2,2,3,3,4,4,5,5-Octa­fluorohexa­ne-1,6-diol

Feightner, K.; Powell, D.R.; Burba, C.M.

doi:10.1107/S2414314620004459

organic compounds

IUCrDATA

ISSN: 2414-3146

Volume 5| Part 4| April 2020| x200445

https://doi.org/10.1107/S2414314620004459

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ADDENDA AND ERRATA
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2,2,3,3,4,4,5,5-Octafluorohexane-1,6-diol

Kylie Feightner,^a Douglas R. Powell ^b and Christopher M. Burba ^a ^*

^aDepartment of Natural Sciences, Northeastern State University, 611 N. Grand Ave., Tahlequah, OK 74464, USA, and ^bDepartment of Chemistry and Biochemistry, University of Oklahoma, 101 Stephenson Parkway, Norman, OK 73019, USA
^*Correspondence e-mail: burba@nsuok.edu

Edited by A. J. Lough, University of Toronto, Canada (Received 25 February 2020; accepted 31 March 2020; online 7 April 2020)

In the crystal of the title compound, C₆H₆F₈O₄, O—H⋯O hydrogen bonds involving the hydroxy groups connect the molecules, forming a two-dimensional network parallel to (100). These hydrogen-bonding interactions appear to drive the O—C—C—O torsion angles into a gauche–trans–trans series of conformations along the backbone of the molecule.

Keywords: crystal structure; fluorinated glycol; hydrogen bonding.

CCDC reference: 1993931

Structure description

Ionic liquids have attracted considerable interest as solvents for a variety of applications. `Solvate' ionic liquids (SILs) are a new class of ionic liquids that consist of equimolar mixtures of inorganic salts and molecular solvents capable of chelating the cations of the salt (Ueno et al., 2012 , 2015 ; Mandai et al., 2014 , 2015 ). Most research on SILs focus on methyl-capped ethylene oxide molecular solvents, which are collectively known as `glymes'. Structural variation of the chelating compound will undoubtedly influence cation–solvent interactions and provide alternative means for tuning SIL properties (Saito et al., 2016 ). Our lab has pursued this line of research by examining partially fluorinated molecular solvents for SIL applications. During our experiments, we isolated and determined the structure of the title compound, a partially fluorinated derivative of triethylene glycol. The molecular structure of the title compound is shown in Fig. 1. In the crystal, O—H⋯O hydrogen bonds involving the terminal hydroxyl groups (see Table 1) connect the molecules, forming a two-dimensional network parallel to (100) (Fig. 2). In addition, a weak intermolecular C—H⋯F hydrogen bond is observed within this network. These hydrogen-bonding interactions appear to drive the O—C—C—O torsion angles into a gauche–trans–trans series of conformations along the backbone of the molecule: O1—C1—C2—O2 = 66.3 (2), O2—C3—C4—O2 = −168.91 (15), and O3—C5—C6—O4 = −177.92 (15)°. By way of comparison, the O—C—C—O torsion angles are gauche in monoglyme (Yoshihiro et al., 1996 ) and longer chain glymes (Johansson et al., 2010 ; Hyun et al., 2001 ; Tadokoro, 1964 ).

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1—H1O⋯O4ⁱ	0.84 (4)	1.87 (4)	2.705 (2)	172 (3)
O4—H4O⋯O1ⁱⁱ	0.85 (4)	1.82 (4)	2.661 (2)	173 (3)
C6—H6B⋯F4ⁱⁱⁱ	0.99	2.52	3.416 (2)	151
Symmetry codes: (i) x, y, z+1; (ii) $[-x+1, y-{\script{1\over 2}}, -z+1]$ ; (iii) $[-x+1, y+{\script{1\over 2}}, -z+1]$ .

Figure 1
The molecular structure of the title compound. Displacement ellipsoids are shown at 50% probability level.

Figure 2
Part of the crystal structure with hydrogen bonds shown as dashed lines.

Synthesis and crystallization

2,2,3,3,4,4,5,5-Octafluoro-1,6-hexanediol (1.94 mmol) was added to a 1:1 molar ratio mixture of lithium bis(trifluoromethanesulfonyl)imide (2.3 mmol) and 2,2′-[ethane-1,2-diylbis(oxy)]di(ethan-1-ol) (commonly known as triethylene glycol; 2.3 mmol). The resulting mixture was stirred at 353 K for 6 h to produce a homogenous, viscous solution. Colorless, plate-shaped single crystals formed from the solution upon standing over a period of days.

