Synthesis of helical conjugated ladder polymers

摘要

The synthesis is described of the first helical ladder polymers with unbroken pathways of conjugation that extend not only through each monomeric unit, but between them as well. The key step is the condensation of 1,2-phenylenediamine and a transition metal salt with a helicene having salicylaldehyde's functionality at both ends. This gives rise to "metal salophen" units that bind adjacent helicenes, provide conjugated links from one ring system to the next, and constrain the p-orbitals of the rings they unite to be nearly parallel.