research communications\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890

About the polymorphism of [Li(C4H8O)3]I: crystal structures of trigonal and tetra­gonal polymorphs

aUniversity of Regensburg, Institute of Inorganic Chemistry, Universitätsstrasse 31, 93053 Regensburg, Germany, and bUniversity of Regensburg, Institute of Organic Chemistry, Universitätsstrasse 31, 93053 Regensburg, Germany
*Correspondence e-mail: stefanie.gaertner@ur.de

Edited by M. Weil, Vienna University of Technology, Austria (Received 8 November 2014; accepted 18 November 2014; online 21 November 2014)

Two new trigonal and tetra­gonal polymorphs of the title compound, iodido­tris­(tetra­hydro­furan-κO)lithium, are presented, which both include the isolated ion pair Li(THF)3+·I. One Li—I ion contact and three tetra­hydro­furan (THF) mol­ecules complete the tetra­hedral coordination of the lithium cation. The three-dimensional arrangement in the two polymorphs differs notably. In the trigonal structure, the ion pair is located on a threefold rotation axis of space group P-3 and only one THF mol­ecule is present in the asymmetric unit. In the crystal, strands of ion pairs parallel to [001] are observed with an eclipsed conformation of the THF mol­ecules relative to the Li⋯I axis of two adjacent ion pairs. In contrast, the tetra­gonal polymorph shows a much larger unit cell in which all atoms are located on general positions of the space group I41cd. The resulting three-dimensional arrangement shows helical chains of ion pairs parallel to [001]. Apart from van der Waals contacts, no remarkable inter­molecular forces are present between the isolated ion pairs in both structures.

1. Chemical context

The tetra­hedral arrangement of the [Li(THF)3]+·I ion pair has already been reported in the monoclinic crystal structure (space group P21/n) by Nöth & Waldhör (1998[Nöth, H. & Waldhör, R. (1998). Z. Naturforsch. Teil B, 53, 1525-1530.]). Crystals of this phase could be obtained during the reaction of tmp2AlI (tmp = tetra­methyl­piperidine) with LiHAsPh (Ph = phen­yl) in toluene/tetra­hydro­furan (THF) or, more conveniently, from LiH and iodine in THF. The applied crystallization temperature was 233 K and the data collection for structure analysis was performed at 193 K.

[Scheme 1]

In our case, we obtained two new polymorphs of [Li(THF)3]+·I from a solution of (H3C)2CuLi·LiI in diethyl ether covered with THF. The reaction mixture was stored at 193 K, and the measurements for the single-crystal structure analysis were performed at 123 K. The observation of such contact ion pairs directly confirms the NMR spectroscopic findings (Henze et al., 2005[Henze, W., Vyater, A., Krause, N. & Gschwind, R. (2005). J. Am. Chem. Soc. 127, 17335-17342.]) that upon addition of THF, the LiI units are separated from the cuprate by the coordination of Li+ by three THF mol­ecules (Fig. 1[link]).

[Figure 1]
Figure 1
Proposed by NMR in solution: THF addition to iodidocuprates in diethyl ether solutions yields predominantly iodine-free cuprates and solvated Li–I units.

2. Structural commentary

The polymorphs reported herein are higher in symmetry compared to the known monoclinic phase as they crystallize in the trigonal space group P[\overline{3}] and the tetra­gonal space group I41cd. In the asymmetric unit of the trigonal polymorph, the lithium and iodide ion pair is located on a threefold rotation axis (Wyckoff position 2d) and one THF mol­ecule is located on a general position. This results in a symmetric coordination of the lithium cation by the three THF mol­ecules. The unit cell of this polymorph is small and contains two formula units. In contrast, in the structure of the tetra­gonal polymorph, all atoms are located on general positions. The resultant unit cell is considerably larger and contains 16 formula units. Nevertheless, the mol­ecular structures of the [Li(THF)3]+·I ion pair in all three polymorphs are very similar in terms of bond lengths and angles. Table 1[link] compiles Li—I and Li—O distances for all three structures.

Table 1
Li—I and Li—O distances (Å) of the [Li(THF)3]I unit in all three known polymorphs.

Data for the monoclinic polymorph are from Nöth & Waldhör (1998[Nöth, H. & Waldhör, R. (1998). Z. Naturforsch. Teil B, 53, 1525-1530.]).

  monoclinic trigonal tetra­gonal
Li—I 2.741 (7) 2.744 (7) 2.721 (11)
Li—O1 1.927 (7) 1.932 (4) 1.934 (13)
Li—O2 1.915 (8)   1.961 (13)
Li—O3 1.947 (7)   1.944 (14)

3. Supra­molecular features

The reasons for the same mol­ecular [Li(THF)3]+·I unit crystallizing in three different crystal systems and space groups lies in the supra­molecular assembly of these ion pairs. The three-dimensional arrangement of the [Li(THF)3]+·I ion pairs is different in all three known polymorphs. The differences in the supra­molecular structures can best be demonstrated when taking the shortest supra­molecular Li⋯I distances (∼5.7 Å) into account. Although this is a formal procedure since at distances of more than 5 Å no chemically reasonable inter­actions are present, it allows for a better understanding of the packing of the ion pairs in the unit cell.

