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

The structural unit of the title compound, [K(C(6)H(3)N(2)O(4))(C(6)H(4)N(2)O(4))(H(2)O)(2)](n), consists of one potassium cation, one hydrogen pyrazine-2,3-dicarboxyl-ate anion, one pyrazine-2,3-dicarboxylic acid mol-ecule and two water mol-ecules; this is twice the asymmetric unit, since the potassium cation lies on an inversion centre. Each anion or acid mol-ecule 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 mol-ecule. 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)(C6n class="Species">H4N2O4)(H2O)2]

M = 410.35

Triclinic,

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[F 2 > 2σ(F 2)] = 0.029

wR(F 2) = 0.089

S = 0.82

1639 reflections

141 parameters

3 restraints

H atoms treated by a mixture of independent and constrained refinement

Δρmax = 0.30 e Å−3

Δρmin = −0.24 e Å−3

Data collection: CrysAlis CCD (Oxford Diffraction, 2006 ▶); cell refinement: CrysAlis RED (Oxford Diffraction, 2006 ▶); data n class="Disease">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 ▶).

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

Structure factors: contains datablocks I. DOI: 10.1107/S1600536807066202/cf2158Isup2.hkl

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

[K(C6H3N2O4)(C6H4N2O4)(H2O)2]	Z = 1
Mr = 410.35	F000 = 210
Triclinic, P1	Dx = 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 = 2.7–27.5º
c = 8.1153 (13) Å	µ = 0.40 mm−1
α = 68.39 (2)º	T = 303 (2) K
β = 81.18 (1)º	Prism, colorless
γ = 64.24 (2)º	0.40 × 0.36 × 0.14 mm
V = 404.43 (13) Å3

Oxford Diffraction Xcalibur diffractometer with Sapphire CCD detector	1639 independent reflections
Radiation source: Enhance (Mo) X-ray Source	1357 reflections with I > 2σ(I)
Monochromator: graphite	Rint = 0.017
Detector resolution: 8.4012 pixels mm-1	θmax = 26.4º
T = 303(2) K	θmin = 2.7º
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
Tmin = 0.858, Tmax = 0.947	l = −10→10
4541 measured reflections

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(Fo2) + (0.0664P)2 + 0.1925P] where P = (Fo2 + 2Fc2)/3
S = 0.82	(Δ/σ)max < 0.001
1639 reflections	Δρmax = 0.30 e Å−3
141 parameters	Δρmin = −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)

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.

	x	y	z	Uiso*/Ueq	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)

	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)

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—K1iv	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—K1iv	154.68 (13)
N2—C3—C4—C5	−174.99 (13)	C3—C6—O2—K1iv	−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)

D—H···A	D—H	H···A	D···A	D—H···A
O3—H3A···O4v	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···O3vi	0.86 (3)	1.76 (3)	2.5994 (17)	168 (2)
O1—H1···O1v	0.80 (4)	1.68 (4)	2.480 (2)	171 (5)

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) ; (ii) ; (iii) .

Table 2

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O3—H3A⋯O4iv	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⋯O3v	0.86 (3)	1.76 (3)	2.5994 (17)	168 (2)
O1—H1⋯O1iv	0.80 (4)	1.68 (4)	2.480 (2)	171 (5)

Symmetry codes: (ii) ; (iv) ; (v) .