Synthesis of new T-shaped hypervalent complexes of tellurium showing Te–π-aryl interactions: X-ray characterization of [(mes)XTe(μ-X)Te(mes)(etu)] (X = Br, I) and [Ph(etu)Te(μ-I)Te(etu)Ph][PhTeI4] (mes = mesityl; etu = ethylenethiourea)

Dimesityl ditelluride, (mesTe)2, reacts with bromine/iodine and ethylenethiourea in methanol to give [(mes)XTe(μ-X)Te(mes)(etu)] {X = Br (1), I (2)}. The salt [Ph(etu)Te(μ-I)Te(etu)Ph][PhTeI4] (3) is obtained by reflux of a mixture of (PhTe)2, iodine, ethylenethiourea and PhTeI3 in methanol. The new complexes were prepared in good yields by a one-pot procedure and characterized by single crystal X-ray diffraction. In the complexes 1 and 2, the tellurium atoms perform Te–π-aryl interactions and attain T-shaped coordinations with a bridging halogen ligand. The [PhTeI4]− anions of complex 3 are associated in a quasi-dimeric configuration and the tellurium atoms achieve an octahedral coordination through secondary Te–I bonds.

The new complexes [(mes)XTe(μ-X)Te(mes)(etu)] {X = Br (1), I (2)} and [Ph(etu)Te(μ-I)Te(etu)Ph][PhTeI4] (3) were prepared by one-pot procedures and their structures were solved by X-ray diffraction analysis. In 1 and 2, the tellurium atoms attain Te–π-aryl interactions and T-shaped coordinations, achieving an octahedral coordination in 3 through secondary Te–I bonds.Figure optionsDownload as PowerPoint slide