2,2'-Diiodo-azobenzene.

The mol-ecular structure of the title compound, C(12)H(8)I(2)N(2) [systematic name: (E)-bis-(2-iodo-phen-yl)diazene], exhibits an essentially planar trans geometry [maximum deviation = 0.022 (4) Å] with the iodine atoms ortho to the azo bridge. In the crystal, offset π-stacking leads to the formation of columns along the a axis [closest C⋯C distance = 3.383 (4) Å].

Related literature

For analogous 2,2′-dichloro­azobenzenes, see: Komeyama et al. (1973 ▶); Crispini et al. (1998 ▶). For the structure of a related o-halogenated azobenzene, see: Wragg et al. (2011 ▶).

Experimental

Crystal data

C12H8I2N2

M = 433.88

Monoclinic,

a = 4.6306 (3) Å

b = 18.1105 (12) Å

c = 15.3748 (10) Å

β = 98.532 (1)°

V = 1275.10 (14) Å3

Z = 4

Mo Kα radiation

μ = 4.91 mm−1

T = 296 K

0.63 × 0.09 × 0.04 mm

Data collection

Bruker SMART CCD area-detector diffractometer

Absorption correction: analytical (SADABS; Sheldrick, 1996 ▶) T min = 0.322, T max = 0.873

16726 measured reflections

3186 independent reflections

2536 reflections with I > 2σ(I)

R int = 0.027

Refinement

R[F 2 > 2σ(F 2)] = 0.027

wR(F 2) = 0.059

S = 1.03

3186 reflections

145 parameters

H-atom parameters constrained

Δρmax = 0.56 e Å−3

Δρmin = −0.56 e Å−3

Data collection: SMART (Bruker, 2000 ▶); cell refinement: SMART (Bruker, 2000 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: Mercury (Macrae et al., 2006 ▶); software used to prepare material for publication: SHELXTL.

Click here for additional data file.

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536812040718/tk5154sup1.cif

Click here for additional data file.

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812040718/tk5154Isup2.hkl

Click here for additional data file.

Supplementary material file. DOI: 10.1107/S1600536812040718/tk5154Isup3.cml

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

C12H8I2N2	F(000) = 800
Mr = 433.88	Dx = 2.261 Mg m−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 4767 reflections
a = 4.6306 (3) Å	θ = 2.6–24.6°
b = 18.1105 (12) Å	µ = 4.91 mm−1
c = 15.3748 (10) Å	T = 296 K
β = 98.532 (1)°	Rod, orange
V = 1275.10 (14) Å3	0.63 × 0.09 × 0.04 mm
Z = 4

Bruker SMART CCD area-detector diffractometer	3186 independent reflections
Radiation source: fine-focus sealed tube	2536 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.027
φ and ω scans	θmax = 28.4°, θmin = 2.3°
Absorption correction: analytical (SADABS; Sheldrick, 1996)	h = −4→6
Tmin = 0.322, Tmax = 0.873	k = −24→22
16726 measured reflections	l = −20→18

Refinement on F2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.027	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.059	H-atom parameters constrained
S = 1.03	w = 1/[σ2(Fo2) + (0.0243P)2 + 0.9205P] where P = (Fo2 + 2Fc2)/3
3186 reflections	(Δ/σ)max = 0.001
145 parameters	Δρmax = 0.56 e Å−3
0 restraints	Δρmin = −0.56 e Å−3

Experimental. Azobenzene (0.184 g, 1.01 mmol) and mercury trifluoroacetate (0.43 g, 1.01 mmol) were combined with freshly distilled trifluoroacetic acid (0.13 mL) under a nitrogen atmosphere. The mixture was heated with stirring during 4 h at 68°C, after which a concentrated solution of sodium chloride (0.345 g, 5.90 mmol) and sodium acetate (2.085 g, 14.7 mmol) was added and the entire sample was placed in an ultrasonic bath for 20 min. After decanting the solvent, a mixture of iodine (0.279 g, 1.10 mmol) in methanol was added. With time, crystals of 2,2'-diiodoazobenzene grew from the solution and were collected by filtration. Yield = 0.047 g, 10%.

Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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 > 2σ(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.

	x	y	z	Uiso*/Ueq
C1	1.0033 (6)	0.62044 (15)	0.74337 (19)	0.0362 (6)
C2	1.1608 (6)	0.67355 (16)	0.7950 (2)	0.0391 (6)
C3	1.3471 (7)	0.72094 (17)	0.7587 (2)	0.0469 (7)
C4	1.3732 (7)	0.71515 (18)	0.6711 (2)	0.0511 (8)
C5	1.2147 (7)	0.66291 (18)	0.6191 (2)	0.0447 (7)
C6	1.0330 (7)	0.61521 (17)	0.6548 (2)	0.0440 (7)
I1	1.12360 (6)	0.685129 (15)	0.927841 (16)	0.06511 (10)
H1	1.4537	0.7564	0.7936	0.056*
H2	1.4983	0.7466	0.6468	0.061*
H3	1.2306	0.6599	0.5596	0.054*
H4	0.9297	0.5794	0.6196	0.053*
N1	0.8151 (5)	0.57362 (13)	0.78379 (16)	0.0409 (6)
N2	0.6804 (5)	0.52810 (14)	0.73326 (16)	0.0400 (5)
C7	0.4922 (6)	0.48055 (16)	0.77216 (18)	0.0366 (6)
C8	0.3371 (6)	0.42818 (16)	0.71848 (19)	0.0380 (6)
C9	0.1496 (6)	0.37976 (17)	0.7525 (2)	0.0451 (7)
C10	0.1187 (7)	0.38397 (18)	0.8396 (2)	0.0511 (8)
C11	0.2731 (7)	0.43536 (19)	0.8935 (2)	0.0494 (8)
C12	0.4562 (7)	0.48416 (18)	0.8602 (2)	0.0480 (8)
I2	0.37973 (5)	0.421268 (15)	0.585578 (15)	0.06002 (9)
H5	0.0457	0.3447	0.7163	0.054*
H6	−0.0076	0.3518	0.8624	0.061*
H7	0.2537	0.4371	0.9528	0.059*
H8	0.5561	0.5196	0.8967	0.058*

