3,9-Dibromo-5,7-dihydro­dibenzo[c,e]oxepine

Abstract

The title compound, C₁₄H₁₀Br₂O, is a biphenyl derivative containing a –CH₂—O—CH₂– bridge in the 2,2′-position. The compound displays a twisted conformation with the two benzene rings making a dihedral angle of 45.02 (5)°, while the central seven-membered ring is in a boat conformation. The mol­ecule lies on a crystallographic twofold axis of symmetry passing through the O atom and bis­ecting the 1,1′ C—C bond.

Related literature

For a previous synthesis of related biphenyl mol­ecules, see: Mislow & Glass (1961 ▶).

Experimental

Crystal data

• C₁₄H₁₀Br₂O

• M _r = 354.04

• Orthorhombic,

• a = 16.5965 (3) Å

• b = 10.2476 (6) Å

• c = 7.2626 (14) Å

• V = 1235.2 (2) ų

• Z = 4

• Mo Kα radiation

• μ = 6.54 mm⁻¹

• T = 291 (2) K

• 0.14 × 0.14 × 0.12 mm

Data collection

• Rigaku R-AXIS RAPID diffractometer

• Absorption correction: multi-scan (ABSCOR; Higashi, 1995 ▶) T _min = 0.457, T _max = 0.498 (expected range = 0.419–0.456)

• 2468 measured reflections

• 1371 independent reflections

• 896 reflections with I > 2σ(I)

• R _int = 0.014

Refinement

• R[F ² > 2σ(F ²)] = 0.024

• wR(F ²) = 0.042

• S = 1.05

• 1371 reflections

• 78 parameters

• H-atom parameters constrained

• Δρ_max = 0.28 e Å⁻³

• Δρ_min = −0.46 e Å⁻³

Data collection: RAPID-AUTO (Rigaku, 1998 ▶); cell refinement: RAPID-AUTO; data reduction: CrystalStructure (Rigaku/MSC, 2002 ▶); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: PLATON (Spek, 2003 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

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

supplementary crystallographic information

Comment

The dibenzo[c,e]oxepine derivatives were studied due to their optical activity as discussed in a previous article (Mislow & Glass, 1961). Introducing functional groups such as Br on the benzene ring of the dibenzo[c,e]oxepine can expand the range of their applications, such as photoluminescence, electro-luminescence devices and nonlinear optics. Herein we present the crystal structure of the title compound. In orthorhombic (space group Pbcn) crystals of 3,9-dibromo-5,7-dihydro-dibenzo[c,e]oxepine, there are four molecules in the unit cell. The molecule lies on a crystallographic 2-fold axis of symmetry passing through the O and bisecting the C4-C4a bond. The compound exhibits twisted conformation between two phenyl rings with a dihedral angle of 45.02 (5)°, while central 7-member ring is in a boat conformation.

Experimental

The four-step reaction to prepare 3,9-dibromo-5,7 -dihydro dibenzo [c,e] oxepin is described as follows: (1) 2,7-Dibromo-phenanthrenequinone was obtained by directly brominating phenanthrenequinone in presence N-bromosuccinamide (NBS) in H₂SO₄. (2) This was followed by oxidation of 2,7-dibromophenanthrenequinone in the presence of pure oxygen and Cu(I)Cl to give 4,4-dibromodiphenic acid. (3). The reduction of 4,4-dibromodiphenic acid using NaBH₄ gave 4,4'-dibromo-2,2'-bis-(hydroxymethyl)-biphenyl. (4) The final production was obtained by ring closure of 4,4'-dibromo-2,2'-bis-(hydroxymethyl)-biphenyl in the presence of HBr acid. Single-crystals of X-ray diffraction quality were grown by slow evaporation of a ethanol solution.

Refinement

C-bound H atoms were geometrically positioned with C—H = 0.97 Å, U_iso(H) = 1.5U_eq(C) for methyl and C—H = 0.93 Å, U_iso(H) = 1.2U_eq(C) for carbon atoms.

Figures

Fig. 1.

The structure of the title compound, with the atom-labelling Displacement ellipsoids are drawn at the 30% probability level of arbitrary radii.

Fig. 2.

The synthesis route for the preparation of 3,9-dibromo-5,7-dihydro-dibenzo[c,e]oxepine.

