Sodium bis­(2-methyl­lactato)borate

Gokila, G.; Thiruvalluvar, A.A.; Ramachandra Raja, C.

doi:10.1107/S2414314619005935

metal-organic compounds

IUCrDATA

ISSN: 2414-3146

Volume 4| Part 5| May 2019| x190593

https://doi.org/10.1107/S2414314619005935

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Sodium bis(2-methyllactato)borate

Govindharajan Gokila,^a Aravazhi Amalan Thiruvalluvar ^b ^* and Chidambaram Ramachandra Raja ^a

^aDepartment of Physics, Government Arts College (Autonomous), Kumbakonam 612 002, Tamilnadu, India, and ^bPrincipal, Kunthavai Naacchiyaar Government Arts College for Women (Autonomous), Thanjavur 613 007, Tamilnadu, India
^*Correspondence e-mail: thiruvalluvar.a@gmail.com

Edited by M. Weil, Vienna University of Technology, Austria (Received 24 April 2019; accepted 29 April 2019; online 3 May 2019)

The asymmetric unit of the title organic–inorganic hybrid salt, poly[[μ₄-bis(2-methyllactato)borato]sodium], [Na(C₈H₁₂BO₆)]_n, comprises a sodium cation and a bis(2-methyllactato)borate anion. The sodium cation exhibits a [4 + 1] coordination by borate and carbonyl O atoms of the bis(2-methyllactato)borate anion, leading to a three-dimensional polymeric structure.

Keywords: crystal structure; inorganic–organic hybrid material; borate.

CCDC reference: 1912840

Structure description

Alkaline cations such as lithium, potassium and sodium, together with different anions, are used in the development of rechargeable batteries. Allen et al. (2012 ) have reported the structure of lithium bis(2-methyllactato)borate monohydrate. In our current investigation we have replaced lithium by sodium and report here the growth and structural analysis of sodium bis(2-methyllactato)borate, [Na(C₈H₁₂BO₆)]_n, prepared by the slow evaporation method. Whereas other alkaline bis(2-methyllactato)borate salts crystallize as hydrates (Li as a monohydrate, Allen et al., 2012; K as a hemihydrate, Gokila et al., 2019a ; Rb as a monohydrate; Golika et al., 2019b ), the title sodium salt is anhydrous.

The asymmetric unit of the title compound comprises a sodium cation and a bis(2-methyllactato)borate anion (Fig. 1). The sodium cation is surrounded in a pseudo-tetrahedral manner by four O atoms (O1, O4ⁱ, O6ⁱⁱⁱ and O6ⁱⁱ; for symmetry codes: see Table 1) at short distances. The τ₄ descriptor (Yang et al., 2007 ) amounts to 0.81 (extreme forms 0 for ideal square-planar and 1 for ideal tetrahedral coordination). However, the coordination sphere around Na1 is augmented by a fifth O atom (O5ⁱⁱⁱ) at a considerably longer distances (Table 1). In the anion, the five-membered ring O2/C1/C2/O3/B1 is essentially planar [r.m.s. deviation 0.0312 Å, with the greatest deviation for O3 of 0.045 (1) Å], whereas ring O4/C6/C5/O5/B1 has a conformation between planar and an envelope form [puckering parameters Q₂ = 0.1015 (17) Å, φ₂ = 172.9 (9)°]. The dihedral angle between these two rings is 89.81 (9)°. The packing of the three-dimensional polymeric crystal structure is shown in Fig. 2.

Table 1
Selected bond lengths (Å)

Na1—O1	2.2262 (12)	O5—B1	1.528 (2)
Na1—O4ⁱ	2.2733 (12)	O4—B1	1.447 (2)
Na1—O6ⁱⁱ	2.3149 (12)	O2—B1	1.492 (2)
Na1—O6ⁱⁱⁱ	2.3880 (13)	O3—B1	1.417 (2)
Na1—O5ⁱⁱⁱ	2.8768 (12)
Symmetry codes: (i) -x+1, -y+1, -z+1; (ii) $[x-{\script{1\over 2}}, -y+{\script{3\over 2}}, z+{\script{1\over 2}}]$ ; (iii) $[-x+{\script{1\over 2}}, y-{\script{1\over 2}}, -z+{\script{1\over 2}}]$ .

