Inclusion of Cavitands and Calix[4]arenes into a Metallobridged para‐(1H‐Imidazo[4,5‐f][3,8]phenanthrolin‐2‐yl)‐Expanded Calix[4]arene

A hunter hunted! A highly preorganized, deep metallocavitand of nanoscale dimensions containing rhenium atoms at the four corners can be readily synthesized from a simple formyl-substituted calix[4]arene and 3,8-phenanthroquinone. Unsubstituted calix[4]arenes and cavitands without substituents on the lower rim are the ideal guests for such an expanded calixarene (see picture), and are included with binding constants of 103–105 M−1.