In the previously reported monoclinic structure, the formation of linear chains of individual ion pairs parallel to [10[\overline{1}]] is observed (Fig. 2[link], top), where the THF mol­ecules form a staggered conformation relative to a fictive Li—I axis of the shortest supra­molecular Li⋯I distance (Fig. 2[link], bottom). The complete structure is characterized by anti­parallel oriented chains. The resulting calculated density of the compound is 1.468 g cm−3 (Nöth & Waldhör, 1998[Nöth, H. & Waldhör, R. (1998). Z. Naturforsch. Teil B, 53, 1525-1530.]).

[Figure 2]
Figure 2
Linear chains in the monoclinic polymorph of [Li(THF)3]+·I (top) show a staggered arrangement of the THF mol­ecules relative to the Li⋯I axis (bottom). Displacement ellipsoids (except for hydrogen atoms) are drawn at the 50% probability level.

A similar supra­molecular arrangement is found in the trigonal structure. Here, the ion pairs are likewise aligned in linear chains, in this case parallel to [001] (Fig. 3[link], top), but in contrast to the monoclinic variant, the THF mol­ecules assemble in an eclipsed fashion relative to the fictive Li—I axis of the shortest supra­molecular Li⋯I distance (Fig. 3[link], bottom left). These chains again are packed with an anti­parallel orientation in the crystal structure (Fig. 3[link], bottom right), and the calculated density is 1.516 g cm−3.

[Figure 3]
Figure 3
Linear chains extend parallel to [001] in the trigonal polymorph (top) and show an eclipsed conformation of the THF mol­ecules relative to the Li⋯I axis (bottom, left) in an anti­parallel arrangement in the unit cell (bottom, right). Displacement ellipsoids (except for hydrogen atoms) are drawn at the 50% probability level.

Finally, in the tetra­gonal structure, the situation is completely different, as the ion pairs form helical chains along the 41 screw axis of space group I41cd (Fig. 4[link], top and bottom left). This assembly in the unit cell (Fig. 4[link], bottom right) results in a calculated density of 1.503 g cm−3.

[Figure 4]
Figure 4
Helical chains parallel to [001] (top and bottom, left) are present in the crystal structure of the tetra­gonal polymorph. Displacement ellipsoids (except for hydrogen atoms) are drawn at the 50% probability level.

The higher temperature during synthesis/crystallization of the monoclinic polymorph compared to the conditions applied for the title compounds obviously caused the crystallization of the two new polymorphs. Both have a very similar density and co-exist in one reaction batch. At higher temperatures, the crystals became amorphous, indicating an irreversible phase transition.

4. Synthesis and crystallization

A Schlenk flask, equipped with a stirring bar and 0.5 mmol (1 eq) CuI, was dried four times in vacuo to remove residual moisture. Then 5 ml of diethyl ether was added and the Cu(I) salt was suspended. Upon addition of 2 eq (H3C)Li in diethyl ether, the mixture gave a colourless solution. After removal of the stirring bar, the solution was covered with THF. The flask was then stored at 193 K. After several days, clear colourless needles could be observed. Suitable crystals were isolated in nitro­gen-cooled perfluoro­ether oil and mounted on the goniometer for data collection at 123 K. The crystals of the two compounds did not differ in their forms. For several crystals, the unit cell was determined, proving the presence of either the tetra­gonal or the trigonal polymorph.

5. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2[link]. The positions of the lithium cations were located in difference Fourier maps. H atoms were positioned with idealized geometry and were refined with C—H = 0.99 Å and Uiso(H) = 1.2Ueq(C).

Table 2
Experimental details

  Trigonal polymorph Tetragonal polymorph
Crystal data
Chemical formula [Li(C4H8O)3]I [Li(C4H8O)3]I
Mr 350.15 350.15
Crystal system, space group Trigonal, P[\overline{3}] Tetragonal, I41cd
Temperature (K) 123 123
a, b, c (Å) 10.2530 (14), 10.2530 (14), 8.4250 (17) 18.288 (3), 18.288 (3), 18.511 (4)
α, β, γ (°) 90, 90, 120 90, 90, 90
V3) 767.0 (3) 6191 (2)
Z 2 16
Radiation type Mo Kα Mo Kα
μ (mm−1) 2.08 2.06
Crystal size (mm) 0.10 × 0.07 × 0.05 0.10 × 0.05 × 0.03
 
Data collection
Diffractometer Stoe IPDS Stoe IPDS
Absorption correction Analytical (X-RED and X-SHAPE; Stoe & Cie, 2002[Stoe & Cie (2002). X-AREA, X-RED and X-SHAPE. Stoe & Cie, Darmstadt, Germany.]) Analytical (X-RED and X-SHAPE; Stoe & Cie, 2002[Stoe & Cie (2002). X-AREA, X-RED and X-SHAPE. Stoe & Cie, Darmstadt, Germany.])
Tmin, Tmax 0.760, 0.827 0.629, 0.744
No. of measured, independent and observed [I > 2σ(I)] reflections 4938, 1185, 994 14474, 2802, 2130
Rint 0.048 0.044
(sin θ/λ)max−1) 0.652 0.605
 
