Poly[μ₆-(naphthalene-2,6-di­carboxyl­ato)-bis­­(aqua­lithium)]

The title compound, [Li₂(C₁₂H₆O₄)(H₂O)₂]_n, crystallizes with one half of the molecular entities in the asymmetric unit. The second half is gererated by inversion symmetry. The crystal structure has a layered arrangement built from distorted edge-sharing LiO₃(OH)₂ tetra­hedra parallel to (100), with naphthalenedi­carboxyl­ate bridging the LiO₃(OH)₂ layers along the [100] direction. Hydrogen bonding between the water molecule and adjacent carboxylate groups consolidates the packing.

Related literature

For the synthesis and crystal structure of 2,6-naphthalenedi­carb­oxy­lic acid, see Kaduk & Golab (1999). For the synthesis and crystal structure of dilithium-2,6-naphthalene di­carboxyl­ate [Li₂(2,6-NDC)], see: Banerjee et al. (2009a). For related compounds, see: Banerjee et al. (2009b). [Li₂(2,6-NDC)] was recently reported to exhibit good electrochemical performance, see: Fédèle et al. (2014).

Experimental

Crystal data

• [Li₂(C₁₂H₆O₄)(H₂O)₂]

• M_r = 132.04

• Monoclinic, C 2/c

• a = 23.5695 (18) Å

• b = 6.8115 (5) Å

• c = 7.5327 (6) Å

• β = 90.325 (3)°

• V = 1209.31 (16) ų

• Z = 8

• Mo Kα radiation

• μ = 0.11 mm⁻¹

• T = 293 K

• 0.12 × 0.05 × 0.03 mm

Data collection

• Bruker D8 Venture diffractometer

• Absorption correction: multi-scan (SADABS; Bruker, 2007) T_min = 0.707, T_max = 0.746

• 12848 measured reflections

• 1388 independent reflections

• 1032 reflections with I > 2σ(I)

• R_int = 0.050

Refinement

• R[F² > 2σ(F²)] = 0.043

• wR(F²) = 0.109

• S = 1.06

• 1388 reflections

• 99 parameters

• H atoms treated by a mixture of independent and constrained refinement

• Δρ_max = 0.23 e Å⁻³

• Δρ_min = −0.24 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O2—H1W⋯O1^i	0.81 (3)	2.10 (3)	2.905 (2)	176 (3)
O2—H2W⋯O3^ii	0.89 (3)	2.01 (3)	2.883 (2)	169 (3)
Symmetry codes: (i) ; (ii) -x, -y+2, -z+1.

Data collection: APEX2 (Bruker, 2007); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXLE (Hübschle et al., 2011); molecular graphics: VESTA (Momma & Izumi, 2011); software used to prepare material for publication: publCIF (Westrip, 2010).

Supporting information

S1. Comment

For the last 30 years, inorganic compounds involving at least one transition metal as a redox center (such as LiCoO₂ or LiFePO₄) have been the traditional electrodes for Li-ion batteries. While they exhibit good performances in terms of cyclability, output voltage capacity, main drawbacks such as toxicity, sustainability and eco-conception still remain. In this context, organic based electrodes for Li-ion batteries recently regained attention. Among them, the dilithium 2,6-naphthalene dicarboxylate (Li₂-2,6-NDC) was recently reported to exhibit good electrochemical performances (Fédèle et al. 2014). The title compound (dilithium 2,6-naphthalene dicarboxylate dihydrate) is the hydrated form of the Li₂-2,6-NDC. In the former, pairs of edge-sharing LiO₄ tetrahedra are connected to each other by corners (Banerjee et al. 2009a). In the hydrated form, the corner sharing arrangement is no longer possible as one oxygen is replaced by a water molecule. Edge-sharing LiO₃(OH₂) tetrahedra are connected into sheets that extend in the yz plane. These are linked by the naphthalene dicarboxylate into a 3-D array. Crystal data, data collection and structure refinement details are summarized in Table 1.

