Synthesis of C70 -Based Fluorophores through Sequential Functionalization to Form Isomerically Pure Multiadducts.

Selective addition to the C70 cage divides its π-conjugated system into various smaller π-conjugated systems with enhanced fluorescent properties. Key reactions include chlorination, methoxylation, ozonation, and Bingel or Bingel-Hirsch reactions. The maximum emission wavelength of the C70 multiadducts ranges from 450 to 655 nm. Among the C70 multiadducts, C70 (OMe)8 (C(COOEt)2 )3 showed the highest quantum yield (ΦF =0.18) and the largest Δ[λmax (emission)- λmax (absorption)] (402 nm), with maximum emission at 655 nm.