Synthesis of Contorted Polycyclic Aromatic Compounds via Alkyne Benzannulation on Zigzag-Edged Dibenzochrysene Derivatives.

Organic dyes are interesting building blocks for the preparation of organic semiconductors as they possess synthetic handles that can be used to functionalize them and, consequently, change their electronic properties. However, reactions to extend their π-conjugated framework through ring annulation have only been scarcely tested. Herein, we report the use of alkyne benzannulation on 2,8-dibromo-dibenzo[def,mno]chrysene (vat orange 3) and 2,9-dibromo-dibenzo[b,def]chrysene (vat orange 1) to extend the conjugation and reduce their bandgap.

Synthesis of an azulene-containing graphene nanoribbon.

The solution-phase synthesis of a non-benzenoid nanoribbon from an azulene-containing polymer alkyne benzannulation is reported. The nanoribbon is soluble in common organic solvents and exhibits conductivity values up to 1.5 × 10 S cm once doped by protonation in the thin film state.

Dibenzannulated -acenoacenes from anthanthrene derivatives.

A series of dibenzannulated phenyl-annulated [4,2]-acenoacenes have been synthesized in three straightforward steps from 4,10-dibromoanthanthrone (vat orange 3). The phenyl bisannulation of [4,2]-acenoacene provides extra stability by increasing the overall aromatic character of the molecules, and allows for a 45-80% increase of the molar extinction coefficient () compared to their [5,2]-acenoacene isomers. Depending on the substituents attached to the π-conjugated core, some derivatives exhibit strong aggregation in the solid state with association constant () up to 255 M, resulting in a significant broadening of the absorption spectrum and a substantial decrease of the bandgap value (more than 0.