X-ray crystal structure of trans-bis­­(pyridin-3-yl)ethyl­ene: comparing the supra­molecular structural features among the symmetrical bis­­(n-pyrid­yl)ethyl­enes (n = 2, 3, or 4) constitutional isomers

The mol­ecular structure of trans-bis­(pyridin-3-yl)ethyl­ene (3,3′-bpe), C12H10N2, as determined by single-crystal X-ray diffraction is reported. The mol­ecule self-assembles into two dimensional arrays by a combination of C—H⋯N hydrogen bonds and edge-to-face C—H⋯π inter­actions that stack in a herringbone arrangement perpendicular to the crystallographic c-axis. The supra­molecular forces that direct the packing of 3,3′-bpe as well as its packing assembly within the crystal are also compared to those observed within the structures of the other symmetrical isomers trans-1,2-bis­(n-pyrid­yl)ethyl­ene (n,n′-bpe, where n = n′ = 2 or 4).