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

Selective addition to the C-70 cage divides its pi-conjugated system into various smaller -conjugated systems with enhanced fluorescent properties. Key reactions include chlorination, methoxylation, ozonation, and Bingel or Bingel-Hirsch reactions. The maximum emission wavelength of the C-70 multiadducts ranges from 450 to 655nm. Among the C-70 multiadducts, C-70(OMe)(8)(C(COOEt)(2))(3) showed the highest quantum yield (Phi(F)=0.18) and the largest Delta[lambda(max)(emission)-lambda(max)(absorption)] (402nm), with maximum emission at 655nm.