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.029, 0.067, 1.01 0.027, 0.058, 0.95
No. of reflections 1185 2802
No. of parameters 52 154
No. of restraints 0 1
H-atom treatment H-atom parameters constrained H-atom parameters constrained
Δρmax, Δρmin (e Å−3) 1.26, −0.35 0.74, −0.21
Absolute structure Flack x determined using 922 quotients [(I+)−(I)]/[(I+)+(I)] (Parsons et al., 2013[Parsons, S., Flack, H. D. & Wagner, T. (2013). Acta Cryst. B69, 249-259.])
Absolute structure parameter −0.03 (2)
Computer programs: X-AREA (Stoe & Cie, 2002[Stoe & Cie (2002). X-AREA, X-RED and X-SHAPE. Stoe & Cie, Darmstadt, Germany.]), SHELXS97 and SHELXL2014 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]), DIAMOND (Brandenburg, 2012[Brandenburg, K. (2012). DIAMOND. Crystal Impact GbR, Bonn, Germany.]) and OLEX2 (Dolomanov et al., 2009[Dolomanov, O. V., Bourhis, L. J., Gildea, R. J., Howard, J. A. K. & Puschmann, H. (2009). J. Appl. Cryst. 42, 339-341.]).

Supporting information


Chemical context top

The tetra­hedral arrangement of the [Li(THF)3]I ion pair has already been reported in the monoclinic crystal structure (space group P21/n) by Nöth & Waldhör (1998). Crystals of this phase could be obtained during the reaction of tmp2AlI (tmp = tetra­methyl­piperidine) with LiHAsPh (Ph = phenyl) in toluene/tetra­hydro­furan (THF) or, more conveniently, from LiH and iodine in THF. The applied crystallization temperature was 233 K and the data collection for structure analysis was performed at 193 K. In our case, we obtained two new polymorphs of [Li(THF)3]+ I- from a solution of (H3C)2CuLi·LiI in di­ethyl ether covered with THF. The reaction mixture was stored at 193 K, and the measurements for the single-crystal structure analysis were performed at 123 K. The observation of such contact ion pairs directly confirms the NMR spectroscopic findings (Henze et al., 2005) that upon addition of THF, the LiI units are separated from the cuprate by the coordination of Li+ by three THF molecules (Fig. 1).

Structural commentary top

The polymorphs reported herein are higher in symmetry compared to the known monoclinic phase as they crystallize in the trigonal space group P3, and the tetra­gonal space group I41cd. In the asymmetric unit of the trigonal polymorph, the lithium and iodine atom pair is located on a threefold rotation axis (Wyckoff position 2d) and one THF molecule is located on a general position. This results in a symmetric coordination of the lithium cation by the three THF molecules. The unit cell of this polymorph is small and contains two formula units. In contrast, in the structure of the tetra­gonal polymorph, all atoms are located on general positions. The resultant unit cell is considerably larger and contains 16 formula units. Nevertheless, the molecular structures of the [Li(THF)3]+ I- ion pair in all three polymorphs are very similar in terms of bond lengths and angles. Table 1 compiles Li—I and Li—O distances for all three structures.

Supra­molecular features top

The reasons for the same molecular [Li(THF)3]I unit crystallizing in three different crystal systems and space groups lies in the supra­molecular assembly of these ion pairs. The three-dimensional arrangement of the Li(THF)3+.I- ion pairs is different in all three known polymorphs. The differences in the supra­molecular structures can best be demonstrated when taking the shortest supra­molecular Li···I distances (~5.7 Å) into account. Although this is a formal procedure since at distances of more than 5 Å no chemically reasonable inter­actions are present, it allows for a better understanding of the packing of the ion pairs in the unit cell.

In the previously reported monoclinic structure, the formation of linear chains of individual ion pairs parallel to [101] is observed (Fig. 2, top), where the THF molecules form a staggered conformation relative to a fictive Li—I axis of the shortest supra­molecular Li···I distance (Fig. 2, bottom). The complete structure is characterized by anti­parallel oriented chains. The resulting calculated density of the compound is 1.468 g cm-3 (Nöth & Waldhör, 1998).

A similar supra­molecular arrangement is found in the trigonal structure. Here, the ion pairs are likewise aligned in linear chains, in this case parallel to [001] (Fig. 3, top), but in contrast to the monoclinic variant, the THF molecules assemble in an eclipsed fashion relative to the fictive Li—I axis of the shortest supra­molecular Li···I distance (Fig. 2, bottom left). These chains again are packed with an anti­parallel orientation in the crystal structure (Fig. 3, bottom right), and the calculated density is 1.516 g cm-3.