Related literature

For the synthesis and crystal structure of 2,6-naphthalenedicarboxylic acid, see Kaduk et al., (1999). For the synthesis and crystal structure of dilithium-2,6-naphthalene dicarboxylate [Li₂(2,6-NDC)], see Banerjee et al. (2009a). For related compounds see Banerjee et al. (2009b). [Li₂(2,6-NDC)] was recently reported to exhibit good electrochemical performance, see: Fédèle et al. (2014).

S2. Experimental

Reagent and chemicals. The 2,6 naphthalene dicarboxylic acid (98+%) and lithium hydroxide were purchased from Alfa Aesar and Sigma-Aldrich, respectively. They were used as received without further purification. De-ionized water was utilized for the synthesis of the di-lithium salt.

Hydrothermal Lithiation procedure. 1 g of 2,6-naphthalene dicarboxylic acid (4.6 mmol) was added into 10 ml de-ionized water and added to a 23 ml autoclave. Two equivalents of anhydrous lithium hydroxide (222 mg, 9.3 mmol) were incorporated with the naphthalene derivative. The autoclave was then placed into a temperature controlled oven set at 150°C for 12 h duration before to be cooled down to room temperature with a ramp of 10°C/h. The resulting green solution was poured into a 50 ml beaker while the excess water was slowly evaporated under ambient conditions to form the colorless single crystals of the di-lithium-2,6-naphthalene dicarboxylate dihydrate.

S3. Refinement

All H-atoms were positioned geometrically and refined using a riding model with C—H = 0.90–0.93 Å and with U_iso(H) = 1.2Ueq(C). The H atoms of the aqua ligand (H1W and H2W) were found by Fourier difference map and further refined without any constrains.

Computing details

Data collection: APEX2 (Bruker, 2007); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT (Bruker, 2007); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXLE (Hübschle et al., 2011); molecular graphics: VESTA (Momma & Izumi, 2011); software used to prepare material for publication: publCIF (Westrip, 2010).

Figures

	Fig. 1. Molecular view of the title compound. Li, O, C, and H atoms are represented by light green, red, brown and white spheres respectively
	Fig. 2. Crystal structure of the title compound view along the b axis. Layers of LiO3(OH2) edge-sharing tetrahedra in the (yz) plane are connected via naphthalene dicarboxylate molecules.

Poly[µ₆-(naphthalene-2,6-dicarboxylato)-bis(aqualithium)]

Crystal data

[Li2(C12H6O4)(H2O)2]	Z = 8
Mr = 132.04	F(000) = 544
Monoclinic, C2/c	Dx = 1.450 Mg m^−3
Hall symbol: -C 2yc	Mo Kα radiation, λ = 0.71073 Å
a = 23.5695 (18) Å	µ = 0.11 mm^−1
b = 6.8115 (5) Å	T = 293 K
c = 7.5327 (6) Å	Prism, colourless
β = 90.325 (3)°	0.12 × 0.05 × 0.03 mm
V = 1209.31 (16) Å^3

Data collection

Bruker D8 Venture diffractometer	1388 independent reflections
Radiation source: fine-focus sealed tube	1032 reflections with I > 2σ(I)
Multilayer optics monochromator	Rint = 0.050
phi scan	θmax = 27.5°, θmin = 3.1°
Absorption correction: multi-scan (SADABS; Bruker, 2007)	h = −30→29
Tmin = 0.707, Tmax = 0.746	k = −8→8
12848 measured reflections	l = −9→9

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)] = 0.043	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.109	H atoms treated by a mixture of independent and constrained refinement
S = 1.06	w = 1/[σ^2(Fo^2) + (0.0452P)^2 + 1.0165P] where P = (Fo^2 + 2Fc^2)/3
1388 reflections	(Δ/σ)max = 0.010
99 parameters	Δρmax = 0.23 e Å^−3
0 restraints	Δρmin = −0.24 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·A single gross outlier (reflection 3 3 3)was omitted from the final refinement.

