Stability and structure of oligomers and polymers made of xenon and hydrocarbons: theoretical predictions

Calculations at B3LYP level predict the existence of three carbon chain oligomers containing HXeCtriple bond]C- branches: C(7)H(8)Xe(2), C(11)H(12)Xe(3), and C(15)H(16)Xe(4). The geometries and NBO charges of the HXeCtriple bond]C- groups in the species are similar to those of the experimental known HXeCtriple bond]CH molecule, and are insensitive to the length of the carbon chain. The structures of the xenon oligomers are very similar to their hydrocarbon precursors. The energetics for C(11)H(12)Xe(3) is calculated to assess the stability of these polymers. Similar to HXeCCH, C(11)H(12)Xe(3) is kinetically stable and protected by a high barrier of 2.47 eV against dissociation to C(11)H(12)Xe(2)+Xe, and is energetically more stable by 1.30 eV than the C(11)H(11)Xe(2)+Xe+H products, which strongly supports the existence of the molecule. Extrapolation of the results for the oligomers suggests the existence of an extended -CH(2)CH(Ctriple bond]CXeH)-](n) polymer. A strategy for preparation is proposed.