Poly(thiophene iminoborane): A Poly(thiophene vinylene) (PTV) Analogue with a Fully B = N-Doped Backbone.

An unprecedented poly(thiophene iminoborane) - a boron-nitrogen analogue of the well-established conjugated organic polymer poly(thiophene vinylene) (PTV) - is presented. The polymer synthesis has been achieved by selective Si/B exchange polycondensation of a 2,5-diborylthiophene with a 2,5-diaminothiophene derivative. For the latter, a facile synthetic strategy has been devised, which makes this versatile, strongly electron-releasing building block easily accessible. The novel polymer and a series of monodisperse thiophene iminoborane oligomers reveal systematic bathochromic shifts in their absorption with increasing chain length, and thus extended π-conjugation over the B = N units along the backbone, which is further supported by TD-DFT calculations. This article is protected by copyright. All rights reserved.