Refinement

Crystal data, data collection methods, and structural refinement details are provided in Table 2. The absolute structure of the title compound could not be established in the refinement reported here.

Table 2
Experimental details

Crystal data
Chemical formula	C₆H₆F₈O₄
M_r	294.11
Crystal system, space group	Monoclinic, P2₁
Temperature (K)	100
a, b, c (Å)	5.3009 (8), 8.6250 (12), 10.6976 (14)
β (°)	91.146 (5)
V (Å³)	489.00 (12)
Z	2
Radiation type	Mo Kα
μ (mm⁻¹)	0.25
Crystal size (mm)	0.49 × 0.49 × 0.05

Data collection
Diffractometer	Bruker Photon II CMOS
Absorption correction	Multi-scan (SADABS; Krause et al., 2015 )
T_min, T_max	0.543, 0.746
No. of measured, independent and observed [I > 2σ(I)] reflections	14748, 2985, 2896
R_int	0.049
(sin θ/λ)_max (Å⁻¹)	0.715

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.038, 0.100, 1.00
No. of reflections	2985
No. of parameters	170
No. of restraints	1
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.65, −0.40
Computer programs: APEX3 (Bruker, 2018 ), SAINT (Bruker, 2016 ), SHELXT (Sheldrick, 2015a ), SHELXL2018/3 (Sheldrick, 2015b ) and Mercury (Macrae et al., 2020 ).

Structural data

CCDC reference: 1993931

Crystal structure: contains datablock I. DOI: https://doi.org/10.1107/S2414314620004459/lh4054sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2414314620004459/lh4054Isup2.hkl

Supporting information file. DOI: https://doi.org/10.1107/S2414314620004459/lh4054Isup3.cml

checkCIF report

Computing details top

Data collection: APEX3 (Bruker, 2018); cell refinement: SAINT (Bruker, 2016); data reduction: SAINT (Bruker, 2016); program(s) used to solve structure: SHELXT (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2018/3 (Sheldrick, 2015b); molecular graphics: Mercury (Macrae et al., 2020); software used to prepare material for publication: SHELXL2018/3 (Sheldrick, 2015b).

2,2,3,3,4,4,5,5-Octafluorohexane-1,6-diol top

Crystal data top

C₆H₆F₈O₄	F(000) = 292
M_r = 294.11	D_x = 1.997 Mg m⁻³
Monoclinic, P2₁	Mo Kα radiation, λ = 0.71073 Å
a = 5.3009 (8) Å	Cell parameters from 9936 reflections
b = 8.6250 (12) Å	θ = 3.0–30.5°
c = 10.6976 (14) Å	µ = 0.25 mm⁻¹
β = 91.146 (5)°	T = 100 K
V = 489.00 (12) Å³	Plate, colourless
Z = 2	0.49 × 0.49 × 0.05 mm

Data collection top

Bruker Photon II CMOS diffractometer	2896 reflections with I > 2σ(I)
Radiation source: microfocus sealed tube	R_int = 0.049
ω and φ scans	θ_max = 30.5°, θ_min = 3.0°
Absorption correction: multi-scan (SADABS; Krause et al., 2015)	h = −7→7
T_min = 0.543, T_max = 0.746	k = −12→12
14748 measured reflections	l = −15→15
2985 independent reflections

Refinement top

Refinement on F²	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: mixed
R[F² > 2σ(F²)] = 0.038	H atoms treated by a mixture of independent and constrained refinement
wR(F²) = 0.100	w = 1/[σ²(F_o²) + (0.075P)² + 0.078P] where P = (F_o² + 2F_c²)/3
S = 1.00	(Δ/σ)_max < 0.001
2985 reflections	Δρ_max = 0.65 e Å⁻³
170 parameters	Δρ_min = −0.40 e Å⁻³
1 restraint	Absolute structure: Refined as an inversion twin
Primary atom site location: dual	Absolute structure parameter: 0.5 (6)

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.

Refinement. Refined as a 2-component inversion twin.

