The sulfoneamidohelicene tetramer in solution exhibits different molecular responses to the same cooling stimulus delivered once and twice under thermal hysteresis conditions. Its random-coil state at a high temperature was cooled and maintained at a given temperature for which its molecules remained in a random coil (first cooling); the resulting solution was heated and cooled, after which a helix dimer formed (second cooling). Such a property can be regarded as a molecular function of counting the numbers 1 and 2. Chemistry that counts! The sulfoneamidohelicene tetramer in solution responds not to the first cooling stimulus but to the second under thermal hysteresis conditions; this changes the structure from a random coil to a helix dimer (see figure; Boc=tert-butoxycarbonyl). This is a molecular function of counting the numbers 1 and 2.
- helical structures
- thermal hysteresis