Chemical CD oscillation and chemical resonance phenomena in a competitive self-catalytic reaction system: a single temperature oscillation induces CD oscillations twice

• Published in: Chemical science (Cambridge) Vol. 10; no. 6; pp. 1735 - 1740
• Main Authors: Sawato, Tsukasa, Shinozaki, Yasuhiro, Saito, Nozomi, Yamaguchi, Masahiko
• Format: Journal Article
• Language: English
• Published: England Royal Society of Chemistry 14.02.2019
• Subjects: Catalysis; Chemical reactions; Coils; Organic chemistry; Toluene
• ISSN: 2041-6520; 2041-6539
• DOI: 10.1039/c8sc03109f

Chemical CD oscillation and chemical resonance phenomena appear in a competitive chemical reaction system involving amplification. A pseudoenantiomeric mixture of an aminomethylenehelicene ( )-tetramer and an ( )-hexamer in toluene forms three states, namely hetero-double-helix , hetero-double-helix , and dissociated random-coil 2 . When the temperature of the solution is oscillated between -5 and 38 °C at a rate of 2 K min , Δ reaches maxima twice during a single temperature oscillation, which is called a chemical CD oscillation phenomenon. The phenomenon arises from the sharp competition between the two self-catalytic 2 + -to-2 and 2 + -to-2 reactions. In addition, the chemical CD oscillation appears, when temperature oscillation occurs at a rate of 2 K min , and higher and lower rates provide a single maximum, a process referred to as the chemical resonance phenomenon. The changes in concentration induced by temperature oscillation repeatedly crossed equilibrium.