Calyx- and Tub-Shaped Polydentate σ-Hole Systems Revealing Intermolecular Chalcogene···π–Alkyne Interactions

Abstract

Poly σ-hole donors, i.e., molecules that contain more than one σ-hole donating function, can interact through weak noncovalent interactions with molecules that have regions of high electron density, like the lone pairs of anions, Lewis bases, and π-systems. Therefore, such mono- and bidentate systems have been intensively studied in recent years and used in host-guest chemistry and catalysis. Here we present the synthesis of tri-, tetra-, and hexadentate systems with CCSb(C₂F₅)₂ and CCSeCF₃ functions using tin-element exchange reactions. These systems are based on both the calyx-shaped hexadehydrotribenzo[12]annulene and the tub-shaped dibenzo[a,e]cyclooctatetraene. The molecular structure of the tub-shaped systems shows inter- and intramolecular contacts related to the interaction of the σ-holes with the electron-rich fluorine and alkyne functions.