Nitrene-functionalized ruthenium nanoparticles: Selective manipulation of nanoparticle electronic conductivity by vinyl derivatives

The electronic conductivity of solid films of nitrene-functionalized ruthenium nanoparticles was measured and compared in the presence of organic vapors of various relative polarity that included ethanol, acetone, n-hexane, 1-hexene, toluene, and styrene. The nanoparticle conductivity was found to decrease upon the exposure to the vapors tested, and the largest drop was observed with styrene and toluene. Interestingly, the diminishment of the nanoparticle conductivity was found to be 2.5 times more sensitive to styrene than to toluene, despite their similar relative polarity and nanoparticle solubility. This was accounted for by the combined contributions of (i) increased distance between nanoparticle metal cores as a result of film swelling from solvation as well as (ii) selective chemical reactivity of the Ru=N interfacial bonds to vinyl moieties that altered the tunneling pathway for interparticle charge transfer. These results suggest that functional nanoparticles may serve as a unique platform for chemical vapor detection with enhanced sensitivity and selectivity.