Selenacalix[4]dithienothiophene: Synthesis, Structure, and Complexation of a Cyclic Tetramer of Selenide-Bridging Dithienothiophene.

An efficient cyclization toward a cyclic tetramer of dithienothiophene (DTT) linked by divalent selenium atoms has been developed via palladium-catalyzed coupling reaction of (nBu3 Sn)2 Se. X-ray analysis revealed its highly symmetrical structure had an alternate arrangement of DTT units. There are several Se⋅⋅⋅π interactions forming a supramolecular network leading to large void channel space. The cyclic tetramer possesses moderate electron-donating ability. Furthermore, the cyclic tetramer undergoes complexation with C60 in a 1:2 ratio in the solid state to give a highly symmetrical three-dimensional array of C60 .