1-(4,4′′-Difluoro-5′-meth­oxy-1,1′:3′,1′′-terphenyl-4′-yl)ethanone

Hoong-Kun Fun; Madhukar Hemamalini; S Samshuddin; B Narayana; B K Sarojini

doi:10.1107/S1600536811053037

. 2011 Dec 17;68(Pt 1):o163. doi: 10.1107/S1600536811053037

1-(4,4′′-Difluoro-5′-methoxy-1,1′:3′,1′′-terphenyl-4′-yl)ethanone

Hoong-Kun Fun ^a,^*,^‡, Madhukar Hemamalini ^a, S Samshuddin ^b, B Narayana ^b, B K Sarojini ^c

PMCID: PMC3254504 PMID: 22259448

Abstract

In the title compound, C₂₁H₁₆F₂O₂, the central benzene ring is inclined at dihedral angles of 30.91 (8) and 46.88 (7)° to the two terminal fluoro-substituted rings. The dihedral angle between the two terminal fluoro-subsituted rings is 68.34 (8)°. An intramolecular C—H⋯O hydrogen bond generates an S(6) ring motif. The crystal structure is stabilized by weak C—H⋯π interactions.

Related literature

For a related structure and background to terphenyls, see: Fun, Chia et al. (2011 ▶); Samshuddin et al. (2011 ▶). For chalcone derivatives of the title compound, see: Fun, Hemamalini et al. (2011 ▶); Betz et al. (2011a ▶,b ▶). For the synthetic procedure, see: Kotnis (1990 ▶). For hydrogen-bond motifs, see: Bernstein et al. (1995 ▶).

Experimental

Crystal data

C₂₁H₁₆F₂O₂
M _r = 338.34
Monoclinic,
a = 6.0816 (7) Å
b = 25.997 (3) Å
c = 10.9061 (12) Å
β = 100.866 (2)°
V = 1693.4 (3) Å³
Z = 4
Mo Kα radiation
μ = 0.10 mm⁻¹
T = 296 K
0.74 × 0.31 × 0.10 mm

Data collection

Bruker APEXII DUO CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2009 ▶) T _min = 0.930, T _max = 0.990
17519 measured reflections
4923 independent reflections
2883 reflections with I > 2σ(I)
R _int = 0.033

Refinement

R[F ² > 2σ(F ²)] = 0.050
wR(F ²) = 0.167
S = 1.03
4923 reflections
228 parameters
H-atom parameters constrained
Δρ_max = 0.23 e Å⁻³
Δρ_min = −0.27 e Å⁻³

Data collection: APEX2 (Bruker, 2009 ▶); cell refinement: SAINT (Bruker, 2009 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009 ▶).

Supplementary Material

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536811053037/rz2681sup1.cif

e-68-0o163-sup1.cif^{(20KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536811053037/rz2681Isup2.hkl

e-68-0o163-Isup2.hkl^{(236.3KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536811053037/rz2681Isup3.cml

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

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

Cg1 is the centroid of the C1–C6 ring.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C14—H14A⋯O2	0.93	2.58	3.188 (2)	124
C19—H19A⋯Cg1ⁱ	0.96	2.80	3.6432 (19)	147

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Symmetry code: (i) Inline graphic .

Acknowledgments

HKF and MH thank the Malaysian Government and Universiti Sains Malaysia for the Research University grant No. 1001/PFIZIK/811160. MH also thanks Universiti Sains Malaysia for a post-doctoral research fellowship. BN thanks the UGC for financial assistance through the SAP and BSR one-time grant for the purchase of chemicals. SS thanks Mangalore University for research facilities.

supplementary crystallographic information

Comment

As a part of our ongoing studies on synthesis of terphenyl moiety from 4,4'-difluoro chalcone (Fun, Chia et al., 2011; Samshuddin et al., 2011), the title compound was prepared and its crystal structure is reported. We have used this acetyl terphenyl as a starting material for many chalcones (Fun, Hemamalini et al., 2011; Betz et al., 2011a,b).

The asymmetric unit of the title compound is shown in Fig. 1. The central benzene (C7–C12) ring is inclined at dihedral angles of 30.91 (8) and 46.88 (7)° to the two terminal fluoro-substituted phenyl (C1–C6, C13–C18) rings, respectively. The corresponding angle between the two terminal fluoro-subsituted phenyl rings is 68.34 (8)°.

An intramolecular C—H···O hydrogen bond generates an S(6) (Bernstein et al., 1995) ring motif in the molecule (Fig. 1; Table 1). The crystal structure (Fig. 2) is stabilized by weak C—H···π interactions (Table 1) involving the C1–C6 ring (centroid Cg1).

Experimental

The title compound was prepared by the aromatization of the cyclohexenone derivative, (6Z)-3,5-bis(4-fluorophenyl)-6-(1-hydroxyethylidene)cyclo hex-2-en-1-one, using iodine and methanol at reflux condition (Kotnis, 1990). Single crystal of the product was grown from a mixture of ethanol and DMF (1:1 v/v) by slow evaporation method (m.p. 391K).