THE 1,2,3,5-DITELLURADIAZOLYL [HCN2TE2] SPECIES - THEORETICAL CHARACTERIZATIONS OF THE CATION, RADICAL, AND RADICAL DIMERS

Dithia- and diselena-diazolyl radicals (HCN(2)E(2)E = S, Se) and dimer s are important building blocks in the design of low-dimensional molec ular conductors. Research on the tellurium-based analogues is much rar er. This work reports the molecular and electronic structures of the c ation, radical, and radical dimers of 1,2,3,5-ditelluradiazolyl using ab initio theory including electron correlation by Moller-Plesset pert urbation theory up to partial fourth order (MP4SDQ). A face-to-face C- 2v dimer is predicted to be bound with respect to two radicals by appr oximately 18 kcal/mol. A C-2h dimer also has been studied and is ca. 2 kcal/mol less stable than the C-2v conformer. Relaxing symmetry const raints on the dimers led to more energetically stable structures at th e Hartree-Fock level but the C-2v structure remains the most stable at a level of theory including electron correlation effects. The results for the Te compounds along with our earlier research on the S and Se analogues provide predictions for the geometries, vibrational frequenc ies, and ionization potentials for the Te species to assist in future experiments.