Formal Metal-Dependent (M = Pt, Pd) Switching between\nArene π‑Hole and σ‑(Te)-Hole in the Arenetellurium(II)\nNoncovalent Binding

The\ndiketonate complexes M(acac)<sub>2</sub> (M = Pd (<b>1</b>),\nPt (<b>2</b>)) were cocrystallized with bis(perfluoropyridin-4-yl)tellane\n(Py<sup>F</sup><sub>2</sub>Te). Single-crystal X-ray studies of the\nresulting adducts revealed that the binding mode and stoichiometry\nbetween the coformers dramatically depend on the identity of metal\nsites. Pd(acac)<sub>2</sub> formed adduct <b>1</b><sub>3</sub>·(Py<sup>F</sup><sub>2</sub>Te)<sub>2</sub> where Te···C<sub>acac</sub> and π<sub>hole</sub>···Pd noncovalent\ninteractions were detected. In contrast to <b>1</b>, Pt(acac)<sub>2</sub> formed adduct <b>2</b>·Py<sup>F</sup><sub>2</sub>Te where the Te···Pt metal-involving chalcogen bond\nwas observed. Various DFT methods, including the calculation of fully\noptimized dimeric assemblies and their mutated dimers, allowed for\na detailed examination of the corresponding metal-involving noncovalent\ninteractions. Our findings support the notion that metal-involving\ninteractions are the primary structure-determining factors, and the\nformal transition to the Te···Pt chalcogen bond can\nbe attributed to the increased <i>d</i><sub><i>z</i></sub><sup>2</sup>-nucleophilicity of the platinum atom compared\nto the palladium site.