Bis(2-methyl­lactato)borate tetra­hydrate

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

doi:10.1107/S2414314619009829

organic compounds

IUCrDATA

ISSN: 2414-3146

Volume 4| Part 7| July 2019| x190982

https://doi.org/10.1107/S2414314619009829

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Bis(2-methyllactato)borate tetrahydrate

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 K. Fejfarova, Institute of Biotechnology CAS, Czech Republic (Received 27 June 2019; accepted 9 July 2019; online 12 July 2019)

The asymmetric unit of the title compound (systematic name: 3,3,8,8-tetramethyl-1,4,6,9-tetraoxa-λ⁴-boraspiro[4.4]nonane-2,7-dione tetrahydrate), C₈H₁₂BO₆·4H₂O, consists of half a bis(2-methyllactato)borate molecule and two water molecules of solvation. In the crystal, O—H⋯O hydrogen bonds link the components into a three-dimensional network.

Keywords: crystal structure; organic material; borate; O—H⋯O hydrogen bonds.

CCDC reference: 1939448

Structure description

Allen et al. (2012 ) have reported the structure of lithium bis(2-methyllactato)borate monohydrate. We report here the growth and structural analysis of bis(2-methyllactato)borate tetrahydrate, prepared by the slow evaporation method. Whereas the lithium salt crystallizes in the space group Pbca with Z = 8, the title compound crystallizes in the space group P2₁2₁2 with Z = 2.

The asymmetric unit of the title compound consists of a (2-methyllactato)borate molecule and two water molecules (Fig. 1). The five-membered ring O1/C1/C2/O3/B1 adopts an envelope form on O3 atom [puckering parameters Q₂ = 0.104 (2) Å, φ₂ = 288.5 (11)°] and B1/O1ⁱ/C1ⁱ/C2ⁱ/O3ⁱ adopts an envelope form on O3ⁱ atom [puckering parameters Q₂ = 0.104 (2) Å, φ₂ = 144.5 (11)°]. The dihedral angle between the above two five-membered rings is 89.83 (12)°. In the crystal, O—H⋯O hydrogen bonds (Table 1) link the components into a three-dimensional network, as shown in Fig. 2.

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O4—H1⋯O3	0.90 (2)	1.77 (2)	2.645 (2)	165 (4)
O5—H3⋯O2ⁱ	0.88 (2)	1.92 (2)	2.805 (3)	179 (3)
O5—H4⋯O2ⁱⁱ	0.87 (2)	1.92 (2)	2.795 (2)	175 (4)
O4—H2⋯O5	0.92 (2)	1.67 (2)	2.591 (2)	173 (4)
Symmetry codes: (i) -x+1, -y+1, z-1; (ii) $[-x+{\script{1\over 2}}, y-{\script{1\over 2}}, -z+1]$ .

Figure 1
A view of the asymmetric unit of the title compound showing the atom numbering with displacement ellipsoids drawn at the 30% probability level. Symmetry code: (i) −x + 1, −y + 1, z.

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

Synthesis and crystallization

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

Refinement

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

Table 2
Experimental details

Crystal data
Chemical formula	C₈H₁₂BO₆·4H₂O
M_r	287.05
Crystal system, space group	Orthorhombic, P2₁2₁2
Temperature (K)	296
a, b, c (Å)	7.0809 (1), 16.7912 (3), 6.5001 (1)
V (Å³)	772.84 (2)
Z	2
Radiation type	Mo Kα
μ (mm⁻¹)	0.11
Crystal size (mm)	0.15 × 0.15 × 0.10

Data collection
Diffractometer	Bruker Kappa APEX3 CMOS
Absorption correction	Multi-scan (SADABS; Krause et al., 2015 )
T_min, T_max	0.568, 0.746
No. of measured, independent and observed [I > 2σ(I)] reflections	18957, 1680, 1585
R_int	0.052
(sin θ/λ)_max (Å⁻¹)	0.639

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.036, 0.094, 1.08
No. of reflections	1680
No. of parameters	104
No. of restraints	6
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.21, −0.12
Absolute structure	Flack x determined using 587 quotients [(I⁺)−(I⁻)]/[(I⁺)+(I⁻)] (Parsons et al., 2013 )
Absolute structure parameter	0.4 (4)
Computer programs: APEX3, SAINT and XPREP (Bruker, 2016 ), SHELXT2018 (Sheldrick, 2015a ), SHELXL2018 (Sheldrick, 2015b ), ORTEP-3 for Windows (Farrugia, 2012 ), PLATON (Spek, 2009 ) and publCIF (Westrip, 2010 ).