Figure 1
A view of the asymmetric unit of the title compound showing the atom numbering with displacement ellipsoids drawn at the 50% probability level.

Figure 2
Packing diagram of the title compound viewed along the b axis.

Synthesis and crystallization

The title compound was synthesized by reacting 2-methyllactic acid, boric acid and sodium carbonate (molar ratio 4:2:1) in double-distilled water. Slow evaporation of the solvent yielded good quality crystals over a period of about three months.

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2.

Table 2
Experimental details

Crystal data
Chemical formula	[Na(C₈H₁₂BO₆)]
M_r	237.98
Crystal system, space group	Monoclinic, P2₁/n
Temperature (K)	296
a, b, c (Å)	10.1398 (5), 10.8359 (6), 11.2588 (5)
β (°)	115.687 (3)
V (Å³)	1114.80 (10)
Z	4
Radiation type	Mo Kα
μ (mm⁻¹)	0.15
Crystal size (mm)	0.20 × 0.20 × 0.15

Data collection
Diffractometer	Bruker APEXII CCD
Absorption correction	Multi-scan (SADABS; Krause et al., 2015 )
T_min, T_max	0.711, 0.746
No. of measured, independent and observed [I > 2σ(I)] reflections	23270, 2425, 1844
R_int	0.039
(sin θ/λ)_max (Å⁻¹)	0.639

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.035, 0.096, 1.04
No. of reflections	2425
No. of parameters	145
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.17, −0.25
Computer programs: APEX2 and SAINT (Bruker, 2016 ), SHELXT2014 (Sheldrick, 2015a ), ORTEP-3 for Windows (Farrugia, 2012 ), SHELXL2018 (Sheldrick, 2015b ), PLATON (Spek, 2009 ) and publCIF (Westrip, 2010 ).

Structural data

CCDC reference: 1912840

Crystal structure: contains datablock I. DOI: https://doi.org/10.1107/S2414314619005935/wm4104sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2414314619005935/wm4104Isup2.hkl

Supporting information file. DOI: https://doi.org/10.1107/S2414314619005935/wm4104Isup3.cdx

checkCIF report

Computing details top

Data collection: APEX2 (Bruker, 2016); cell refinement: SAINT (Bruker, 2016); data reduction: SAINT (Bruker, 2016); program(s) used to solve structure: SHELXT2014 (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2018 (Sheldrick, 2015b); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012) and PLATON (Spek, 2009); software used to prepare material for publication: SHELXL2018 (Sheldrick, 2015b), PLATON (Spek, 2009) and publCIF (Westrip, 2010).

Poly[[µ₄-bis(2-methyllactato)borato]sodium] top

Crystal data top

[Na(C₈H₁₂BO₆)]	F(000) = 496
M_r = 237.98	D_x = 1.418 Mg m⁻³
Monoclinic, P2₁/n	Mo Kα radiation, λ = 0.71073 Å
a = 10.1398 (5) Å	Cell parameters from 6833 reflections
b = 10.8359 (6) Å	θ = 2.8–24.0°
c = 11.2588 (5) Å	µ = 0.15 mm⁻¹
β = 115.687 (3)°	T = 296 K
V = 1114.80 (10) Å³	Block, colourless
Z = 4	0.20 × 0.20 × 0.15 mm

Data collection top

Bruker APEXII CCD diffractometer	2425 independent reflections
Radiation source: fine-focus sealed tube	1844 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.039
ω and φ scan	θ_max = 27.0°, θ_min = 2.3°
Absorption correction: multi-scan (SADABS; Krause et al., 2015)	h = −12→12
T_min = 0.711, T_max = 0.746	k = −13→13
23270 measured reflections	l = −14→14

Refinement top

Refinement on F²	0 restraints
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F² > 2σ(F²)] = 0.035	H-atom parameters constrained
wR(F²) = 0.096	w = 1/[σ²(F_o²) + (0.0434P)² + 0.3964P] where P = (F_o² + 2F_c²)/3
S = 1.04	(Δ/σ)_max < 0.001
2425 reflections	Δρ_max = 0.17 e Å⁻³
145 parameters	Δρ_min = −0.25 e Å⁻³

Special details top

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
Na1	0.18199 (6)	0.45991 (6)	0.51222 (6)	0.03053 (18)
O5	0.46526 (11)	0.77164 (10)	0.18007 (11)	0.0313 (3)
O4	0.66535 (11)	0.65000 (11)	0.30890 (12)	0.0350 (3)
O2	0.46401 (12)	0.66651 (10)	0.37142 (11)	0.0324 (3)
O3	0.43130 (13)	0.54882 (11)	0.18818 (12)	0.0369 (3)
O6	0.57136 (12)	0.90904 (11)	0.10432 (11)	0.0366 (3)
O1	0.30453 (14)	0.57492 (12)	0.42985 (13)	0.0444 (3)
C5	0.57869 (16)	0.81707 (14)	0.16973 (15)	0.0261 (3)
C6	0.71409 (16)	0.74006 (15)	0.24391 (15)	0.0286 (4)
C1	0.36231 (17)	0.58448 (15)	0.35573 (16)	0.0301 (4)
C2	0.32873 (17)	0.50650 (15)	0.23385 (17)	0.0312 (4)
C7	0.83631 (19)	0.81732 (18)	0.34405 (19)	0.0463 (5)
H7A	0.867862	0.877269	0.299050	0.069*
H7B	0.801478	0.858795	0.400292	0.069*
H7C	0.917013	0.764826	0.396243	0.069*
C4	0.3549 (2)	0.37084 (17)	0.2705 (2)	0.0456 (5)
H4A	0.285302	0.342945	0.301244	0.068*
H4B	0.343855	0.323734	0.194535	0.068*
H4C	0.452253	0.360107	0.338941	0.068*
C8	0.7591 (2)	0.67706 (19)	0.1464 (2)	0.0482 (5)
H8A	0.791616	0.738048	0.103218	0.072*
H8B	0.837097	0.620028	0.192549	0.072*
H8C	0.676838	0.633343	0.081969	0.072*
B1	0.50800 (19)	0.65314 (17)	0.26160 (18)	0.0283 (4)
C3	0.1733 (2)	0.5293 (2)	0.1311 (2)	0.0565 (6)
H3A	0.105661	0.500202	0.163653	0.085*
H3B	0.158845	0.616150	0.113199	0.085*
H3C	0.157003	0.486080	0.051534	0.085*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Na1	0.0254 (3)	0.0345 (4)	0.0338 (4)	0.0025 (3)	0.0148 (3)	0.0069 (3)
O5	0.0213 (5)	0.0356 (6)	0.0378 (6)	0.0034 (4)	0.0135 (5)	0.0119 (5)
O4	0.0239 (6)	0.0373 (7)	0.0439 (7)	0.0033 (5)	0.0147 (5)	0.0217 (5)
O2	0.0357 (6)	0.0326 (6)	0.0334 (6)	−0.0093 (5)	0.0194 (5)	−0.0019 (5)
O3	0.0419 (7)	0.0385 (7)	0.0406 (7)	−0.0120 (5)	0.0274 (6)	−0.0075 (5)
O6	0.0341 (6)	0.0336 (6)	0.0399 (7)	0.0028 (5)	0.0140 (5)	0.0173 (5)
O1	0.0528 (8)	0.0449 (8)	0.0536 (8)	−0.0071 (6)	0.0401 (7)	0.0007 (6)
C5	0.0258 (7)	0.0270 (8)	0.0257 (8)	0.0010 (6)	0.0113 (6)	0.0038 (6)
C6	0.0230 (7)	0.0302 (8)	0.0325 (8)	0.0015 (6)	0.0120 (7)	0.0127 (7)
C1	0.0283 (8)	0.0294 (8)	0.0359 (9)	0.0004 (6)	0.0171 (7)	0.0062 (7)
C2	0.0272 (8)	0.0316 (9)	0.0379 (9)	−0.0057 (7)	0.0172 (7)	−0.0021 (7)
C7	0.0315 (9)	0.0516 (12)	0.0443 (11)	−0.0089 (8)	0.0058 (8)	0.0130 (9)
C4	0.0492 (11)	0.0326 (10)	0.0636 (13)	−0.0076 (8)	0.0326 (10)	−0.0041 (9)
C8	0.0500 (11)	0.0490 (12)	0.0569 (12)	0.0128 (9)	0.0338 (10)	0.0137 (10)
B1	0.0254 (8)	0.0307 (10)	0.0316 (9)	0.0000 (7)	0.0151 (8)	0.0054 (7)
C3	0.0344 (10)	0.0682 (15)	0.0542 (13)	−0.0007 (10)	0.0074 (9)	−0.0095 (11)

