2,3,5,6-Tetra­fluoro-1,4-di­iodo­benzene–di­methyl sulfoxide (1/1)

Tetra­fluoro­di­iodo­benzene and di­methyl sulfoxide (DMSO) crystallize in a 1/1 complex, C₆F₄I₂·C₂H₆OS, in space group Pbca. Infinite ...C₆I...O...IC₆I... chains are held together by strong I...O contacts. The DMSO mol­ecules, which lie on mirror planes, are disordered, giving rise to two I...O contacts of 2.898 (9) and 2.803 (10) Å, both with approximately linear C—I...O arrangements. The C₆F₄I₂ mol­ecules lie on inversion centers.

Key indicators

• Single-crystal X-ray study
• T = 297 K
• Mean [sigma](C-C) = 0.013 Å
• R factor = 0.045
• wR factor = 0.125
• Data-to-parameter ratio = 14.1

checkCIF/PLATON results

No syntax errors found



Alert level A
PLAT052_ALERT_1_A (Proper) Absorption Correction Method Missing ..          ?
PLAT431_ALERT_2_A Short Inter HL..A Contact  I1     ..  O2       =       2.80 Ang.

Author Response: This value is correct. It is discussed in the text.

PLAT431_ALERT_2_A Short Inter HL..A Contact  I1     ..  O1       =       2.90 Ang.

Author Response: This value is correct. It is discussed in the text.

Alert level C
PLAT042_ALERT_1_C Calc. and Rep. MoietyFormula Strings Differ ....          ?
PLAT057_ALERT_3_C Correction for Absorption Required   RT(exp)   =       1.15
PLAT213_ALERT_2_C Atom C12     has ADP max/min Ratio .............       3.20 prolat
PLAT250_ALERT_2_C Large U3/U1 ratio for average U(i,j) tensor ....       2.10
PLAT301_ALERT_3_C Main Residue  Disorder .........................      20.00 Perc.
PLAT342_ALERT_3_C Low Bond Precision on C-C bonds (x 1000) Ang ...         13
PLAT790_ALERT_4_C Centre of Gravity not Within Unit Cell: Resd.  #          1
              C2 H6 O S

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

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

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S1. Comment

In the course of preparing the complex between dicyanodurene and tetrafluorodiiodobenzene (Britton & Gleason, 2002), a similar complex, (I), of DMSO and tetrafluorodiiodobenzene was discovered. Its structure is reported here.

The labelling and the anisotropic displacement parameters are shown in Fig. 1. The bond lengths and angles in the diiodide are normal; within experimental error they are the same as in the dicyanodurene complex or in the high-temperature polymorph of tetrafluorodiiodobenzene itself (Chaplot et al., 1981).

The packing is shown in Fig. 2. There are zigzagI-C₆F₄– I···O···I—C₆F₄—I···O··· chains parallel to the b axis. The geometry of the interaction is consistent with the I···O interaction having a Lewis acid–base character [C—I···O = 173.0 (8) and 174.9 (8)°, I···O = 2.898 (9) and 2.803 (9) Å, and I···O—S = 131.0 (7) and 122.6 (7)°; the two values given in each case are for the major and minor components of the disorder, respectively]. The only other I···O interaction involving C₆F₄I₂, in p-tetrafluorodiiodobenzene/4,4'-dipyridyl-N,N'- dioxide (Messina et al., 2001), has an I···O distance of 2.754 (2) Å; this is the shortest intramolecular I···O distance yet reported. It is possible that the longer distance found in the DMSO complex is a consquence of the dibasic character of the O atom in DMSO compared with the monobasic character of the O atom in the dipyridyldioxide.

S2. Experimental

The diiodide was obtained from Aldrich Chemical Co. Inc. In an attempt to recrystallize it from DMSO, crystals of the title complex were obtained instead.

S3. Refinement

The DMSO complex is disordered. Two orientations, inverted with respect to one another, were refined with variable occupancies. The bond distances and angles were constrained to have normal values. The S1 orientation (see Fig. 1) had an occupancy of 0.64 (2). The anisotropic displacement ellipsoids are large. The four highest peaks in the final difference map are in the DMSO region rather than near the I atoms where the peaks might be expected. Together, these observations suggest that the disorder is not completely modeled, but no better model could be found. Presumably, the O-atom position is reasonably well defined by the I···O interactions, but the rest of the molecule is only loosely constrained.

Computing details

Data collection: CAD-4 Software (Enraf–Nonius, 1983); cell refinement: CAD-4 Software; data reduction: TEXSAN (Molecular Structure Corporation, 1985); program(s) used to solve structure: TEXSAN, MITHRIL (Gilmore, 1984) and DIRDIF (Beurskens, 1984).; program(s) used to refine structure: SHELXTL (Sheldrick, 1994); molecular graphics: TEXSAN and SHELXTL; software used to prepare material for publication: SHELXTL.

Figures

	Fig. 1. C6F4I2/DMSO. Displacement ellipsoids are shown at the 50% probability level. The unlabeled atoms are related to the labeled atoms by a center of symmetry in the C6F4I2 molecule and by a mirror plane in the DMSO molecule.
	Fig. 2. A view of the structure of (I) along the c axis. I···O interactions are shown as dotted lines. Only the more abundant of the disordered DMSO are shown.

2,3,5,6-Tetrafluoro-1,4-diiodobenzene–dimethyl sulfoxide (1/1)

Crystal data

C6F4I2·C2H6OS	F(000) = 880
Mr = 479.99	Dx = 2.411 Mg m^−3
Orthorhombic, Pnma	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2n	Cell parameters from 24 reflections
a = 11.819 (3) Å	θ = 16.5–19.7°
b = 18.418 (5) Å	µ = 4.94 mm^−1
c = 6.0750 (15) Å	T = 297 K
V = 1322.4 (6) Å^3	Needle, colorless
Z = 4	0.50 × 0.15 × 0.15 mm

Data collection

Enraf-Nonius CAD-4 Diffractometer	673 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.065
Graphite monochromator	θmax = 26.0°, θmin = 2.2°
ω–2θ scans	h = 0→14
Absorption correction: ψ scans North et al., 1968	k = 0→22
Tmin = 0.42, Tmax = 0.48	l = −7→7
2820 measured reflections	3 standard reflections every 70 min
1340 independent reflections	intensity decay: less than 1%

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.045	H-atom parameters constrained
wR(F^2) = 0.125	w = 1/[σ^2(Fo^2) + (0.051P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 0.92	(Δ/σ)max = 0.001
1340 reflections	Δρmax = 0.78 e Å^−3
95 parameters	Δρmin = −0.59 e Å^−3
73 restraints	Extinction correction: SHELXTL, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0029 (4)

Special details

Refinement. The DMSO molecules are disordered. Two different molecules were used to model the disorder with the bond distances and angles constrained to reasonable values.

