Poly[di-μ-aqua-μ(4)-(pyrazine-2,5-dicarboxyl-ato)-dilithium(I)].

In the title coordination polymer, [Li(2)(C(6)H(2)N(2)O(2))(H(2)O)(2)](n) the pyrazine-2,5-dicarboxyl-ate dianionic ligand bridges two symmetry-independent Li(+) ions using both its N,O-chelating sites. The carboxyl-ate O atom of one of them also bridges to another Li(+) ion, while the second O atom of this group is bonded to another Li(+) ion. Two symmetry-independent water O atoms participate also in the bridging system, which gives rise to a polymeric three-dimensional framework. Both Li(+) ions show distorted trigonal-bipyramidal LiNO(4) coordination geometries, with the N atom in an axial site in both cases. The packing is consolidated by O-H⋯O hydrogen bonds, which occur between water mol-ecules as donors and carboxyl-ate O atoms as acceptors.

Related literature

For the crystal structures of transition metal complexes with the title ligand, see: Beobide et al. (2003 ▶); Xu et al. (2003 ▶); Beobide et al. (2006 ▶). For the structures of Cd and Zn complexes, see: Liu et al. (2009 ▶); Yang & Wu (2009 ▶); Yang et al. (2009 ▶). For the structures of polymeric lanthanide complexes, see: Zheng & Jin (2005 ▶); Yang et al. (2009 ▶). For the structure of a Th(IV) complex, see: Frisch & Cahill (2008 ▶). For the structure of an Sr(II) complex, see: Ptasiewicz-Bąk & Leciejewicz (1998a ▶). The structures of Li(I) complexes with pyrazine-2,3-dicarboxyl­ate and water ligands (Tombul et al., 2008 ▶), 3-amino­pyrazine-2-carboxyl­ate and water ligands (Starosta & Leciejewicz, 2010a ▶) and pyrazine-2,3,5,6-tetra­carboxyl­ate and water ligands (Starosta & Leciejewicz, 2010b ▶) have been published. For the structure of pyrazine-2,5-dicarb­oxy­lic acid dihydrate, see: Ptasiewicz-Bąk & Leciejewicz (1998b ▶); Vishweshwar et al. (2002 ▶).

Experimental

Crystal data

[Li2(C6H2N2O2)(H2O)2]

M = 216.01

Monoclinic,

a = 7.2107 (14) Å

b = 7.3646 (15) Å

c = 15.327 (3) Å

β = 99.71 (3)°

V = 802.2 (3) Å3

Z = 4

Mo Kα radiation

μ = 0.16 mm−1

T = 293 K

0.33 × 0.17 × 0.15 mm

Data collection

Kuma KM-4 four-circle diffractometer

Absorption correction: analytical (CrysAlis RED; Oxford Diffraction, 2008 ▶) T min = 0.976, T max = 0.985

2520 measured reflections

2348 independent reflections

1694 reflections with I > 2σ(I)

R int = 0.069

3 standard reflections every 200 reflections intensity decay: 0.6%

Refinement

R[F 2 > 2σ(F 2)] = 0.054

wR(F 2) = 0.161

S = 0.99

2348 reflections

161 parameters

H atoms treated by a mixture of independent and constrained refinement

Δρmax = 0.73 e Å−3

Δρmin = −0.62 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.

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536810050762/hb5759sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810050762/hb5759Isup2.hkl

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

[Li2(C6H2N2O2)(H2O)2]	F(000) = 440
Mr = 216.01	Dx = 1.788 Mg m−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 25 reflections
a = 7.2107 (14) Å	θ = 6–15°
b = 7.3646 (15) Å	µ = 0.16 mm−1
c = 15.327 (3) Å	T = 293 K
β = 99.71 (3)°	Plates, colourless
V = 802.2 (3) Å3	0.33 × 0.17 × 0.15 mm
Z = 4

Kuma KM-4 four-circle diffractometer	1694 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.069
graphite	θmax = 30.1°, θmin = 2.7°
profile data from ω/2θ scans	h = 0→10
Absorption correction: analytical (CrysAlis RED; Oxford Diffraction, 2008)	k = 0→10
Tmin = 0.976, Tmax = 0.985	l = −21→21
2520 measured reflections	3 standard reflections every 200 reflections
2348 independent reflections	intensity decay: 0.6%