	U11	U22	U33	U12	U13	U23
C1	0.0328 (14)	0.0323 (15)	0.0429 (16)	0.0017 (12)	0.0041 (12)	0.0035 (12)
C2	0.0373 (15)	0.0366 (16)	0.0435 (16)	0.0024 (12)	0.0062 (12)	−0.0016 (12)
C3	0.0422 (17)	0.0358 (17)	0.063 (2)	−0.0028 (13)	0.0096 (15)	0.0017 (14)
C4	0.0454 (18)	0.0444 (19)	0.067 (2)	0.0018 (15)	0.0191 (16)	0.0139 (16)
C5	0.0493 (18)	0.0481 (18)	0.0387 (16)	0.0036 (14)	0.0138 (14)	0.0088 (13)
C6	0.0478 (17)	0.0414 (18)	0.0429 (17)	−0.0018 (14)	0.0063 (14)	−0.0012 (13)
I1	0.07890 (19)	0.07058 (18)	0.04761 (14)	−0.02011 (13)	0.01516 (12)	−0.01476 (11)
N1	0.0414 (13)	0.0395 (14)	0.0417 (14)	−0.0054 (11)	0.0055 (11)	0.0003 (11)
N2	0.0386 (13)	0.0388 (14)	0.0420 (13)	−0.0048 (11)	0.0040 (11)	0.0009 (11)
C7	0.0339 (14)	0.0373 (16)	0.0384 (15)	0.0009 (12)	0.0045 (12)	0.0029 (12)
C8	0.0377 (15)	0.0369 (16)	0.0393 (15)	0.0032 (12)	0.0051 (12)	0.0028 (12)
C9	0.0412 (16)	0.0395 (17)	0.0541 (19)	−0.0053 (13)	0.0050 (14)	−0.0001 (14)
C10	0.0509 (19)	0.049 (2)	0.056 (2)	−0.0044 (15)	0.0161 (16)	0.0109 (16)
C11	0.059 (2)	0.055 (2)	0.0338 (15)	−0.0093 (16)	0.0077 (14)	0.0050 (14)
C12	0.0529 (19)	0.0504 (19)	0.0393 (16)	−0.0092 (15)	0.0030 (14)	−0.0020 (14)
I2	0.07077 (17)	0.06949 (17)	0.04103 (13)	−0.01261 (12)	0.01232 (11)	−0.01094 (10)

C1—C2	1.384 (4)	N2—C7	1.419 (3)
C2—C3	1.391 (4)	C7—C8	1.386 (4)
C3—C4	1.374 (5)	C8—C9	1.390 (4)
C4—C5	1.378 (5)	C9—C10	1.370 (4)
C5—C6	1.375 (4)	C10—C11	1.374 (5)
C6—C1	1.393 (4)	C11—C12	1.374 (4)
C2—I1	2.085 (3)	C12—C7	1.390 (4)
C3—H1	0.9300	C8—I2	2.086 (3)
C4—H2	0.9300	C9—H5	0.9300
C5—H3	0.9300	C10—H6	0.9300
C6—H4	0.9300	C11—H7	0.9300
C1—N1	1.423 (3)	C12—H8	0.9300
N1—N2	1.236 (3)
C1—C2—C3	120.3 (3)	N1—N2—C7	115.1 (2)
C2—C3—C4	119.7 (3)	C7—C8—C9	120.3 (3)
C3—C4—C5	120.3 (3)	C8—C9—C10	119.6 (3)
C4—C5—C6	120.3 (3)	C9—C10—C11	120.4 (3)
C5—C6—C1	120.1 (3)	C10—C11—C12	120.4 (3)
C6—C1—C2	119.2 (3)	C11—C12—C7	120.1 (3)
C1—C2—I1	121.2 (2)	C12—C7—N2	123.5 (3)
C3—C2—I1	118.5 (2)	C8—C7—C12	119.1 (3)
C2—C3—H1	120.1	C8—C7—N2	117.4 (2)
C4—C3—H1	120.1	C7—C8—I2	120.6 (2)
C3—C4—H2	119.9	C9—C8—I2	119.1 (2)
C5—C4—H2	119.9	C8—C9—H5	120.2
C4—C5—H3	119.8	C10—C9—H5	120.2
C6—C5—H3	119.8	C9—C10—H6	119.8
C5—C6—H4	119.9	C11—C10—H6	119.8
C1—C6—H4	119.9	C10—C11—H7	119.8
C6—C1—N1	122.8 (3)	C12—C11—H7	119.8
C2—C1—N1	117.9 (3)	C11—C12—H8	119.9
C1—N1—N2	114.0 (2)	C7—C12—H8	119.9