Bromido(12-crown-4)lithium

The Br and Li ions of the title compound, bromido(1,4,7,10-tetra­oxacyclo­dodecane-κ⁴O)lithium(I), [LiBr(C₈H₁₆O₄)], are located on special positions of site symmetry 4mm. The crown ether ring is disordered over two positions with one C atom located on a mirror plane.

Key indicators

• Single-crystal X-ray study
• T = 173 K
• Mean [sigma](r-Li) = 0.030 Å
• Disorder in main residue
• R factor = 0.056
• wR factor = 0.159
• Data-to-parameter ratio = 10.6

checkCIF/PLATON results

No syntax errors found



Alert level A
PLAT722_ALERT_1_A Angle   Calc      148.00, Rep      108.00 Dev...      40.00 Deg.
              H2C  -C2   -H2D     1.555   1.555   1.555

Alert level B
PLAT301_ALERT_3_B Main Residue  Disorder .........................      36.00 Perc.

Alert level C
PLAT062_ALERT_4_C Rescale T(min) & T(max) by .....................       0.93
PLAT213_ALERT_2_C Atom C2      has ADP max/min Ratio .............       4.00 prola
PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for         C1
PLAT764_ALERT_4_C Overcomplete CIF Bond List Detected (Rep/Expd) .       2.40 Ratio

Alert level G
ABSTM02_ALERT_3_G  When printed, the submitted absorption T values will be
            replaced by the scaled T values. Since the ratio of scaled T's
            is identical to the ratio of reported T values, the scaling
            does not imply a change to the absorption corrections used in
            the study.
            Ratio of Tmax expected/reported      0.933
            Tmax scaled      0.536 Tmin scaled      0.388

   1 ALERT level A = In general: serious problem
   1 ALERT level B = Potentially serious problem
   4 ALERT level C = Check and explain
   1 ALERT level G = General alerts; check

   1 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   2 ALERT type 2 Indicator that the structure model may be wrong or deficient
   2 ALERT type 3 Indicator that the structure quality may be low
   2 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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S1. Comment

Generally, LiBr is nearly insoluble in organic solvents. However, coordination of Li cation with organic ligands such as 12-crown-4 increases the solubility of LiBr therein. Therefore, we were able to obtain single crystals of the complex LiBr.12-crown-4 in a hexane–tetraydrofuran solution.

The Br and Li ions of the title compound are located on a special position of site symmetry 4 mm. The crown ether ring is disordered over two positions with one C atom located on a mirror plane.

Related literature

For [Li(12-crown-4)Cl, see Gingl et al. (1991).

S2. Experimental

Crystallization by slow diffusion of hexane to a tetrahydrofuran (10 ml) solution of 1,4-phenylene-bridged Li scorpionate Li₂[C₆H₄(Bpz₃)₂] (0.09 mmol) in the presence of LiBr and 12-crown-4 (32 mg; 0.2 mmol) gave colourless X-ray quality crystals of LiBr.12-crown-4.

S3. Refinement

H atoms were refined with fixed individual displacement parameters [U_iso(H) = 1.2U_eq(C)] using a riding model with C—H = 0.99 Å. One C and the O atom are disordered over two sites with occupation factors of 0.5 each.

Computing details

Data collection: X-AREA (Stoe & Cie, 2001); cell refinement: X-AREA; data reduction: X-AREA; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: XP in SHELXTL-Plus (Sheldrick, 1991); software used to prepare material for publication: SHELXL97.

Figures

	Fig. 1. Perspective view of the title compound with the atom numbering scheme; displacement ellipsoids are at the 50% probability level; H atoms are drawn as small spheres of arbitrary radii. Only one site of the disordered atoms is shown. Symmetry operators for generating equivalent atoms: (A) 1/2 - y, x, z; (B) 1/2 - x, y, z; (C) y, 1/2 - x, z.
	Fig. 2. Perspective view of the title compound showing the disorder of the crown ether ring. H atoms omitted for clarity. Colour codes: C: black, Br: brown, Li: magenta, O: red.

bromido(1,4,7,10-tetraoxacyclododecane-κ⁴O)lithium(I)