Finally, in the tetra­gonal structure, the situation is completely different, as the ion pairs form helical chains along the 41 screw axis of space group I41cd (Fig. 4 top and bottom left). This assembly in the unit cell (Fig. 4 bottom right) results in a calculated density of 1.503 g cm-3.

The higher temperature during synthesis/crystallization of the monoclinic polymorph compared to the conditions applied for the title compounds obviously caused the crystallization of the two new polymorphs. Both have a very similar density and co-exist in one reaction batch. At higher temperatures, the crystals became amorphous, indicating an irreversible phase transition.

Synthesis and crystallization top

A Schlenk flask, equipped with a stirring bar and 0.5 mmol (1 eq) CuI, was dried four times in vacuo to remove residual moisture. Then 5 ml of di­ethyl ether was added and the Cu(I) salt was suspended. Upon addition of 2 eq (H3C)Li in di­ethyl ether, the mixture gave a colourless solution. After removal of the stirring bar, the solution was covered with THF. The flask was then stored at 193 K. After several days, clear colourless needles could be observed. Suitable crystals were isolated in nitro­gen-cooled perfluoro­ether oil and mounted on the goniometer for data collection at 123 K. The crystals of the two compounds did not differ in their forms. For several crystals, the unit cell was determined, proving the presence of either the tetra­gonal or the trigonal polymorph.

Refinement top

Crystal data, data collection and structure refinement details are summarized in Table 2. The positions of the lithium cations were located in difference Fourier maps. H atoms were positioned with idealized geometry and were refined with C—H = 0.99 Å and Uiso(H) = 1.2Ueq(C).

Related literature top

For related literature, see: Henze et al. (2005); Nöth & Waldhör (1998); Sheldrick (2008).

Computing details top

For both compounds, data collection: X-AREA (Stoe & Cie, 2002); cell refinement: X-AREA (Stoe & Cie, 2002); data reduction: X-AREA (Stoe & Cie, 2002); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 2012); software used to prepare material for publication: OLEX2 (Dolomanov et al., 2009).

Figures top
Proposed by NMR in solution: THF addition to iodido cuprates in diethyl ether solutions yields predominantly iodine free cuprates and solvated Li–I units.

Linear chains in the monoclinic polymorph of Li(THF)3+.I- (top) show a staggered arrangement of the THF molecules relative to the Li···I axis (bottom). Displacement ellipsoids (except for hydrogen atoms) are drawn at the 50% probability level.

Linear chains extend parallel to [001] in the trigonal polymorph (top) and show an eclipsed conformation of the THF molecules relative to the Li···I axis (bottom, left) in an antiparallel arrangement in the unit cell (bottom, right). Displacement ellipsoids (except for hydrogen atoms) are drawn at the 50% probability level.

Helical chains parallel to [001] (top and bottom, left) are present in the crystal structure of the tetragonal polymorph. Displacement ellipsoids (except for hydrogen atoms) are drawn at the 50% probability level.
(LiI_3THF_trigonal) Iodidotris(tetrahydrofuran-κO)lithium top
Crystal data top
[Li(C4H8O)3]IF(000) = 352
Mr = 350.15Dx = 1.516 Mg m3
Trigonal, P3Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 3θ = 2.3–27.5°
a = 10.2530 (14) ŵ = 2.08 mm1
c = 8.4250 (17) ÅT = 123 K
V = 767.0 (3) Å3Needle, clear colourless
Z = 20.10 × 0.07 × 0.05 mm
Data collection top
Stoe IPDS
diffractometer
994 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.048
phi scansθmax = 27.6°, θmin = 2.4°
Absorption correction: analytical
(X-RED and X-SHAPE; Stoe & Cie, 2002)
h = 1313
Tmin = 0.760, Tmax = 0.827k = 1313
4938 measured reflectionsl = 910
1185 independent reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.029H-atom parameters constrained
wR(F2) = 0.067 w = 1/[σ2(Fo2) + (0.0375P)2]
where P = (Fo2 + 2Fc2)/3
S = 1.01(Δ/σ)max = 0.001
1185 reflectionsΔρmax = 1.26 e Å3
52 parametersΔρmin = 0.35 e Å3
0 restraints
Crystal data top
[Li(C4H8O)3]IZ = 2
Mr = 350.15Mo Kα radiation
Trigonal, P3µ = 2.08 mm1
a = 10.2530 (14) ÅT = 123 K
c = 8.4250 (17) Å0.10 × 0.07 × 0.05 mm
V = 767.0 (3) Å3
Data collection top
Stoe IPDS
diffractometer
1185 independent reflections
Absorption correction: analytical
(X-RED and X-SHAPE; Stoe & Cie, 2002)
994 reflections with I > 2σ(I)
Tmin = 0.760, Tmax = 0.827Rint = 0.048
4938 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0290 restraints
wR(F2) = 0.067H-atom parameters constrained
S = 1.01Δρmax = 1.26 e Å3
1185 reflectionsΔρmin = 0.35 e Å3
52 parameters
Special details top

