An Experimental and Theoretical Insight into I /Br Oxidation of Bis(pyridin-2-yl)Diselane and Ditellane.

The reactivity between bis(pyridin-2-yl)diselane Py Se and ditellane Py Te (L1 and L2, respectively; Py=pyridyn-2-yl) and I /Br is discussed. Single-crystal structure analysis revealed that the reaction of L1 with I yielded [(HL1 )(I )⋅5/2I ] (1) in which monoprotonated cations HL1 template a self-assembled infinite pseudo-cubic polyiodide 3D-network, while the reaction with Br yielded the dibromide H PySe Br (2). The oxidation of L2 with I and Br yielded the compounds H PyTe I (3) and H PyTe Br (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, H PyTe Br (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.