Redetermination of 4,4′-di­bromo­bi­phenyl

The title compound, C₁₂H₈Br₂, previously reported by Kronebusch, Gleason & Britton [Cryst. Struct. Commun. (1976), 5, 839–842] has been rerefined against new intensity data. Geometric parameters agree quite well. However, the positions of the hydroxyl H atoms could be determined employing our new data. Furthermore, the results of the present structure determination are of significantly higher precision. There are two almost identical mol­ecules in the asymmetric unit, which show close intermolecular Br...Br contacts less than 3.48 Å.

Key indicators

• Single-crystal X-ray study
• T = 173 K
• Mean [sigma](C-C) = 0.008 Å
• R factor = 0.036
• wR factor = 0.077
• Data-to-parameter ratio = 15.1

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry

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S1. Comment

A perspective view of the title compound, (I), is shown in Fig. 1. The original structure was reported by Kronebusch et al. (1976) in space group P2₁/c. We have kept the atom numbering of these authors, but we have decided to describe the structure in P2₁/n, because the angle β decreases from 116.6 (2) to 97.32 (3)°. The geometric parameters of both determinations agree quite well (Table 1). However, the present work is of significantly improved precision and we were able to determine the position of the H atoms. There are two almost identical molecules in the asymmetric unit, which show rather close intermolecular Br···Br contacts: Br1···Br2ⁱ = 3.4316 (10) Å and Br1'···Br2'ⁱ = 3.4782 (10) Å [symmetry code: (i) x, 1 + y, z]. Furthermore, it is interesting to note that the structure of (I) is isostructural with 4,4'-dichlorobiphenyl (Brock et al., 1978), but not with 4,4'-difluorobiphenyl (Halstead et al., 1976).

S2. Experimental

Our aim was to synthesize a long-chain metallosiloxane containing Si–O–Si framework by adding CoCl₂, 4,4'dibromobiphenyl and tetrasodium bis(1,1,3,3,5,5,7,7-octaphenyltetrasiloxanediolate) in pyridine solution. From the product mixture, we isolated suitable single crystals. Unfortunately, we got the crystal structure of the starting material.

S3. Refinement

All H atoms could be located unequivocally by difference Fourier synthesis. They were refined with fixed individual displacement parameters [U_iso(H) = 1.2U_eq(C)], using a riding model with C—H = 0.99 Å.

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, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: XP in SHELXTL-Plus (Sheldrick, 1991).

Figures

Fig. 1. Perspective view of the title compound with the atom numbering. Displacement ellipsoids are shown at the 50% probability level.

4,4'-Dibromobiphenyl

Crystal data

C12H8Br2	F(000) = 1200
Mr = 312.00	Dx = 1.955 Mg m^−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 9816 reflections
a = 9.7007 (19) Å	θ = 3.4–25.2°
b = 14.114 (3) Å	µ = 7.60 mm^−1
c = 15.610 (3) Å	T = 173 K
β = 97.32 (3)°	Block, colourless
V = 2119.8 (7) Å^3	0.18 × 0.16 × 0.11 mm
Z = 8

Data collection

STOE IPDS-II two-circle diffractometer	3820 independent reflections
Radiation source: fine-focus sealed tube	2578 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.078
ω scans	θmax = 25.3°, θmin = 3.5°
Absorption correction: multi-scan (MULABS; Spek, 1990; Blessing, 1995)	h = −11→11
Tmin = 0.241, Tmax = 0.433	k = −16→16
17434 measured reflections	l = −18→18

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)] = 0.036	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.077	H-atom parameters constrained
S = 0.87	w = 1/[σ^2(Fo^2) + (0.0364P)^2] where P = (Fo^2 + 2Fc^2)/3
3820 reflections	(Δ/σ)max = 0.001
253 parameters	Δρmax = 0.59 e Å^−3
0 restraints	Δρmin = −0.86 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
Br1	0.91000 (6)	1.16862 (4)	0.39047 (4)	0.04275 (15)
Br2	0.84576 (5)	0.40320 (4)	0.34325 (4)	0.04341 (16)
C2	0.9083 (5)	1.0334 (4)	0.3860 (4)	0.0327 (11)
C3	0.9944 (5)	0.9871 (4)	0.3348 (3)	0.0330 (11)
H3	1.0559	1.0218	0.3040	0.040*
C4	0.9886 (5)	0.8900 (4)	0.3299 (3)	0.0305 (11)
H4	1.0457	0.8581	0.2940	0.037*
C5	0.9018 (4)	0.8369 (4)	0.3758 (3)	0.0278 (10)
C6	0.8185 (5)	0.8867 (4)	0.4286 (3)	0.0334 (11)
H6	0.7595	0.8524	0.4615	0.040*
C7	0.8215 (5)	0.9849 (4)	0.4331 (3)	0.0352 (12)
H7	0.7644	1.0179	0.4683	0.042*
C8	0.8927 (5)	0.7330 (4)	0.3690 (3)	0.0291 (11)
C9	0.8975 (5)	0.6879 (4)	0.2902 (3)	0.0314 (11)
H9	0.9097	0.7248	0.2409	0.038*
C10	0.8849 (5)	0.5898 (4)	0.2820 (3)	0.0345 (11)
H10	0.8880	0.5598	0.2278	0.041*
C11	0.8678 (5)	0.5372 (4)	0.3549 (4)	0.0338 (12)
C12	0.8630 (5)	0.5791 (4)	0.4340 (3)	0.0358 (12)
H12	0.8514	0.5419	0.4833	0.043*
C13	0.8754 (5)	0.6759 (4)	0.4404 (3)	0.0292 (10)
H13	0.8720	0.7052	0.4949	0.035*
Br1'	0.42091 (6)	0.91876 (4)	0.39950 (4)	0.04179 (16)
Br2'	0.32955 (6)	0.15405 (4)	0.35727 (4)	0.04153 (15)
C2'	0.4003 (5)	0.7840 (4)	0.3881 (3)	0.0323 (11)
C3'	0.5087 (5)	0.7325 (4)	0.3618 (4)	0.0352 (12)
H3'	0.5901	0.7630	0.3477	0.042*
C4'	0.4945 (5)	0.6349 (4)	0.3567 (3)	0.0316 (11)
H4'	0.5679	0.5981	0.3391	0.038*
C5'	0.3746 (5)	0.5894 (4)	0.3769 (3)	0.0305 (11)
C6'	0.2676 (5)	0.6453 (4)	0.4013 (3)	0.0319 (11)
H6'	0.1839	0.6158	0.4129	0.038*
C7'	0.2801 (5)	0.7421 (4)	0.4089 (3)	0.0342 (12)
H7'	0.2082	0.7792	0.4280	0.041*
C8'	0.3623 (5)	0.4842 (4)	0.3720 (3)	0.0294 (11)
C9'	0.4763 (5)	0.4263 (4)	0.4031 (3)	0.0293 (10)
H9'	0.5611	0.4552	0.4268	0.035*
C10'	0.4678 (5)	0.3299 (4)	0.4000 (3)	0.0330 (11)
H10'	0.5451	0.2916	0.4214	0.040*
C11'	0.3424 (5)	0.2891 (3)	0.3644 (3)	0.0296 (11)
