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.

Fine-tuning of 2D metal–organic nanostructures is realized by alkali–pyridyl coordination.

Scheme 1. The chemical structure of 2,9-dibromo-1,10-Phenanthroline (1) and its reaction pathways (cyclization and polymerization) on Cu(111), towards the formation of macrocycles via intermolecular cis-connections (green) and polymeric chains via trans-connections (red), respectively. ChemPhysChemCommunications

This paper presents a spectroscopic analysis and solubility study of rosin, copal, and Burmese amber samples to reveal the structural changes that occur during amber formation. The infrared spectra indicate that during the long geological process of amber formation, small resin molecules first crosslinked and slowly oxidized, eventually forming a stable organic polymer mixture. An analysis of Raman peak areas demonstrated that among the tested samples, the degree of polymerization is highest in Burmese amber and lowest in rosin. Ultraviolet-visible spectra indicate the presence of unsaturated bonds (e.g., carbonyl groups) or conjugated systems in Burmese amber, copal, and rosin. The evaluation of amber, rosin, and copal solubility in six solvents (ethanol, acetone, 1,4-dioxane, ethylacetate, N,N-dimethylamide, and dichloromethane) demonstrated that solubility decreases in the following order: rosin > copal > Burmese amber. Together, the results suggest that the structure of Burmese amber includes large organic molecules containing six-membered rings along with CH2, CH3, C=O, C=C, C–O, and C–C groups.