1-Methyl-3,5-bis­(3-methyl­phen­yl)benzene

Dong-Guo Xia; Ke-Wei Lei; Jie Li; Zheng-Yu Su

doi:10.1107/S1600536810024980

. 2010 Jul 3;66(Pt 8):o1915. doi: 10.1107/S1600536810024980

1-Methyl-3,5-bis(3-methylphenyl)benzene

Dong-Guo Xia ^a, Ke-Wei Lei ^a,^*, Jie Li ^a, Zheng-Yu Su ^a

PMCID: PMC3007405 PMID: 21588247

Abstract

In the title compound, C₂₁H₂₀, the dihedral angles formed by the central benzene ring with the outer benzene rings are 21.43 (6) and 31.70 (4)°. The crystal packing is stabilized by a weak π–π stacking interaction, with a centroid–centroid distance of 3.843 (3) Å.

Related literature

For conformational studies on terphenyls, see: Amorim da Costa et al. (1997 ▶); Stanciu et al. (2006 ▶).

Experimental

Crystal data

C₂₁H₂₀
M _r = 272.37
Orthorhombic,
a = 7.6406 (7) Å
b = 12.0326 (11) Å
c = 32.797 (3) Å
V = 3015.3 (5) Å³
Z = 8
Mo Kα radiation
μ = 0.07 mm⁻¹
T = 296 K
0.43 × 0.26 × 0.22 mm

Data collection

Bruker SMART APEXII diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 2000 ▶) T _min = 0.979, T _max = 0.985
20126 measured reflections
2644 independent reflections
2278 reflections with I > 2σ(I)
R _int = 0.036

Refinement

R[F ² > 2σ(F ²)] = 0.041
wR(F ²) = 0.112
S = 1.05
2644 reflections
193 parameters
H-atom parameters constrained
Δρ_max = 0.27 e Å⁻³
Δρ_min = −0.28 e Å⁻³

Data collection: APEX2 (Bruker, 2007 ▶); cell refinement: SAINT (Bruker, 2007 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXTL.

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536810024980/fj2321sup1.cif

e-66-o1915-sup1.cif^{(17.7KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810024980/fj2321Isup2.hkl

e-66-o1915-Isup2.hkl^{(129.9KB, hkl)}

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

Acknowledgments

This project was supported by the Talent Fund of Ningbo University (grant No. 2008087) and sponsored by the K. C. Wong Magna Fund in Ningbo University.

supplementary crystallographic information

Comment

Sterically crowding ligands have been used with remarkable success in inorganic and organometallic chemistry over the past three decades. They have allowed the first syntheses of molecules featuring previously unknown bonding types, geometries, electron configurations or oxidation states.Recent work has also described the use of m-terphenyls that allowed the synthesis of several new compound classes that were not accessible by using other bulky ligands(Corneliu Stanciu et al., 2006). The use of the m-terphenyl substituent has facilitated the synthesis of numerous unusual molecules containing main group elements;because these molecules are formed by three phenyl rings connected by two C—C bonds, characteristic conformational changes occur with the rotations around the C—C bonds (Amorim da Costa et al., 1997). Herein we report the synthesis and crystal structure of a new terphenyl compound.

The molecular structure of the title compound is illustrated in Fig. 1. Bond lengths and bond angles are within normal ranges.The dihedral angle formed by the peripheral C8—C13 and C15—C20 benzene rings with the central C2—C7 benzene ring are 21.43 (6) and 31.70 (4)° respectively. The mean centroid-to-centroid distance of 3.843 (3)Å between the planes of adjacent C15—C20 benzene rings in the crystal packing, suggests that the molecules are engaged in offset face-to-face π-π stacking interactions(Fig. 2).

Experimental

1,3-dibromo-5-methylbenzene(88.1 mmol,22.02 g), 3-methylphenylboronic acid (211.6 mmol, 28.77 g)and triphenylphosphine (17.62 mmol, 4.62 g) were dissolved in 1,2-dimethoxyethoxyethane (120 ml).240 ml of a 2M K₂CO₃ (480 mmol)aqueous solution were added and the mixture was purged with nitrogen. Palladium acetate (0.988 g;0.025eq.)was added and the mixture was refluxed for 18 h.The two phases were then separated and the aqueous phase was extracted with ethyl acetate(3 X 250 ml).The combined organic phases were washed with water (250 ml) and were dried over MgSO₄.After evaporation of the solvent,the oily residue was purified by bulb-to-bulb distillation to afford the crude title compound. Recrystallization from ethyl acetate gave colourless crystal after 3 days.Yield:83.7%.Calcd.for C₂₁H₂₀:C,92.65; H,7.35;Found:C,91.78;H,7.08%.