catena-Poly[[lithium-μ2-(di-hydrogen pyrazine-2,3,5,6-tetra-carboxyl-ato)-κ(6) O (2),N (1),O (6);O (3),N (4),O (5)-lithium-di-μ-aqua-κ(4) O:O] 2.5-hydrate].

The title coordination polymer, {[Li2(C8H2N2O8)(H2O)2]·2.5H2O} n , is built up from mol-ecular ribbons propagating in the c-axis direction of the ortho-rhom-bic unit cell; the ligand bridges two Li(+) ions using both its N,O,O'-bonding sites and adjacent Li(+) ions are bridged by pairs of water mol-ecules. The coordination geometry of the metal ion is distorted trigonal bipyramidal, with the ligand O atoms in the axial sites. Two of the carboxyl-ate groups of the ligand remain protonated and form short symmetric O-H⋯O hydrogen bonds. In the crystal, the ribbons inter-act via a network of O-H⋯O hydrogen bonds in which coordinating water mol-ecules act as donors and carboxyl-ate O atoms within adjacent ribbons act as acceptors, giving rise to a three-dimensional framework. O-H⋯N inter-actions are also observed. The asymmetric unit contains quarter of the ligand and the complete ligand has 2/m symmetry; the Li(+) ion lies on a special position with m.. site symmetry. Both bridging water mol-ecules have m2m site symmetry and both lattice water mol-ecules have m.. site symmetry; one of the latter was modelled with a site occupancy of 0.25.

Related literature

For the structures of related lithium complexes with pyrazine-2,3,5,6-tetra­carboxyl­ate and water ligands, see: Starosta & Leciejewicz (2010 ▶, 2014 ▶).

Experimental

Crystal data

[Li2(C8H2N2O8)(H2O)2]·2.5H2O

M = 174.53

Orthorhombic,

a = 12.0554 (3) Å

b = 6.39040 (17) Å

c = 19.3383 (4) Å

V = 1489.80 (6) Å3

Z = 8

Mo Kα radiation

μ = 0.15 mm−1

T = 567 K

0.24 × 0.20 × 0.05 mm

Data collection

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

Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2011 ▶) T min = 0.701, T max = 1.000

7496 measured reflections

1151 independent reflections

997 reflections with I > 2σ(I)

R int = 0.029

Refinement

R[F 2 > 2σ(F 2)] = 0.042

wR(F 2) = 0.122

S = 1.07

1151 reflections

85 parameters

3 restraints

H atoms treated by a mixture of independent and constrained refinement

Δρmax = 0.25 e Å−3

Δρmin = −0.29 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/S160053681401174X/hb7224sup1.cif

Structure factors: contains datablock(s) I. DOI: 10.1107/S160053681401174X/hb7224Isup2.hkl

CCDC reference: 1004410

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

[Li(C8H2N2O8)(H2O)2]·2.5H2O	F(000) = 716
Mr = 349.06	Dx = 1.556 Mg m−3
Orthorhombic, Cmcm	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2c 2	Cell parameters from 3296 reflections
a = 12.0554 (3) Å	θ = 3.8–31.9°
b = 6.39040 (17) Å	µ = 0.15 mm−1
c = 19.3383 (4) Å	T = 293 K
V = 1489.80 (6) Å3	Block, colourless
Z = 4	0.24 × 0.20 × 0.05 mm