Experimental. crystal mounting in perfluorether (T. Kottke, D. Stalke, J. Appl. Crystallogr. 26, 1993, p. 615)

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 (Å2) top
xyzUiso*/Ueq
I10.33330.66671.27890 (4)0.02804 (13)
O10.5317 (2)0.7555 (2)0.8601 (2)0.0248 (4)
C10.5755 (4)0.8318 (4)0.7087 (4)0.0262 (6)
H1A0.62290.93990.72290.031*
H1B0.48840.79860.64030.031*
C40.6296 (4)0.6955 (4)0.8981 (4)0.0293 (7)
H4A0.57700.58710.88390.035*
H4B0.66410.71851.00710.035*
C20.6852 (5)0.7903 (5)0.6383 (4)0.0401 (9)
H2A0.75770.86970.57010.048*
H2B0.63330.69740.57800.048*
C30.7608 (4)0.7712 (4)0.7843 (5)0.0382 (8)
H3A0.80420.70800.76240.046*
H3B0.83850.86760.82490.046*
Li10.33330.66670.9532 (9)0.0237 (18)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
I10.03426 (15)0.03426 (15)0.01561 (16)0.01713 (8)0.0000.000
O10.0256 (11)0.0301 (11)0.0211 (10)0.0157 (9)0.0035 (8)0.0063 (8)
C10.0316 (16)0.0292 (16)0.0209 (14)0.0174 (13)0.0034 (12)0.0062 (11)
C40.0326 (17)0.0341 (17)0.0263 (15)0.0206 (14)0.0006 (13)0.0054 (12)
C20.051 (2)0.048 (2)0.0333 (18)0.0332 (19)0.0213 (16)0.0166 (15)
C30.0279 (17)0.0327 (18)0.056 (2)0.0171 (15)0.0087 (16)0.0106 (16)
Li10.027 (3)0.027 (3)0.017 (4)0.0136 (14)0.0000.000
Geometric parameters (Å, º) top
I1—Li12.744 (8)C4—C31.512 (5)
O1—C11.445 (3)C2—H2A0.9700
O1—C41.451 (4)C2—H2B0.9700
O1—Li11.931 (4)C2—C31.518 (6)
C1—H1A0.9700C3—H3A0.9700
C1—H1B0.9700C3—H3B0.9700
C1—C21.509 (5)Li1—O1i1.931 (4)
C4—H4A0.9700Li1—O1ii1.931 (4)
C4—H4B0.9700
C1—O1—C4109.3 (2)C1—C2—C3102.6 (3)
C1—O1—Li1125.6 (3)H2A—C2—H2B109.2
C4—O1—Li1119.9 (2)C3—C2—H2A111.2
O1—C1—H1A110.6C3—C2—H2B111.2
O1—C1—H1B110.6C4—C3—C2101.5 (3)
O1—C1—C2105.5 (2)C4—C3—H3A111.5
H1A—C1—H1B108.8C4—C3—H3B111.5
C2—C1—H1A110.6C2—C3—H3A111.5
C2—C1—H1B110.6C2—C3—H3B111.5
O1—C4—H4A110.6H3A—C3—H3B109.3
O1—C4—H4B110.6O1i—Li1—I1114.0 (2)
O1—C4—C3105.6 (3)O1ii—Li1—I1114.0 (2)
H4A—C4—H4B108.8O1—Li1—I1114.0 (2)
C3—C4—H4A110.6O1—Li1—O1ii104.6 (3)
C3—C4—H4B110.6O1i—Li1—O1ii104.6 (3)
C1—C2—H2A111.2O1i—Li1—O1104.6 (3)
C1—C2—H2B111.2
O1—C1—C2—C331.3 (4)C4—O1—C1—C211.0 (4)
O1—C4—C3—C232.8 (4)Li1—O1—C1—C2143.4 (3)
C1—O1—C4—C314.0 (4)Li1—O1—C4—C3170.1 (3)
C1—C2—C3—C438.8 (4)
Symmetry codes: (i) y+1, xy+1, z; (ii) x+y, x+1, z.
(LiI_3THF_tetragonal) Iodidotris(tetrahydrofuran-κO)lithium top
Crystal data top
[Li(C4H8O)3]IDx = 1.503 Mg m3
Mr = 350.15Mo Kα radiation, λ = 0.71073 Å
Tetragonal, I41cdθ = 2.2–25.5°
a = 18.288 (3) ŵ = 2.06 mm1
c = 18.511 (4) ÅT = 123 K
V = 6191 (2) Å3Needle, clear colourless
Z = 160.10 × 0.05 × 0.03 mm
F(000) = 2816
Data collection top
Stoe IPDS
diffractometer
2130 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.044
ω scansθmax = 25.5°, θmin = 2.2°
Absorption correction: analytical
(X-RED and X-SHAPE; Stoe & Cie, 2002)
h = 2122
Tmin = 0.629, Tmax = 0.744k = 2221
14474 measured reflectionsl = 2022
2802 independent reflections
Refinement top
Refinement on F2Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: fullH-atom parameters constrained
R[F2 > 2σ(F2)] = 0.027 w = 1/[σ2(Fo2) + (0.0296P)2]
where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.058(Δ/σ)max = 0.001
S = 0.95Δρmax = 0.74 e Å3
2802 reflectionsΔρmin = 0.21 e Å3
154 parametersAbsolute structure: Flack x determined using 922 quotients [(I+)-(I-)]/[(I+)+(I-)] (Parsons et al., 2013)
1 restraintAbsolute structure parameter: 0.03 (2)
Primary atom site location: structure-invariant direct methods
Crystal data top
[Li(C4H8O)3]IZ = 16
Mr = 350.15Mo Kα radiation
Tetragonal, I41cdµ = 2.06 mm1
a = 18.288 (3) ÅT = 123 K
c = 18.511 (4) Å0.10 × 0.05 × 0.03 mm
V = 6191 (2) Å3
Data collection top
Stoe IPDS
diffractometer
2802 independent reflections
Absorption correction: analytical
(X-RED and X-SHAPE; Stoe & Cie, 2002)
2130 reflections with I > 2σ(I)
Tmin = 0.629, Tmax = 0.744Rint = 0.044
14474 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.027H-atom parameters constrained
wR(F2) = 0.058Δρmax = 0.74 e Å3
S = 0.95Δρmin = 0.21 e Å3
2802 reflectionsAbsolute structure: Flack x determined using 922 quotients [(I+)-(I-)]/[(I+)+(I-)] (Parsons et al., 2013)
154 parametersAbsolute structure parameter: 0.03 (2)
1 restraint
Special details top

