2,2′-Dimethoxy­biphen­yl

Kosuke Nakaema; Akiko Okamoto; Satoshi Maruyama; Keiichi Noguchi; Noriyuki Yonezawa

doi:10.1107/S1600536808025178

. 2008 Aug 9;64(Pt 9):o1731. doi: 10.1107/S1600536808025178

2,2′-Dimethoxybiphenyl

Kosuke Nakaema ^a, Akiko Okamoto ^a, Satoshi Maruyama ^b, Keiichi Noguchi ^c, Noriyuki Yonezawa ^a,^*

PMCID: PMC2960700 PMID: 21201714

Abstract

The molecule of the title compound, C₁₄H₁₄O₂, lies on a crystallographic twofold axis perpendicular to the central C—C bond; there is one half-molecule in the asymmetric unit. The angle between the least-squares planes of the two aromatic rings is 66.94 (7)°. The methoxy group, with a twist angle of 10.69 (8)°, is slightly out of the plane of the benzene ring. In the crystal structure, C—H⋯π interactions are observed between adjacent molecules along the c-axis direction.

Related literature

For related literature, see: Hargreaves et al. (1961 ▶); Yonezawa et al. (1993 ▶, 2000 ▶, 2003 ▶); Iyoda et al. (1990 ▶).

Experimental

Crystal data

C₁₄H₁₄O₂
M _r = 214.25
Tetragonal,
a = 7.39307 (13) Å
c = 20.1623 (4) Å
V = 1102.02 (4) Å³
Z = 4
Cu Kα radiation
μ = 0.68 mm⁻¹
T = 193 K
0.40 × 0.20 × 0.10 mm

Data collection

Rigaku R-AXIS RAPID diffractometer
Absorption correction: numerical (NUMABS; Higashi, 1999 ▶) T _min = 0.813, T _max = 0.934
20356 measured reflections
651 independent reflections
640 reflections with I > 2σ(I)
R _int = 0.024

Refinement

R[F ² > 2σ(F ²)] = 0.024
wR(F ²) = 0.071
S = 1.14
651 reflections
75 parameters
H-atom parameters constrained
Δρ_max = 0.15 e Å⁻³
Δρ_min = −0.11 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 global, I. DOI: 10.1107/S1600536808025178/fl2209sup1.cif

e-64-o1731-sup1.cif^{(13.8KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808025178/fl2209Isup2.hkl

e-64-o1731-Isup2.hkl^{(31.9KB, 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
C3—H3⋯Cg1ⁱ	0.95	2.85	3.7266 (14)	154

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Symmetry code: (i) Inline graphic . Cg1 is the centroid of atoms C1–C6.

Acknowledgments

This work was partially supported by The Shorai Foundation for Science and Technology, Tokyo, Japan.

supplementary crystallographic information

Comment

Biphenyl is the simplest example of aromatic ring assemblies in which aromatic rings are connected by a single bond. The apparent single bond lies behind the characteristic diversity in the molecular structure and chemical properties of these assemblies. As with the formal single bonding of alternative polyenes, the single bond between the aromatic rings has the nature of double bonding. However, the steric hindrance of substituents, especially at the o-positions, collapses coplanarity lowering the stabilizing conjugative effects on the structure. The non-substituted biphenyl is planar in the solid state in spite of the o-protons' repulsion (Hargreaves et al., 1961) but it has a twisted conformation in solution. In the past decade and a half, the authors have demonstrated the excellent acyl-accepting ability of (I), an o,o'-disubstituted biphenyl, in consecutive dual electrophilic aromatic aroylation reactions, especially in condensation polymerization or monomer preparation for wholly aromatic polyketones (Yonezawa et al., 1993, 2000, 2003). The strong electron donating ability of the o-methoxy group should make (I) highly reactive against electrophiles not only for a first acylation but also for a second one, even though the introduced ketonic carbonyl group has a strong electron-withdrawing nature. The maintenance of high reactivity after the first acylation is thought to be brought about by the suitable conformation of the mono-acylated intermediate preventing the transmission of the electron-withdrawing effect of the acyl group to the other aromatic ring.

The molecule of (I) lies across a crystallographic 2-fold axis so that the asymmetric unit contains one-half molecule (Fig. 1). The 2-fold axis is perpendicular to the central C—C bond of (I). The angle between the least-squares planes of the two phenyl rings is 66.94 (7)°. The methoxy group is slightly out of the plane of the phenyl ring with the angle between the O1—C7 bond and least-squares plane of the phenyl ring at 10.69 (8)°. The molecular packing of (I) is mainly stabilized by van der Waals interactions. In addition, C—H···π interactions are observed between adjacent molecules along the c-direction (Fig. 2). The distance between H3 and Cg (the ring center of gravity) at (3/2 - x, y - 1/2, 1/4 - z) is 2.85 Å. The slightly short intermolecular C6···H7A at (y + 1/2, 1/2 - x, z - 1/4) contact of 2.86 Å is also found.

Experimental

To the solution of 2,2'-dihydroxybiphenyl (5.5 g, 26 mmol) in an aqueous NaOH solution (3.2 wt-%, 220 ml), dimethyl sulfate (16 g, 127 mmol) was added dropwise over a period of 10 min with ice-cooling and vigorous stirring. After stirring for 3 h, the resulting precipitate was collected by filtration and dissolved in chloroform (ca 100 ml). The solution was washed with aqueous 1 M NaOH solution (ca 100 ml) and dried over granular magnesium sulfate. The crude product obtained by evaporation of the above solution was recrystallized from acetone. Yield 72%. M.p. 154–154.5°C. Lit. 154–155°C(Iyoda et al., 1990). Colorless single crystals suitable for X-ray diffraction were obtained by simple standing of the hot acetone solution of the crude crystals at room temperature in an Erlenmeyer flask with a cork-stopper.