Reaction of imidazoline-2-selone derivatives with mesityltellurenyl iodide: a unique example of a 3c-4e Se→Te←Se three-body system embedding a tellurenyl cation

The reactions of 1,1'-bis(3-methyl-4-imidazolin-2-selone)methane (L-1) and 1,2-bis(3-methyl-4-imidazolin-2-selone)ethane (L-2) with mesityltellurenyl iodide (MesTeI) [Mes = 2,4,6-Me3C6H2] yielded the neutral [L-1 center dot 2MesTeI]center dot 2CH(2)Cl(2) and the ionic [L-2 center dot MesTe](2)(MesTeI(2))(2) compounds, respectively, which were characterized by X-ray diffraction analysis. DFT (mPW1PW//LANL08d/def2-SVP) and NBO calculations, supported by structural and FT-Raman measurements, show that the latter compound represents the first example of an authentic mesityltellurenyl cation, [MesTe](+), stabilized within a [MesTe(B)(2)](+) (B = Lewis base) charge transfer adduct featuring a 3c-4e Se -> Te <- Se three-body system.