3,6-Fluoren[5]arenes: synthesis, structure and complexation with fullerenes C60 and C70

A new class of macrocyclic arenes, 3,6-fluoren[5]arenes, were conveniently synthesized in good yields by one-step reaction. The 3,6-fluoren[5]arenes had symmetric pentagon structures with big and rich-electron cavities, which made them form 1 : 1 complexes with fullerenes C60 and C70. The association constants of the complexes were all greater than 105 M-1.