PULSED-EPR ON THE PHOTOEXCITED TRIPLET-STATE OF C60 IN FLUID SOLUTION- ELECTRON-TRANSFER FROM END-CAPPED QUATERTHIOPHENE AND C60-RADICAL ANION FORMATION

The photoexcited triplet state of C60 in fluid toluene solution was in vestigated by pulsed-EPR spectroscopy in a temperature range T = 200-3 00 K. The time evolution of the triplet EPR signal is found to be dete rmined by the spin-lattice relaxation time T1 and the triplet decay. I n the presence of the electron donor end-capped quaterthiophene the C6 0-triplet decay is quenched by electron transfer reaction. The tempera ture dependence of the triplet quenching rate k(q) suggests the format ion of an exciplex intermediate. Moreover we observe the formation of the C60-radical anion following electron transfer. The kinetics and po larization of the C60- EPR signal are discussed.