Agilent SuperNova (Dual, Cu at zero, Eos) diffractometer	1151 independent reflections
Radiation source: SuperNova (Mo) X-ray Source	997 reflections with I > 2σ(I)
Mirror monochromator	Rint = 0.029
Detector resolution: 16.0131 pixels mm-1	θmax = 30.0°, θmin = 3.4°
ω scans	h = −16→16
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2011)	k = −8→8
Tmin = 0.701, Tmax = 1.000	l = −27→27
7496 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)] = 0.042	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.122	H atoms treated by a mixture of independent and constrained refinement
S = 1.07	w = 1/[σ2(Fo2) + (0.0592P)2 + 0.9014P] where P = (Fo2 + 2Fc2)/3
1151 reflections	(Δ/σ)max < 0.001
85 parameters	Δρmax = 0.25 e Å−3
3 restraints	Δρmin = −0.29 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)
O1	0.67161 (8)	0.07053 (19)	0.35355 (5)	0.0435 (3)
O4	0.5000	−0.1345 (3)	0.2500	0.0388 (4)
O2	0.79263 (8)	0.04117 (18)	0.43921 (5)	0.0413 (3)
O5	0.33035 (11)	0.4166 (2)	0.7500	0.0379 (3)
O3	0.5000	0.3004 (4)	0.2500	0.0533 (6)
N1	0.5000	0.0321 (2)	0.43101 (7)	0.0270 (3)
C2	0.59630 (8)	0.01679 (18)	0.46407 (6)	0.0259 (3)
C7	0.69421 (10)	0.0441 (2)	0.41465 (6)	0.0310 (3)
Li1	0.5000	0.0823 (7)	0.32284 (17)	0.0463 (8)
H4	0.555 (2)	−0.229 (5)	0.2500	0.070 (9)*
H3	0.445 (3)	0.377 (7)	0.2500	0.097 (13)*
H5	0.2920 (19)	0.432 (3)	0.7135 (10)	0.068 (7)*
H2	0.797 (3)	0.0000	0.5000	0.097 (12)*
O6	0.5000	0.4486 (17)	0.3733 (5)	0.077 (2)	0.25
H61	0.5000	0.578 (7)	0.386 (7)	0.115*	0.25
H62	0.5000	0.39 (2)	0.413 (4)	0.115*	0.25

	U11	U22	U33	U12	U13	U23
O1	0.0302 (5)	0.0732 (8)	0.0270 (5)	−0.0022 (4)	0.0051 (3)	0.0037 (4)
O4	0.0299 (9)	0.0406 (10)	0.0459 (11)	0.000	0.000	0.000
O2	0.0207 (4)	0.0659 (7)	0.0374 (5)	−0.0024 (4)	0.0029 (3)	0.0018 (4)
O5	0.0240 (6)	0.0562 (9)	0.0334 (7)	0.0024 (6)	0.000	0.000
O3	0.0336 (11)	0.0356 (11)	0.0908 (18)	0.000	0.000	0.000
N1	0.0207 (6)	0.0370 (7)	0.0232 (6)	0.000	0.000	−0.0010 (5)
C2	0.0198 (5)	0.0335 (6)	0.0244 (5)	−0.0005 (4)	0.0010 (4)	−0.0025 (4)
C7	0.0226 (5)	0.0410 (7)	0.0295 (6)	−0.0015 (4)	0.0048 (4)	−0.0021 (5)
Li1	0.0421 (18)	0.070 (2)	0.0271 (15)	0.000	0.000	0.0075 (15)
O6	0.049 (4)	0.101 (7)	0.081 (5)	0.000	0.000	−0.020 (5)