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)] = 0.054	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.161	H atoms treated by a mixture of independent and constrained refinement
S = 0.99	w = 1/[σ2(Fo2) + (0.1327P)2 + 0.0049P] where P = (Fo2 + 2Fc2)/3
2348 reflections	(Δ/σ)max = 0.001
161 parameters	Δρmax = 0.73 e Å−3
0 restraints	Δρmin = −0.62 e Å−3

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
O5	0.92850 (16)	0.21032 (15)	1.23861 (7)	0.0235 (3)
N2	0.85719 (16)	0.06063 (16)	0.86051 (8)	0.0178 (3)
O3	0.99726 (17)	0.31016 (14)	0.76139 (7)	0.0248 (3)
O6	0.54300 (17)	0.41912 (16)	1.12325 (8)	0.0248 (3)
N1	0.76024 (18)	0.16459 (17)	1.02138 (8)	0.0194 (3)
O1	0.65141 (17)	−0.08194 (16)	1.12869 (7)	0.0258 (3)
C7	0.69244 (18)	−0.14435 (18)	1.05880 (8)	0.0171 (3)
C3	0.85787 (18)	0.23438 (19)	0.88494 (9)	0.0167 (3)
C8	0.9150 (2)	0.37044 (19)	0.82054 (9)	0.0194 (3)
O2	0.68766 (17)	−0.30725 (14)	1.03608 (7)	0.0252 (3)
O4	0.8671 (2)	0.53125 (16)	0.83062 (9)	0.0342 (3)
C5	0.80318 (19)	−0.06117 (19)	0.91591 (9)	0.0177 (3)
H5	0.7990	−0.1835	0.9006	0.021*
C6	0.75335 (17)	−0.00880 (18)	0.99566 (8)	0.0155 (3)
C2	0.8103 (2)	0.28635 (19)	0.96561 (9)	0.0202 (3)
H2	0.8136	0.4087	0.9808	0.024*
Li2	0.9486 (5)	0.0403 (4)	0.7358 (2)	0.0360 (7)
Li1	0.6732 (4)	0.1742 (4)	1.1630 (2)	0.0298 (6)
H51	0.908 (4)	0.263 (4)	1.284 (2)	0.063 (9)*
H62	0.609 (4)	0.503 (4)	1.1012 (17)	0.049 (7)*
H52	0.994 (4)	0.294 (4)	1.2126 (18)	0.051 (7)*
H61	0.472 (5)	0.375 (5)	1.079 (3)	0.093 (12)*

	U11	U22	U33	U12	U13	U23
O5	0.0301 (6)	0.0199 (5)	0.0225 (5)	−0.0017 (4)	0.0104 (4)	−0.0037 (4)
N2	0.0191 (5)	0.0162 (5)	0.0190 (5)	0.0008 (4)	0.0059 (4)	0.0006 (4)
O3	0.0301 (6)	0.0227 (5)	0.0246 (5)	0.0010 (4)	0.0137 (4)	0.0013 (4)
O6	0.0298 (6)	0.0216 (5)	0.0246 (5)	−0.0021 (4)	0.0096 (4)	0.0010 (4)
N1	0.0229 (6)	0.0172 (6)	0.0191 (5)	0.0018 (4)	0.0064 (4)	−0.0001 (4)
O1	0.0365 (6)	0.0212 (5)	0.0230 (5)	0.0003 (4)	0.0148 (5)	0.0015 (4)
C7	0.0148 (6)	0.0174 (6)	0.0191 (6)	−0.0001 (5)	0.0033 (5)	0.0010 (5)
C3	0.0156 (6)	0.0166 (6)	0.0182 (6)	0.0019 (4)	0.0037 (5)	0.0015 (4)
C8	0.0213 (7)	0.0169 (6)	0.0211 (6)	0.0007 (5)	0.0063 (5)	0.0025 (5)
O2	0.0335 (6)	0.0178 (5)	0.0259 (5)	−0.0039 (4)	0.0094 (4)	−0.0006 (4)
O4	0.0516 (8)	0.0171 (5)	0.0400 (7)	0.0061 (5)	0.0249 (6)	0.0042 (5)
C5	0.0197 (6)	0.0152 (6)	0.0192 (6)	−0.0008 (5)	0.0057 (5)	−0.0004 (4)
C6	0.0145 (6)	0.0145 (6)	0.0178 (6)	0.0008 (4)	0.0035 (5)	0.0014 (4)
C2	0.0264 (7)	0.0145 (6)	0.0211 (6)	0.0025 (5)	0.0082 (5)	0.0003 (5)
Li2	0.053 (2)	0.0239 (14)	0.0359 (16)	−0.0019 (13)	0.0218 (15)	−0.0027 (11)
Li1	0.0305 (14)	0.0250 (13)	0.0332 (14)	0.0005 (11)	0.0033 (11)	−0.0046 (11)

