Carbene-Functionalized Ruthenium Nanoparticles

Stable ruthenium nanoparticles were synthesized by protecting the particles with diazo molecules that reacted readily with the ruthenium surface forming Ru C carbene bonds, as manifested in Fourier transform infrared and 1 H NMR measurements. The resulting particles, with the core diameter averaged at 2.12 ± 0.72 nm as determined by transmission electron microscopic measurements, showed a Mie scattering profile in optical absorption measurements. In electrochemical studies, the particles exhibited interesting quantized charging characteristics, similar to those observed with alkanethiolate-protected gold (AuSR) nanoparticles. In addition, a proof-of-concept experiment was carried out to demonstrate that metathesis reactions on ruthenium surfaces might be exploited for the chemical functionalization of the particles through efficient surface place exchange reactions. 1 H NMR spectroscopy was used to monitor the reaction kinetics which exhibited a rate constant twice that observed with AuSR particles with another thiol ligand.