New [4]helicene derivatives: Synthesis, characterization and photophysical properties

The design and synthesis of new[4]helicene derivatives were carried out by incorporating well-defined electron donor and acceptor groups at selected positions of the aromatic nuclei, aiming to use them in optical applications. Helicenes have been obtained in good overall yields through a five-step sequence involving mild experimental conditions and easy purification. Photophysical properties of these tetracyclic systems have been evaluated by UV-visible absorption and fluorescence spectroscopies and an emission in the visible region was observed. (C) 2018 Elsevier B.V. All rights reserved.