Experimental. crystal mounting in perfluorether (T. Kottke, D. Stalke, J. Appl. Crystallogr. 26, 1993, p. 615)

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 (Å2) top
xyzUiso*/Ueq
I10.52335 (2)0.24851 (5)0.75879 (6)0.04154 (13)
C40.3881 (8)0.4855 (7)0.6892 (7)0.048 (3)
H4A0.34990.48360.65140.058*
H4B0.43410.50320.66710.058*
O10.3985 (3)0.4151 (3)0.7204 (3)0.0466 (14)
C10.3853 (6)0.4187 (5)0.7953 (5)0.057 (2)
H1A0.42340.39130.82200.069*
H1B0.33700.39710.80690.069*
C20.3867 (10)0.4949 (9)0.8153 (8)0.065 (4)
H2A0.43640.50950.83110.078*
H2B0.35190.50460.85520.078*
C30.3650 (6)0.5353 (5)0.7492 (7)0.065 (3)
H3A0.39060.58290.74610.077*
H3B0.31160.54380.74810.077*
O20.3480 (3)0.2781 (3)0.6374 (3)0.0416 (14)
C90.4427 (5)0.3790 (6)0.5212 (6)0.061 (3)
H9A0.41380.42470.52470.073*
H9B0.40900.33760.51270.073*
C120.5599 (4)0.3560 (5)0.5662 (5)0.052 (2)
H12A0.57960.31260.59150.063*
H12B0.58970.39910.57950.063*
O30.4851 (4)0.3676 (4)0.5859 (4)0.0423 (18)
C100.4998 (11)0.3845 (10)0.4602 (8)0.074 (5)
H10A0.48150.36160.41520.089*
H10B0.51270.43610.45020.089*
C110.5620 (5)0.3447 (5)0.4885 (5)0.057 (2)
H11A0.60820.36390.46800.069*
H11B0.55810.29210.47680.069*
C70.2604 (5)0.1901 (5)0.6642 (5)0.045 (2)
H7A0.25550.19290.71740.053*
H7B0.24130.14240.64730.053*
C60.2217 (5)0.2522 (6)0.6282 (5)0.051 (3)
H6A0.17560.26450.65350.061*
H6B0.21090.24110.57690.061*
C80.3374 (4)0.2008 (4)0.6414 (4)0.0432 (17)
H8A0.37130.17880.67700.052*
H8B0.34620.17780.59370.052*
C50.2781 (5)0.3140 (5)0.6351 (7)0.055 (3)
H5A0.27510.34750.59320.066*
H5B0.26970.34250.67990.066*
Li10.4357 (6)0.3295 (6)0.6710 (6)0.039 (3)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
I10.03936 (19)0.0441 (2)0.0412 (2)0.0038 (4)0.0042 (6)0.00914 (17)
C40.055 (7)0.044 (6)0.046 (7)0.006 (5)0.000 (5)0.002 (5)
O10.067 (4)0.041 (3)0.031 (3)0.015 (3)0.001 (3)0.002 (2)
C10.075 (6)0.057 (6)0.041 (6)0.018 (4)0.008 (4)0.006 (4)
C20.088 (11)0.062 (9)0.045 (9)0.010 (8)0.003 (8)0.004 (6)
C30.092 (7)0.042 (5)0.059 (7)0.014 (4)0.003 (6)0.003 (5)
O20.037 (3)0.039 (3)0.049 (4)0.004 (2)0.000 (3)0.005 (2)
C90.049 (5)0.085 (7)0.049 (8)0.009 (4)0.009 (5)0.015 (6)
C120.034 (4)0.070 (6)0.053 (6)0.001 (4)0.009 (4)0.008 (4)
O30.035 (3)0.058 (4)0.034 (4)0.010 (3)0.001 (3)0.009 (3)
C100.077 (9)0.106 (11)0.039 (9)0.010 (10)0.009 (7)0.009 (8)
C110.052 (6)0.066 (6)0.054 (7)0.007 (4)0.012 (4)0.006 (4)
C70.041 (4)0.043 (5)0.050 (6)0.006 (4)0.006 (4)0.009 (4)
C60.033 (4)0.056 (5)0.063 (7)0.002 (5)0.007 (5)0.008 (5)
C80.049 (4)0.038 (4)0.043 (5)0.002 (3)0.001 (3)0.001 (3)
C50.034 (4)0.053 (6)0.080 (7)0.005 (4)0.001 (4)0.014 (7)
Li10.047 (7)0.040 (6)0.031 (7)0.003 (5)0.002 (5)0.002 (5)
Geometric parameters (Å, º) top
I1—Li12.721 (11)C12—H12A0.9900
C4—H4A0.9900C12—H12B0.9900
