For this study, Cu-In-S nanocrystals were developed as a low toxic fluorescent. The stoichiometric CuInS(2) nanocrystals were synthesized facilely by heating a solution of metal complexes and dodecanethiol. The fluorescence would be originated from the crystal defect. We intentionally introduced the crystal defect in nanocrystal with the prospect that the fluorescence intensity would be increased. The defect structure of products was analyzed using Raman spectroscopy and other techniques. The nanocrystals have many defects without phase separation as observed in the bulk material. Consequently, the fluorescence quantum yield achieved approximately 5%. Moreover, the fluorescence quantum yield was increased up to 15% by the ZnS coating.

The structure-selective precise synthesis of carbon nanotubes (CNTs) has been long sought in materials science. The aromatic molecules corresponding to segment structures of CNTs, i.e. carbon nanobelts (CNBs), have been of interest as templates for CNT growth. Although two of three types, armchair and chiral CNBs, have been synthesized recently, zigzag CNBs remain elusive. Herein we report the synthesis and isolation of a zigzag CNB. The synthesis involves an iterative Diels-Alder reaction sequence followed by reductive aromatization of oxygen-bridged moieties. As predicted by theoretical calculations, this CNB was isolated as a stable compound. The structure of the zigzag CNB was fully characterized by X-ray crystallography, and its wide energy gap with blue fluorescence properties were revealed by photophysical measurement. With synthetic strategies towards all three types of CNBs in hand, the road to the precise synthesis of CNTs can now proceed to the next stage. File list (3) download file view on ChemRxiv CheungZigzag_.pdf (9.75 MiB) download file view on ChemRxiv SI_CheungZigzag_.pdf (4.72 MiB) download file view on ChemRxiv cheung.cif (1.23 MiB)

Technologies for the creation of topological carbon nanostructures have greatly advanced synthetic organic chemistry and materials science. Although simple molecular nanocarbons with a belt topology have been constructed, analogous carbon nanobelts with a twist—more specifically, Möbius carbon nanobelts (MCNBs)—have not yet been synthesized owing to their high intrinsic strain. Here we report the synthesis, isolation and characterization of a MCNB. Calculations of strain energies suggest that large MCNBs are synthetically accessible. Designing a macrocyclic precursor with an odd number of repeat units led to a successful synthetic route via Z-selective Wittig reactions and nickel-mediated intramolecular homocoupling reactions, which yielded (25,25)MCNB over 14 steps. NMR spectroscopy and theoretical calculations reveal that the twist moiety of the Möbius band moves quickly around the MCNB molecule in solution. The topological chirality that originates from the Möbius structure was confirmed experimentally using chiral HPLC separation and circular dichroism spectroscopy.