Lithium tri­fluoro­methane­sulfonate aceto­nitrile adduct

The title compound, poly­[[(aceto­nitrile)­lithium(I)]-μ-triflato], [Li(CF₃O₃S)(C₂H₃N)]_∞, was synthesized by reaction of LiCF₃SO₃ with CH₃CN and is found to exist as a one-dimensional polymer in the solid state. Each Li⁺ cation is tetrahedrally coordinated by three oxy­gen donors from three different CF₃SO₃⁻ anions [Li—O = 1.925 (3), 1.926 (3) and 1.940 (2) Å] and one CH₃CN nitro­gen donor [Li—N = 2.042 (3) Å]. The unit cell has a β angle of 90.064 (3)°, but the Laue symmetry is 2/m. As a result of this, the crystals exist as pseudo-merohedral twins related by the twin law (00/00/001).

Key indicators

• Single-crystal X-ray study
• T = 173 K
• Mean [sigma](C-C) = 0.002 Å
• R factor = 0.022
• wR factor = 0.061
• Data-to-parameter ratio = 15.6

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry

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S1. Comment

In the course of studies on the reactions of LiCF₃SO₃ with various short- and long-chain ethylene oxide compounds, it has been found that addition of CH₃CN can result in the formation of crystals of [Li(CF₃SO₃)(CH₃CN)]_∞. The crystals for this study were grown from a solution of LiCF₃SO₃ in poly(ethylene glycol) dimethyl ether (PEGDME500, Aldrich) and CH₃CN. The structure has been determined to be that of one-dimensional polymers that propagate along the a axis. Partial details of this structure have previously been reported (Huang, 1994).

Each Li atom is tetrahedrally coordinated by three oxygen donors from three different CF₃SO₃ anions [Li—O = 1.925 (3), 1.926 (3) and 1.940 (2) Å] and one CH₃CN nitrogen donor [Li—N = 2.042 (3) Å; Fig. 1]. In turn, each CF₃SO₃^- anion is coordinated to three different Li atoms. The arrangement of the two three-connecting units is such that centrosymmetric eight-atom [LiOSOLiOSO] rings are formed (Fig. 2). These eight-atom rings are fused on opposite edges with like rings creating the one-dimensional polymer.

S2. Experimental

Preparations were carried out in a dry room (<1% relative humidity) using anhydrous materials. From a poly(ethylene glycol)dimethyl ether (PEGDME500, Aldrich) and CH₃CN solution of LiCF₃SO₃, crystals of [Li(CF₃SO₃)(CH₃CN)]_∞ separated over a period of two weeks.

S3. Refinement

The crystal is a pseudomerohedral twin with the two components related by the twin law (100/010/001). The twin fraction refines to 67.3 (1)%.

Computing details

Data collection: SMART (Bruker, 2000); cell refinement: SAINT (Bruker, 2000); data reduction: SAINT); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL/PC (Bruker, 1998); software used to prepare material for publication: SHELXTL/PC and PLATON (Spek, 2001).

Figures

	Fig. 1. View of the title compound showing the Li coordination environment and the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level. [Symmetry codes: (i) -x, 1 - y, -z; (ii) 1 - x, 1 - y, -z.]
	Fig. 2. View of the polymeric structure of the title compound. Key: C shaded, H open, Li dotted, O right-hatched, S left-hatched and F cross-hatched.

lithium trifluoromethanesulfonate acetonitrile adduct

Crystal data

[Li(CF3O3S)(C2H3N)]	F(000) = 392
Mr = 197.06	Dx = 1.716 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
a = 5.4814 (11) Å	Cell parameters from 2977 reflections
b = 14.790 (3) Å	θ = 2.6–27.5°
c = 9.409 (2) Å	µ = 0.44 mm^−1
β = 90.064 (3)°	T = 173 K
V = 762.8 (3) Å^3	Block, colourless
Z = 4	0.46 × 0.40 × 0.30 mm

Data collection

Siemens CCD area-detector diffractometer	1731 independent reflections
Radiation source: fine-focus sealed tube	1693 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.022
ϕ and ω scans	θmax = 27.5°, θmin = 2.2°
Absorption correction: multi-scan (SADABS; Blessing, 1995; Sheldrick, 2000)	h = −7→7
Tmin = 0.797, Tmax = 0.893	k = −19→19
6487 measured reflections	l = −12→12

Refinement

Refinement on F^2	Primary atom site location: direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier synthesis
R[F^2 > 2σ(F^2)] = 0.022	Hydrogen site location: placed geometrically
wR(F^2) = 0.061	H-atom parameters constrained
S = 1.11	w = 1/[σ^2(Fo^2) + (0.0351P)^2 + 0.139P] where P = (Fo^2 + 2Fc^2)/3
1731 reflections	(Δ/σ)max < 0.001
111 parameters	Δρmax = 0.24 e Å^−3
0 restraints	Δρmin = −0.26 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.

