Bis(4-bromo­benzo­yl)(2,7-dimethoxy­naphthalene-1,8-di­yl)dimethanone

Shoji Watanabe; Kosuke Nakaema; Toyokazu Muto; Akiko Okamoto; Noriyuki Yonezawa

doi:10.1107/S1600536810001819

. 2010 Jan 20;66(Pt 2):o403. doi: 10.1107/S1600536810001819

Bis(4-bromobenzoyl)(2,7-dimethoxynaphthalene-1,8-diyl)dimethanone

Shoji Watanabe ^a, Kosuke Nakaema ^a, Toyokazu Muto ^a, Akiko Okamoto ^a, Noriyuki Yonezawa ^a,^*

PMCID: PMC2979875 PMID: 21579823

Abstract

In the title compound, C₂₆H₁₈Br₂O₄, the two 4-bromobenzoyl groups at the 1- and 8-positions of the naphthalene ring system are anti to each other. The dihedral angle between the two benzene rings is 50.92 (14)°. The dihedral angles between the two benzene rings and the naphthalene ring system are 70.18 (11) and 74.98 (12)°. A weak intermolecular C—H⋯O hydrogen bond exists between the methyl group and the carbonyl O atom.

Related literature

For general background to the regioselective formation of peri-aroylnaphthalene compounds, see: Okamoto & Yonezawa (2009 ▶). For related structures, see: Mitsui et al. (2009 ▶); Nakaema et al. (2007 ▶, 2008 ▶); Watanabe et al. (2010 ▶).

Experimental

Crystal data

C₂₆H₁₈Br₂O₄
M _r = 554.22
Monoclinic,
a = 7.8748 (5) Å
b = 25.7908 (16) Å
c = 11.5618 (7) Å
β = 100.982 (4)°
V = 2305.2 (2) Å³
Z = 4
Cu Kα radiation
μ = 4.71 mm⁻¹
T = 296 K
0.60 × 0.30 × 0.20 mm

Data collection

Rigaku R-AXIS RAPID diffractometer
Absorption correction: numerical (NUMABS; Higashi, 1999 ▶) T _min = 0.164, T _max = 0.452
42468 measured reflections
4220 independent reflections
3825 reflections with I > 2σ(I)
R _int = 0.064

Refinement

R[F ² > 2σ(F ²)] = 0.038
wR(F ²) = 0.103
S = 1.05
4220 reflections
292 parameters
H-atom parameters constrained
Δρ_max = 0.73 e Å⁻³
Δρ_min = −0.66 e Å⁻³

Data collection: PROCESS-AUTO (Rigaku, 1998 ▶); cell refinement: PROCESS-AUTO; data reduction: CrystalStructure (Rigaku/MSC, 2004 ▶); program(s) used to solve structure: SIR2004 (Burla et al., 2005 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEPIII (Burnett & Johnson, 1996 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536810001819/is2516sup1.cif

e-66-0o403-sup1.cif^{(22.6KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810001819/is2516Isup2.hkl

e-66-0o403-Isup2.hkl^{(202.6KB, hkl)}

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

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C25—H25B⋯O1ⁱ	0.96	2.42	3.313 (4)	155

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Symmetry code: (i) Inline graphic .

Acknowledgments

The authors would express their gratitude to Professor Keiichi Noguchi for his technical advice. This work was partially supported by the Iketani Science and Technology Foundation, Tokyo, Japan.

supplementary crystallographic information

Comment

In the course of our study on selective electrophilic aromatic aroylation of 2,7-dimethoxynaphthalene, peri-aroylnaphthalene compounds have proved to be formed regioselectively with the aid of suitable acidic mediator (Okamoto & Yonezawa, 2009). The aroyl groups at 1,8-positions of the naphthalene rings in these compounds are oriented in opposite fashion and are found to be non-coplanar resulting in partial disruption in π-conjugation systems. Recently, we have reported the X-ray crystal structures of 1,8-bis(4-chlorobenzoyl)-2,7-dimethoxynaphthalene (Nakaema et al., 2007), 1,8-dibenzoyl-2,7-dimethoxynaphthalene (Nakaema et al., 2008) and (2,7-dimethoxynaphthalene-1,8-diyl)-bis(4-fluorobenzoyl)dimethanone (Watanabe et al., 2010). As a part of the course of our continuous study on the molecular structures of this kind of homologous molecules, the X-ray crystal structure of title compound, peri-aroylnaphthalene bearing bromo groups, is discussed in this report.

The molecular structure of the title molecule is displayed in Fig. 1. The two 4-bromobenzoyl groups are situated in anti orientation. Furthermore, these 4-bromobenzoyl groups are twisted away from the attached naphthalene ring. The interplanar angle between the best planes of two benzene rings is 50.92 (14)°. On the other hand, the two interplanar angles between the best planes of the peri-bromophenyl rings and the naphthalene ring are 70.18 (11) and 74.98 (12)°. The torsion angles between the carbonyl groups and the naphthalene ring are relatively large [C10—C1—C11—O3 = -53.3 (3)° and C10—C9—C18—O1 = -47.3 (3)°] and those between 4-bromophenyl groups and carbonyl groups are rather small [O3—C11—C12—C17 = -16.8 (4)° and O1—C18—C19—C20 = -20.0 (4)°]. The crystal packing is stabilized by weak C—H···O hydrogen bonds (Table 1).

Experimental

The title compound was prepared by electrophilic aromatic diaroylation reaction of 2,7-dimethoxynaphthalene with 4-bromobenzoic acid. Colorless single crystals suitable for X-ray diffraction were obtained by recrystallization from ethanol.

Spectroscopic Data: ¹H NMR (300 MHz, CDCl₃): δ 3.69 (6H, s), 7.19 (2H, d, J = 9.0 Hz), 7.47 (4H, d, J = 8.4 Hz), 7.54 (4H, d, J = 8.4 Hz), 7.95 (2H, d, J = 9.0 Hz); ¹³C NMR (75.0 MHz, CDCl₃): δ 56.3, 111.1, 120.6, 125.5, 127.9, 123.0, 130.6, 131.4, 132.5, 137.5, 156.5, 196.2; IR (KBr cm^-1): 1660, 1269; m.p. = 250 °C.