Bis(perfluoroaryl)chalcolanes Ar^F₂Ch (Ch = S, Se, Te) as σ/π-Hole Donors for Supramolecular Applications Based on Noncovalent Bonding

Perfluorinated arenes (perfluoropyridine, perfluorotoluene, and perfluorobiphenyl) were converted to the bis(perfluoroaryl)chalcolanes Ar^F₂Ch (Ch = S 59-88%, Se 54-84%, Te 10-41%) via the developed one-pot methodology. This method includes the generation of Na₂Ch (formed in situ by the reduction of Ch with the system Na⁺[C₁₀H₈]^·-) followed by its treatment with any one of the arenes. The crystal structures of (4-NC₅F₄)₂S (2), (C₁₂F₉)₂S (3) (p-CF₃C₆F₄)₂Se (4), (C₁₂F₉)₂Se (6^A,B; two polymorphs), (C₁₂F₉)₂Te (9), and (4-NC₅F₄)₂Te (8^B; a novel polymorph) were determined by X-ray crystallography. In the solid state, compounds Ar^F₂Ch are self-associated via σ-(Ch)-hole interactions with F (or N for 8^B) and also π-π stacking between the arenes. The σ/π-hole donor properties of Ar^F₂Ch were evaluated by molecular electrostatic potential surface analysis using the density functional theory approach. The maximum V_s(σ-hole) values (from +25 to +38 kcal/mol) increase in the order S < Se < Te along with an increase in the polarizability and decrease in the electronegativity of the Ch sites, while the π-hole depths (+14 to +20 kcal/mol) follow the opposite trend being the lowest for the Te^II derivatives.