Structure Géométrique Et Électronique De Trois Dérivés Analogues Du Butanedinitrile‐1,4

From X-ray measurements at 155K, the electronic deformation densities for 1,1,2,2-ethanetetracarbonitrile(1) and meso 2,3-dimethyl-2,3-bis(p-cyanophenyl)-1,4-butanedinitrile(2) have been obtained by multipolar refinement. Comparison of the maps does not show any indication of substitution effects. The X-X deformation maps obtained for 2,3-dimethyl-2,3-diphenyl-1,4-butanedinitrile(3) show an orientational disorder with a very weak occupation of the second orientation. This explains the abnormal bond lengths that were observed at room temperature.