The quenching processes of the exited triplet state of fullerene ( 3C60*) by ferrocene (Fc) derivatives have been observed by the transient absorption spectroscopy and thermal lens methods. Although 3C60* was efficiently quenched by Fc in the rate close to the diffusion controlled limit, the quantum yields (φet) for the generation of the radical anion of C60 (C60) via 3C60* were quite low even in polar solvents; nevertheless, the free-energy changes (ΔG et) of electron transfer from Fc to 3C60* are sufficiently negative. In benzonitrile (BN), the φet value for unsubstitued Fc was less than 0.1. The thermal lens method indicates that energy transfer from 3C60* to Fc takes place efficiently, suggesting that the excited triplet energy level of Fc was lower than that of 3C60*. Therefore, energy transfer from 3C60* to ferrocene decreases the electron-transfer process from ferrocene to 3C60*. To increase the participation of electron transfer, introduction of electron-donor substituents to Fc (φet = 0.46 for decamethylferrocene in BN) and an increase in solvent polarity (φet = 0.58 in BN:DMF (1:2) for decamethylferrocene) were effective.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films
- Materials Chemistry