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

	x	y	z	Uiso*/Ueq	Occ. (<1)
I1	0.36013 (6)	0.36685 (3)	0.19612 (12)	0.0897 (4)
F2	0.5900 (5)	0.4535 (3)	0.1187 (9)	0.0995 (17)
F6	0.3012 (5)	0.4464 (3)	0.6511 (9)	0.0987 (17)
C1	0.4419 (8)	0.4464 (4)	0.3754 (16)	0.074 (2)
C2	0.5439 (8)	0.4762 (5)	0.3094 (14)	0.071 (2)
C6	0.4006 (7)	0.4727 (5)	0.5706 (17)	0.074 (3)
S1	0.1839 (8)	0.2500	−0.2530 (18)	0.161 (6)	0.620 (17)
O1	0.2724 (13)	0.2500	−0.074 (3)	0.125 (6)	0.620 (17)
C11	0.0903 (8)	0.32247 (6)	−0.183 (3)	0.189 (14)	0.620 (17)
H11A	0.0326	0.3266	−0.2935	0.284*	0.620 (17)
H11B	0.1321	0.3671	−0.1750	0.284*	0.620 (17)
H11C	0.0559	0.3127	−0.0430	0.284*	0.620 (17)
S2	0.1322 (12)	0.2500	−0.079 (3)	0.140 (7)	0.380 (17)
O2	0.2561 (16)	0.2500	−0.019 (6)	0.125 (6)	0.380 (17)
C12	0.120 (2)	0.3147 (14)	−0.297 (4)	0.167 (18)	0.380 (17)
H12A	0.0416	0.3199	−0.3370	0.250*	0.380 (17)
H12B	0.1622	0.2983	−0.4221	0.250*	0.380 (17)
H12C	0.1488	0.3607	−0.2485	0.250*	0.380 (17)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
I1	0.0945 (5)	0.0786 (5)	0.0960 (6)	−0.0039 (3)	−0.0200 (4)	−0.0101 (3)
F2	0.088 (3)	0.123 (5)	0.087 (4)	0.001 (3)	0.012 (3)	−0.021 (4)
F6	0.083 (3)	0.127 (5)	0.086 (4)	−0.021 (3)	0.003 (3)	−0.004 (3)
C1	0.074 (6)	0.069 (5)	0.078 (7)	0.012 (5)	−0.015 (5)	−0.009 (5)
C2	0.067 (6)	0.081 (6)	0.067 (7)	0.008 (5)	0.004 (6)	−0.004 (5)
C6	0.066 (6)	0.074 (5)	0.081 (8)	−0.007 (5)	−0.006 (6)	−0.005 (5)
S1	0.120 (8)	0.164 (10)	0.198 (13)	0.000	−0.028 (8)	0.000
O1	0.139 (10)	0.094 (7)	0.143 (14)	0.000	−0.065 (10)	0.000
C11	0.21 (3)	0.22 (3)	0.14 (2)	0.09 (2)	−0.09 (2)	−0.10 (2)
S2	0.119 (13)	0.202 (16)	0.099 (13)	0.000	−0.010 (9)	0.000
O2	0.139 (10)	0.094 (7)	0.143 (14)	0.000	−0.065 (10)	0.000
C12	0.10 (2)	0.14 (3)	0.26 (4)	−0.05 (2)	0.03 (3)	−0.14 (3)

Geometric parameters (Å, º)

I1—C1	2.066 (9)	C11—H11A	0.9600
F2—C2	1.347 (10)	C11—H11B	0.9600
F6—C6	1.361 (10)	C11—H11C	0.9600
C1—C6	1.370 (12)	S2—O2	1.5088 (15)
C1—C2	1.384 (12)	S2—C12^ii	1.7850 (15)
C2—C6^i	1.360 (12)	S2—C12	1.7850 (15)
C6—C2^i	1.360 (12)	C12—H12A	0.9600
S1—O1	1.5089 (11)	C12—H12B	0.9600
S1—C11^ii	1.7851 (11)	C12—H12C	0.9600
S1—C11	1.7851 (11)
C6—C1—C2	114.9 (8)	H11A—C11—H11B	109.5
C6—C1—I1	122.7 (7)	S1—C11—H11C	109.5
C2—C1—I1	122.4 (8)	H11A—C11—H11C	109.5
F2—C2—C6^i	118.7 (8)	H11B—C11—H11C	109.5
F2—C2—C1	118.6 (9)	O2—S2—C12^ii	104.98 (16)
C6^i—C2—C1	122.7 (9)	O2—S2—C12	104.98 (16)
C2^i—C6—F6	118.0 (9)	C12^ii—S2—C12	84 (2)
C2^i—C6—C1	122.4 (9)	S2—C12—H12A	109.5
F6—C6—C1	119.5 (8)	S2—C12—H12B	109.5
O1—S1—C11^ii	104.97 (13)	H12A—C12—H12B	109.5
O1—S1—C11	104.97 (13)	S2—C12—H12C	109.5
C11^ii—S1—C11	96.80 (12)	H12A—C12—H12C	109.5
S1—C11—H11A	109.5	H12B—C12—H12C	109.5
S1—C11—H11B	109.5

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