Geometric parameters (Å, º) top

Na1—O1	2.2262 (12)	C6—C7	1.515 (2)
Na1—O4ⁱ	2.2733 (12)	C6—C8	1.521 (2)
Na1—O6ⁱⁱ	2.3149 (12)	C1—C2	1.519 (2)
Na1—O6ⁱⁱⁱ	2.3880 (13)	C2—C3	1.518 (3)
Na1—O5ⁱⁱⁱ	2.8768 (12)	C2—C4	1.519 (3)
Na1—C5ⁱⁱⁱ	2.9808 (16)	C7—H7A	0.9600
Na1—Na1^iv	3.6840 (12)	C7—H7B	0.9600
O5—C5	1.3019 (18)	C7—H7C	0.9600
O5—B1	1.528 (2)	C4—H4A	0.9600
O4—C6	1.4302 (18)	C4—H4B	0.9600
O4—B1	1.447 (2)	C4—H4C	0.9600
O2—C1	1.3141 (18)	C8—H8A	0.9600
O2—B1	1.492 (2)	C8—H8B	0.9600
O3—B1	1.417 (2)	C8—H8C	0.9600
O3—C2	1.4211 (18)	C3—H3A	0.9600
O6—C5	1.2221 (18)	C3—H3B	0.9600
O1—C1	1.2141 (19)	C3—H3C	0.9600
C5—C6	1.512 (2)

