Three substituted (E)-3-aryl-2-(thienyl)acrylonitriles: isolated molecules, simple hydrogen-bonded chains and hydrogen-bonded sheets

Abstract

The molecule of compound (I), showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 30% probability level and H atoms are shown as small spheres of arbitrary radii.

(E)-3-(4-Methylphenyl)-2-(2-thienyl)acrylonitrile hasZ′ = 0.75 in the space groupC2/m: fourfold disordered molecules lie in channels enclosed by fully ordered molecules

“…There is no evidence for any orientational disorder of the 2-thienyl unit in molecule 1. By contrast, both (II) and (III) show orientational disorder of the thienyl unit, with unequal populations for the two orientations in an approximate 4:1 ratio (Cobo et al, 2005;Cobo, Quiroga et al, 2006). In addition, the non-H skeletons of (II) and (III) are not planar, with the aryl ring markedly displaced from the plane of the rest of the molecule in both cases; the respective C27-C17-C11-C12 torsion angles in (II) and (III) are 37.9 (3) and 38.7 (4) .…”

“…In both (V) and the unsubstituted analogue (VI) (Cobo, Quiroga et al, 2006), pairs of molecules again form short contacts involving paired C-HÁ Á ÁN interactions, leading to an R 2 2 (12) motif similar to that in (I), except that in (V) and (VI) the participating molecules are related by inversion, whereas in (I) they are related by rotation. Compounds (I) and (V) show very similar dimensions for this contact, but only in compound (VI) are the dimensions of the C-HÁ Á ÁN interaction such that it can be regarded as a genuine hydrogen bond.…”

“…1). Although related pairs of compounds containing, respectively, Me and Cl substituents, such as (I) and (II), are not infrequently isomorphous, the crystal structure of (I) shows some significant differences from the pair of analogues (II) (Cobo et al, 2005) and (III) (Cobo, Quiroga et al, 2006), which are isomorphous and isostructural with one another.…”

“…In addition, the non-H skeletons of (II) and (III) are not planar, with the aryl ring markedly displaced from the plane of the rest of the molecule in both cases; the respective C27-C17-C11-C12 torsion angles in (II) and (III) are 37.9 (3) and 38.7 (4) . On the other hand, the molecules of (IV) (Cobo, Quiroga et al, 2006) are almost planar apart from the C atom of the central methoxy group. As in compounds (II)-(IV), the nitrile units in (I) show long C-C distances and short C-N distances (Table 1), but otherwise the bond distances in (I) show no unexpected features.…”

“…1). Although related pairs of compounds containing, respectively, Me and Cl substituents, such as (I) and (II), are not infrequently isomorphous, the crystal structure of (I) shows some significant differences from the pair of analogues (II) (Cobo et al, 2005) and (III) (Cobo, Quiroga et al, 2006), which are isomorphous and isostructural with one another.While the isomorphous pair of compounds (II) and (III) both crystallize with Z 0 = 1 in the common space group P2 1 /n, compound (I) crystallizes in the rather uncommon space group C2/m with Z 0 = 0.75. There are two independent molecules of (I) in the unit cell.…”