Modification of fulleropyrazolines modulates their cleavage by light.
Rutte RN., Parsons TB., Davis BG.
The extraordinary electrochemistry and the tunability of their energy levels allows the use of fulleropyrazolines in photovoltaics and charge-transfer systems. Here we show that substitution in position 1 tunes photolytic stability; electron-donating groups facilitate 1,3-dipolar cycloreversion to fullerene. This discovery has implications not only for photovoltaic stability but also highlights a potential strategy for photo-controlled fullerene release systems ('photo-caged'/'photo-activated' fullerene).