Mono- and multiply-functionalized fullerene derivatives through 1,3-dipolar cycloadditions: A DFT study

We have performed a computational study to investigate the electronic and chemical properties of mono- and multiply-functionalized fullerene derivatives through the [2+3] cycloaddition reactions of 1,3 dipoles such as nitriloxide (HC=N+-O-), azide (N=N+-NH-) and azomethine ylides (H2C-NH+-CH2-) with C-60 fullerene. The 1,3-dipolar cycloadditions (1,3 DCs) of one to six dipoles with a C-60 molecule are theoretically investigated in terms of geometry, energies, electronic structures, stability and the electrophilicity index. Negative values of reaction energies E-I are obtained, which indicate the exothermic character of the adsorption process. Generally, absolute values of E-r for the C-60/(H2C-NH+-CH2-)(n) compounds are always larger than those of their corresponding compounds C-60/ (HC=N+-O-)(n) and C-60/(N=N+-NH-)(n). The results indicate that the successive 1,3-DC reactions of nitriloxides (HC=N+-O-) and azides (N=N+-NH-), n=1,2, 4 and 6 on the exterior surface of fullerene increases the electrophilicity while the reverse trend is observed for C-60/(H2C-NH+-CH2-)(n). Furthermore, electrophilicity values for the C-60/(HC=N+-O-)(n) and C-60/(N=N+-NH-)(n) compounds are always greater than those of C-60. (C) 2013 Elsevier B.V. All rights reserved.