Cs-Symmetric Donor–Acceptor Bis(thiazole)s: Synthesis and Photophysical, Electrochemical, and Computational Studies

Abstract

We herein report the design and synthesis of Cs-symmetric donor–acceptor (D–A) molecular systems that have electron-donating and electron-withdrawing groups of the type D-π-A-π-D and D-A1-A-A1-D by using a Pd-catalyzed Sonogshira cross-coupling and [2+2] cycloaddition–retroelectrocyclization reactions. The photophysical and electrochemical properties as well as computational studies of these systems were explored, and strong donor–acceptor interactions were found. The [2+2] cycloaddition–retroelectrocyclization reaction pathway was studied by computational calculations, which revealed that bis(thiazole)s that contain donor groups at the terminal positions were favored in the reaction with tetracyanoethene (TCNE), whereas bis(thiazole)s that contain electron-withdrawing groups were disfavored. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim