Cover Picture: The Synthesis of Carboracycles Derived from B , B ′‐Bis(aryl) Derivatives of Icosahedral ortho ‐Carborane (Chem. Eur. J. 12/2003)

The cover picture shows a space‐filling model of a macrocycle consisting of four bis‐aryl‐substituted icosahedral ortho ‐carborane modules that are tethered with propylene linkers (carbon: gray, boron: green, hydrogen: white). All eight para ‐functionalized aryl groups are attached to a propylene chain carrying a terminal sulfonate group (sulfur: yellow, oxygen: blue). This amphiphilic octasulfonate anion exemplifies the first water‐soluble carboracycle. The hydrophobic cavity in the cycle is clearly viable and adjustable by inter‐cage linker modification. The development of new supramolecular chemistry and its use in molecular recognition employing solvent systems that range from organic to aqueous represent future applications of these novel carboracycle derivatives. For more details concerning the synthesis and characterization of these multifunctionalized carborane‐based macrocycles see the article by M. F. Hawthorne et al. on p. 2732 ff.