Aggregation-induced CD effects in chiral poly(2,5-dialkoxy-1,4-phenylene)s

Abstract

_We have investigated the chiroptical properties of novel PPPs containing chiral side chains. The synthesis of poly(2,5-bis[2-(S)-methylbutoxy]-1,4-phenylene) (BMB-PPP) has been successfully achieved in a Suzuki-type aryl—aryl cross coupling (Mn: 9700, Dp: 40, PPP calibration). The very good solubility of BMB-PPP allows for a detailed study of its chiroptical properties. Our studies demonstrate that the bisignated CD spectra of BMB-PPP are associated with an intermolecular aggregation phenomenon. BMB-PPP shows remarkably high dissymmetry factors both in poor solvent/good solvent mixtures and in the solid state (Δε/ε up to 0.01). BMB-PPP exhibits an intense blue photoluminescence in solution, and in the solid state. In addition, the first execution of the so-called "sergeant and soldier" principle for a chiral-substituted, conjugated polymer is described.