(E)-1-(4-Aminophenyl)-3-(2-chlorophenyl)prop-2-en-1-one

The title compound, C15H12ClNO, a substituted chalcone, adopts an E configuration with respect to the C=C bond of the enone unit. The molecule is not planar, as can be seen from the dihedral angle of 28.9 (2)° between the two rings which are twisted from each other. The enone segment of the molecule is not coplanar with the chlorophenyl ring, making a dihedral angle of 23.4 (3)° with it. The amino group is also not coplanar with the ring to which it is bound, making a dihedral angle of 35 (4)°. In the crystal structure, adjacent molecules are linked by N—H⋯O interactions into one-dimensional infinite chains along the c axis, and are further stacked as one-dimensional zigzag chains down the b axis, forming two-dimensional extended networks parallel to the bc plane.


Comment
Chalcone derivatives exhibit fascinating nonlinear optical properties (Agrinskaya et al., 1999). Among the nonlinear optical applications, optical limiting (OL) has been particularly promising (Gu et al., 2008a;Gu, et al., 2008c). Optical limiters are devices that strongly attenuate intense optical beams while exhibiting high transmittance for low-intensity ambient light levels. This behavior has applications such as the protection of human eyes and optically sensitive equipments. Chalcone derivatives are very good candidates for optical limiting applications (Gu et al., 2008b). As a part of our crystallographic studies (Patil et al., 2007a;Patil et al., 2007b;Patil et al., 2007c), the title compound was synthesized and its crystal structure is reported.
The title compound (I, Fig 1), a substituted chalcone, adopts an E configuration with respect to the C═C bond of the enone unit. Intramolecular C-H···O and C-H···Cl hydrogen bonds involving the enone group generate S(5) ring motifs (Bernstein et al., 1995). The bond lengths are within the normal ranges (Allen et al., 1987). The molecule is not planar, with a maximum deviation from the mean plane of C1-C15/N1/O1 being -1.135 (3) Å for atom Cl1. The amino group is also not coplanar with the phenyl ring to which it is bound. The dihedral angle between the C10-C15 ring and the N1-H1N1-H2N1 plane of the NH 2 group is 34.7(3.7)°. The two phenyl rings are twisted to each other with the dihedral angle of 28.9 (2)°.
Adjacent molecules are linked together by N-H···O interactions (Table 1) into 1-D infinite chains along the c axis in the crystal structure (Fig. 2). Such chains are further stacked as 1-D zigzag chains down the b-axis (Fig. 3), too, to form 2-D extended networks parallel to the bc plane.
After stirring (6 h), the contents of the flask were poured into ice-cold water (500 ml) and left to stand for 5 h. The resulting crude solid was filtered and dried. Crystals suitable for X-ray analysis were grown by slow evaporation of an acetone solution at room temperature.

Refinement
The hydrogen atoms of the amino group were located from the difference Fourier map and refined freely. The remaining H atoms were located in the riding model approximation with C-H= 0.93 Å, and with U iso (H) = 1.2U eq (C).