Covalently Assembled Gold Nanoparticle-Carbon Nanotube Hybrids via a Photoinitiated Carbene Addition Reaction

A nanohybrid consisting of monolayer protected gold nanoparticles (AuNPs) covalently attached to multiwalled carbon nanotubes (CNT) was prepared using a photoinitiated carbene addition approach. Photolysis of 3-aryl-3-(trifluoromethyl)diazirine-modified gold nanoparticles (Diaz-AuNPs) of two core sizes (3.9 ± 0.9 nm and 1.8 ± 0.3 nm in diameter) resulted in the generation of reactive carbene intermediates on the monolayer of the AuNPs. In the presence of untreated CNT the reactive carbenes undergo an addition reaction with the π-conjugated carbon skeleton. The AuNPs are well dispersed on the sidewall of the CNT and the hybrids are robust enough to survive vigorous washing in a variety of solvents. In the absence of photolysis no covalent attachment occurs with the same AuNP. The nanohybrid AuNP-CNTs were characterized using transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman, and UV−visible spectroscopy. All of the characterization studies confirm the presence of the AuNPs. This methodology provides support that this photoinitiated carbene reactivity can be utilized for the functionalization of other materials with nanoparticles.