Bay-Substituted Thiazahelicenes: Synthesis and Implications on Structural and Spectroscopic Properties
journal contributionposted on 2019-10-07, 11:35 authored by Mathias Daniels, Flip de Jong, Tom Vandermeeren, Luc Van Meervelt, Mark Van der Auweraer, Wim Dehaen
A series of bay-substituted thiazahelicenes was synthesized to investigate the effect of different substituents on the properties of these helicenes. These thiazahelicenes with different substituents were prepared in a straightforward manner through indole- and benzo[b]thiophene synthesis, palladium-catalyzed Suzuki coupling, oxidative cyclization, and functional group interconversion reactions. We investigated the impact of these different bay area substituents compared to the unsubstituted thiazahelicene on the structural parameters and studied the steady-state electronic spectroscopy of these thiazahelicenes in toluene and acetonitrile. We found that different functional groups influence the solid state structure and spectroscopic properties, but a single substituent in the bay area of a thiazahelicene was not enough to prevent enantiomerization at room temperature.