Crystal data

C14H10Br2O	F000 = 688
Mr = 354.04	Dx = 1.904 Mg m−3
Orthorhombic, Pbcn	Mo Kα radiation λ = 0.71073 Å
Hall symbol: -P 2n 2ab	Cell parameters from 10356 reflections
a = 16.5965 (3) Å	θ = 2.5–54.9º
b = 10.2476 (6) Å	µ = 6.54 mm−1
c = 7.2626 (14) Å	T = 291 (2) K
V = 1235.2 (2) Å3	Block, colorless
Z = 4	0.14 × 0.14 × 0.12 mm

Data collection

Rigaku R-AXIS RAPID diffractometer	1371 independent reflections
Radiation source: fine-focus sealed tube	896 reflections with I > 2σ(I)
Monochromator: graphite	Rint = 0.014
T = 291(2) K	θmax = 27.5º
ω scans	θmin = 2.3º
Absorption correction: multi-scan(ABSCOR; Higashi, 1995)	h = −21→21
Tmin = 0.457, Tmax = 0.498	k = −13→12
2468 measured reflections	l = −9→9

Refinement

Refinement on F2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.024	H-atom parameters constrained
wR(F2) = 0.042	w = 1/[σ2(Fo2) + (0.0103P)2] where P = (Fo2 + 2Fc2)/3
S = 1.05	(Δ/σ)max < 0.001
1371 reflections	Δρmax = 0.28 e Å−3
78 parameters	Δρmin = −0.46 e Å−3
Primary atom site location: structure-invariant direct methods	Extinction correction: none

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	0.677363 (15)	0.36711 (3)	0.14224 (4)	0.04966 (11)
O1	1.0000	0.0746 (2)	0.2500	0.0401 (7)
C1	0.79077 (14)	0.3698 (3)	0.1813 (3)	0.0333 (6)
C6	0.82561 (17)	0.4814 (3)	0.2538 (3)	0.0392 (7)
H6A	0.7943	0.5534	0.2846	0.047*
C3	0.91882 (13)	0.2642 (2)	0.1600 (3)	0.0251 (5)
C7	0.96934 (14)	0.1504 (2)	0.1017 (3)	0.0342 (6)
H7A	0.9373	0.0944	0.0228	0.041*
H7B	1.0143	0.1825	0.0293	0.041*
C4	0.95561 (13)	0.3761 (2)	0.2353 (3)	0.0273 (5)
C2	0.83600 (13)	0.2626 (2)	0.1339 (3)	0.0295 (6)
H2A	0.8112	0.1891	0.0845	0.035*
C5	0.90852 (16)	0.4830 (3)	0.2793 (3)	0.0361 (7)
H5A	0.9329	0.5574	0.3270	0.043*

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
Br1	0.03162 (14)	0.0648 (2)	0.05259 (17)	0.01473 (19)	−0.00240 (17)	0.0052 (2)
O1	0.0350 (15)	0.0224 (14)	0.0629 (18)	0.000	−0.0084 (15)	0.000
C1	0.0301 (13)	0.0443 (16)	0.0257 (13)	0.0091 (16)	0.0001 (11)	0.0004 (15)
C6	0.0487 (17)	0.0390 (16)	0.0299 (13)	0.0231 (19)	−0.0067 (15)	−0.0083 (12)
C3	0.0245 (13)	0.0250 (13)	0.0260 (12)	0.0011 (12)	0.0036 (13)	0.0030 (12)
C7	0.0270 (13)	0.0304 (15)	0.0452 (16)	−0.0031 (13)	0.0024 (12)	−0.0083 (12)
C4	0.0331 (13)	0.0259 (13)	0.0230 (11)	0.0045 (14)	−0.0011 (12)	0.0022 (12)
C2	0.0321 (15)	0.0282 (13)	0.0283 (12)	0.0001 (12)	0.0023 (15)	−0.0005 (12)
C5	0.0489 (18)	0.0275 (15)	0.0321 (13)	0.0069 (16)	−0.0108 (14)	−0.0061 (12)

Geometric parameters (Å, °)

Br1—C1	1.904 (2)	C3—C4	1.410 (3)
O1—C7i	1.422 (3)	C3—C7	1.497 (3)
O1—C7	1.422 (3)	C7—H7A	0.9700
C1—C2	1.375 (3)	C7—H7B	0.9700
C1—C6	1.386 (3)	C4—C5	1.383 (3)
C6—C5	1.389 (3)	C4—C4i	1.489 (4)
C6—H6A	0.9300	C2—H2A	0.9300
C3—C2	1.388 (3)	C5—H5A	0.9300
C7i—O1—C7	113.8 (2)	O1—C7—H7B	108.7
C2—C1—C6	121.8 (2)	C3—C7—H7B	108.7
C2—C1—Br1	119.40 (19)	H7A—C7—H7B	107.6
C6—C1—Br1	118.8 (2)	C5—C4—C3	119.3 (2)
C1—C6—C5	118.3 (2)	C5—C4—C4i	121.75 (17)
C1—C6—H6A	120.9	C3—C4—C4i	118.96 (16)
C5—C6—H6A	120.9	C1—C2—C3	119.8 (2)
C2—C3—C4	119.5 (2)	C1—C2—H2A	120.1
C2—C3—C7	120.5 (2)	C3—C2—H2A	120.1
C4—C3—C7	120.0 (2)	C4—C5—C6	121.4 (3)
O1—C7—C3	114.29 (19)	C4—C5—H5A	119.3
O1—C7—H7A	108.7	C6—C5—H5A	119.3
C3—C7—H7A	108.7

Symmetry codes: (i) −x+2, y, −z+1/2.