(2E)-1-(4,4′′-Difluoro-5′-methoxy-1,1′:3′,1′′-terphenyl-4′-yl)-3-(4-fluorophenyl)prop-2-en-1-one

In the title compound, C28H19F3O2, the C=C double bond has an E configuration. In the crystal, C—H⋯F contacts link the molecules into chains along [111]. The shortest centroid–centroid distance between two π systems is 3.8087 (8) Å and is apparent between the para-fluorophenyl group attached to the Michael system and its symmetry-generated equivalent.


Comment
Chalcones constitute an important family of substances belonging to flavonoids, a large group of natural and synthetic products with interesting physicochemical properties, biological activity and structural characteristics. They have been reported to possess many interesting pharmacological activities (Dhar, 1981) including anti-inflammatory, antimicrobial, antifungal, antioxidant, cytotoxic, antitumor and anticancer activities (Dimmock et al., 1999;Satyanarayana et al., 2004). In recent years, it has been reported that some terphenyls exhibit considerable biological activities (e.g. being potent anticoagulants, immunosuppressants, antithrombotics, neuroprotectives, specific 5-lipoxygenase inhibitors) and showing cytotoxic activities (Liu, 2006). In view of the pharmacological importance of terphenyls and chalcones, and in continuation of our work on synthesis of various derivatives of 4,4'-difluoro chalcone /b, Fun et al., 2010a/b, Jasinski et al., 2010a/b, Baktir et al., 2011a, the molecular and crystal structure of the title compound is reported.
The C=C double of the Michael system is (E)-configured. The least-squares planes defined by the carbon atoms of the para-fluoro phenyl rings of the terphenyl moiety and its central phenyl ring enclose angles of 40.37 (6)° and 44.04 (6)°, respectively ( Fig. 1).
In the crystal, two different C-H···F contacts whose range falls by more than 0.1 Å below the sum of van-der-Waals radii of the atoms participating are observed. The first contact is apparent between one of the fluorine atoms on the terphenyl skeleton and a hydrogen atom on the terminal aromatic substituent on the Michael system's substituent. The second one is supported by the second fluorine atom on the terphenyl skeleton and a hydrogen atom on its symmetry-generated equivalent.
Both contacts connect the molecules in such a way that cyclic patterns with local inversion symmetry are generated. In terms of graph-set analysis (Etter et al., 1990;Bernstein et al., 1995), the descriptor for the C-H···F contacts is R 2 2 (8)R 2 2 (28) on the unitary level. In total, the molecules are connected to infinite chains along [1 1 1]. Metrical parameters as well as information about the symmetry of these contacts is summarized in Table 1. The shortest intercentroid distance between two π systems was found at 3.8087 (8) Å and is apparent between the para-fluoro phenyl moiety attached to the Michael system and its symmetry-generated equivalent. (Fig. 2).
The packing of the title compound in the crystal is shown in Figure 3.
Single crystals suitable for the X-ray diffraction study were grown from a 1:1 (v:v) mixture of DMF and ethanol by slow evaporation at room temperature.