O5—Li2i	2.056 (4)	O6—H62	0.88 (3)
O3—Li1ii	2.131 (3)	O6—H61	0.84 (4)
O6—Li2iii	1.981 (3)	N1—C2	1.3303 (18)
O4—Li2iv	2.332 (4)	N1—C6	1.3348 (18)
Li1—O1	1.958 (3)	O1—C7	1.2463 (17)
Li1—O5	2.020 (3)	C7—O2	1.2481 (17)
Li1—O6	2.077 (3)	C7—C6	1.5064 (18)
Li1—O3iii	2.131 (3)	C3—C2	1.3913 (18)
Li1—N1	2.360 (3)	C3—C8	1.5117 (19)
Li2—O6ii	1.981 (3)	C8—O4	1.2506 (19)
Li2—O3	2.045 (3)	C5—C6	1.3857 (18)
Li2—O5i	2.056 (3)	C5—H5	0.9300
Li2—O4v	2.332 (4)	C2—H2	0.9300
Li2—N2	2.129 (3)	Li2—Li1ii	2.983 (4)
O5—H51	0.83 (3)	Li2—Li1i	3.303 (5)
O5—H52	0.91 (3)	Li1—Li2iii	2.983 (4)
N2—C3	1.3330 (18)	Li1—Li2i	3.303 (5)
N2—C5	1.3376 (17)	Li1—H61	2.30 (4)
O3—C8	1.2458 (17)
Li1—O5—Li2i	108.24 (14)	O3—Li2—N2	80.13 (12)
Li1—O5—H51	105 (2)	O5i—Li2—N2	94.63 (14)
Li2i—O5—H51	113 (2)	O6ii—Li2—O4v	94.45 (15)
Li1—O5—H52	109.1 (17)	O3—Li2—O4v	103.58 (15)
Li2i—O5—H52	117.0 (18)	O5i—Li2—O4v	114.53 (15)
H51—O5—H52	103 (3)	N2—Li2—O4v	88.10 (13)
C3—N2—C5	116.94 (12)	O6ii—Li2—Li1ii	43.94 (9)
C3—N2—Li2	109.43 (13)	O3—Li2—Li1ii	45.59 (9)
C5—N2—Li2	133.63 (13)	O5i—Li2—Li1ii	117.39 (15)
C8—O3—Li2	113.48 (13)	N2—Li2—Li1ii	123.78 (15)
C8—O3—Li1ii	155.36 (13)	O4v—Li2—Li1ii	114.10 (14)
Li2—O3—Li1ii	91.16 (13)	O6ii—Li2—Li1i	95.92 (14)
Li2iii—O6—Li1	94.61 (13)	O3—Li2—Li1i	105.87 (15)
Li2iii—O6—H62	121.1 (18)	O5i—Li2—Li1i	35.51 (9)
Li1—O6—H62	118.3 (19)	N2—Li2—Li1i	88.18 (13)
Li2iii—O6—H61	120 (3)	O4v—Li2—Li1i	149.19 (14)
Li1—O6—H61	95 (3)	Li1ii—Li2—Li1i	93.17 (11)
H62—O6—H61	105 (3)	O1—Li1—O5	107.76 (15)
C2—N1—C6	117.11 (12)	O1—Li1—O6	138.27 (17)
C2—N1—Li1	135.56 (12)	O5—Li1—O6	112.16 (15)
C6—N1—Li1	107.34 (11)	O1—Li1—O3iii	102.21 (15)
C7—O1—Li1	124.49 (14)	O5—Li1—O3iii	100.41 (14)
O1—C7—O2	126.51 (13)	O6—Li1—O3iii	82.36 (12)
O1—C7—C6	116.42 (12)	O1—Li1—N1	75.27 (11)
O2—C7—C6	117.07 (12)	O5—Li1—N1	100.00 (14)
N2—C3—C2	121.60 (12)	O6—Li1—N1	86.19 (12)
N2—C3—C8	116.19 (11)	O3iii—Li1—N1	159.18 (16)
C2—C3—C8	122.21 (12)	O1—Li1—Li2iii	139.07 (16)
O3—C8—O4	127.07 (13)	O5—Li1—Li2iii	101.09 (13)
O3—C8—C3	117.04 (13)	O6—Li1—Li2iii	41.45 (9)
O4—C8—C3	115.82 (12)	O3iii—Li1—Li2iii	43.25 (9)
C8—O4—Li2iv	104.05 (13)	N1—Li1—Li2iii	127.64 (14)
N2—C5—C6	121.33 (13)	O1—Li1—Li2i	71.81 (11)
N2—C5—H5	119.3	O5—Li1—Li2i	36.25 (8)
C6—C5—H5	119.3	O6—Li1—Li2i	148.18 (15)
N1—C6—C5	121.63 (12)	O3iii—Li1—Li2i	103.68 (13)
N1—C6—C7	116.40 (11)	N1—Li1—Li2i	95.21 (12)
C5—C6—C7	121.96 (12)	Li2iii—Li1—Li2i	128.23 (11)
N1—C2—C3	121.33 (13)	O1—Li1—H61	117.0 (10)
N1—C2—H2	119.3	O5—Li1—H61	131.5 (10)
C3—C2—H2	119.3	O6—Li1—H61	21.3 (10)
O6ii—Li2—O3	86.97 (13)	O3iii—Li1—H61	88.0 (9)
O6ii—Li2—O5i	95.80 (14)	N1—Li1—H61	75.4 (9)
O3—Li2—O5i	141.4 (2)	Li2iii—Li1—H61	54.9 (10)
O6ii—Li2—N2	167.10 (18)	Li2i—Li1—H61	164.0 (10)

