Crystal structures of methyl (E)-3-(2-chlorophenyl)-2-({2-[(E)-2-nitrovinyl]phenoxy}methyl)acrylate and methyl (E)-2-({4-chloro-2-[(E)-2-nitrovinyl]phenoxy}methyl)-3-(2-chlorophenyl)acrylate

In the title compounds, (I) and (II), both of which crystallize in the monoclinic space group P21/n, the methyl acrylate and nitrovinyl units are relatively planar with an E conformation about the C=C bonds. The two aromatic rings are inclined to one another by 74.87 (9) and 75.65 (2)° for compounds (I) and (II), respectively. In the crystal of (I), chains along the b axis are formed via C—H⋯O hydrogen bonds. In the crystal of (II), molecules are linked by C—H⋯O hydrogen bonds, forming sheets parallel to the ac plane.


Chemical context
Recently, 2-cyanoacrylates have been used extensively as agrochemicals because of their unique mechanism of action and good environmental profiles (Govindan et al., 2011). Phenyl acrylates and their derivatives are important compounds because of their agrochemical and medical applications (De Fraine & Martin, 1991). Cinnamic acid derivatives have received attention in medicinal research as traditional as well as recently synthetic antitumor agents (De et al., 2011). They also possess significant antibacterial activity against Staphylococcus aureus (Xiao et al., 2008). In addition, different substitutions on the basic moiety lead to various pharmacological activities, such as anti-oxidant, hepatoprotective, anxiolytic, insect repellent, antidiabetic and anticholesterolemic (Sharma, 2011). Against this background, the title compounds were synthesized and we report herein on their crystal structures.
In both compounds, the nitrovinyl groups [C2 C1-N1(O1,O2)], have an E conformation about the C2 C1 bond. In (I), its mean plane makes a dihedral angle of 2.025 (9) with the benzene ring (C3-C8) to which it is attached, while in compound (II), the corresponding dihedral angle is much larger, at 14.78 (16) . The molecular structure of compound (I), showing the atom labelling. Displacement ellipsoids are drawn at the 30% probability level.

Figure 2
The molecular structure of compound (II), showing the atom labelling. Displacement ellipsoids are drawn at the 30% probability level.

Figure 3
A partial view of the crystal structure of compound (I), showing the hydrogen-bonded (dashed lines) zigzag chains propagating along [010]; see Table 1.

Supramolecular features
In the crystal of (I), adjacent molecules are linked by C-HÁ Á ÁO hydrogen bonds forming chains along the b-axis direction (Table 1 and Fig. 3). The chains are linked via C-HÁ Á ÁCl hydrogen bonds, forming sheets parallel to the ab plane ( Fig. 4 and Table 1). The sheets are linked via C-HÁ Á Á interactions, forming a three-dimensional structure (Table 1).

Figure 5
A partial view of the crystal packing of compound (II), viewed along the b axis. The hydrogen bonds are shown as dashed lines (see Table 2). Table 1 Hydrogen-bond geometry (Å , ) for (I).

Figure 6
The crystal packing of compound (II), viewed along the c axis. The hydrogen bonds are shown as dashed lines (see Table 1).