Synthesis and Chiroptical Properties of a Saddle-Shaped Quadruple Helicene with a Cyclooctatetrapyrrole Core

A quadruple helicene with a cyclooctatetrapyrrole core was synthesized via a simple Ullmann reaction. Its single-crystal structure exhibits a saddle shape. The compound shows fluorescence emission with λ_em = 575 nm and good chiroptical properties, including a dissymmetric absorption factor (|g_abs|) of 5.84 × 10^-3 and a dissymmetric emission factor (|g_lum|) of 1.21 × 10^-2.