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

Abstract

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.