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

	x	y	z	U_iso*/U_eq
F1	0.7033 (3)	0.36867 (16)	0.87486 (11)	0.0193 (3)
F2	1.1035 (3)	0.40107 (18)	0.84955 (14)	0.0238 (3)
F3	0.4638 (2)	0.4558 (2)	0.65888 (13)	0.0241 (3)
F4	0.7907 (3)	0.31004 (16)	0.63351 (13)	0.0232 (3)
F5	0.7219 (3)	0.68928 (15)	0.52189 (12)	0.0214 (3)
F6	1.0050 (2)	0.51638 (17)	0.48334 (12)	0.0192 (3)
F7	0.7953 (2)	0.36716 (19)	0.26323 (13)	0.0225 (3)
F8	0.7493 (3)	0.61560 (17)	0.26968 (12)	0.0204 (3)
O1	0.6422 (3)	0.67095 (18)	0.95429 (14)	0.0166 (3)
H1O	0.556 (6)	0.614 (5)	1.001 (3)	0.020*
O2	0.8372 (3)	0.54080 (17)	0.73056 (13)	0.0155 (3)
O3	0.5994 (3)	0.46959 (19)	0.42741 (13)	0.0167 (3)
O4	0.4017 (3)	0.46960 (18)	0.10482 (13)	0.0155 (3)
H4O	0.395 (6)	0.376 (5)	0.081 (3)	0.019*
C1	0.8841 (4)	0.6040 (2)	0.94631 (18)	0.0155 (3)
H1A	0.935916	0.560859	1.028644	0.019*
H1B	1.007975	0.684471	0.923235	0.019*
C2	0.8810 (3)	0.4762 (2)	0.84895 (17)	0.0144 (3)
C3	0.7124 (3)	0.4577 (2)	0.63955 (17)	0.0137 (3)
C4	0.7627 (3)	0.5366 (2)	0.51257 (17)	0.0130 (3)
C5	0.6362 (3)	0.4807 (2)	0.29963 (17)	0.0133 (3)
C6	0.3799 (3)	0.4651 (2)	0.23611 (17)	0.0138 (3)
H6A	0.301564	0.365806	0.260933	0.017*
H6B	0.269087	0.550509	0.263425	0.017*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
F1	0.0299 (6)	0.0142 (5)	0.0140 (6)	−0.0041 (5)	0.0021 (5)	0.0020 (4)
F2	0.0236 (6)	0.0300 (7)	0.0180 (6)	0.0135 (5)	−0.0003 (5)	0.0004 (5)
F3	0.0166 (5)	0.0397 (8)	0.0161 (5)	−0.0061 (6)	0.0016 (4)	0.0022 (6)
F4	0.0426 (8)	0.0115 (5)	0.0154 (6)	0.0009 (5)	−0.0001 (5)	0.0005 (4)
F5	0.0357 (7)	0.0126 (6)	0.0158 (6)	0.0026 (5)	−0.0025 (5)	0.0015 (5)
F6	0.0138 (5)	0.0295 (7)	0.0145 (5)	−0.0016 (4)	0.0008 (4)	0.0025 (5)
F7	0.0183 (5)	0.0271 (7)	0.0221 (6)	0.0067 (5)	−0.0018 (5)	−0.0056 (6)
F8	0.0256 (6)	0.0218 (6)	0.0139 (5)	−0.0114 (5)	−0.0010 (4)	0.0020 (5)
O1	0.0205 (6)	0.0135 (6)	0.0157 (6)	0.0030 (5)	0.0022 (5)	0.0021 (5)
O2	0.0229 (6)	0.0139 (6)	0.0095 (6)	−0.0027 (5)	−0.0031 (5)	0.0014 (5)
O3	0.0181 (6)	0.0235 (7)	0.0085 (5)	−0.0073 (6)	−0.0021 (4)	0.0004 (6)
O4	0.0224 (6)	0.0143 (6)	0.0097 (6)	−0.0018 (5)	−0.0029 (5)	−0.0011 (5)
C1	0.0178 (8)	0.0169 (8)	0.0116 (7)	0.0003 (6)	−0.0025 (6)	−0.0014 (6)
C2	0.0180 (7)	0.0147 (8)	0.0105 (7)	0.0019 (7)	−0.0017 (6)	0.0021 (6)
C3	0.0169 (7)	0.0132 (8)	0.0111 (7)	−0.0024 (6)	−0.0010 (6)	0.0011 (6)
C4	0.0149 (7)	0.0134 (8)	0.0108 (7)	−0.0009 (6)	−0.0008 (6)	0.0005 (6)
C5	0.0149 (7)	0.0151 (8)	0.0101 (7)	−0.0025 (6)	0.0004 (6)	−0.0007 (6)
C6	0.0136 (6)	0.0163 (8)	0.0116 (7)	−0.0007 (7)	−0.0015 (5)	−0.0010 (6)

