title: Dynamic or nondynamic? Helical trajectory in hexabenzocoronene nanotubes biased by a detachable chiral auxiliary.
abstract: When ether vapor was allowed to diffuse into a CH(2)Cl(2) solution of an enantiomer of a hexa-peri-hexabenzocoronene (HBC) derivative carrying a chiral (BINAP)Pt(II)-appended coordination metallacycle (HBC(Py)([(R)-Pt]) or HBC(Py)([(S)-Pt])), screw-sense-selective assembly took place to give optically active nanotubes (NT(Py)([(R)-Pt]) or NT(Py)([(S)-Pt])) with helical chirality, which were enriched in either left-handed (M)-NT(Py)([(R)-Pt]) or right-handed (P)-NT(Py)([(S)-Pt]), depending on the absolute configuration of the (BINAP)Pt(II) pendant. When MeOH was used instead of ether for the vapor-diffusion-induced assembly, nanocoils formed along with the nanotubes. As determined by scanning electron microscopy, the diastereomeric excess of the nanocoils was 60% (80:20 diastereomeric ratio). Removal of the (BINAP)Pt(II) pendants from NT(Py)([(R)-Pt]) or NT(Py)([(S)-Pt]) with ethylenediamine yielded metal-free nanotubes (NT(Py)) that remained optically active even upon heating without any change in the circular dichroism spectral profile. No helical inversion took place when NT(Py) derived from HBC(Py)([(R)-Pt]) or HBC(Py)([(S)-Pt]) was allowed to complex with (BINAP)Pt(II) with an absolute configuration opposite to the original one.
authors.affiliation: RIKEN Advanced Science Institute, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.forename: Wusong
authors.initials: W
authors.lastname: Jin
authors.forename: Takanori
authors.initials: T
authors.lastname: Fukushima
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Ishii
authors.forename: Takuzo
authors.initials: T
authors.lastname: Aida
mesh_terms: D008958:Models, Molecular; D015394:Molecular Structure; D043942:Nanotubes / Q000737:chemistry*; D010316:Particle Size; D011083:Polycyclic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D011083:Polycyclic Compounds; C507240:hexa-peri-hexabenzocoronene