Chinese scientists have developed a powerful protocol for making new functional units of organic semiconductors. These could be used in molecular sensors and electronic devices. 

Zhaohui Wang, Daoben Zhu and colleagues at the Chinese Academy of Sciences, Beijing, have established a protocol for making S-heterocyclic annelated perylene bisimide (PBI). The reaction is palladium catalysed, and is unusual in that it converts the highly twisted precursor PBI molecule to a planar product. The new S-heterocyclic PBI molecules have unusual self-assembly properties, particularly in the presence of inclusion complexes, and are expected to act as a building block in electronic applications. 

Heteroarenes such as PBIs are recognised as one of the most promising molecular scaffolds for high performance semiconductors. The addition of hetero-groups to these scaffolds is known to affect the molecular electronic structure, and therefore the electronic device performances. Wang's method integrates two sulphur bridges into the PBI structure. PBIs with double hetero-atoms annelated in two bay regions are previously unknown, according to Wang. 

According to the team, this synthetic route should offer a versatile route to a variety of S-heterocyclic annelated polycyclic aromatics. 

Katherine Vickers