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

	x	y	z	Uiso*/Ueq
O1	0.06322 (5)	0.42265 (18)	0.41860 (17)	0.0357 (3)
H1W	0.0611 (12)	0.761 (5)	0.695 (4)	0.082 (10)*
H2W	0.0553 (11)	0.949 (5)	0.635 (4)	0.089 (10)*
O2	0.05985 (7)	0.8245 (3)	0.6045 (2)	0.0496 (4)
O3	−0.05040 (4)	0.75789 (19)	0.34106 (15)	0.0323 (3)
C1	0.08206 (6)	0.3193 (2)	0.5432 (2)	0.0252 (4)
C2	0.14481 (6)	0.2809 (2)	0.5548 (2)	0.0251 (4)
C3	0.17876 (6)	0.3237 (2)	0.4137 (2)	0.0261 (4)
H3	0.1627	0.3764	0.3112	0.031*
C4	0.23825 (6)	0.2893 (2)	0.4209 (2)	0.0245 (4)
C5	0.22574 (7)	0.1697 (3)	0.7239 (2)	0.0300 (4)
H4	0.2412	0.1206	0.8288	0.036*
C6	0.16892 (7)	0.2010 (3)	0.7120 (2)	0.0303 (4)
H5	0.1457	0.1700	0.8074	0.036*
Li1	0.03075 (12)	0.6849 (4)	0.4040 (4)	0.0305 (6)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0262 (6)	0.0378 (7)	0.0432 (7)	0.0097 (5)	−0.0039 (5)	0.0041 (6)
O2	0.0714 (11)	0.0404 (9)	0.0367 (8)	−0.0102 (8)	−0.0102 (7)	−0.0003 (7)
O3	0.0197 (5)	0.0452 (7)	0.0322 (6)	−0.0007 (5)	0.0075 (5)	−0.0052 (6)
C1	0.0190 (7)	0.0253 (8)	0.0313 (9)	0.0018 (6)	0.0016 (6)	−0.0084 (7)
C2	0.0180 (7)	0.0241 (8)	0.0333 (9)	0.0019 (6)	0.0022 (6)	−0.0009 (7)
C3	0.0208 (8)	0.0285 (8)	0.0290 (8)	0.0037 (7)	−0.0011 (6)	0.0035 (7)
C4	0.0215 (8)	0.0236 (8)	0.0283 (8)	0.0021 (6)	0.0010 (6)	0.0023 (7)
C5	0.0241 (8)	0.0365 (9)	0.0293 (9)	0.0035 (7)	0.0005 (6)	0.0096 (8)
C6	0.0239 (8)	0.0366 (9)	0.0304 (9)	0.0016 (7)	0.0063 (6)	0.0053 (7)
Li1	0.0275 (14)	0.0337 (15)	0.0302 (14)	0.0016 (12)	−0.0007 (11)	0.0021 (12)

Geometric parameters (Å, º)

