A Trefoil Macrocycle Synthesized by 3-Fold Benzannulation.

A new trefoil-shaped molecular architecture consisting of three conjugated macrocycles was synthesized through an unprecedented 3-fold copper catalyzed [4 + 2] benzannulation. DFT calculations indicate that the most stable conformation of this trefoil macrocycle is D-symmetric. In agreement with the calculated results, the trefoil macrocycle in single crystals exists as a pair of enantiomers with D-symmetry and exhibits interesting honeycomb-like supramolecular structures.

Twisted Polycyclic Arenes from Tetranaphthyldiphenylbenzenes by Controlling the Scholl Reaction with Substituents.

Herein, we report two new types of twisted polycyclic arenes (2 a, b and 3 a, b) with constitutionally isomeric π-backbones, which are synthesized by controlling the Scholl reaction of 1,2,4,5-tetra(naphth-2-yl)-3,6-diphenylbenzene (1) with properly positioned electron-donating substituents. With a polycyclic backbone containing two [5]helicene and four [4]helicene moieties, 2 a and b are new members of multiple helicenes with interesting stereochemistries. The as-synthesized 2 a and b are the twisted isomers, and thermal isomerization of twisted-2 b results in anti-2 b, a more stable stereoisomer.

An Elemental Phosphorus Photocatalyst with a Record High Hydrogen Evolution Efficiency.

Semiconductive property of elementary substance is an interesting and attractive phenomenon. We obtain a breakthrough that fibrous phase red phosphorus, a recent discovered modification of red phosphorus by Ruck et al., can work as a semiconductor photocatalyst for visible-light-driven hydrogen (H2 ) evolution.