Resolution of 9,10-Diketo[7]helicene and Its Use in One-Step Preparation of Helicene-Based D–A–D Push–Pull Systems

Racemic 9,10-diketo[7]­helicene was successfully separated into enantiomers using a reversible and stereoselective reaction with 2,2′-diamino-1,1′-binaphthalene with moderate yields but with remarkable purity (>99% de). The enantiomerically pure diketone was used as a convenient starting material for the preparation of helicene-based push–pull molecules, which incorporated aza-aryl acceptors and diarylaminophenylene donor groups in a single step. A series of six push–pull systems, along with three reference molecules without donors, were prepared and studied using UV/vis and fluorescence measurements, circular dichroism, and DFT calculations.