Short-step synthesis and chiroptical properties of polyaza[5]–[9]helicenes with blue to green-colour emission†
Abstract
We have developed a two- or three-step synthesis of polyaza[5]–[9]helicenes by consecutive N–H/C–H coupling with a hypervalent iodine reagent. We further evaluated their photophysical properties, and circularly polarized luminescence properties and found that glum values increase with the number of fused rings up to 2.7 × 10−2, which is the highest value among [9]helicenes.