Showing papers by "Doyle Britton published in 2011"

Solid-State Intermolecular Contacts Involving the Nitrile Group in p -Cyano- N -( p -cyanobenzylidene)aniline and 4,4′-(azinodimethylidyne) bis -benzonitrile

Abstract: As part of an investigation of the solid-state intermolecular contacts in which the nitrile group participates, the crystal structures of p-cyano-N-(p-cyanobenzylideneaniline), C15H9N3 (CN/CN) and 4,4′-(azinodimethylidyne)bis-benzonitrile, C16H10N4 (CN//CN) have been determined at −100 °C. Cell parameters for CN/CN: a = 4.7270(9) A, b = 10.443(2) A, c = 11.943(2) A; α = 90°, β = 98.70(3)°, γ = 90°; monoclinic, space group P21/c. Cell parameters for CN//CN: a = 3.8008(8) A, b = 7.9627(16) A, c = 11.181(2) A; α = 70.23(3)°, β = 84.66(3)°, γ = 81.93(3)°; triclinic, space group $$ P\overline{1} $$ . Both molecules occupy crystallographic inversion centers, which requires that (CN/CN) be disordered. Both molecules assume nearly planar conformations in the solid state. Neither (CN/CN) nor (CN//CN) is isostructural with its halogen-nitrile substituted analogues, although (CN/CN) is found to be isostructural with the corresponding stilbene. Both (CN/CN) and (CN//CN) engage in centrosymmetric H-bonding interactions that define an R 2 2 (10) motif. This motif is also observed in many related structures, although noteworthy exceptions can be found. In the crystal structures of p-cyano-N-(p-cyanobenzylideneaniline), C15H9N3 (CN/CN) (a disordered structure) and 4,4′-(azinodimethylidyne)bis-benzonitrile, C16H10N4 (CN//CN), nitrile groups are found to engage in centrosymmetric H-bonding interactions with aromatic ring hydrogen atoms, defining an R 2 2 (10) motif in each case.