O1—Na1—O4ⁱ	111.94 (5)	O4—C6—C8	109.95 (14)
O1—Na1—O6ⁱⁱ	108.03 (5)	C5—C6—C8	109.50 (13)
O4ⁱ—Na1—O6ⁱⁱ	101.58 (5)	C7—C6—C8	112.37 (14)
O1—Na1—O6ⁱⁱⁱ	124.20 (5)	O1—C1—O2	123.35 (16)
O4ⁱ—Na1—O6ⁱⁱⁱ	121.54 (5)	O1—C1—C2	125.97 (15)
O6ⁱⁱ—Na1—O6ⁱⁱⁱ	76.88 (4)	O2—C1—C2	110.68 (13)
O1—Na1—O5ⁱⁱⁱ	106.55 (5)	O3—C2—C3	110.67 (15)
O4ⁱ—Na1—O5ⁱⁱⁱ	103.13 (5)	O3—C2—C4	109.96 (13)
O6ⁱⁱ—Na1—O5ⁱⁱⁱ	125.30 (4)	C3—C2—C4	111.50 (15)
O6ⁱⁱⁱ—Na1—O5ⁱⁱⁱ	48.62 (3)	O3—C2—C1	103.57 (12)
O1—Na1—C5ⁱⁱⁱ	119.55 (5)	C3—C2—C1	110.47 (14)
O4ⁱ—Na1—C5ⁱⁱⁱ	113.41 (5)	C4—C2—C1	110.40 (14)
O6ⁱⁱ—Na1—C5ⁱⁱⁱ	99.72 (4)	C6—C7—H7A	109.5
O6ⁱⁱⁱ—Na1—C5ⁱⁱⁱ	23.11 (4)	C6—C7—H7B	109.5
O5ⁱⁱⁱ—Na1—C5ⁱⁱⁱ	25.60 (4)	H7A—C7—H7B	109.5
O1—Na1—Na1^iv	123.97 (4)	C6—C7—H7C	109.5
O4ⁱ—Na1—Na1^iv	117.72 (4)	H7A—C7—H7C	109.5
O6ⁱⁱ—Na1—Na1^iv	39.15 (3)	H7B—C7—H7C	109.5
O6ⁱⁱⁱ—Na1—Na1^iv	37.73 (3)	C2—C4—H4A	109.5
O5ⁱⁱⁱ—Na1—Na1^iv	86.25 (3)	C2—C4—H4B	109.5
C5ⁱⁱⁱ—Na1—Na1^iv	60.65 (3)	H4A—C4—H4B	109.5
C5—O5—B1	109.88 (11)	C2—C4—H4C	109.5
C5—O5—Na1^v	81.67 (8)	H4A—C4—H4C	109.5
B1—O5—Na1^v	165.39 (9)	H4B—C4—H4C	109.5
C6—O4—B1	111.48 (11)	C6—C8—H8A	109.5
C6—O4—Na1ⁱ	123.86 (9)	C6—C8—H8B	109.5
B1—O4—Na1ⁱ	123.86 (9)	H8A—C8—H8B	109.5
C1—O2—B1	108.78 (12)	C6—C8—H8C	109.5
B1—O3—C2	110.42 (12)	H8A—C8—H8C	109.5
C5—O6—Na1^vi	148.81 (11)	H8B—C8—H8C	109.5
C5—O6—Na1^v	106.82 (10)	O3—B1—O4	115.76 (14)
Na1^vi—O6—Na1^v	103.12 (4)	O3—B1—O2	105.97 (12)
C1—O1—Na1	148.96 (12)	O4—B1—O2	112.04 (14)
O6—C5—O5	122.47 (14)	O3—B1—O5	112.26 (14)
O6—C5—C6	125.92 (14)	O4—B1—O5	102.78 (12)
O5—C5—C6	111.59 (12)	O2—B1—O5	107.90 (13)
O6—C5—Na1^v	50.08 (8)	C2—C3—H3A	109.5
O5—C5—Na1^v	72.73 (8)	C2—C3—H3B	109.5
C6—C5—Na1^v	171.45 (10)	H3A—C3—H3B	109.5
O4—C6—C5	103.11 (11)	C2—C3—H3C	109.5
O4—C6—C7	110.41 (13)	H3A—C3—H3C	109.5
C5—C6—C7	111.11 (14)	H3B—C3—H3C	109.5

