(E)-3-(4-Heptyloxyphenyl)-1-phenylprop-2-en-1-one

In the title compound, C22H26O2, the aromatic rings are inclined to one another by 8.39 (9)° and the molecule has an E conformation about the C=C bond. In the crystal, molecules stack head-to-tail along the b-axis direction. They are linked by very weak C—H⋯O contacts, forming C(4) chains along [100]. Two chains are linked by a pair of very weak C—H⋯O contacts, enclosing inversion-dimeric R 2 2(8) ring motifs. There are also C—H⋯π interactions present, which link the double-stranded chains, forming a two-dimensional network.

In the title compound, C 22 H 26 O 2 , the aromatic rings are inclined to one another by 8.39 (9) and the molecule has an E conformation about the C C bond. In the crystal, molecules stack head-to-tail along the b-axis direction. They are linked by very weak C-HÁ Á ÁO contacts, forming C(4) chains along [100]. Two chains are linked by a pair of very weak C-HÁ Á ÁO contacts, enclosing inversion-dimeric R 2 2 (8) ring motifs. There are also C-HÁ Á Á interactions present, which link the doublestranded chains, forming a two-dimensional network.

Comment
Chalcones along with their derivatives can easily be obtained by means of isolation from natural products or synthesized by classic scientific methods. These compounds are interesting in the medical field because of their antibacterial (Avila et al., 2008), antifungal (ElSohly et al., 2001Gafner et al., 1996), antitumor (Akihisa et al., 2003;Szliszka et al., 2009;Xia et al., 2000;Lahtchev et al., 2008) and anti-inflammatory properties (Bandgar et al., 2010). These compounds have also shown enhanced cytotoxicity towards certain cancers (Won et al., 2005). Synthetically chalcones are derived through an aldol condensation which involves the reaction between an aromatic aldehyde with an aliphatic aldehyde or ketone in the presence of a strong base (hydroxide or alkoxide). The resulting compound contains two aromatic rings joined by a three carbon α,β-unsaturated carbonyl system, and we report herein on its crystal structure.
The molecular structure of the title molecule is illustrated in Fig. 1. The two aromatic rings (C4-C9 and C17-C22) are inclined to one another by 8.39 (9)° and the molecule has an E conformation about the C2═C3 bond.
In the crystal, the molecules stack head-to-tail along the b axis. They molecules are linked by very weak C-H···O and C-H···π interactions (Table 1). Atom O1 of the carbonyl group interacts with the H atom, H2, of the C2═ C3 double bond in a C═O···HC═C fashion, resulting in the formation of C(4) chains along the a-axis direction. In addition, the O atom, O2, of the ether moiety is also involved in a weak hydrogen bond with the central phenyl group of an inversion related neighboring molecule. The two molecules are arranged head-to-tail, which induces formation of an inversion dimeric unit and an eight-membered R 2 2 (8) ring containing a pair of very weak C-H···O hydrogen bonds (Table 1).
As a result of the head-to-tail flipping, there is no ring alignment within the structure, hence the system lacks any significant π-π interactions but there are C-H···π contacts present (Table 1) which link the double stranded chains to form a two-dimensional network.

Experimental
The title compound was obtained by mixing acetophenone (0.150 g, 1.22 mmol), 4-(heptyloxy)benzaldehyde (0.269 g, 1.22 mmol), a 10% solution of NaOH and ethanol at 273 K for 18 h, after which it was acidified with 1 N HCl. The crude product obtained was recrystallized from ethanol yielding yellow plate-like crystals.

Refinement
All the H atoms were located in difference Fourier maps and freely refined.

Computing details
Data collection: SMART (Bruker, 2005; cell refinement: SAINT (Bruker, 2005); data reduction: SAINT (Bruker, 2005); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: JMol (Hanson, 2010); software used to prepare material for publication: publCIF (Westrip, 2010).  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 of F 2 against ALL reflections. The weighted R-factor wR and goodness 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 threshold expression of F 2 > σ(F 2 ) is used only for calculating R-factors(gt) 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.