O1—C7	1.2242 (16)	O3—Li1ii	1.982 (4)
Li1—O1	2.1538 (13)	O3—H3	0.82 (4)
Li1—O1i	2.1538 (13)	N1—C2	1.3289 (12)
Li1—O3	1.982 (4)	N1—C2i	1.3289 (12)
Li1—O4	1.976 (4)	C2—C2iii	1.406 (2)
Li1—N1	2.116 (3)	C2—C7	1.5287 (15)
O4—Li1ii	1.976 (4)	Li1—O6	2.536 (11)
O4—H4	0.90 (3)	Li1—Li1ii	2.817 (7)
O2—C7	1.2780 (15)	O6—H61	0.86 (2)
O2—H2	1.2057 (19)	O6—H62	0.87 (2)
O5—H5	0.85 (2)
C7—O1—Li1	119.00 (12)	O3—Li1—O1	102.74 (10)
Li1ii—O4—Li1	91.0 (2)	N1—Li1—O1	73.87 (9)
Li1ii—O4—H4	118.2 (11)	O4—Li1—O1i	99.91 (12)
Li1—O4—H4	118.2 (11)	O3—Li1—O1i	102.74 (10)
C7—O2—H2	113.8 (18)	N1—Li1—O1i	73.87 (9)
Li1—O3—Li1ii	90.6 (3)	O1—Li1—O1i	147.72 (17)
Li1—O3—H3	114.8 (18)	O4—Li1—O6	157.2 (3)
Li1ii—O3—H3	114.8 (18)	O3—Li1—O6	67.9 (3)
C2—N1—C2i	121.76 (13)	N1—Li1—O6	76.1 (3)
C2—N1—Li1	119.12 (7)	O1—Li1—O6	85.76 (13)
C2i—N1—Li1	119.12 (7)	O1i—Li1—O6	85.76 (13)
N1—C2—C2iii	119.12 (7)	O4—Li1—Li1ii	44.52 (11)
N1—C2—C7	111.44 (10)	O3—Li1—Li1ii	44.70 (13)
C2iii—C2—C7	129.43 (6)	N1—Li1—Li1ii	171.28 (12)
O1—C7—O2	124.56 (11)	O1—Li1—Li1ii	106.01 (9)
O1—C7—C2	116.56 (11)	O1i—Li1—Li1ii	106.01 (9)
O2—C7—C2	118.87 (11)	O6—Li1—Li1ii	112.6 (3)
O4—Li1—O3	89.22 (15)	Li1—O6—H61	174 (10)
O4—Li1—N1	126.8 (2)	Li1—O6—H62	85 (10)
O3—Li1—N1	144.0 (2)	H61—O6—H62	101 (3)
O4—Li1—O1	99.91 (12)
C2i—N1—C2—C2iii	0.1 (3)	Li1ii—O3—Li1—O6	180.000 (2)
Li1—N1—C2—C2iii	−179.94 (18)	C2—N1—Li1—O4	90.02 (13)
C2i—N1—C2—C7	−178.85 (10)	C2i—N1—Li1—O4	−90.02 (13)
Li1—N1—C2—C7	1.1 (2)	C2—N1—Li1—O3	−89.98 (13)
Li1—O1—C7—O2	−177.66 (16)	C2i—N1—Li1—O3	89.98 (13)
Li1—O1—C7—C2	1.3 (2)	C2—N1—Li1—O1	−0.42 (18)
N1—C2—C7—O1	−1.57 (17)	C2i—N1—Li1—O1	179.54 (12)
C2iii—C2—C7—O1	179.61 (16)	C2—N1—Li1—O1i	−179.55 (12)
N1—C2—C7—O2	177.46 (12)	C2i—N1—Li1—O1i	0.42 (18)
C2iii—C2—C7—O2	−1.4 (2)	C2—N1—Li1—O6	−89.98 (13)
Li1ii—O4—Li1—O3	0.0	C2i—N1—Li1—O6	89.98 (13)
Li1ii—O4—Li1—N1	180.0	C2—N1—Li1—Li1ii	90.02 (13)
Li1ii—O4—Li1—O1	−102.80 (12)	C2i—N1—Li1—Li1ii	−90.02 (13)
Li1ii—O4—Li1—O1i	102.80 (12)	C7—O1—Li1—O4	−126.14 (15)
Li1ii—O4—Li1—O6	0.000 (4)	C7—O1—Li1—O3	142.40 (14)
Li1ii—O3—Li1—O4	0.0	C7—O1—Li1—N1	−0.56 (19)
Li1ii—O3—Li1—N1	180.0	C7—O1—Li1—O1i	1.0 (5)
Li1ii—O3—Li1—O1	99.99 (14)	C7—O1—Li1—O6	76.2 (3)
Li1ii—O3—Li1—O1i	−99.99 (14)	C7—O1—Li1—Li1ii	−171.48 (10)

D—H···A	D—H	H···A	D···A	D—H···A
O6—H62···N1	0.87 (2)	2.28 (11)	2.886 (12)	127 (12)
O5—H5···O1iv	0.85 (2)	1.95 (2)	2.7711 (13)	163 (2)
O3—H3···O5v	0.82 (4)	1.92 (4)	2.730 (2)	173 (4)
O4—H4···O5vi	0.90 (3)	1.83 (3)	2.726 (2)	179 (3)
O2—H2···O2iii	1.21 (1)	1.21 (1)	2.409 (3)	175 (1)

Table 1

Selected bond lengths (Å)

Li1—O1	2.1538 (13)
Li1—O3	1.982 (4)
Li1—O4	1.976 (4)
Li1—N1	2.116 (3)

Table 2

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O6—H62⋯N1	0.87 (2)	2.28 (11)	2.886 (12)	127 (12)
O5—H5⋯O1i	0.85 (2)	1.95 (2)	2.7711 (13)	163 (2)
O3—H3⋯O5ii	0.82 (4)	1.92 (4)	2.730 (2)	173 (4)
O4—H4⋯O5iii	0.90 (3)	1.83 (3)	2.726 (2)	179 (3)
O2—H2⋯O2iv	1.21 (1)	1.21 (1)	2.409 (3)	175 (1)

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