A comparative study on optical properties of pyrene-fused [4]helicenes and vinyl precursors

Spectrochim Acta A Mol Biomol Spectrosc. 2024 Jan 15:305:123529. doi: 10.1016/j.saa.2023.123529. Epub 2023 Oct 12.

Abstract

Polycyclic aromatic hydrocarbon-fused [n]helicene derivatives (PAH-fused [n]helicenes) have been widely investigated due to their excellent photoelectric and chiroptical properties. Herein, a series of pyrene-fused helicenes were synthesized by a photocyclization reaction and characterized by 1H/13C NMR spectroscopy and single crystal X-ray diffraction. All compounds and their vinyl precursors were studied as emitting materials. The experimental results reveal that these compounds possess reasonable emission efficiency (ΦFL = 97% for 3a) and tunable optical properties, and a wide emission band from bluish violet for 3c (401 nm) to green-yellow for 4c (530 nm) was observed. The detailed investigation indicated that an efficient, structure-controlled strategy was established to develop pyrene-based [n]helicene materials.

Keywords: Helicene; Pyrene chemistry; Structure-controlled strategy; π-Conjugation.