title: Optically active single-walled carbon nanotubes.
abstract: The optical, electrical and mechanical properties of single-walled carbon nanotubes (SWNTs) are largely determined by their structures, and bulk availability of uniform materials is vital for extending their technological applications. Since they were first prepared, much effort has been directed toward selective synthesis and separation of SWNTs with specific structures. As-prepared samples of chiral SWNTs contain equal amounts of left- and right-handed helical structures, but little attention has been paid to the separation of these non-superimposable mirror image forms, known as optical isomers. Here, we show that optically active SWNT samples can be obtained by preferentially extracting either right- or left-handed SWNTs from a commercial sample. Chiral 'gable-type' diporphyrin molecules bind with different affinities to the left- and right-handed helical nanotube isomers to form complexes with unequal stabilities that can be readily separated. Significantly, the diporphyrins can be liberated from the complexes afterwards, to provide optically enriched SWNTs.
authors.forename: Xiaobin
authors.initials: X
authors.lastname: Peng
authors.forename: Naoki
authors.initials: N
authors.lastname: Komatsu
authors.forename: Sumanta
authors.initials: S
authors.lastname: Bhattacharya
authors.forename: Takanori
authors.initials: T
authors.lastname: Shimawaki
authors.forename: Shuji
authors.initials: S
authors.lastname: Aonuma
authors.forename: Takahide
authors.initials: T
authors.lastname: Kimura
authors.forename: Atsuhiro
authors.initials: A
authors.lastname: Osuka
mesh_terms: D003460:Crystallization / Q000379:methods*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008027:Light; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing; D008968:Molecular Conformation; D036103:Nanotechnology / Q000295:instrumentation*; D037742:Nanotubes, Carbon / Q000737:chemistry* / Q000648:ultrastructure*; D055095:Optics and Photonics / Q000295:instrumentation*; D010316:Particle Size; D011166:Porphyrins / Q000737:chemistry*; D012542:Scattering, Radiation; D013499:Surface Properties
chemical_list: D046911:Macromolecular Substances; D037742:Nanotubes, Carbon; D011166:Porphyrins