Bottom-up Synthesis and Thread-in-Bead Structures of Finite (n,0)-Zigzag Single-Wall Carbon Nanotubes

Abstract

The last remaining synthetic target of finite single-wall carbon nanotube models, the zigzag nanotube, has been accomplished through bottom-up chemical synthesis. The zigzag nanotube was synthetically accessible without constructing long-sought yet elusive cyclacene structures but with a cycloarylene structure by devising its cutout positions. The persistent tubular shape was also perfected in this last model by cyclization of zigzag-shaped aromatic molecules with a synchronous topological arrangement. The crystal structure of this nanotube further revealed an entangled supramolecular assembly, which showed a novel way to align nanotube molecules by utilizing their open-end functional groups in a thread-in-bead molecular assembly.

Solid-state structures of peapod bearings composed of finite single-wall carbon nanotube and fullerene molecules

“…Although severe disorders inherent to the dynamic bearing system hampered the analysis with ordinary X-ray beams, a synchrotron macromolecular crystallography beamline (BL41XU; SPring-8) (18) allowed us to solve the complex structure of the peapod at the atomic level. In the presence of chlorine atoms of CH 2 Cl 2 molecules in a single crystal of the chiral trigonal P3 2 space group at -173°C, we unequivocally assigned the absolute configuration of (12,8)- [4]CC 2,8 as (M)-helicity with a reliable Flack parameter of 0.13 (13). Note that this assignment finally confirmed the previous conclusion from the spectral and theoretical investigations (11).…”

“…Crystallographic Analysis of (12,8)- [4]CC. A single crystal of racemic (12,8)- [4]CC was obtained from a solution in methanol/CH 2 Cl 2 [∼1:1 (vol/vol)] at 25°C in aloosely sealed vial.…”

“…A single crystal of racemic (12,8)- [4]CC was obtained from a solution in methanol/CH 2 Cl 2 [∼1:1 (vol/vol)] at 25°C in aloosely sealed vial. The single crystal was mounted on a thin polymer tip with cryoprotectant oil and frozen at -178°C with flash-cooling.…”

“…Crystallographic Analysis of (M)- (12,8) )] at 25°C in a loosely sealed vial. The single crystal was mounted on a thin polymer tip with cryoprotectant oil and frozen at -258°C with flashcooling, and the temperature was gradually raised to -173°C.…”

“…The average diameter of the tube was measured at the carbon atoms closest to the equator (2-and 8-positions) and was 14.03 ± 0.04 (14.101 × 2 and 13.951 × 2) Å (13,26). The molecules were packed in a thread-in-bead entanglement between enantiomers, a packing motif similar to the packing of the (16,0)-isomer (12), but the molecules of (12,8)-isomer were further knitted to form a 2D network of the molecules by accommodating hexyl chains of two different enantiomeric molecules in the tube. Each of the enantiomers was separately stacked through an interdigitated entanglement of hexyl chains to form homochiral columns of (P)-and (M)-structures, respectively (26).…”