Polymer Growth by Functionalized Ruthenium Nanoparticles

Abstract

We detail here a method to integrate reactive sites onto the surface atoms of ruthenium particles and use these sites as catalysts for oligomer growth. This way we can easily integrate nanoscale metal spheres both structurally and electronically with a shell of organic materials. We study the reaction of a zerovalent ruthenium precursor, Ru(η4-cyclooctadiene)(η6-cyclooctatriene), with different coordinating ligands. Using alcohol ligands produces large particles (∼50 nm in diameter) that are composed of agglomerates of smaller particles. These particles are able to initiate olefin metathesis when they react with diazoalkanes and then strained olefins such as dicyclopentadiene, but the rates of reaction and number of active sites are low. When we use diazoalkanes directly without the intermediacy of the alcohol ligands, the activity of the particles increases, and we are able to produce particles that are as active as other heterogeneous olefin metathesis catalysts.