Structural data

CCDC reference: 1939448

Crystal structure: contains datablocks I, 1R. DOI: https://doi.org/10.1107/S2414314619009829/ff4030sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2414314619009829/ff4030Isup2.hkl

Supporting information file. DOI: https://doi.org/10.1107/S2414314619009829/ff4030Isup3.cdx

Supporting information file. DOI: https://doi.org/10.1107/S2414314619009829/ff4030Isup4.cml

checkCIF report

Computing details top

Data collection: APEX3 (Bruker, 2016); cell refinement: APEX3 and SAINT (Bruker, 2016); data reduction: SAINT and XPREP (Bruker, 2016); program(s) used to solve structure: SHELXT2018 (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).

3,3,8,8-Tetramethyl-1,4,6,9-tetraoxa-λ⁴-boraspiro[4.4]nonane-2,7-dione tetrahydrate top

Crystal data top

C₈H₁₂BO₆·4H₂O	D_x = 1.234 Mg m⁻³
M_r = 287.05	Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, P2₁2₁2	Cell parameters from 6304 reflections
a = 7.0809 (1) Å	θ = 3.1–30.4°
b = 16.7912 (3) Å	µ = 0.11 mm⁻¹
c = 6.5001 (1) Å	T = 296 K
V = 772.84 (2) Å³	Block, colourless
Z = 2	0.15 × 0.15 × 0.10 mm
F(000) = 306

Data collection top

Bruker Kappa APEX3 CMOS diffractometer	1680 independent reflections
Radiation source: fine-focus sealed tube	1585 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.052
ω and φ scan	θ_max = 27.0°, θ_min = 3.8°
Absorption correction: multi-scan (SADABS; Krause et al., 2015)	h = −9→9
T_min = 0.568, T_max = 0.746	k = −21→21
18957 measured reflections	l = −8→8

Refinement top

Refinement on F²	H atoms treated by a mixture of independent and constrained refinement
Least-squares matrix: full	w = 1/[σ²(F_o²) + (0.0444P)² + 0.1071P] where P = (F_o² + 2F_c²)/3
R[F² > 2σ(F²)] = 0.036	(Δ/σ)_max < 0.001
wR(F²) = 0.094	Δρ_max = 0.21 e Å⁻³
S = 1.08	Δρ_min = −0.12 e Å⁻³
1680 reflections	Extinction correction: SHELXL2018 (Sheldrick 2015b), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
104 parameters	Extinction coefficient: 0.26 (3)
6 restraints	Absolute structure: Flack x determined using 587 quotients [(I⁺)-(I^-)]/[(I⁺)+(I^-)] (Parsons et al., 2013)
Hydrogen site location: mixed	Absolute structure parameter: 0.4 (4)

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
B1	0.500000	0.500000	0.6216 (5)	0.0446 (7)
C1	0.4604 (3)	0.62908 (10)	0.7335 (3)	0.0450 (5)
C2	0.3039 (3)	0.61335 (11)	0.5802 (3)	0.0451 (5)
C3	0.1148 (3)	0.61058 (17)	0.6908 (5)	0.0718 (7)
H3A	0.085017	0.662541	0.743128	0.108*
H3B	0.018307	0.594026	0.596294	0.108*
H3C	0.121754	0.573415	0.802770	0.108*
C4	0.3052 (5)	0.67396 (15)	0.4066 (4)	0.0705 (7)
H4A	0.273454	0.725527	0.460141	0.106*
H4B	0.428708	0.675832	0.345758	0.106*
H4C	0.214397	0.658807	0.304184	0.106*
O1	0.5687 (2)	0.56635 (8)	0.7558 (3)	0.0529 (4)
O2	0.4861 (3)	0.69107 (8)	0.8287 (3)	0.0627 (5)
O3	0.3516 (2)	0.53588 (8)	0.5003 (3)	0.0550 (4)
O4	0.1638 (3)	0.47942 (11)	0.1802 (3)	0.0664 (5)
O5	0.2299 (3)	0.32920 (10)	0.1250 (4)	0.0780 (6)
H1	0.223 (6)	0.491 (2)	0.299 (5)	0.124 (14)*
H2	0.180 (6)	0.4259 (15)	0.153 (7)	0.132 (16)*
H3	0.319 (4)	0.322 (2)	0.032 (5)	0.103 (12)*
H4	0.160 (5)	0.2871 (18)	0.146 (6)	0.109 (12)*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
B1	0.0511 (17)	0.0316 (13)	0.0511 (16)	0.0068 (12)	0.000	0.000
C1	0.0458 (10)	0.0308 (8)	0.0584 (10)	0.0052 (7)	0.0008 (8)	0.0009 (7)
C2	0.0465 (10)	0.0298 (8)	0.0589 (11)	0.0086 (7)	−0.0018 (9)	0.0000 (8)
C3	0.0498 (13)	0.0664 (15)	0.0994 (19)	0.0000 (11)	0.0100 (13)	−0.0073 (14)
C4	0.0858 (18)	0.0534 (13)	0.0721 (15)	0.0146 (12)	−0.0064 (14)	0.0165 (11)
O1	0.0551 (8)	0.0353 (7)	0.0683 (9)	0.0125 (6)	−0.0147 (7)	−0.0036 (6)
O2	0.0651 (10)	0.0360 (7)	0.0870 (11)	0.0082 (7)	−0.0124 (9)	−0.0131 (7)
O3	0.0640 (9)	0.0370 (7)	0.0640 (9)	0.0160 (6)	−0.0158 (7)	−0.0091 (7)
O4	0.0687 (11)	0.0631 (11)	0.0673 (10)	0.0098 (8)	−0.0077 (8)	−0.0156 (8)
O5	0.0820 (13)	0.0421 (9)	0.1098 (16)	−0.0100 (8)	0.0335 (12)	−0.0042 (9)

