Molecular Function of Counting the Numbers 1 and 2 Exhibited by a Sulfoneamidohelicene Tetramer

• Published in: Chemistry : a European journal Vol. 20; no. 40; pp. 12759 - 12762
• Main Authors: Shigeno, Masanori, Kushida, Yo, Kobayashi, Yuta, Yamaguchi, Masahiko
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 26.09.2014; WILEY‐VCH Verlag; Wiley Subscription Services, Inc
• Subjects: Chemistry; Coiling; Cooling; Counting; Dimerization; Dimers; helical structures; Hysteresis; Molecular Conformation; Molecular structure; sulfonamides; Sulfonamides - chemistry; Temperature; thermal hysteresis; threshold; counting; thermal hysteresis; sulfonamides; threshold; helical structures
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.201403358

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.