Helix-sense controlled polymerization of a single phenyl isocyanide enantiomer leading to diastereomeric helical polyisocyanides with opposite helix-sense and cholesteric liquid crystals with opposite twist-sense.
We report the unprecedented helix-sense controlled polymerization of enantiomerically pure phenyl isocyanides bearing an l- or d-alanine pendant with a long alkyl chain. The polymerization with an achiral nickel catalyst diastereoselectively proceeds, resulting in either a right- or left-handed helical polymer, whose helix-sense can be controlled by the polymerization solvent and temperature. Both the diastereomeric right- and left-handed helical polymers further self-assemble into lyotropic cholesteric liquid crystals with opposite twist-senses. Consequently, the macromolecular helicity and mesoscopic, supramolecular cholesteric twist can be controlled by the molecular chirality of the pendant of a single enantiomeric phenyl isocyanide through the polymerization under either kinetic or thermodynamic control assisted by hydrogen bonds. High-resolution atomic force microscopy revealed their helical conformations and enabled the determination of the helical sense.
Kajitani
Takashi
T
Yashima Super-structured Helix Project, Exploratory Research for Advanced Technology, Japan Science and Technology Agency, 101 Creation Core Nagoya, 2266-22 Anagahora, Shimoshidami, Moriyama-ku, Nagoya 463-0003, Japan.
Okoshi
Kento
K
Sakurai
Shin-ichiro
S
Kumaki
Jiro
J
Yashima
Eiji
E
D000409:Alanine / Q000031:analogs & derivatives* / Q000737:chemistry; D008958:Models, Molecular; D008968:Molecular Conformation; D009570:Nitriles / Q000737:chemistry*; D013237:Stereoisomerism
D009570:Nitriles; C019519:phenylisocyanide; D000409:Alanine