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

	x	y	z	Uiso*/Ueq
Li1	0.2780 (5)	0.56145 (15)	−0.1656 (2)	0.0235 (4)
S1	0.22006 (6)	0.378941 (18)	0.01485 (4)	0.01931 (9)
O1	0.2474 (2)	0.43582 (6)	−0.10913 (11)	0.0312 (2)
O2	−0.0251 (2)	0.37213 (7)	0.06935 (13)	0.0317 (3)
O3	0.4034 (2)	0.39132 (8)	0.12214 (12)	0.0317 (3)
C1	0.2774 (3)	0.26604 (9)	−0.05637 (15)	0.0276 (3)
F1	0.1151 (2)	0.24573 (8)	−0.15510 (12)	0.0476 (3)
F2	0.4995 (2)	0.26235 (7)	−0.11398 (13)	0.0494 (3)
F3	0.2645 (2)	0.20396 (6)	0.04545 (10)	0.0418 (2)
N1	0.2498 (3)	0.56156 (8)	−0.38202 (12)	0.0298 (3)
C2	0.2447 (3)	0.57544 (10)	−0.50076 (15)	0.0281 (3)
C3	0.2376 (4)	0.59454 (16)	−0.65316 (17)	0.0472 (4)
H3A	0.0835	0.5725	−0.6931	0.071*
H3B	0.3743	0.5641	−0.7001	0.071*
H3C	0.2502	0.6599	−0.6685	0.071*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Li1	0.0239 (11)	0.0253 (10)	0.0214 (10)	−0.0004 (9)	−0.0019 (9)	0.0017 (8)
S1	0.01964 (14)	0.01844 (14)	0.01987 (15)	−0.00028 (10)	−0.00041 (12)	−0.00057 (11)
O1	0.0439 (6)	0.0230 (4)	0.0266 (5)	−0.0016 (5)	−0.0018 (5)	0.0048 (4)
O2	0.0218 (5)	0.0324 (6)	0.0408 (6)	0.0012 (4)	0.0044 (5)	−0.0050 (5)
O3	0.0270 (6)	0.0400 (6)	0.0279 (6)	−0.0082 (5)	−0.0065 (5)	−0.0001 (4)
C1	0.0362 (7)	0.0199 (6)	0.0266 (7)	0.0018 (6)	0.0051 (6)	0.0012 (5)
F1	0.0698 (7)	0.0361 (5)	0.0367 (5)	−0.0055 (5)	−0.0102 (5)	−0.0135 (4)
F2	0.0501 (6)	0.0358 (5)	0.0622 (7)	0.0123 (5)	0.0301 (6)	0.0004 (5)
F3	0.0605 (7)	0.0231 (4)	0.0417 (5)	0.0041 (4)	0.0077 (5)	0.0102 (4)
N1	0.0328 (7)	0.0331 (6)	0.0236 (6)	−0.0026 (5)	−0.0033 (6)	0.0009 (4)
C2	0.0257 (6)	0.0355 (7)	0.0232 (6)	−0.0031 (5)	−0.0026 (7)	0.0018 (5)
C3	0.0381 (10)	0.0822 (13)	0.0213 (7)	−0.0047 (10)	−0.0024 (7)	0.0103 (8)

Geometric parameters (Å, º)

Li1—O1	1.940 (2)	O3—Li1^ii	1.925 (3)
Li1—O2^i	1.926 (3)	C1—F1	1.3202 (19)
Li1—O3^ii	1.925 (3)	C1—F3	1.3290 (16)
Li1—N1	2.042 (3)	C1—F2	1.3343 (18)
S1—O3	1.4353 (12)	N1—C2	1.1362 (19)
S1—O2	1.4424 (12)	C2—C3	1.4620 (19)
S1—O1	1.4461 (10)	C3—H3A	0.9800
S1—C1	1.8266 (14)	C3—H3B	0.9800
O2—Li1^i	1.926 (3)	C3—H3C	0.9800
N1—Li1—O1	105.52 (11)	F1—C1—F3	108.28 (13)
N1—Li1—O2^i	114.53 (13)	F1—C1—F2	108.62 (13)
N1—Li1—O3^ii	106.22 (12)	F3—C1—F2	108.29 (13)
O1—Li1—O2^i	107.28 (12)	F1—C1—S1	110.49 (10)
O1—Li1—O3^ii	111.60 (13)	F3—C1—S1	110.97 (9)
O2^i—Li1—O3^ii	111.61 (12)	F2—C1—S1	110.12 (10)
O3—S1—O2	114.25 (8)	C2—N1—Li1	169.24 (14)
O3—S1—O1	114.85 (7)	N1—C2—C3	179.26 (18)
O2—S1—O1	115.13 (7)	C2—C3—H3A	109.5
O3—S1—C1	104.71 (7)	C2—C3—H3B	109.5
O2—S1—C1	103.15 (7)	H3A—C3—H3B	109.5
O1—S1—C1	102.58 (6)	C2—C3—H3C	109.5
S1—O1—Li1	141.93 (9)	H3A—C3—H3C	109.5
S1—O2—Li1^i	143.40 (10)	H3B—C3—H3C	109.5
S1—O3—Li1^ii	146.13 (10)

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