Purification of molecularly bridged metal nanoparticle arrays by centrifugation and size exclusion chromatography.

Size exclusion chromatography and centrifugation separation protocols were developed and compared for isolating enriched fractions of phenylethynyl-bridged metal nanoparticle dimers and trimers from the monomeric particle starting material. Both methods enabled the isolation of enriched fractions of a desired array without causing significant sample aggregation or replacement of the phenylethynyl bridge. Solutions containing ca. 70% bridged gold dimers were obtained using either method. The further development of methods for separating discrete arrays of covalently bridged nanoparticle homo and hetero structures is expected to help advance our understanding of collective metal particle electronic structure-function relationships.