Copper nanoparticle heterogeneous catalytic 'click' cycloaddition confirmed by single-molecule spectroscopy

Colloidal or heterogeneous nanocatalysts can improve the range and diversity of Cu(I)catalysed click reactions and facilitate catalyst separation and reuse. Catalysis by metal nanoparticles raises the question as to whether heterogeneous catalysts may cause homogeneous catalysis through metal ion leaching, since the catalytic process could be mediated by the particle, or by metal ions released from it. The question is critical as unwanted homogeneous processes could offset the benefits of heterogeneous catalysis. Here, we combine standard bench scale techniques with single-molecule spectroscopy to monitor single catalytic events in real time and demonstrate that click catalysis occurs directly at the surface of copper nanoparticles; this general approach could be implemented in other systems. We use 'from the mole to the molecule' to describe this emerging idea in which mole scale reactions can be optimized through an intimate understanding of the catalytic process at the single-molecule-single catalytic nanoparticle level.The Natural Sciences and Engineering Research Council of Canada supported this work through its Discovery and CREATE programs, while the Canadian Foundation for Innovation enabled the purchase of the instrumentation used in this work. M. L. M. thanks the Spanish Ministerio de Educacion, Cultura y Deporte (Programa Salvador de Madariaga) for its financial support.Decan, MR.; Impellizzeri, S.; Marín García, ML.; Scaiano, J. (2014). Copper nanoparticle heterogeneous catalytic 'click' cycloaddition confirmed by single-molecule spectroscopy. Nature Communications. 5:4612-4615. doi:10.1038/ncomms5612461246155Rostovtsev, V. V., Green, L. G., Fokin, V. V. & Sharpless, K. B. 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