Crystal structure of (E)-1-(4′-methoxy-[1,1′-biphenyl]-4-yl)-3-(3-nitrophenyl)prop-2-en-1-one

The title compound crystallized with two independent molecules in the asymmetric unit. In the crystal, they are linked to one another, forming chains enclosing (10) and (12) ring motifs.

The title compound, C 22 H 17 NO 4 , crystallizes with two independent molecules (A and B) in the asymmetric unit. Each molecule exists as an E isomer with C-C C-C torsion angles of À175.69 (17) and À178.41 (17) in A and B, respectively. In molecule A, the planes of the terminal benzene rings are twisted by an angle of 26.67 (10) , while the biphenyl unit is non-planar, the dihedral angle between the rings being 30.81 (10) . The dihedral angle between the nitrophenyl ring and the inner phenyl ring is 6.50 (9) . The corresponding values in molecule B are 60.61 (9), 31.07 (8) and 31.05 (9) . In the crystal, molecules are arranged in a head-to-head manner, with the 3-nitrophenyl groups nearly parallel to one another. The A and B molecules are linked to one another via C-HÁ Á ÁO hydrogen bonds, forming chains lying parallel to (320) and enclosing R 2 2 (10) and R 2 2 (12) ring motifs. The methoxy group in both molecules is positionally disordered with a refined occupancy ratio of 0.979 (4):0.021 (4) for molecule A and 0.55 (4):0.45 (4) for molecule B.

Chemical context
Chalcones have been reported to possess many interesting pharmacological activities (Dhar, 1981), including antiinflammatory, antimicrobial, antifungal, antioxidant, cytotoxic, antitumor and anticancer activities (Dimmock et al., 1999;Satyanarayana et al., 2004). The effect of new biphenyl chalcone derivatives against gamma-radiation-induced oxidative stress markers in E. coli K 12, and the evaluation of their antimicrobial activities have been reported (Darshan Raj et al., 2013).

Synthesis and crystallization
A mixture of 4-acetyl-4 0 -methoxybiphenyl (3.59 g, 10 mmol) and 3-nitro benzaldehyde (1.07 g, 10 mmol) in ethanol (25 ml) in the presence of NaOH (10 ml 30%) was heated in a water bath for 30 min. and then allowed to cool. The solid that separated was filtered and recrystallized from ethanol. The yellow-coloured crystals of the title compound used for the X-ray diffraction study were grown by slow evaporation from acetone (yield: 1.48 g; 70%).

Refinement
Crystal data, data collection and structure refinement details are summarized in Table 2. All H-atoms were positioned geometrically and allowed to ride on their parent atoms, with C-H = 0.93 À 0.96 Å with U iso (H) = 1.5U eq (C) for methyl H atoms and = 1.

(E)-1-(4′-Methoxy-[1,1′-biphenyl]-4-yl)-3-(3-nitrophenyl)prop-2-en-1-one
where P = (FO 2 + 2FC 2 )/3 (Δ/σ) max < 0.001 Δρ max = 0.38 e Å −3 Δρ min = −0.18 e Å −3 Special details Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes. Refinement. Refinement on F 2 for ALL reflections except those flagged by the user for potential systematic errors. Weighted R-factors wR and all goodnesses of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The observed criterion of F 2 > σ(F 2 ) is used only for calculating -R-factor-obs etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.