Aminomethylenehelicene Oligomers Possessing Flexible Two‐Atom Linker Form a Stimuli‐Responsive Double‐Helix in Solution. Issue 7 (18th May 2014)

• Record Type: Journal Article
• Authors: Shigeno, Masanori; Sato, Masahiko; Kushida, Yo; Yamaguchi, Masahiko
• Is Part Of: Asian journal of organic chemistry. Volume 3:Issue 7(2014:Jul.)
• Page Start: 797
• Page End: 804
• Publication Date: 2014-05-18
• Subjects: Chemistry, Organic -- Periodicals; Organic compounds -- Synthesis -- Periodicals; 547.005
• DOI: 10.1002/ajoc.201402065
• Languages: English
• ISSNs: 2193-5807

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>Aminomethylenehelicene oligomers up to the (<italic>M</italic>)‐heptamer were synthesized by reductive amination from a formylhelicene building block. The oligomers containing more than three helicenes formed a double helix in 1, 3‐dilfuorobenzene. The (<italic>M</italic>)‐tetramer and (<italic>M</italic>)‐pentamer unfolded into a random coil by heating to 60 °C, whereas the (<italic>M</italic>)‐hexamer only slightly unfolded at the same temperature. A two‐sided thermal hysteresis was detected in the structural change of the (<italic>M</italic>)‐tetramer and (<italic>M</italic>)‐pentamer during cooling and heating. The (<italic>M</italic>)‐pentamer and (<italic>M</italic>)‐hexamer unfolded with the addition of trifluoroacetic acid and regenerated a double helix with the addition of triethylamine.</p> </abstract>