EXCITED-STATE INTERACTIONS IN PYRROLIDINOFULLERENES

Two new pyrrolidinofullerenes, 1 and 2, have been synthesized, and the ir photophysical properties have been investigated. The pyrrolidinoful lerene 1 has three phenyl groups attached to the 1, 2, and 5 positions of the pyrrolidine ring. The pyrrolidinofullerene 2, on the other han d, has a flexible attachment with an N-methylaniline end group and is the prototype of a fullerene-aniline dyed. Singlet and triplet excited -state properties of these two functionalized fullerene derivatives ha ve been examined with picosecond and nanosecond laser flash photolysis . The singlet and triplet excited states of these fullerenes exhibit c haracteristic absorption bands in the vis-IR region of the spectrum. T he functionalization of C-60 with pyrrolidine groups shift the excited -state absorption maxima to the blue. Three different quenchers, O-2, TEMPO, and ferrocene, are employed to investigate the reactivity of tr iplet excited states. The bimolecular quenching rate constants determi ned for these quenchers were in the range of 5.3 x 10(8) to 7.7 x 10(9 ) M-1 s(-1). The excited-state interactions of these functionalized fu llerenes are compared to that of C-60.