Poly[μ-aqua-aqua-μ-3-carboxy­pyrazine-2-carboxyl­ato-sodium(I)]

The crystal structure of the title compound, [Na(C₆H₃N₂O₄)(H₂O)₂]_n, consists of mol­ecular ribbons containing octa­hedral NaO₅N units. Two adjacent Na atoms are bridged by two water mol­ecules to give a centrosymmetric dimeric unit. Each Na centre is coordinated by two carboxylate groups. The ligand also uses one N atom to coordinate to Na. In addition, each Na atom is coordinated by one water O atom, raising the coordination number to six. One of the carboxyl groups retains its H atom, which takes part in an O—H...O [O...O = 2.563 (1) Å] intra­molecular hydrogen bond.

Key indicators

• Single-crystal X-ray study
• T = 295 K
• R factor = 0.029
• wR factor = 0.089
• Data-to-parameter ratio = 15.6

checkCIF/PLATON results

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Computing details

Data collection: MSC/AFC Diffractometer Control Software (Molecular Structure Corporation, 1991); cell refinement: MSC/AFC Diffractometer Control Software; data reduction: TEXSAN (Molecular Structure Corporation, 1999); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEPII (Johnson, 1976) and PLATON (Spek, 2003); software used to prepare material for publication: SHELXL97.

Poly[\-m-aqua-aqua-µ-3-carboxypyrazine-2-carboxylato-sodium(I)]

Crystal data

[Na(C6H3N2O4)(H2O)2]	Z = 2
Mr = 226.13	F(000) = 232
Triclinic, P1	Dx = 1.667 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71069 Å
a = 7.8581 (14) Å	Cell parameters from 25 reflections
b = 8.4416 (19) Å	θ = 10.3–18.3°
c = 7.602 (2) Å	µ = 0.19 mm^−1
α = 108.05 (3)°	T = 295 K
β = 93.71 (2)°	Prism, colourless
γ = 70.139 (14)°	0.4 × 0.4 × 0.2 mm
V = 450.45 (19) Å^3

Data collection

Rigaku AFC-7S diffractometer	2171 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.007
Graphite monochromator	θmax = 30.0°, θmin = 2.7°
ω/2θ scans	h = 0→10
Absorption correction: ψ scan (MSC/AFC Diffractometer Control Software; Molecular Structure Corporation, 1991)	k = −11→11
Tmin = 0.928, Tmax = 0.963	l = −10→10
2737 measured reflections	3 standard reflections every 150 reflections
2561 independent reflections	intensity decay: 0.1%

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.029	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.089	All H-atom parameters refined
S = 1.03	w = 1/[σ^2(Fo^2) + (0.1279P)^2 + 0.6038P] where P = (Fo^2 + 2Fc^2)/3
2561 reflections	(Δ/σ)max = 0.004
164 parameters	Δρmax = 0.40 e Å^−3
0 restraints	Δρmin = −0.22 e Å^−3

Special details

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.

