(μ-Di-hydrogen pyrazine-2,3,5,6-tetra-carboxyl-ato-κ(6) O (2),N (1),O (6);O (3),N (4),O (5))bis-(di-aqua-lithium) monohydrate.

The structure of the title compound, [Li2(C8H2N2O8)(H2O)4]·H2O, is composed of dinuclear mol-ecules in which the ligand bridges two symmetry-related Li(I) ions, each coordinated also by two water O atoms, in an O,N,O'-manner. The Li and N atoms occupy special positions on twofold rotation axes, whereas a crystal water mol-ecule is located at the inter-section of three twofold rotation axes. The Li(I) cation shows a distorted trigonal-bipyramidal coordination. Two carboxyl-ate groups remain protonated and form short inter-ligand hydrogen bonds. The mol-ecules are held together by a network of hydrogen bonds in which the coordinating and solvation water mol-ecules act as donors and carboxyl-ate O atoms as acceptors, forming a three-dimensional architecture.

Related literature

For the structure of a lithium complex with pyrazine-2,3,5,6-tetra­carboxyl­ate and water ligands, see: Starosta & Leciejewicz (2010 ▶). The structure of pyrazine-2,3,5,6-tetra­carb­oxy­lic acid dihydrate was reported by Vishweshwar et al. (2001 ▶).

Experimental

Crystal data

[Li2(C8H2N2O8)(H2O)4]·H2O

M = 358.08

Orthorhombic,

a = 6.3807 (4) Å

b = 9.8331 (6) Å

c = 22.1717 (16) Å

V = 1391.10 (16) Å3

Z = 4

Mo Kα radiation

μ = 0.16 mm−1

T = 293 K

0.12 × 0.10 × 0.06 mm

Data collection

Agilent SuperNova (Dual, Cu at zero, Eos) diffractometer

Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2011 ▶) T min = 0.979, T max = 0.993

3622 measured reflections

917 independent reflections

769 reflections with I > 2σ(I)

R int = 0.061

Refinement

R[F 2 > 2σ(F 2)] = 0.047

wR(F 2) = 0.100

S = 1.06

917 reflections

78 parameters

4 restraints

H atoms treated by a mixture of independent and constrained refinement

Δρmax = 0.25 e Å−3

Δρmin = −0.22 e Å−3

Data collection: CrysAlis PRO (Agilent, 2011 ▶); cell refinement: CrysAlis PRO; data reduction: CrysAlis PRO; 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 datablock(s) I, New_Global_Publ_Block. DOI: 10.1107/S1600536814007223/kp2468sup1.cif

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536814007223/kp2468Isup2.hkl

CCDC reference: 994866

Additional supporting information: crystallographic information; 3D view; checkCIF report

[Li2(C8H2N2O8)(H2O)4]·H2O	Z = 4
Mr = 358.08	F(000) = 736
Orthorhombic, Ibam	Dx = 1.710 Mg m−3
Hall symbol: -I 2 2c	Mo Kα radiation, λ = 0.71073 Å
a = 6.3807 (4) Å	µ = 0.16 mm−1
b = 9.8331 (6) Å	T = 293 K
c = 22.1717 (16) Å	Plate, colourless
V = 1391.10 (16) Å3	0.12 × 0.10 × 0.06 mm

Agilent SuperNova (Dual, Cu at zero, Eos) diffractometer	917 independent reflections
Radiation source: SuperNova (Mo) X-ray Source	769 reflections with I > 2σ(I)
Mirror monochromator	Rint = 0.061
Detector resolution: 16.0131 pixels mm-1	θmax = 29.3°, θmin = 3.7°
ω scans	h = −8→8
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2011)	k = −12→13
Tmin = 0.979, Tmax = 0.993	l = −29→29
3622 measured reflections

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)] = 0.047	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.100	H atoms treated by a mixture of independent and constrained refinement
S = 1.06	w = 1/[σ2(Fo2) + (0.024P)2 + 2.020P] where P = (Fo2 + 2Fc2)/3
917 reflections	(Δ/σ)max < 0.001
78 parameters	Δρmax = 0.25 e Å−3
4 restraints	Δρmin = −0.22 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	Occ. (<1)
N1	1.0000	0.0000	0.06097 (8)	0.0207 (4)
O1	0.7218 (2)	0.11263 (14)	0.12977 (5)	0.0328 (3)
O3	1.1372 (3)	0.14626 (15)	0.19959 (7)	0.0376 (4)
O2	0.5112 (3)	0.16787 (13)	0.05418 (6)	0.0356 (4)
C2	0.8398 (3)	0.05696 (15)	0.03197 (7)	0.0203 (3)
C7	0.6800 (3)	0.11721 (16)	0.07586 (8)	0.0251 (4)
Li1	1.0000	0.0000	0.15359 (19)	0.0360 (10)
O4	0.0000	0.5000	0.2500	0.0595 (9)
H31	1.158 (4)	0.219 (2)	0.1789 (10)	0.056 (8)*
H1	0.506 (12)	0.168 (4)	0.0000	0.097 (15)*
H32	1.068 (6)	0.161 (4)	0.2328 (13)	0.037 (13)*	0.50
H41	0.043 (12)	0.459 (6)	0.2190 (17)	0.10 (3)*	0.50
H33	1.254 (6)	0.111 (6)	0.211 (2)	0.08 (2)*	0.50

