Synthesis and characterization of the first soluble nonracemic chiral main-chain perylene tetracarboxylic diimide polymers

The first two nonracemic chiral main-chain perylene tetracarboxylic diimide (PDI) polymers have been synthesized via acyclic diene metathesis polymerization. The use of optically pure l-α amino acids as the starting materials enables us to tune PDI π-stacking interaction in optically active polymers. The integration of π-stack tuning groups renders two main-chain PDI polymers soluble in chloroform. Spectroscopic evidences suggest that PDI π-stacks form in chloroform solutions of the two PDI polymers, even at very low concentration, probably via an intra-molecular folding process. Inside π-stacks, PDI units organize in a left-handed helical fashion. Flexible free-standing films can be cast from chloroform solution of one polymer.