Crystal data

[LiBr(C8H16O4)]	Dx = 1.567 Mg m^−3
Mr = 263.06	Mo Kα radiation, λ = 0.71073 Å
Tetragonal, P4/nmm	Cell parameters from 2066 reflections
Hall symbol: -P 4a 2a	θ = 3.6–24.9°
a = 8.4895 (10) Å	µ = 3.67 mm^−1
c = 7.7355 (9) Å	T = 173 K
V = 557.51 (11) Å^3	Block, colourless
Z = 2	0.29 × 0.21 × 0.17 mm
F(000) = 268

Data collection

Stoe IPDSII two-circle diffractometer	330 independent reflections
Radiation source: fine-focus sealed tube	316 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.051
ω scans	θmax = 25.5°, θmin = 3.4°
Absorption correction: multi-scan (MULABS; Spek, 2003; Blessing, 1995)	h = −10→9
Tmin = 0.416, Tmax = 0.574	k = −10→9
2624 measured reflections	l = −9→7

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.057	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.159	H-atom parameters constrained
S = 1.29	w = 1/[σ^2(Fo^2) + (0.0565P)^2 + 4.7442P] where P = (Fo^2 + 2Fc^2)/3
330 reflections	(Δ/σ)max < 0.001
31 parameters	Δρmax = 1.25 e Å^−3
0 restraints	Δρmin = −0.83 e Å^−3

Special details

Experimental. ;

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	Occ. (<1)
Br1	0.2500	0.2500	0.2282 (2)	0.0251 (6)
Li1	0.2500	0.2500	0.544 (4)	0.029 (6)
O1	0.2093 (10)	0.0249 (13)	0.6619 (10)	0.040 (3)	0.50
C1	0.3586 (16)	−0.0390 (16)	0.7244 (18)	0.038 (3)	0.50
H1A	0.4217	−0.0809	0.6272	0.046*	0.50
H1B	0.3391	−0.1257	0.8073	0.046*	0.50
C2	0.4316 (9)	0.0684 (9)	0.7956 (14)	0.091 (6)
H2A	0.3661	0.1115	0.8901	0.109*	0.25
H2B	0.5297	0.0259	0.8472	0.109*	0.25
H2C	0.4544	−0.0638	0.8153	0.109*	0.25
H2D	0.4671	0.2250	0.8457	0.109*	0.25

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Br1	0.0250 (7)	0.0250 (7)	0.0252 (9)	0.000	0.000	0.000
Li1	0.020 (8)	0.020 (8)	0.045 (17)	0.000	0.000	0.000
O1	0.039 (9)	0.051 (5)	0.029 (4)	0.008 (4)	−0.004 (4)	−0.004 (4)
C1	0.044 (8)	0.033 (7)	0.037 (7)	0.015 (6)	−0.004 (6)	0.005 (6)
C2	0.117 (11)	0.117 (11)	0.037 (6)	0.100 (12)	−0.006 (3)	0.006 (3)

Geometric parameters (Å, º)

Br1—Li1	2.44 (3)	Li1—O1^vii	2.145 (17)
Li1—O1^i	2.145 (17)	O1—C1	1.460 (15)
Li1—O1^ii	2.145 (17)	O1—C2^v	1.624 (11)
Li1—O1^iii	2.145 (17)	C1—H1A	0.9900
Li1—O1	2.145 (17)	C1—H1B	0.9900
Li1—O1^iv	2.145 (17)	C2—C1^ii	1.232 (14)
Li1—O1^v	2.145 (17)	C2—H2A	0.9890
Li1—O1^vi	2.145 (17)	C2—H2B	0.9909
O1^ii—Li1—O1	96.1 (9)	O1—C1—H1A	110.6
O1^iii—Li1—O1	79.6 (6)	C2—C1—H1B	110.2
O1^ii—Li1—O1^iv	129.8 (15)	O1—C1—H1B	110.2
O1—Li1—Br1	115.1 (7)	H1A—C1—H1B	108.3
C1—O1—C2^v	120.8 (8)	C1—C2—O1^iii	112.0 (10)
C1—O1—Li1	109.4 (7)	H2A—C2—H2B	108.0
O1^i—C1—C2	96.5 (14)	H2C—C2—H2D	108.0
C2—C1—O1	108.1 (11)	C1^ii—C2—H2C	115.3
C2—C1—H1A	109.4	O1^i—C2—H2D	123.0
Br1—Li1—O1—C1	102.9 (7)	C2^v—O1—C1—C2	−72.9 (14)
Br1—Li1—O1—C2^v	−128.8 (5)	O1—C1—C2—O1^iii	−62.7 (13)

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