Journey through the potential energy surfaces for the isomerization and decomposition reactions of the telluroformaldehyde analogues: H2A-Te and HFA-Te (A = C, Si, and Ge).

The journal of physical chemistry. A

PubMedID: 23738800

Jaufeerally NB, Abdallah HH, Ramasami P, Schaefer HF. Journey through the potential energy surfaces for the isomerization and decomposition reactions of the telluroformaldehyde analogues: H2A-Te and HFA-Te (A = C, Si, and Ge). J Phys Chem A. 2013;117(27):5567-77.
The unavailability of monomeric heavy ketone analogues has been ascribed to the evanescence of the very reactive A-E double bond (A and E are the heavier group 14 and group 16 elements, respectively). Can the isolation of any of the monomeric telluro-ketones be assisted by an energetic favorability on its potential energy surface (PES)? In this light, the reaction pathways for the isomerization and decomposition reactions of H2A-Te and HFA-Te (A = C, Si, and Ge) molecules on their singlet state PES have been studied using second-order Møller-Plesset perturbation theory (MP2). The barrier heights reported suggest that telluroformaldehyde, silanetellone, and germatellone are kinetically more resistant to unimolecular reactions than the corresponding lighter chalcogen analogues. However, upon replacing a hydrogen atom by fluorine, the barrier heights of most of the isomerization and decomposition reactions are lowered. Among the unimolecular reactions studied for the H2A-Te and HFA-Te (A = C, Si, and Ge) molecules, the decomposition of cis-FGeTeH into HF and GeTe is found to be the most facile reaction, with a barrier height of only 4.6 kcal/mol. We also predict the ground state telluro-ketones to be viable molecules, as they have no imaginary vibrational frequencies and their lowest vibrational frequencies are always >100 cm(-1). In view of the scarcity of information on the chemistry of the mentioned telluro-ketones, the molecular parameters of various isomers and decomposition products have been reported, and should be useful for future experimental investigations.