Geometric parameters (Å, º) top

F1—C2	1.354 (2)	O3—C4	1.372 (2)
F2—C2	1.345 (2)	O3—C5	1.388 (2)
F3—C3	1.338 (2)	O4—C6	1.412 (2)
F4—C3	1.342 (2)	O4—H4O	0.85 (4)
F5—C4	1.338 (2)	C1—C2	1.517 (3)
F6—C4	1.339 (2)	C1—H1A	0.9900
F7—C5	1.354 (2)	C1—H1B	0.9900
F8—C5	1.351 (2)	C3—C4	1.547 (3)
O1—C1	1.410 (2)	C5—C6	1.513 (2)
O1—H1O	0.84 (4)	C6—H6A	0.9900
O2—C3	1.368 (2)	C6—H6B	0.9900
O2—C2	1.399 (2)

C1—O1—H1O	108 (2)	F4—C3—C4	108.44 (15)
C3—O2—C2	120.31 (16)	O2—C3—C4	107.76 (16)
C4—O3—C5	121.70 (15)	F5—C4—F6	107.64 (16)
C6—O4—H4O	106 (2)	F5—C4—O3	111.28 (16)
O1—C1—C2	109.99 (15)	F6—C4—O3	112.68 (16)
O1—C1—H1A	109.7	F5—C4—C3	109.64 (16)
C2—C1—H1A	109.7	F6—C4—C3	109.31 (15)
O1—C1—H1B	109.7	O3—C4—C3	106.26 (15)
C2—C1—H1B	109.7	F8—C5—F7	105.85 (15)
H1A—C1—H1B	108.2	F8—C5—O3	111.40 (15)
F2—C2—F1	106.43 (17)	F7—C5—O3	109.52 (16)
F2—C2—O2	109.02 (16)	F8—C5—C6	111.64 (16)
F1—C2—O2	110.76 (15)	F7—C5—C6	111.42 (16)
F2—C2—C1	110.45 (15)	O3—C5—C6	107.05 (14)
F1—C2—C1	110.80 (16)	O4—C6—C5	110.69 (14)
O2—C2—C1	109.34 (16)	O4—C6—H6A	109.5
F3—C3—F4	107.59 (17)	C5—C6—H6A	109.5
F3—C3—O2	111.10 (16)	O4—C6—H6B	109.5
F4—C3—O2	112.68 (16)	C5—C6—H6B	109.5
F3—C3—C4	109.20 (15)	H6A—C6—H6B	108.1

C3—O2—C2—F2	89.9 (2)	O2—C3—C4—F5	−48.5 (2)
C3—O2—C2—F1	−26.9 (2)	F3—C3—C4—F6	−169.97 (16)
C3—O2—C2—C1	−149.29 (17)	F4—C3—C4—F6	−53.01 (19)
O1—C1—C2—F2	−173.74 (16)	O2—C3—C4—F6	69.23 (19)
O1—C1—C2—F1	−56.1 (2)	F3—C3—C4—O3	−48.1 (2)
O1—C1—C2—O2	66.3 (2)	F4—C3—C4—O3	68.84 (19)
C2—O2—C3—F3	77.1 (2)	O2—C3—C4—O3	−168.91 (15)
C2—O2—C3—F4	−43.8 (2)	C4—O3—C5—F8	−31.6 (2)
C2—O2—C3—C4	−163.34 (16)	C4—O3—C5—F7	85.1 (2)
C5—O3—C4—F5	78.4 (2)	C4—O3—C5—C6	−153.95 (17)
C5—O3—C4—F6	−42.6 (2)	F8—C5—C6—O4	59.9 (2)
C5—O3—C4—C3	−162.26 (17)	F7—C5—C6—O4	−58.2 (2)
F3—C3—C4—F5	72.2 (2)	O3—C5—C6—O4	−177.92 (15)
F4—C3—C4—F5	−170.79 (16)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1O···O4ⁱ	0.84 (4)	1.87 (4)	2.705 (2)	172 (3)
O4—H4O···O1ⁱⁱ	0.85 (4)	1.82 (4)	2.661 (2)	173 (3)
C6—H6B···F4ⁱⁱⁱ	0.99	2.52	3.416 (2)	151

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

Acknowledgements

The authors wish to thank the Department of Natural Science, Northeastern State University for financial support of this project.

Funding information

Funding for this research was provided by: American Chemical Society Petroleum Research Fund (grant No. 57803-UR10); National Science Foundation (grant No. CHE-1726630).

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