Synthesis and X-ray structural analysis of (2Z)-3(4-hydroxyphenyl)-2-pyridin-4-ylacrylonitrile and (2Z)-3-(3,5-di-tert-butyl-4-hydroxyphenyl)2-pyridin-4-ylacrylonitrile

Synthesis and X-ray structural investigations have been carried out for the two title compounds C14H10N2O (3a) and C22H26N2O (3b). Compound 3a crystallizes in the monoclinic space group P21/c, with a = 3.843(1) Å, b = 24.618(5) Å, c = 11.318(2) Å, β = 92.61(3)∘, V = 1069.7(4) Å,3 and Z = 4. Compound 3b crystallizes in the triclinic space group P-1, with a = 9.004(2) Å, b = 9.447(2) Å, c = 11.713(2) Å, α = 76.70(3), β = 83.12(3)∘, γ = 82.16(3)∘, V = 956.5(3) Å,3 and Z = 2. Both stilbazole derivatives have Z-geometry about the ethylene bridge which links the heterocyclic and aromatic rings. The molecular skeleton of 3a is slightly non-planar: the dihedral angles between the acrylonitrile linkage and the pyridine ring, and between this linkage and the p-hydroxyphenyl ring are 7.2(2) and 4.1(2)∘, respectively. The molecular skeleton of 3b is less planar: the values of similar dihedral angles are 17.0(2) and 20.8(2)∘, respectively. In the crystal of 3a, the molecules are packed in stacks along the a axis with head-to-head orientation. Intermolecular hydrogen bonds O=H ⋅s N and C=H ⋅s N link molecules into sheets parallel to (100) plane. In the crystals of 3b, the molecules have a head-to-tail orientation and intermolecular hydrogen bonds O=H ⋅s N link the molecules into infinite chains along [01-1] direction.