Room-temperature chemical synthesis of C.

Diatomic carbon (C) is historically an elusive chemical species. It has long been believed that the generation of C requires extremely high physical energy, such as an electric carbon arc or multiple photon excitation, and so it has been the general consensus that the inherent nature of C in the ground state is experimentally inaccessible. Here, we present the chemical synthesis of C from a hypervalent alkynyl-λ-iodane in a flask at room temperature or below, providing experimental evidence to support theoretical predictions that C has a singlet biradical character with a quadruple bond, thus settling a long-standing controversy between experimental and theoretical chemists, and that C serves as a molecular element in the bottom-up chemical synthesis of nanocarbons such as graphite, carbon nanotubes, and C.

Practical Synthesis of Ethynyl(phenyl)-λ-Iodane Using Calcium Carbide as an Ethynyl Group Source.

Stannylation of calcium carbide followed by Sn-hypervalent iodine(III) exchange reaction cleanly afforded the electrophilic ethynylating agent ethynyl(phenyl)-λ-iodane in high yield. This two-step method uses very inexpensive materials and is readily operable without any special precautions.

Synthesis of Belt- and Möbius-Shaped Cycloparaphenylenes by Rhodium-Catalyzed Alkyne Cyclotrimerization.

A belt-shaped [8]cycloparaphenylene (CPP) and an enantioenriched Möbius-shaped [10]CPP have been synthesized by high-yielding rhodium-catalyzed intramolecular cyclotrimerizations of a cyclic dodecayne and a pentadecayne, respectively. This Möbius-shaped [10]CPP possesses stable chirality and isolated with high enantiomeric purity. It is evident from the reaction Gibbs energy calculation that the above irreversible cyclotrimerizations are highly exothermic; therefore establishing that the intramolecular alkyne cyclotrimerization is a powerful route to strained cyclic molecular strips.