C12'	0.2291 (5)	0.3432 (4)	0.3333 (3)	0.0332 (11)
H12'	0.1447	0.3141	0.3091	0.040*
C13'	0.2404 (5)	0.4400 (4)	0.3378 (3)	0.0320 (11)
H13'	0.1623	0.4778	0.3168	0.038*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Br1	0.0473 (3)	0.0311 (3)	0.0482 (4)	0.0014 (2)	−0.0001 (2)	−0.0031 (2)
Br2	0.0340 (3)	0.0314 (3)	0.0655 (4)	−0.0012 (2)	0.0088 (3)	−0.0015 (3)
C2	0.035 (3)	0.026 (3)	0.035 (3)	0.001 (2)	−0.002 (2)	0.002 (2)
C3	0.032 (3)	0.038 (3)	0.029 (3)	0.000 (2)	0.003 (2)	0.003 (2)
C4	0.031 (2)	0.037 (3)	0.024 (3)	0.003 (2)	0.007 (2)	0.003 (2)
C5	0.022 (2)	0.039 (3)	0.023 (2)	0.002 (2)	0.0060 (19)	0.001 (2)
C6	0.033 (3)	0.040 (3)	0.028 (3)	−0.002 (2)	0.009 (2)	0.000 (2)
C7	0.035 (3)	0.037 (3)	0.035 (3)	0.003 (2)	0.010 (2)	−0.012 (2)
C8	0.016 (2)	0.037 (3)	0.034 (3)	0.0020 (19)	0.0014 (19)	−0.002 (2)
C9	0.030 (2)	0.036 (3)	0.029 (3)	0.000 (2)	0.006 (2)	0.002 (2)
C10	0.031 (3)	0.039 (3)	0.034 (3)	0.001 (2)	0.005 (2)	−0.005 (2)
C11	0.023 (2)	0.029 (3)	0.049 (4)	0.002 (2)	0.004 (2)	0.003 (2)
C12	0.029 (2)	0.047 (3)	0.031 (3)	−0.002 (2)	0.007 (2)	0.006 (2)
C13	0.030 (2)	0.034 (3)	0.024 (3)	−0.001 (2)	0.0052 (19)	0.001 (2)
Br1'	0.0412 (3)	0.0340 (3)	0.0510 (4)	0.0023 (2)	0.0088 (3)	−0.0037 (2)
Br2'	0.0474 (3)	0.0342 (3)	0.0462 (3)	−0.0015 (2)	0.0184 (2)	0.0014 (2)
C2'	0.033 (3)	0.030 (3)	0.033 (3)	0.003 (2)	0.000 (2)	−0.005 (2)
C3'	0.024 (2)	0.044 (3)	0.038 (3)	−0.003 (2)	0.004 (2)	−0.004 (2)
C4'	0.023 (2)	0.036 (3)	0.037 (3)	0.0028 (19)	0.005 (2)	−0.009 (2)
C5'	0.029 (2)	0.041 (3)	0.022 (3)	−0.001 (2)	0.002 (2)	−0.004 (2)
C6'	0.026 (2)	0.036 (3)	0.034 (3)	0.005 (2)	0.004 (2)	0.001 (2)
C7'	0.028 (3)	0.046 (3)	0.029 (3)	0.007 (2)	0.008 (2)	0.001 (2)
C8'	0.031 (3)	0.034 (3)	0.024 (3)	0.005 (2)	0.007 (2)	0.000 (2)
C9'	0.024 (2)	0.037 (3)	0.026 (3)	0.002 (2)	−0.0006 (19)	−0.001 (2)
C10'	0.029 (2)	0.044 (3)	0.027 (3)	0.009 (2)	0.0062 (19)	0.003 (2)
C11'	0.033 (3)	0.029 (3)	0.029 (3)	−0.003 (2)	0.011 (2)	−0.002 (2)
C12'	0.026 (2)	0.043 (3)	0.031 (3)	−0.004 (2)	0.006 (2)	0.000 (2)
C13'	0.021 (2)	0.045 (3)	0.030 (3)	0.003 (2)	0.0043 (19)	0.002 (2)

