Metal-free FRET macrocycles of perylenediimide and aza-BODIPY for multifunctional sensing.

Two multichromophoric FRET macrocycles M1 [1+1] and M2 [2+2] with red emission ( λ em ∼ 721 nm) composed of perylenediimide (PDI) as the energy donor and aza-BODIPY (ABDP) as the energy acceptor were synthesized by click reaction in a metal-free fashion. M1 and M2 exhibited distinct reversible ratiometric temperature responsive emission with temperature sensitivities of 0.09-0.14% °C -1 and owing to the redox active chromophores, they showed solution phase redox responsive reversible colour changes.