Na1^vi—O6—C5—O5	−170.73 (14)	B1—O3—C2—C4	−125.15 (15)
Na1^v—O6—C5—O5	−7.54 (19)	B1—O3—C2—C1	−7.18 (17)
Na1^vi—O6—C5—C6	7.2 (3)	O1—C1—C2—O3	−176.35 (16)
Na1^v—O6—C5—C6	170.42 (13)	O2—C1—C2—O3	4.00 (17)
Na1^vi—O6—C5—Na1^v	−163.2 (2)	O1—C1—C2—C3	65.1 (2)
B1—O5—C5—O6	176.78 (15)	O2—C1—C2—C3	−114.54 (16)
Na1^v—O5—C5—O6	6.05 (15)	O1—C1—C2—C4	−58.7 (2)
B1—O5—C5—C6	−1.44 (18)	O2—C1—C2—C4	121.67 (15)
Na1^v—O5—C5—C6	−172.17 (12)	C2—O3—B1—O4	132.54 (14)
B1—O5—C5—Na1^v	170.74 (11)	C2—O3—B1—O2	7.69 (17)
B1—O4—C6—C5	10.23 (17)	C2—O3—B1—O5	−109.88 (14)
Na1ⁱ—O4—C6—C5	−159.78 (10)	C6—O4—B1—O3	111.76 (16)
B1—O4—C6—C7	129.00 (15)	Na1ⁱ—O4—B1—O3	−78.23 (17)
Na1ⁱ—O4—C6—C7	−41.01 (18)	C6—O4—B1—O2	−126.57 (14)
B1—O4—C6—C8	−106.45 (16)	Na1ⁱ—O4—B1—O2	43.44 (18)
Na1ⁱ—O4—C6—C8	83.53 (15)	C6—O4—B1—O5	−10.99 (17)
O6—C5—C6—O4	176.60 (15)	Na1ⁱ—O4—B1—O5	159.02 (9)
O5—C5—C6—O4	−5.25 (17)	C1—O2—B1—O3	−5.00 (17)
O6—C5—C6—C7	58.3 (2)	C1—O2—B1—O4	−132.13 (14)
O5—C5—C6—C7	−123.53 (15)	C1—O2—B1—O5	115.44 (14)
O6—C5—C6—C8	−66.4 (2)	C5—O5—B1—O3	−117.61 (14)
O5—C5—C6—C8	111.76 (15)	Na1^v—O5—B1—O3	23.2 (4)
Na1—O1—C1—O2	−157.82 (16)	C5—O5—B1—O4	7.45 (17)
Na1—O1—C1—C2	22.6 (3)	Na1^v—O5—B1—O4	148.3 (3)
B1—O2—C1—O1	−179.09 (16)	C5—O5—B1—O2	125.98 (13)
B1—O2—C1—C2	0.58 (17)	Na1^v—O5—B1—O2	−93.2 (4)
B1—O3—C2—C3	111.22 (16)

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

Acknowledgements

The authors thank the Sophisticated Analytical Instrument Facility (SAIF), Indian Institute of Technology Madras (IITM), Chennai 600 036, Tamilnadu, India, for the single-crystal X-ray diffraction data.

References

Allen, J. L., Paillard, E., Boyle, P. D. & Henderson, W. A. (2012). Acta Cryst. E68, m749. CSD CrossRef IUCr Journals Google Scholar
Bruker (2016). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Farrugia, L. J. (2012). J. Appl. Cryst. 45, 849–854. Web of Science CrossRef CAS IUCr Journals Google Scholar
Gokila, G., Thiruvalluvar, A. A. & Ramachandra Raja, C. (2019a). IUCrData, 4, x190202. Google Scholar
Gokila, G., Thiruvalluvar, A. A. & Ramachandra Raja, C. (2019b). IUCrData, 4, x190039. Google Scholar
Krause, L., Herbst-Irmer, R., Sheldrick, G. M. & Stalke, D. (2015). J. Appl. Cryst. 48, 3–10. Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
Sheldrick, G. M. (2015a). Acta Cryst. A71, 3–8. Web of Science CrossRef IUCr Journals Google Scholar
Sheldrick, G. M. (2015b). Acta Cryst. C71, 3–8. Web of Science CrossRef IUCr Journals Google Scholar
Spek, A. L. (2009). Acta Cryst. D65, 148–155. Web of Science CrossRef CAS IUCr Journals Google Scholar
Westrip, S. P. (2010). J. Appl. Cryst. 43, 920–925. Web of Science CrossRef CAS IUCr Journals Google Scholar
Yang, L., Powell, D. R. & Houser, R. P. (2007). Dalton Trans. pp. 955–964. Web of Science CSD CrossRef PubMed CAS Google Scholar

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