Synthesis and characterization of aryltellurium compounds including mixed-valence derivatives − evaluation of Te⋅⋅⋅S, Te⋅⋅⋅X and X⋅⋅⋅X (X = Br, I) interactions

An Experimental and Theoretical Insight into I2 /Br2 Oxidation of Bis(pyridin-2-yl)Diselane and Ditellane

The reactivity between bis(pyridin-2-yl)diselane o Py2 Se2 and ditellane o Py2 Te2 (L1 and L2, respectively; o Py=pyridyn-2-yl) and I2 /Br2 is discussed. Single-crystal structure analysis revealed that the reaction of L1 with I2 yielded [(HL1+ )(I- )⋅5/2I2 ]∞ (1) in which monoprotonated cations HL1+ template a self-assembled infinite pseudo-cubic polyiodide 3D-network, while the reaction with Br2 yielded the dibromide Ho PySeII Br2 (2). The oxidation of L2 with I2 and Br2 yielded the compounds Ho PyTeII I2 (3) and Ho PyTeIV Br4 (6), respectively, whose structures were elucidated by X-ray diffraction analysis. FT-Raman spectroscopy measurements are consistent with a 3c-4e description of all the X-Ch-X three-body systems (Ch=Se, Te; X=Br, I) in compounds 2, 3, Ho PyTeII Br2 (5), and 6. The structural and spectroscopic observations are supported by extensive theoretical calculations carried out at the DFT level that were employed to study the electronic structure of the investigated compounds, the thermodynamic aspects of their formation, and the role of noncovalent σ-hole halogen and chalcogen bonds in the X⋅⋅⋅X, X⋅⋅⋅Ch and Ch⋅⋅⋅Ch interactions evidenced structurally.

Large Telluroxane Bowls Connected by a Layer of Iodine Ions

Phenyltelluroxane clusters of the composition [{(PhTe)₁₉O₂₄}₂I₁₈(solv)] (1) are formed during the hydrolysis of [PhTeI₃]₂ or the oxidation of various phenyltellurium(II) compounds with iodine under hydrolytic conditions. The compounds consist of two half‐spheres with a {(PhTe)₁₉O₂₄}⁹⁺ network, which are connected by 18 iodine atoms. The spherical clusters can accommodate solvent molecules such as pyridine or methanol in the center of two rings formed by iodine atoms. The presence of other metal ions during the cluster formation results in a selective replacement of the central {PhTe}³⁺ units of each half‐sphere as has been demonstrated with the isolation of [{(PhTe)₁₈({Ca(H₂O)₂}O₂₄}₂I₁₆] (2) and [{(PhTe)₁₈({Y(NO₃)(H₂O)}O₂₄}₂I₁₆] (3). A crownether‐like coordination by six oxygen atoms of the telluroxane network is found for the {Ca(H₂O}₂}²⁺ and {Y(NO₃)(H₂O)}²⁺ building blocks. Mass spectrometric studies show that considerable amounts of the intact clusters are transferred to the gas phase without dissociation.