Berthold Kersting

A series of tetraaza‐expanded calix[4]arene analogues ( 2 – 4 ), in which two of the four aryl groups are ethylene‐protected thiophenol components were prepared from tetraaldehyde 1 . Two of these strapped macrocycles were characterized crystallographically, as well as the dipalladium complex of 4 . The same tetraaldehyde had been previously used for the synthesis of a macrotricycle ( 5 ) and a macropentacycle ( 6 ), the coordination properties of which have been investigated. In particular, ligand 6 was shown to be able to encapsulate a Cu + or a Ag + ion in the tetrahedral coordination pocket offered by a bridgehead nitrogen atom and the three proximal thioether sulfur atoms.