C4—H4B0.9900C12—O31.432 (11)
C4—O11.425 (13)C12—C111.453 (14)
C4—C31.496 (16)O3—Li11.944 (14)
O1—C11.410 (10)C10—H10A0.9900
O1—Li11.934 (13)C10—H10B0.9900
C1—H1A0.9900C10—C111.448 (19)
C1—H1B0.9900C11—H11A0.9900
C1—C21.442 (19)C11—H11B0.9900
C2—H2A0.9900C7—H7A0.9900
C2—H2B0.9900C7—H7B0.9900
C2—C31.484 (18)C7—C61.496 (15)
C3—H3A0.9900C7—C81.483 (11)
C3—H3B0.9900C6—H6A0.9900
O2—C81.429 (9)C6—H6B0.9900
O2—C51.438 (10)C6—C51.535 (14)
O2—Li11.961 (13)C8—H8A0.9900
C9—H9A0.9900C8—H8B0.9900
C9—H9B0.9900C5—H5A0.9900
C9—O31.442 (13)C5—H5B0.9900
C9—C101.542 (18)
H4A—C4—H4B108.6C12—O3—Li1126.7 (7)
O1—C4—H4A110.4C9—C10—H10A111.1
O1—C4—H4B110.4C9—C10—H10B111.1
O1—C4—C3106.7 (9)H10A—C10—H10B109.0
C3—C4—H4A110.4C11—C10—C9103.5 (10)
C3—C4—H4B110.4C11—C10—H10A111.1
C4—O1—Li1126.0 (7)C11—C10—H10B111.1
C1—O1—C4109.4 (8)C12—C11—H11A110.7
C1—O1—Li1124.3 (6)C12—C11—H11B110.7
O1—C1—H1A110.3C10—C11—C12105.4 (9)
O1—C1—H1B110.3C10—C11—H11A110.7
O1—C1—C2107.2 (10)C10—C11—H11B110.7
H1A—C1—H1B108.5H11A—C11—H11B108.8
C2—C1—H1A110.3H7A—C7—H7B109.1
C2—C1—H1B110.3C6—C7—H7A111.2
C1—C2—H2A110.7C6—C7—H7B111.2
C1—C2—H2B110.7C8—C7—H7A111.2
C1—C2—C3105.3 (11)C8—C7—H7B111.2
H2A—C2—H2B108.8C8—C7—C6102.9 (7)
C3—C2—H2A110.7C7—C6—H6A111.4
C3—C2—H2B110.7C7—C6—H6B111.4
C4—C3—H3A111.0C7—C6—C5101.8 (7)
C4—C3—H3B111.0H6A—C6—H6B109.3
C2—C3—C4103.6 (9)C5—C6—H6A111.4
C2—C3—H3A111.0C5—C6—H6B111.4
C2—C3—H3B111.0O2—C8—C7105.9 (6)
H3A—C3—H3B109.0O2—C8—H8A110.6
C8—O2—C5109.5 (6)O2—C8—H8B110.6
C8—O2—Li1124.7 (6)C7—C8—H8A110.6
C5—O2—Li1121.2 (7)C7—C8—H8B110.6
H9A—C9—H9B108.9H8A—C8—H8B108.7
O3—C9—H9A110.8O2—C5—C6105.2 (6)
O3—C9—H9B110.8O2—C5—H5A110.7
O3—C9—C10104.7 (10)O2—C5—H5B110.7
C10—C9—H9A110.8C6—C5—H5A110.7
C10—C9—H9B110.8C6—C5—H5B110.7
H12A—C12—H12B108.5H5A—C5—H5B108.8
O3—C12—H12A110.2O1—Li1—I1111.4 (5)
O3—C12—H12B110.2O1—Li1—O2104.5 (6)
O3—C12—C11107.4 (8)O1—Li1—O3104.8 (6)
C11—C12—H12A110.2O2—Li1—I1114.2 (5)
C11—C12—H12B110.2O3—Li1—I1113.9 (5)
C9—O3—Li1118.4 (7)O3—Li1—O2107.1 (6)
C12—O3—C9108.8 (8)
C4—O1—C1—C216.1 (14)C11—C12—O3—C911.9 (10)
O1—C4—C3—C217.6 (12)C11—C12—O3—Li1139.8 (9)
O1—C1—C2—C327.1 (14)C7—C6—C5—O227.9 (10)
C1—C2—C3—C427.1 (12)C6—C7—C8—O234.6 (9)
C3—C4—O1—C11.5 (13)C8—O2—C5—C67.1 (9)
C3—C4—O1—Li1175.0 (8)C8—C7—C6—C537.6 (9)
C9—C10—C11—C1231.8 (14)C5—O2—C8—C717.1 (9)
O3—C9—C10—C1124.6 (14)Li1—O1—C1—C2157.6 (10)
O3—C12—C11—C1028.1 (12)Li1—O2—C8—C7138.7 (7)
C10—C9—O3—C127.9 (12)Li1—O2—C5—C6163.8 (8)
C10—C9—O3—Li1162.2 (10)
Li—I and Li—O distances (Å) of the [Li(THF)3]I unit in all three known polymorphs. top
Data for the monoclinic polymorph are from Nöth & Waldhör (1998).
monoclinictrigonaltetragonal
Li—I2.741 (7)2.744 (7)2.721 (11)
Li—O11.927 (7)1.932 (4)1.934 (13)
Li—O21.915 (8)1.961 (13)
Li—O31.947 (7)1.944 (14)

