Synthesis and Photoinduced Intermolecular Electronic Acceptor Ability of Pyrazolo[60]fullerenes vs Tetrathiafulvalene

The synthesis of three novel pyrazolo[60]fullerene derivatives containing electron-withdrawing substituents has been described. High solubility in ordinary organic solvents was proved. Their electrochemical properties of pyrazolo[60]fullerenes showed better electron affinity than pristine C60 in the ground state. The nanosecond transient absorption spectra showed clear evidence for photoinduced electron transfer from TTF to the excited triplet state of the pyrazolo[60]fullerenes, in which stronger electron-withdrawing substituents accelerate the rates of the photoinduced electron-transfer, indicating a high electron-acceptor ability of the excited triplet state of pyrazolo[60]fullerenes.