Makoto Nakagawa, and Takeshi Kawai, Tokyo University of Science, Japan, have developed chirality-controllable syntheses of double-helical Au nanowires (NWs). They used chiral soft-templates containing two organogelators. One organogelator (D- or L-12-hydroxystearic acid (D- or L-HSA)) introduces helicity into the template. The other organogelator (long chain amidoamine (C18AA)) controlls the Au shape as as a capping agent. Both organogelators were mixed in water containing a small amount of toluene, followed by the addition of LiCl, to prepare one-dimensional twisted-nanoribbon templates.

The handedness of the selfassembled twisted nanoribbon is completely controllable by the chirality of the HSA used as the chiral source. The Au NWs grow between the twisted nanoribbons with right- or left-handed helicities. Dispersions of the right- and left-handed double-helical Au NWs show opposite circular dichroism (CD) signals.

According to the researchers, this bifunctional strategy using two compounds that individually perform different functions into the template can be applied to the synthesis of other shape-controlled metallic nano-objects.

• Chirality-Controlled Syntheses of Double-Helical Au Nanowires,
  Makoto Nakagawa, Takeshi Kawai
  J. Am. Chem. Soc. 2018.
  https://doi.org/10.1021/jacs.8b00910