All H atoms were located from a difference Fourier synthesis map for the structure. They were refined with a rotating model, with U_iso values 1.5 times those of the attached atoms.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Na1	0.97622 (6)	0.64028 (6)	0.22505 (6)	0.02584 (12)
O1	0.79734 (12)	0.45813 (11)	0.25491 (11)	0.02530 (17)
O2	1.20465 (11)	0.71143 (12)	0.08883 (11)	0.02787 (18)
O3	1.16355 (12)	0.35439 (11)	0.06391 (12)	0.02768 (18)
O4	0.99969 (12)	0.74130 (11)	0.54513 (11)	0.0323 (2)
O5	0.82941 (14)	0.90906 (12)	0.80501 (12)	0.0372 (2)
C1	0.87549 (15)	0.87414 (13)	0.64057 (14)	0.0226 (2)
C2	0.76445 (14)	1.00726 (13)	0.54464 (13)	0.02005 (19)
N1	0.54326 (13)	1.28835 (12)	0.56208 (13)	0.0264 (2)
N2	0.77081 (14)	0.95409 (12)	0.35922 (13)	0.0276 (2)
C3	0.65340 (13)	1.17601 (13)	0.64532 (13)	0.01980 (19)
C4	0.55027 (17)	1.23306 (16)	0.37675 (16)	0.0306 (2)
C5	0.66546 (19)	1.06815 (16)	0.27621 (15)	0.0325 (3)
C6	1.35008 (14)	0.75012 (13)	0.14636 (14)	0.02121 (19)
O6	1.47951 (12)	0.71939 (14)	0.04803 (12)	0.0373 (2)
H4	0.473 (2)	1.313 (2)	0.315 (2)	0.037 (4)*
H6	0.665 (2)	1.032 (2)	0.146 (3)	0.044 (5)*
H1	1.212 (3)	0.659 (3)	−0.036 (3)	0.070 (6)*
H2	0.696 (3)	0.513 (3)	0.308 (2)	0.042 (5)*
H3	1.165 (2)	0.274 (3)	0.101 (2)	0.040 (4)*
H5	0.862 (3)	0.393 (3)	0.325 (3)	0.052 (5)*
H7	1.273 (3)	0.333 (3)	0.036 (3)	0.054 (5)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Na1	0.0288 (2)	0.0229 (2)	0.0211 (2)	−0.00581 (17)	0.00212 (16)	0.00281 (16)
O1	0.0234 (4)	0.0270 (4)	0.0207 (3)	−0.0028 (3)	0.0000 (3)	0.0068 (3)
O2	0.0289 (4)	0.0357 (4)	0.0192 (3)	−0.0156 (3)	0.0009 (3)	0.0031 (3)
O3	0.0238 (4)	0.0258 (4)	0.0323 (4)	−0.0033 (3)	0.0035 (3)	0.0119 (3)
O4	0.0349 (5)	0.0257 (4)	0.0239 (4)	0.0041 (3)	−0.0013 (3)	0.0066 (3)
O5	0.0553 (6)	0.0265 (4)	0.0228 (4)	−0.0004 (4)	0.0064 (4)	0.0114 (3)
C1	0.0276 (5)	0.0182 (4)	0.0204 (4)	−0.0057 (4)	−0.0026 (4)	0.0065 (3)
C2	0.0223 (5)	0.0183 (4)	0.0181 (4)	−0.0047 (3)	−0.0004 (3)	0.0059 (3)
N1	0.0269 (5)	0.0232 (4)	0.0231 (4)	−0.0006 (3)	−0.0009 (3)	0.0076 (3)
N2	0.0367 (5)	0.0220 (4)	0.0182 (4)	−0.0037 (4)	−0.0010 (3)	0.0047 (3)
C3	0.0200 (4)	0.0207 (4)	0.0178 (4)	−0.0058 (3)	0.0004 (3)	0.0056 (3)
C4	0.0357 (6)	0.0275 (5)	0.0240 (5)	−0.0030 (4)	−0.0058 (4)	0.0110 (4)
C5	0.0455 (7)	0.0275 (5)	0.0179 (5)	−0.0049 (5)	−0.0038 (4)	0.0068 (4)
C6	0.0214 (5)	0.0199 (4)	0.0192 (4)	−0.0031 (3)	0.0010 (3)	0.0056 (3)
O6	0.0255 (4)	0.0561 (6)	0.0260 (4)	−0.0118 (4)	0.0067 (3)	0.0071 (4)

Geometric parameters (Å, º)

