An experimental and theoretical insight into I2/Br2 oxidation of bis(pyridin‐2‐yl)diselane and ditellane

Abstract

The reactivity between bis(pyridin-2-yl)diselane oPy2Se2 and ditellane oPy2Te2 ( L1 and L2 , respectively; oPy=pyridyn-2-yl) and I2/Br2 is discussed. Single-crystal structure analysis revealed that the reaction of L1 with I2 yielded [(H L1 +)(I−)⋅5/2I2]∞ ( 1 ) in which monoprotonated cations H L1 + template a self-assembled infinite pseudo-cubic polyiodide 3D-network, while the reaction with Br2 yielded the dibromide HoPySeIIBr2 ( 2 ). The oxidation of L2 with I2 and Br2 yielded the compounds HoPyTeIII2 ( 3 ) and HoPyTeIVBr4 ( 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 , HoPyTeIIBr2 ( 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.