Push-pull [7]helicene diimide: excited-state charge transfer and solvatochromic circularly polarised luminescence.

In this communication we describe a helically chiral push-pull molecule named 9,10-dimethoxy-[7]helicene diimide, displaying fluorescence (FL) and circularly polarised luminescence (CPL) over nearly the entire visible spectrum dependent on solvent polarity. The synthesised molecule exhibits an unusual solvent polarity dependence of FL quantum yield and nonradiative rate constant, as well as remarkable g abs and g lum values along with high configurational stability.