Generation of fullerenyl radicals and chemiluminescence in the (C60—R3Al)—O2 system

Abstract

Fullerenyl radicals (FR) RС 60• and chemiluminescence (CL) are generated in the pres ence of O 2 in С 60 -R 3 Al (R = Et, Bu i ) solutions in toluene (T = 298 K). The FR are formed due to the addition of the R • radical, which is an intermediate of R 3 Al autooxidation, to C 60 . Mass spectroscopy and HPLC were used to identify Et n С 60 H m (n, m = 1-6), Et p C 60 (p = 2-6), and dimer EtС 60 С 60 Et as stable products of FR transformations. As found by ESR, the EtС 60 • radical (g = 2.0037) is also generated by photolysis of solutions obtained after interaction in the (C 60 -R 3 Al)-O 2 system. In the presence of dioxygen, the FR is not oxidized but yields complexes with O 2 , which appear as broadening of the ESR signals. Chemiluminescence arising in the (C 60 -R 3 Al)-O 2 system is much brighter (I max = 1.86•10 8 photon s -1 mL -1 ) than the known background CL (I max = 6.0•10 6 photon s -1 mL -1 ) for the autooxidation of R 3 Al and is localized in a longer wavelength spectral region (λ max = 617 and 664 nm). This CL is generated as a result of energy transfer from the primary emitter 3 СН 3 СНО* to the products of FR transformation: R n С 60 H m , R p C 60 , and EtС 60 С 60 Et.