Suzuki coupling reactions for the surface functionalization of single-walled carbon nanotubes

Suzuki coupling reactions for the covalent functionalization of single-walled carbon nanotubes (SWNT) with conjugated chromophores was investigated. The Raman spectrum shows a large increase in the disorder band when compared to the spectrum of pristine nanotubes indicating a high degree of functionalization. The reactions were carried out in dimethylformamide at 100 °C. It was found that the cross-coupled SWNT products exhibited high solubility in tetrahydrofurans (THF). Spectrometric measurement of nanotube solubility was done in THF using reported methods. TRansmission electron microscopy (TEM) and atomic force microscopy (AFM) were used to characterize the porphyrin-functionalized SWNT. It was observed that quenching efficiency is nearly quantitative and was found to occur regardless of which chromophore was attached. It was also observed that the covalently functionalized nanotubes can serve as efficient quenchers.