X-ray crystal structure of trans-bis-(pyridin-3-yl)ethyl-ene: comparing the supra-molecular structural features among the symmetrical bis-(n-pyrid-yl)ethyl-enes (n = 2, 3, or 4) constitutional isomers.

The mol-ecular structure of trans-bis-(pyridin-3-yl)ethyl-ene (3,3'-bpe), C12H10N2, as determined by single-crystal X-ray diffraction is reported. The mol-ecule self-assembles into two dimensional arrays by a combination of C-H⋯N hydrogen bonds and edge-to-face C-H⋯π inter-actions that stack in a herringbone arrangement perpendicular to the crystallographic c-axis. The supra-molecular 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-pyrid-yl)ethyl-ene ( n , n '-bpe, where n = n' = 2 or 4).