A sensible route to covalent functionalization of carbon nanoparticles with aromatic compounds

We report the functionalization of onion-like carbon (OLC) nanoparticles with anthracene by direct covalent binding. The new chemical route is based on the bromine/lithium exchange, commonly used for aliphatic compounds, but applied here to aromatic carbon. Our results provide a new procedure for the chemical functionalization of the OLC nanoparticles, which could be also a new route to functionalization of other species in the carbon nanoparticle family. X-ray photoelectron spectroscopy and infrared spectroscopy were used to monitor the functionalization. The data obtained account for the nature of the ligands at the surface of the OLC and also for the degree of functionalization. We discuss the differences observed between the shifts in the vibrational bands of the anthracene chemisorbed and physisorbed by the OLC. Polycyclic aromatic hydrocarbons (PAHs) and carbon nanoparticles are produced simultaneously in certain regions of space, but also in our atmospheric environment due to the incomplete combustion of hydrocarbons; therefore the spectroscopic changes in the vibrational spectrum of PAHs upon adsorption by carbon nanoparticles can be worthy of multidisciplinary attention. The new functionalization route provides a tool for the manipulation of a highly promising type of carbon nanoparticles with potential applications in nanoelectronics and nanomedicine.