Geometric parameters (Å, º)

Br1—C2	1.909 (5)	Br1'—C2'	1.918 (5)
Br2—C11	1.910 (5)	Br2'—C11'	1.912 (5)
C2—C7	1.370 (8)	C2'—C7'	1.383 (7)
C2—C3	1.390 (7)	C2'—C3'	1.382 (7)
C3—C4	1.373 (7)	C3'—C4'	1.385 (8)
C3—H3	0.9500	C3'—H3'	0.9500
C4—C5	1.392 (7)	C4'—C5'	1.399 (7)
C4—H4	0.9500	C4'—H4'	0.9500
C5—C6	1.413 (7)	C5'—C6'	1.395 (7)
C5—C8	1.472 (7)	C5'—C8'	1.491 (7)
C6—C7	1.388 (8)	C6'—C7'	1.375 (7)
C6—H6	0.9500	C6'—H6'	0.9500
C7—H7	0.9500	C7'—H7'	0.9500
C8—C9	1.391 (7)	C8'—C13'	1.382 (7)
C8—C13	1.401 (7)	C8'—C9'	1.411 (7)
C9—C10	1.393 (7)	C9'—C10'	1.364 (7)
C9—H9	0.9500	C9'—H9'	0.9500
C10—C11	1.386 (8)	C10'—C11'	1.395 (7)
C10—H10	0.9500	C10'—H10'	0.9500
C11—C12	1.376 (8)	C11'—C12'	1.376 (7)
C12—C13	1.374 (7)	C12'—C13'	1.372 (8)
C12—H12	0.9500	C12'—H12'	0.9500
C13—H13	0.9500	C13'—H13'	0.9500
C7—C2—C3	121.9 (5)	C7'—C2'—C3'	122.7 (5)
C7—C2—Br1	118.9 (4)	C7'—C2'—Br1'	118.9 (4)
C3—C2—Br1	119.2 (4)	C3'—C2'—Br1'	118.4 (4)
C2—C3—C4	118.6 (5)	C2'—C3'—C4'	117.8 (5)
C2—C3—H3	120.7	C2'—C3'—H3'	121.1
C4—C3—H3	120.7	C4'—C3'—H3'	121.1
C5—C4—C3	122.1 (5)	C5'—C4'—C3'	121.5 (5)
C5—C4—H4	118.9	C5'—C4'—H4'	119.2
C3—C4—H4	118.9	C3'—C4'—H4'	119.2
C4—C5—C6	117.4 (5)	C6'—C5'—C4'	118.1 (5)
C4—C5—C8	122.3 (4)	C6'—C5'—C8'	121.3 (4)
C6—C5—C8	120.3 (4)	C4'—C5'—C8'	120.6 (4)
C5—C6—C7	121.2 (5)	C5'—C6'—C7'	121.6 (5)
C5—C6—H6	119.4	C5'—C6'—H6'	119.2
C7—C6—H6	119.4	C7'—C6'—H6'	119.2
C2—C7—C6	118.8 (5)	C2'—C7'—C6'	118.2 (5)
C2—C7—H7	120.6	C2'—C7'—H7'	120.9
C6—C7—H7	120.6	C6'—C7'—H7'	120.9
C9—C8—C13	117.4 (5)	C13'—C8'—C9'	117.8 (5)
C9—C8—C5	120.7 (5)	C13'—C8'—C5'	121.9 (5)
C13—C8—C5	121.8 (5)	C9'—C8'—C5'	120.3 (5)
C8—C9—C10	121.6 (5)	C10'—C9'—C8'	121.6 (5)
C8—C9—H9	119.2	C10'—C9'—H9'	119.2
C10—C9—H9	119.2	C8'—C9'—H9'	119.2
C11—C10—C9	118.3 (5)	C11'—C10'—C9'	118.2 (5)
C11—C10—H10	120.8	C11'—C10'—H10'	120.9
C9—C10—H10	120.8	C9'—C10'—H10'	120.9
C12—C11—C10	121.9 (5)	C10'—C11'—C12'	121.9 (5)
C12—C11—Br2	119.7 (4)	C10'—C11'—Br2'	118.8 (4)
C10—C11—Br2	118.4 (4)	C12'—C11'—Br2'	119.3 (4)
C11—C12—C13	118.6 (5)	C11'—C12'—C13'	118.7 (5)
C11—C12—H12	120.7	C11'—C12'—H12'	120.7
C13—C12—H12	120.7	C13'—C12'—H12'	120.7
C8—C13—C12	122.1 (5)	C8'—C13'—C12'	121.8 (5)
C8—C13—H13	118.9	C8'—C13'—H13'	119.1
C12—C13—H13	118.9	C12'—C13'—H13'	119.1
C7—C2—C3—C4	1.9 (8)	C7'—C2'—C3'—C4'	−0.1 (8)
Br1—C2—C3—C4	−177.8 (4)	Br1'—C2'—C3'—C4'	177.8 (4)
C2—C3—C4—C5	−1.4 (8)	C2'—C3'—C4'—C5'	0.3 (8)
C3—C4—C5—C6	−0.1 (7)	C3'—C4'—C5'—C6'	1.0 (8)
C3—C4—C5—C8	178.5 (5)	C3'—C4'—C5'—C8'	−179.2 (5)
C4—C5—C6—C7	1.2 (7)	C4'—C5'—C6'—C7'	−2.6 (8)
C8—C5—C6—C7	−177.4 (5)	C8'—C5'—C6'—C7'	177.6 (5)
C3—C2—C7—C6	−0.9 (8)	C3'—C2'—C7'—C6'	−1.4 (8)
Br1—C2—C7—C6	178.8 (4)	Br1'—C2'—C7'—C6'	−179.3 (4)
C5—C6—C7—C2	−0.7 (8)	C5'—C6'—C7'—C2'	2.8 (8)
C4—C5—C8—C9	−38.1 (7)	C6'—C5'—C8'—C13'	41.5 (7)
C6—C5—C8—C9	140.4 (5)	C4'—C5'—C8'—C13'	−138.3 (5)
C4—C5—C8—C13	143.6 (5)	C6'—C5'—C8'—C9'	−138.2 (5)
C6—C5—C8—C13	−37.9 (7)	C4'—C5'—C8'—C9'	42.1 (7)
C13—C8—C9—C10	0.3 (7)	C13'—C8'—C9'—C10'	−0.1 (7)
C5—C8—C9—C10	−178.1 (4)	C5'—C8'—C9'—C10'	179.6 (5)
C8—C9—C10—C11	−0.3 (7)	C8'—C9'—C10'—C11'	0.3 (8)
C9—C10—C11—C12	0.0 (7)	C9'—C10'—C11'—C12'	−0.1 (8)
C9—C10—C11—Br2	178.4 (4)	C9'—C10'—C11'—Br2'	178.7 (4)
C10—C11—C12—C13	0.1 (7)	C10'—C11'—C12'—C13'	−0.3 (8)
Br2—C11—C12—C13	−178.3 (4)	Br2'—C11'—C12'—C13'	−179.2 (4)
C9—C8—C13—C12	−0.2 (7)	C9'—C8'—C13'—C12'	−0.3 (7)
C5—C8—C13—C12	178.2 (4)	C5'—C8'—C13'—C12'	180.0 (5)
C11—C12—C13—C8	0.0 (7)	C11'—C12'—C13'—C8'	0.5 (8)