Construction\nand Circularly Polarized Luminescence\nof Thiophene-Based Multiple Helicenes

Thiophene-based monohelicene (<b>TS[7]H</b>), triple\nhelicenes\n(<b>TT[7]H</b>), and hexapole helicenes (<b>TH[7]H</b>) were synthesized via oxidative photocyclization and cascade Suzuki/intramolecular\ncyclization as the crucial steps. The enantiomers of <b>TS[7]H</b>, <b>TT[7]H-2</b>, and <b>TH[7]H</b> exhibited circularly\npolarized luminescence (CPL), and the luminescence dissymmetry factors\n(<i>g</i><sub>lum</sub>) gradually increased from −5.1\n× 10<sup>–4</sup> to −2.0 × 10<sup>–3</sup> with an increase in multiplicity from <b>TS[7]H</b> to <b>TH[7]H</b>. In addition, <b>TS[7]H</b>, <b>TT[7]H</b>, and <b>TH[7]H</b> displayed a second-level long afterglow\nat 77 K.