Molecular Structure of Tris(dimethylamino)arsenic and -antimony as Studied by Gas-Phase Electron Diffraction and ab initio Calculations

Academic Article

Abstract

  • The compounds E(NMe2)3, where E = As and Sb, were studied by gas-phase electron diffraction and ab initio calculations on the MP2/6-31G* level. Calculations revealed two stable conformers of C3 and Cs symmetry. The latter is more stable by 7 kcal mol-1 (E = As) or 4 kcal mol-1 (E = Sb). The electron diffraction data for the As and Sb trisamides were recorded with a nozzle temperature of about 20°C. Structural parameters were refined on models of the C3, Cs, and C1 symmetry in the framework of the geometrically consistent rα-structure. The mean amplitudes of vibration and shrinkage corrections were calculated from force constants obtained by ab initio RHF/6-31G* method. The C3 model showed a poor agreement with the experiment and was rejected. Satisfactory agreement is obtained for the Cs model; however, the possibility of existence of the model with the lower symmetry C1 cannot be ruled out experimentally. The structural parameters were compared with those for similar molecules.
  • Authors

    Author List

  • Belyakov AV; Baskakova PE; Haaland A; Krannich LK; Swang O
  • Start Page

  • 245
  • End Page

  • 252
  • Volume

  • 67
  • Issue

  • 2