Cover Picture: The Ouroborand: A Cavitand with a Coordination-Driven Switching Device (Angew. Chem. Int. Ed. 18/2010)



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The Armadillo Lizard is a South African reptile that holds its tail in its mouth as a defensive tactic. This is reminiscent of the Ouroboros, an ancient Greek symbol depicting a serpent swallowing its own tail, famous as the inspiration for Kekule's formulation of benzene 150 years ago. In their Communication on page 3189 ff., F. Durola and J. Rebek, Jr. report how a self-hosting cavitand, which is named an “Ouroborand”, can switch between closed and open states by addition of zinc ions. (Picture courtesy of P. le F. N. Mouton)