Mechanistic insight into the Z-E isomerization catalysis of azobenzenes mediated by bare and core-shell gold nanoparticles
We explored the catalytic effect of 15 nm diameter gold nanoparticles (AuNPs) upon the thermal Z-E isomerization reaction of azobenzene and nine 4 and 4-4′ substituted azobenzenes (ABs). The kinetics follows a first order rate in ranges of [ABs] = 5 to 50 μM and [AuNPs] = 50 pM to 1 nM. A kinetic an...
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| Autores principales: | , |
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2015
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| Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_20444753_v5_n4_p2110_Simoncelli http://hdl.handle.net/20.500.12110/paper_20444753_v5_n4_p2110_Simoncelli |
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| Sumario: | We explored the catalytic effect of 15 nm diameter gold nanoparticles (AuNPs) upon the thermal Z-E isomerization reaction of azobenzene and nine 4 and 4-4′ substituted azobenzenes (ABs). The kinetics follows a first order rate in ranges of [ABs] = 5 to 50 μM and [AuNPs] = 50 pM to 1 nM. A kinetic analysis of this compartmentalized system renders the thermal Z-E isomerization rate constant associated with each AuNP. Enhancements of 10- to 106-fold were measured for this rate constant in comparison to the same free ABs in solution. Experiments with selective Au facet coverage, as well as the kinetics studied in gold-silica core-shell nanoparticles (AuNP@SiO2) of different thicknesses, demonstrate the surface nature of the catalysis and allow one to evaluate the diffusion coefficient of azobenzene in the silica layer. This journal is © The Royal Society of Chemistry 2015. |
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