	U11	U22	U33	U12	U13	U23
N1	0.0218 (8)	0.0189 (8)	0.0214 (9)	0.0016 (8)	0.000	0.000
O1	0.0355 (7)	0.0383 (7)	0.0244 (6)	0.0065 (6)	0.0072 (6)	−0.0025 (5)
O3	0.0474 (9)	0.0347 (8)	0.0308 (8)	−0.0074 (7)	−0.0008 (7)	0.0004 (6)
O2	0.0293 (7)	0.0400 (7)	0.0376 (7)	0.0154 (6)	0.0050 (7)	0.0002 (6)
C2	0.0198 (8)	0.0174 (7)	0.0239 (8)	0.0002 (6)	0.0008 (6)	−0.0009 (6)
C7	0.0258 (8)	0.0203 (7)	0.0293 (9)	0.0019 (6)	0.0047 (7)	−0.0008 (6)
Li1	0.046 (2)	0.039 (2)	0.024 (2)	−0.005 (2)	0.000	0.000
O4	0.076 (3)	0.065 (2)	0.0372 (19)	0.000	0.000	0.000

N1—C2i	1.3313 (18)	O2—C7	1.280 (2)
N1—C2	1.3313 (18)	O2—H1	1.202 (3)
Li1—N1	2.053 (4)	C2—C2ii	1.418 (3)
O1—C7	1.226 (2)	C2—C7	1.529 (2)
Li1—O1	2.1581 (17)	Li1—O3i	1.969 (3)
Li1—O3	1.969 (3)	Li1—O1i	2.1580 (17)
O3—H31	0.858 (16)	Li1—H33	2.33 (5)
O3—H32	0.870 (19)	O4—H41	0.84 (2)
O3—H33	0.86 (2)
C2i—N1—C2	122.24 (19)	O2—C7—C2	118.22 (15)
C2i—N1—Li1	118.88 (10)	O3i—Li1—O3	117.6 (2)
C2—N1—Li1	118.88 (10)	O3i—Li1—N1	121.21 (11)
C7—O1—Li1	115.89 (16)	O3—Li1—N1	121.21 (11)
Li1—O3—H31	113.4 (17)	O3i—Li1—O1i	96.76 (7)
Li1—O3—H32	110 (3)	O3—Li1—O1i	97.81 (7)
H31—O3—H32	113 (3)	N1—Li1—O1i	75.84 (11)
Li1—O3—H33	104 (4)	O3i—Li1—O1	97.81 (7)
H31—O3—H33	111 (4)	O3—Li1—O1	96.76 (7)
H32—O3—H33	105 (4)	N1—Li1—O1	75.84 (11)
C7—O2—H1	113 (4)	O1i—Li1—O1	151.7 (2)
N1—C2—C2ii	118.88 (10)	O3i—Li1—H33	111.5 (14)
N1—C2—C7	111.58 (14)	O3—Li1—H33	20.9 (10)
C2ii—C2—C7	129.53 (9)	N1—Li1—H33	123.2 (14)
O1—C7—O2	124.31 (16)	O1i—Li1—H33	78.6 (10)
O1—C7—C2	117.47 (16)	O1—Li1—H33	117.7 (10)

D—H···A	D—H	H···A	D···A	D—H···A
O2—H1···O2ii	1.20 (1)	1.20 (1)	2.402 (3)	177 (8)
O3—H32···O3iii	0.87 (2)	2.00 (2)	2.839 (3)	163 (4)
O3—H31···O1iv	0.86 (2)	2.03 (2)	2.8825 (19)	177 (2)
O3—H33···O4v	0.86 (2)	2.10 (2)	2.9454 (17)	169 (6)

Table 1

Selected bond lengths (Å)

Li1—N1	2.053 (4)
Li1—O1	2.1581 (17)
Li1—O3	1.969 (3)
Li1—O3i	1.969 (3)
Li1—O1i	2.1580 (17)

Symmetry code: (i) .

Table 2

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O2—H1⋯O2ii	1.20 (1)	1.20 (1)	2.402 (3)	177 (8)
O3—H32⋯O3iii	0.87 (2)	2.00 (2)	2.839 (3)	163 (4)
O3—H31⋯O1iv	0.86 (2)	2.03 (2)	2.8825 (19)	177 (2)
O3—H33⋯O4v	0.86 (2)	2.10 (2)	2.9454 (17)	169 (6)

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