.8655 (15)	K1—O2ⁱⁱⁱ	3.0897 (13)

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

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O3—H3A···O4^iv	0.85 (2)	1.899 (10)	2.7334 (17)	167 (2)
O3—H3B···N2ⁱⁱ	0.848 (9)	2.035 (10)	2.8701 (19)	168 (2)
O5—H5···O3^v	0.86 (3)	1.76 (3)	2.5994 (17)	168 (2)
O1—H1···O1^iv	0.80 (4)	1.68 (4)	2.480 (2)	171 (5)

Symmetry codes: (ii) −x+1, −y, −z+1; (iv) −x+1, −y+1, −z+1; (v) x+1, y−1, z+1.

Acknowledgements

The authors gratefully acknowledge Kırıkkale University for the financial support of this research and Professor Dr Hartmut Fuess, Darmstadt University of Technology, for use of the diffractometer.

References

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