SUMMARY: The solvent and temperature dependent aggregation of high molecular weight bis[S-(+)-3,7-dimethyloctyl)] substituted poly(p-phenyleneethynylene) (PPE, 2) was examined by absorption, emission and circular dichroism spectroscopy. All herein employed methods strongly support the view that 2 forms ordered aggregates in the solid state and in solvent mixtures. This is the first case in which a chiral high molecular weight PPE displays its aggregation by both optical and chiroptical methods.

_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.

The introduction of cyclic ansa-substituents allows for the synthesis of soluble poly-(para-pheny1ene)s PPPs possessing main chain chirality. The novel chiral PPP's represent an attractive combination of n-conjugated character and chirality. We have synthesized open chain (single-stranded) as well as ladder-type chiral PPPs. The singlestranded chiral PPP's exhibit temperature-dependent changes of chiroptical properties. The behaviour should be assigned to conformational changes. The chiral ladder polymers contain the cyclophane loops exclusively on one side of the molecular board and are characterized by an unexpectedly high chiroptical activity of the n-n*-transition. They are potential candidates to study non-linear chiroptical properties and to investigate circulary polarized luminescence (photo-and electroluminescence) effects.

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