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

Poly σ-hole systems with a calyx-like structure and tetradentate systems with a tub-like structure have been prepared by tin-element exchange reactions. The solid-state structures of the tub-shaped systems reveal σ-hole···fluorine as well as σ-hole···alkyne interactions, extending not only the poly σ-hole systems but also the understanding of chalcogen bonding.

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.

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