Crown Ether Assisted Convex Cesium Binding to a Sumanenyl Bowl

The first convex cesium-bound complex
with a bowl-shaped carbanion,
namely [{Cs+(dc-18-crown-6)}­(C21H11–)] (1), has been isolated and crystallographically
characterized. In the structure of 1, the cesium ion
capped by dicyclohexano-18-crown-6 ether coordinates to the deprotonated
five-membered ring of a sumanenyl bowl in an exo fashion with the
Cs···C distances ranging from 3.315(5) to 3.609(6)
Å. Theoretical modeling, including a topological QTAIM approach,
reveals the cumulative effect of multiple weak CH···π
interactions between the cationic {Cs+(dc-18-crown-6)}
moiety and the convex surface of the C21H11– anion, explaining the formation and stability of the
product.