Novel chiral poly(para-phenylene) derivatives containing cyclophane-type moieties

The introduction of cyclic ansa-substituents allows for the synthesis of soluble poly(para-phenylene)s PPP's possessing main chain chirality. The novel chiral PPP's represent an attractive combination of pi-conjugated character and chirality. We have synthesized open chain (single-stranded) as well as ladder-type chiral PPP's. The single-stranded 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 pi-pi*-transition. They are potential candidates to study non-linear chiroptical properties and to investigate circulary polarized luminescence (photo- and electroluminescence) effects.