Experimental details

(LiI_3THF_trigonal)(LiI_3THF_tetragonal)
Crystal data
Chemical formula[Li(C4H8O)3]I[Li(C4H8O)3]I
Mr350.15350.15
Crystal system, space groupTrigonal, P3Tetragonal, I41cd
Temperature (K)123123
a, b, c (Å)10.2530 (14), 10.2530 (14), 8.4250 (17)18.288 (3), 18.288 (3), 18.511 (4)
α, β, γ (°)90, 90, 12090, 90, 90
V3)767.0 (3)6191 (2)
Z216
Radiation typeMo KαMo Kα
µ (mm1)2.082.06
Crystal size (mm)0.10 × 0.07 × 0.050.10 × 0.05 × 0.03
Data collection
DiffractometerStoe IPDS
diffractometer
Stoe IPDS
diffractometer
Absorption correctionAnalytical
(X-RED and X-SHAPE; Stoe & Cie, 2002)
Analytical
(X-RED and X-SHAPE; Stoe & Cie, 2002)
Tmin, Tmax0.760, 0.8270.629, 0.744
No. of measured, independent and
observed [I > 2σ(I)] reflections
4938, 1185, 994 14474, 2802, 2130
Rint0.0480.044
(sin θ/λ)max1)0.6520.605
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.029, 0.067, 1.01 0.027, 0.058, 0.95
No. of reflections11852802
No. of parameters52154
No. of restraints01
H-atom treatmentH-atom parameters constrainedH-atom parameters constrained
Δρmax, Δρmin (e Å3)1.26, 0.350.74, 0.21
Absolute structure?Flack x determined using 922 quotients [(I+)-(I-)]/[(I+)+(I-)] (Parsons et al., 2013)
Absolute structure parameter?0.03 (2)

Computer programs: X-AREA (Stoe & Cie, 2002), SHELXS97 (Sheldrick, 2008), SHELXL2014 (Sheldrick, 2008), DIAMOND (Brandenburg, 2012), OLEX2 (Dolomanov et al., 2009).

 

References

First citationBrandenburg, K. (2012). DIAMOND. Crystal Impact GbR, Bonn, Germany.  Google Scholar
First citationDolomanov, O. V., Bourhis, L. J., Gildea, R. J., Howard, J. A. K. & Puschmann, H. (2009). J. Appl. Cryst. 42, 339–341.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationHenze, W., Vyater, A., Krause, N. & Gschwind, R. (2005). J. Am. Chem. Soc. 127, 17335–17342.  Web of Science CrossRef PubMed CAS Google Scholar
First citationNöth, H. & Waldhör, R. (1998). Z. Naturforsch. Teil B, 53, 1525–1530.  Google Scholar
First citationParsons, S., Flack, H. D. & Wagner, T. (2013). Acta Cryst. B69, 249–259.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationStoe & Cie (2002). X-AREA, X-RED and X-SHAPE. Stoe & Cie, Darmstadt, Germany.  Google Scholar

This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
Follow Acta Cryst. E
Sign up for e-alerts
Follow Acta Cryst. on Twitter
Follow us on facebook
Sign up for RSS feeds