O1—C1	1.253 (2)	C3—C4	1.422 (2)
O1—Li1	1.946 (3)	C3—H3	0.9300
O2—Li1	1.910 (3)	C4—C5^iii	1.414 (2)
O2—H1W	0.81 (3)	C4—C4^iii	1.417 (3)
O2—H2W	0.89 (3)	C5—C6	1.359 (2)
O3—C1^i	1.265 (2)	C5—C4^iii	1.414 (2)
O3—Li1^ii	1.969 (3)	C5—H4	0.9300
O3—Li1	2.030 (3)	C6—H5	0.9300
C1—O3^i	1.265 (2)	Li1—O3^ii	1.969 (3)
C1—C2	1.504 (2)	Li1—C1^i	2.691 (3)
C1—Li1^i	2.691 (3)	Li1—Li1^ii	2.728 (6)
C2—C3	1.365 (2)	Li1—Li1^i	3.250 (6)
C2—C6	1.419 (2)
C1—O1—Li1	134.09 (14)	C5—C6—C2	120.35 (15)
Li1—O2—H1W	114 (2)	C5—C6—H5	119.8
Li1—O2—H2W	129.8 (19)	C2—C6—H5	119.8
H1W—O2—H2W	107 (3)	O2—Li1—O1	105.84 (15)
C1^i—O3—Li1^ii	133.11 (14)	O2—Li1—O3^ii	122.04 (16)
C1^i—O3—Li1	107.22 (13)	O1—Li1—O3^ii	100.98 (14)
Li1^ii—O3—Li1	86.02 (13)	O2—Li1—O3	113.35 (15)
O1—C1—O3^i	122.81 (14)	O1—Li1—O3	127.43 (16)
O1—C1—C2	119.05 (14)	O3^ii—Li1—O3	86.88 (12)
O3^i—C1—C2	118.13 (14)	O2—Li1—C1^i	103.83 (13)
O1—C1—Li1^i	76.73 (11)	O1—Li1—C1^i	111.74 (13)
O3^i—C1—Li1^i	46.09 (10)	O3^ii—Li1—C1^i	112.28 (13)
C2—C1—Li1^i	164.10 (13)	O3—Li1—C1^i	26.69 (6)
C3—C2—C6	119.84 (14)	O2—Li1—Li1^ii	149.25 (11)
C3—C2—C1	119.89 (14)	O1—Li1—Li1^ii	104.78 (10)
C6—C2—C1	120.27 (14)	O3^ii—Li1—Li1^ii	47.92 (9)
C2—C3—C4	121.15 (15)	O3—Li1—Li1^ii	46.06 (9)
C2—C3—H3	119.4	C1^i—Li1—Li1^ii	66.74 (11)
C4—C3—H3	119.4	O2—Li1—Li1^i	101.12 (15)
C5^iii—C4—C4^iii	119.35 (17)	O1—Li1—Li1^i	55.92 (10)
C5^iii—C4—C3	122.30 (14)	O3^ii—Li1—Li1^i	136.12 (18)
C4^iii—C4—C3	118.35 (17)	O3—Li1—Li1^i	82.63 (12)
C6—C5—C4^iii	120.93 (15)	C1^i—Li1—Li1^i	58.82 (9)
C6—C5—H4	119.5	Li1^ii—Li1—Li1^i	98.18 (13)
C4^iii—C5—H4	119.5
Li1—O1—C1—O3^i	71.7 (2)	C1—O1—Li1—O2	24.8 (2)
Li1—O1—C1—C2	−109.69 (19)	C1—O1—Li1—O3^ii	152.87 (15)
Li1—O1—C1—Li1^i	72.46 (19)	C1—O1—Li1—O3	−112.6 (2)
O1—C1—C2—C3	−13.1 (2)	C1—O1—Li1—C1^i	−87.6 (2)
O3^i—C1—C2—C3	165.63 (15)	C1—O1—Li1—Li1^ii	−158.04 (16)
Li1^i—C1—C2—C3	159.3 (4)	C1—O1—Li1—Li1^i	−68.08 (18)
O1—C1—C2—C6	166.67 (15)	C1^i—O3—Li1—O2	−73.79 (18)
O3^i—C1—C2—C6	−14.6 (2)	Li1^ii—O3—Li1—O2	152.12 (13)
Li1^i—C1—C2—C6	−21.0 (5)	C1^i—O3—Li1—O1	61.0 (2)
C6—C2—C3—C4	0.2 (3)	Li1^ii—O3—Li1—O1	−73.05 (18)
C1—C2—C3—C4	179.88 (14)	C1^i—O3—Li1—O3^ii	162.48 (11)
C2—C3—C4—C5^iii	179.28 (16)	Li1^ii—O3—Li1—O3^ii	28.40 (17)
C2—C3—C4—C4^iii	−0.5 (3)	Li1^ii—O3—Li1—C1^i	−134.08 (16)
C4^iii—C5—C6—C2	−1.7 (3)	C1^i—O3—Li1—Li1^ii	134.08 (16)
C3—C2—C6—C5	1.0 (3)	C1^i—O3—Li1—Li1^i	25.18 (15)
C1—C2—C6—C5	−178.74 (15)	Li1^ii—O3—Li1—Li1^i	−108.90 (8)

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O2—H1W···O1^iv	0.81 (3)	2.10 (3)	2.905 (2)	176 (3)
O2—H2W···O3^v	0.89 (3)	2.01 (3)	2.883 (2)	169 (3)

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