1-(4-{2-[(E)-3-(4-Chlorophenyl)-3-oxoprop-1-en-1-yl]phenoxy}butyl)-1H-indole-3-carbaldehyde

In the title compound, C28H24ClNO3, the dihedral angles between the central benzene ring and the indole ring system and the chlorobenzene ring are 70.81 (5) and 78.62 (5)°, respectively. The molecular structure is stabilized by a weak intramolecular C—H⋯O interaction. In the crystal, pairs of C—H⋯O hydrogen bonds link the molecules into inversion dimers with an R 2 2(14) motif.

In the title compound, C 28 H 24 ClNO 3 , the dihedral angles between the central benzene ring and the indole ring system and the chlorobenzene ring are 70.81 (5) and 78.62 (5) , respectively. The molecular structure is stabilized by a weak intramolecular C-HÁ Á ÁO interaction. In the crystal, pairs of C-HÁ Á ÁO hydrogen bonds link the molecules into inversion dimers with an R 2 2 (14) motif.
The indole ring is planar and it makes the dihedral angle with the chlorophenyl ring of 78.62 (05)°.
Experimental 2 g (13.7 mmol) of 1H-indole-3-carbaldehyde in 25 mL dry DMF and anhydrous potassium carbonate (2 g, 13.7 mmol) were stirred for 15 min at room temperature followed by addition of 5.4 g (13.7 mmol) of (E)-3-(2-(4-bromobutoxy)phenyl)-1-(4-chlorophenyl)prop-2-en-1-one in 30 mL dry DMF with continued stirring for about 3 h at room temperature. After the completion of the reaction as evidenced from TLC, the solvent was filtered into crushed ice and extracted with chloroform. The organic extract was dried over Na2SO4 and concentrated under reduced pressure.

Refinement
Hydrogen atoms were positioned geometrically and allowed to ride on their parent atoms, with C-H = 0.93 -0.97 Å and U iso (H) = 1.5U eq (C) for methyl H atoms and 1.2 U eq (C) for other H atoms.

Figure 1
The molecular structure of the title compound, showing the atom-numbering scheme and displacement ellipsoids drawn at the 30% probability level.  The crystal packing of the title compound. Hydrogen bonds are shown by dashed lines.

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.