Carbon nanobelts are milestones in the bottom-up approach to challenging chirality-specific synthesis of carbon nanotubes. This study puts forth an unprecedented armchair carbon nanobelt and the first chiral carbon nanobelt, which represent sidewall segments of (12,12)CNT and (18,12)CNT, respectively. These carbon nanobelts were efficiently synthesized by p-expansion of the corresponding polyarylated carbon nanorings through Scholl reactions, which are accompanied by either a small increase or even a decrease in strain energy, as found from the theoretical calculations.

We report the synthesis and characterization of two hexapole [7]helicenes (H7Hs). Single crystal X-ray diffraction unambiguously confirms the molecular structure. H7H absorbs light, with distinct Cotton effect, from ultraviolet to the near-infrared (λ = 618 nm). Cyclic voltammetry reveals nine reversible redox states, consecutively from -2 to +6. These chiroptical and electronic properties of H7H are inaccessible from helicene's small homologues.

Zigzag carbon nanobelts are al ong-sought-after target for organic synthesis.Herein we report new strategies for designing and synthesizing unprecedented zigzag carbon nanobelts,which present awave-like arrangement of hexagons in the unrolled lattice of (n,0) single wall carbon nanotubes (n = 16 or 24). The precursors of these zigzag carbon nanobelts are hybrid cyclic arylene oligomers consisting of metaphenylene and 2,6-naphthalenylene as well as para-phenylene units.T he Scholl reactions of these cyclic arylene oligomers form multiple carbon-carbon bonds selectively at the apositions of naphthalene units resulting in the corresponding zigzag carbon nanobelts.A sm onitored with fluorescence spectroscopy, one of these nanobelts binds C 60 with an association constant as high as (6.6 AE 1.1) 10 6 M À1 in the solution in toluene.C omputational studies combining linear regression analysis and hypothetical homodesmotic reactions reveal that these zigzag nanobelts have strain in the range of 67.5 to 69.6 kcal mol À1 ,a nd the ladderization step through Scholl reactions is accompanied by increase of strain as large as 69.6 kcal mol À1 .T he successful synthesis of these nanobelts demonstrates the powerfulness and efficiency of Scholl reactions in synthesizing strained polycyclic aromatics. Figure 1. (a) [n]Cyclacene and zigzag carbon nanobelts reported very recently;( b) structures of zigzag carbon nanobelts 1-3.

Tw os ynthetic nanographenes (NGs), N-H7H and C-H7H,w ere prepared. N-H7H is doped with nitrogen, and C-H7H is the all-carbon analogue.B oth are hexapole [7]helicenes (H7Hs), and their structures were identified by singlecrystal X-raydiffraction. Sharp contrasts in absorption ( abs l max , 683 vs.5 93 nm), emission ( em l max ,8 94 vs.7 77 nm), and electrochemical behavior ( ox E 1 ,0.28 vs.0.53 V) were observed between N-H7H and C-H7H,a nd the origin of these differences was rationalized by theoretical calculations.S tudies on N-H7H and C-H7H set ac lear example to elucidate the remarkable effects of N-doping on the physical properties of NGs.Supportinginformation and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.

Oxanorbornene-fused double-stranded macrocycles, as represented by kohnkene, are not only synthetic precursors toward short segments of zigzag carbon nanotubes but also typical cavitands processing an intrinsic cavity. However, their capability...