Na1—O4	2.3333 (12)	O5—C1	1.2402 (14)
Na1—O3	2.3407 (12)	C1—C2	1.5216 (14)
Na1—O2	2.4523 (10)	C2—N2	1.3388 (14)
Na1—O1	2.4734 (10)	C2—C3	1.3938 (14)
Na1—N2	2.5093 (13)	N1—C3	1.3387 (13)
Na1—Na1^i	3.4637 (16)	N1—C4	1.3381 (15)
O1—H2	0.83 (2)	N2—C5	1.3333 (15)
O1—H5	0.89 (2)	C3—C6^ii	1.5097 (15)
O2—C6	1.3055 (13)	C4—C5	1.3840 (17)
O2—H1	0.91 (2)	C4—H4	0.964 (17)
O3—H3	0.807 (19)	C5—H6	0.938 (18)
O3—H7	0.84 (2)	C6—O6	1.2081 (14)
O4—C1	1.2570 (14)
O4—Na1—O3	118.02 (4)	Na1—O3—H3	118.1 (13)
O4—Na1—O3^i	155.20 (4)	Na1^i—O3—H3	116.2 (12)
O3—Na1—O3^i	86.07 (4)	Na1—O3—H7	121.4 (14)
O4—Na1—O2	105.90 (4)	Na1^i—O3—H7	102.0 (13)
O3—Na1—O2	80.13 (4)	H3—O3—H7	104.2 (18)
O3^i—Na1—O2	82.79 (4)	C1—O4—Na1	119.33 (7)
O4—Na1—O1	92.02 (4)	O5—C1—O4	127.56 (10)
O3—Na1—O1	78.04 (4)	O5—C1—C2	115.25 (9)
O3^i—Na1—O1	87.15 (4)	O4—C1—C2	117.17 (9)
O2—Na1—O1	156.50 (3)	N2—C2—C3	120.89 (9)
O4—Na1—N2	68.81 (4)	N2—C2—C1	117.61 (9)
O3—Na1—N2	172.79 (4)	C3—C2—C1	121.44 (9)
O3^i—Na1—N2	87.42 (4)	C3—N1—C4	116.59 (10)
O2—Na1—N2	96.00 (4)	C5—N2—C2	117.27 (10)
O1—Na1—N2	104.74 (4)	C5—N2—Na1	130.49 (8)
O4—Na1—Na1^i	161.05 (3)	C2—N2—Na1	112.17 (7)
O3—Na1—Na1^i	43.68 (3)	N1—C3—C2	121.81 (9)
O3^i—Na1—Na1^i	42.39 (3)	N1—C3—C6^ii	114.39 (9)
O2—Na1—Na1^i	78.30 (3)	C2—C3—C6^ii	123.78 (9)
O1—Na1—Na1^i	79.95 (3)	N1—C4—C5	121.73 (10)
N2—Na1—Na1^i	129.74 (4)	N1—C4—H4	117.6 (10)
Na1—O1—H2	116.0 (13)	C5—C4—H4	120.7 (10)
Na1—O1—H5	105.2 (12)	N2—C5—C4	121.64 (10)
H2—O1—H5	106.2 (17)	N2—C5—H6	118.5 (11)
C6—O2—Na1	135.32 (7)	C4—C5—H6	119.8 (11)
C6—O2—H1	111.4 (14)	O6—C6—O2	124.80 (10)
Na1—O2—H1	108.6 (14)	O6—C6—C3^ii	122.84 (10)
Na1—O3—Na1^i	93.93 (4)	O2—C6—C3^ii	112.15 (9)
O4—Na1—O2—C6	18.68 (11)	C3—C2—N2—Na1	−178.03 (8)
O3—Na1—O2—C6	−97.82 (10)	C1—C2—N2—Na1	−0.88 (12)
O3^i—Na1—O2—C6	174.94 (10)	O4—Na1—N2—C5	175.15 (12)
O1—Na1—O2—C6	−119.69 (11)	O3^i—Na1—N2—C5	−12.08 (12)
N2—Na1—O2—C6	88.31 (11)	O2—Na1—N2—C5	70.39 (12)
Na1^i—Na1—O2—C6	−142.29 (10)	O1—Na1—N2—C5	−98.45 (12)
O4—Na1—O3—Na1^i	173.79 (4)	Na1^i—Na1—N2—C5	−9.36 (13)
O3^i—Na1—O3—Na1^i	0.0	O4—Na1—N2—C2	−8.05 (8)
O2—Na1—O3—Na1^i	−83.35 (4)	O3^i—Na1—N2—C2	164.72 (8)
O1—Na1—O3—Na1^i	87.91 (4)	O2—Na1—N2—C2	−112.81 (8)
O3—Na1—O4—C1	−163.55 (8)	O1—Na1—N2—C2	78.35 (8)
O3^i—Na1—O4—C1	1.56 (15)	Na1^i—Na1—N2—C2	167.44 (7)
O2—Na1—O4—C1	109.34 (9)	C4—N1—C3—C2	−2.53 (16)
O1—Na1—O4—C1	−86.03 (9)	C4—N1—C3—C6^ii	175.80 (10)
N2—Na1—O4—C1	19.00 (9)	N2—C2—C3—N1	3.03 (16)
Na1^i—Na1—O4—C1	−150.25 (10)	C1—C2—C3—N1	−174.01 (10)
Na1—O4—C1—O5	151.95 (10)	N2—C2—C3—C6^ii	−175.15 (10)
Na1—O4—C1—C2	−26.61 (13)	C1—C2—C3—C6^ii	7.82 (15)
O5—C1—C2—N2	−161.00 (11)	C3—N1—C4—C5	0.01 (19)
O4—C1—C2—N2	17.74 (15)	C2—N2—C5—C4	−1.74 (19)
O5—C1—C2—C3	16.13 (15)	Na1—N2—C5—C4	174.92 (10)
O4—C1—C2—C3	−165.13 (10)	N1—C4—C5—N2	2.2 (2)
C3—C2—N2—C5	−0.76 (17)	Na1—O2—C6—O6	151.40 (10)
C1—C2—N2—C5	176.38 (11)	Na1—O2—C6—C3^ii	−23.45 (14)

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O2—H1···O1^i	0.91 (2)	1.66 (2)	2.563 (1)	168.18 (3)
O1—H5···O4^iii	0.89 (1)	1.79 (1)	2.671 (1)	176.61 (3)
O1—H2···N1^iv	0.83 (2)	2.11 (2)	2.902 (2)	164.67 (3)
O3—H3···O5^iii	0.81 (2)	1.88 (2)	2.688 (2)	177.33 (3)
O3—H7···O6^v	0.84 (2)	1.95 (2)	2.788 (2)	174.45 (3)

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