关键词: ¹³C 化学位移, 核磁共振(NMR), 密度泛函理论计算, 碳纳米管, 加成反应

Abstract: Surface chemical modification of carbon nanotubes has become a hot research topic nowadays. The dispersion of carbon nanotubes in polar solvents can be greatly improved by attaching hydrophilic groups onto their surfaces, increasing the range of their application. In this study, a C₈₀ H₂₀ model was used to represent the (10, 0) zig-zag carbon nanotube. Based on this model, the structures, dipole moments and the nuclear magnetic resonance parameters were calculated for a series of functionalized nanotubes, including nitrene and carbene modification, as well as 1, 2- and 1, 4-fluorination. The results indicated that the high level density functional theory (DFT) calculations can be used to predict the ¹³C chemical shifts of the modified nanotubes. The calculated results also provided the characteristic chemical shifts values of nitrene-, carbene- and 1, 2- and 1,4-fluorinated nanotubes, which would be helpful for experimental spectrogram assignments. Combined with NMR experiments, these predicted characteristic chemical shifts can be further used to monitor the addition mechanism and the extent of surface modifications on nanotubes.

Key words:

NMR, ¹³C chemical shift, DFT calculation, carbon nanotube, addition reaction