Donor-Acceptor (Push-Pull) Ethanes: Possible Bond Stretch Isomers of 1,1,1-Triamino-2,2,2-tricyanoethane and 1,1,1-Triamino-2,2,2-trinitroethane Academic Article uri icon


  • Previous work has shown that limited basis set self-consistent field calculations on the title compounds yield structures with two stable minima. One minimum corresponds to a covalent isomer while the second minimum corresponds to an ionic one. In this work, we show that even with larger basis sets and perturbation corrections for electron correlation two minima are still apparent. Since frequency calculations produced only real frequencies for both minima for the tricyano molecules and produced only a pair of imaginary frequencies corresponding to a degenerate set of rotations for the trinitro molecules, it was concluded that both stationary points on each potential surface are true minima. The minima corresponding to the ionic isomers are much more stable than the ones corresponding to the covalent isomers, which are barely bound with respect to the barrier separating them. Thus, the latter could be detected only spectroscopically if at all. The structure of several other possible isomers and dimer were also investigated. These calculations suggest that the solid material will be mainly ionic with a network of hydrogen bonds. © 1994 American Chemical Society.

author list (cited authors)

  • Pietsch, M. A., & Hall, M. B.

citation count

  • 4

publication date

  • November 1994