On the oxidative coupling of N,N-disubstituted 2-aminothiophenes—synthesis of N,N′-persubstituted 5,5′-diamino-2,2′-bithiophenes

The oxidative coupling of N,N-disubstituted 2-aminothiophenes performed by several heavy-metal free oxidizing agents gives rise to the formation of N,N′-persubstituted 5,5′-diamino-2,2′-bithiophenes which are of interest as hole-transport materials for optoelectronic applications.