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The ability of plasmonic metal nanostructures (PMNs), such as silver and gold nanoparticles, to manipulate and concentrate electromagnetic fields at the nanoscale is the foundation for wide range o...

Transient absorption captures dynamics of nanocubes, showing negative delay-time signals associated with perturbed free induction. This validates dielectric-resonance energy transfer between electromagnetic modes for light-harvesting applications.

Copper based nanocatalysts have recently emerged as attractive catalysts for a diversity of bond formations, such as C–C, C–N, C–O, C–S, and C–Se. However, the identification of truly heterogeneous versus homogeneous catalytic conditions remains an ongoing challenge within the field. Herein, we report that in cuprous oxide (Cu2O) nanoparticle-mediated C–C homo-coupling and cross-coupling reactions, the presence of a base facilitates the copper complex mediated homogeneous catalytic pathway. Whereas in the absence of a base, the reaction can proceed heterogeneously on the surface of Cu2O nanoparticles. We distinguished the homogenous versus heterogeneous pathways using a combination of reactor study, ultraviolet-visible extinction spectroscopy, electrospray ionization mass spectrometry, flame atomic absorption spectroscopy, transmission electron microscopy, and density-functional theory calculations. Our findings indicate that Cu2O nanoparticles can catalyze C–C coupling reactions under lingandless and base-free conditions via a truly heterogeneous pathway paving the way for the development of highly efficient, robust and sustainable processes.

Metal nanoparticle-catalyzed reactions such as hydrogenation, cross-coupling, carbonylation, and hydroformylation reactions are the most widely used reactions in the pharmaceutical and fine chemical industries. However, there is no operando spectroscopic technique that exists to monitor the size of functioning nanocatalyst. By exploiting localized surface plasmon resonance of catalytically relevant nanostructures, such as monometallic (e.g., Pd, Pt, Ni, Rh, Au, and Cu) nanoparticles and bimetallic core–shell (e.g., Ag-Pd) nanoparticles, we show UV–Vis spectroscopy can be used to determine the size of functioning nanocatalyst. Based on our finite-difference time-domain simulations, it is possible to detect leaching of even a monolayer of atoms from the surface of widely used metal nanocatalysts with a conventional UV–Vis spectrometer. This sensitive, inexpensive and robust spectroscopic approach can be potentially used as in-line process analytical technology (PAT) in pharmaceutical development and manufacturing.