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.