D—H···A	D—H	H···A	D···A	D—H···A
O6—H62···O2vi	0.88 (3)	1.86 (3)	2.7210 (16)	165 (3)
O6—H61···O2vii	0.84 (4)	2.00 (4)	2.8351 (19)	170 (4)
O5—H52···O4viii	0.91 (3)	1.82 (3)	2.7292 (17)	175 (3)
O5—H51···O1ix	0.83 (3)	1.87 (3)	2.6842 (16)	169 (3)

Table 1

Selected bond lengths (Å)

Li1—O1	1.958 (3)
Li1—O5	2.020 (3)
Li1—O6	2.077 (3)
Li1—O3i	2.131 (3)
Li1—N1	2.360 (3)
Li2—O6ii	1.981 (3)
Li2—O3	2.045 (3)
Li2—O5iii	2.056 (3)
Li2—O4iv	2.332 (4)
Li2—N2	2.129 (3)

Symmetry codes: (i) ; (ii) ; (iii) ; (iv) .

Table 2

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O6—H62⋯O2v	0.88 (3)	1.86 (3)	2.7210 (16)	165 (3)
O6—H61⋯O2vi	0.84 (4)	2.00 (4)	2.8351 (19)	170 (4)
O5—H52⋯O4vii	0.91 (3)	1.82 (3)	2.7292 (17)	175 (3)
O5—H51⋯O1viii	0.83 (3)	1.87 (3)	2.6842 (16)	169 (3)

Symmetry codes: (v) ; (vi) ; (vii) ; (viii) .