Stabilizing cyanosols: amorphous cyanide bridged transition metal polymer nanoparticles

Abstract

Nanoparticles of an amorphous, cyanide bridged, transition metal polymer are isolated by exchanging the counter-ions of the polymer network with cetyltrimethylammonium (CTA⁺). The nanoparticles isolated are stable, soluble in organic solvents such as dichloromethane and have an average diameter of 4 ± 1 nm (mean ± std). The reported technique is amenable to a variety of transition metals as Pd–Co, Pd–Ru and Pd–Fe cyanometalate polymer nanoparticles are isolated. Increasing the reaction time prior to counter-ion exchange allows for the isolation of nanoparticle agglomerates. The transition metal ratio of the nanoparticulate polymer network is demonstrated to be under synthetic control. Subsequent chemical alteration of the nanoparticles is afforded due to the free coordination sites of the transition metals in the polymer. The nanoparticles also serve as chemical precursors to transition metal alloy nanoparticles due to the ability of bridging cyanides to act as reducing agents at relatively low temperatures.