Synthesis of dithioureado-bridged bis-pillar[5]arenes and formation of unique bis-[1]rotaxanes

The addition reaction of mono-amide-functionalized pillar[5]arenes with 1,4-diisothiocyanatobenzene or 1,4-diisothiocyanatohexane in chloroform resulted in various dithioureado-bridged bis-pillar[5]arenes. 1H and 2D NMR spectroscopy as well as X-ray single crystal structure indicated that the longer dithioureado chain threaded into both cavities of the two pillar[5]arenes to form the unique bis-[1]rotaxane structures in solution and in solid state.