Geometric parameters (Å, º) top

B1—O3ⁱ	1.445 (2)	C3—H3A	0.9600
B1—O3	1.445 (2)	C3—H3B	0.9600
B1—O1	1.496 (2)	C3—H3C	0.9600
B1—O1ⁱ	1.496 (2)	C4—H4A	0.9600
C1—O2	1.225 (2)	C4—H4B	0.9600
C1—O1	1.311 (2)	C4—H4C	0.9600
C1—C2	1.513 (3)	O4—H1	0.90 (2)
C2—O3	1.441 (2)	O4—H2	0.92 (2)
C2—C4	1.520 (3)	O5—H3	0.88 (2)
C2—C3	1.521 (3)	O5—H4	0.87 (2)

O3ⁱ—B1—O3	113.9 (2)	C2—C3—H3B	109.5
O3ⁱ—B1—O1	113.09 (9)	H3A—C3—H3B	109.5
O3—B1—O1	104.13 (7)	C2—C3—H3C	109.5
O3ⁱ—B1—O1ⁱ	104.13 (7)	H3A—C3—H3C	109.5
O3—B1—O1ⁱ	113.09 (9)	H3B—C3—H3C	109.5
O1—B1—O1ⁱ	108.7 (2)	C2—C4—H4A	109.5
O2—C1—O1	122.67 (19)	C2—C4—H4B	109.5
O2—C1—C2	126.17 (17)	H4A—C4—H4B	109.5
O1—C1—C2	111.17 (16)	C2—C4—H4C	109.5
O3—C2—C1	102.92 (15)	H4A—C4—H4C	109.5
O3—C2—C4	109.59 (18)	H4B—C4—H4C	109.5
C1—C2—C4	111.57 (19)	C1—O1—B1	110.08 (14)
O3—C2—C3	110.44 (18)	C2—O3—B1	110.48 (14)
C1—C2—C3	109.80 (18)	H1—O4—H2	108 (3)
C4—C2—C3	112.1 (2)	H3—O5—H4	114 (3)
C2—C3—H3A	109.5

O2—C1—C2—O3	174.2 (2)	O3—B1—O1—C1	6.8 (2)
O1—C1—C2—O3	−6.5 (2)	O1ⁱ—B1—O1—C1	−114.04 (16)
O2—C1—C2—C4	56.7 (3)	C1—C2—O3—B1	10.8 (2)
O1—C1—C2—C4	−123.9 (2)	C4—C2—O3—B1	129.6 (2)
O2—C1—C2—C3	−68.2 (3)	C3—C2—O3—B1	−106.4 (2)
O1—C1—C2—C3	111.1 (2)	O3ⁱ—B1—O3—C2	−134.64 (16)
O2—C1—O1—B1	179.2 (2)	O1—B1—O3—C2	−11.0 (2)
C2—C1—O1—B1	−0.2 (2)	O1ⁱ—B1—O3—C2	106.76 (18)
O3ⁱ—B1—O1—C1	130.86 (18)

Symmetry code: (i) −x+1, −y+1, z.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O4—H1···O3	0.90 (2)	1.77 (2)	2.645 (2)	165 (4)
O5—H3···O2ⁱⁱ	0.88 (2)	1.92 (2)	2.805 (3)	179 (3)
O5—H4···O2ⁱⁱⁱ	0.87 (2)	1.92 (2)	2.795 (2)	175 (4)
O4—H2···O5	0.92 (2)	1.67 (2)	2.591 (2)	173 (4)

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

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

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