Enhanced coalescence reactions of fullerenes by laser desorption of C60 derivatives

Abstract

We observed enhanced coalescence reactions of fullerenes by laser desorption of chemical adducts of (C6H5CH2)nC60, (C9H7)mHnC60, (CCl2)xC60 and the newly available poly-N-vinylcarbazole (PVK)-C60/70. The mass spectra of the laser-produced species reveal a characteristic bi-modal profile, with one maximum abundance distribution of parent fullerene ions located at C60 and the other at nearly twice C60. The mass spectra of both pristine C60 and the non-reactive PS/C60 mixture show monotonically descending intensity of daughter fullerenes with successive C2 captures, whereas slightly enhanced coalescence products are observed for the reactive PVK/C60/70 mixture which is known as a charge transfer complex. The mechanism of efficient coalescence is believed to be cluster collisional nucleation of pairs of reactive fullerene fragments (nascent C60, C58, etc.) induced by photofragmentation of the reactive Rn-C60 adduct or Rn⋯C60 charge transfer system, which is indicated by the laser power dependence features and the correlation between enhanced fullerene fragments and coalescence products. © 1997 Elsevier Science B.V.