Gold nanoparticle catalysis of the cis–trans isomerization of azobenzene

Abstract

Ablated, "pseudo-naked" gold nanoparticles (AuNPs) catalyze the cis-trans isomerization of substituted azobenzenes. para-Substitution was found to affect the rate of isomerization, suggesting the participation of AuNP-mediated electron transfer in the isomerization mechanism.

Thermal Cis-to-Trans Isomerization of Azobenzene-Containing Molecules Enhanced by Gold Nanoparticles: An Experimental and Theoretical Study

“…Finally, we made a simple estimate of the 4-R-AB ion formation energies in the presence of a gold surface and revealed that the energy for cation formation is smaller than for anion formation; for some of the molecules the cation formation energy was even negative. This result suggests an easier cation formation and, thus, corroborates the possible electron transfer from the azobenzene-containing molecule to the gold nanoparticle surface, proposed by Hallet-Tapley et al 13 Certainly, this is still a hypothesis, which should be verified. …”

Modulation of Electronic Mobility of a One‐Dimensional Coordination Polymeric Molecular Wire with Light

“…The effect of metal ions on the photoisomerization of azobenzene systems were studied in a Ag I ‐complex with a 24‐membered cyclic azobenzene by Tamaoki (Figure A) where the trans ‐complex was found to be more stable. Scaiano and Santer's groups have reported the enhanced photoswitching rate of acyclic azobenzene systems in presence of AuNPs (Figure B) . These observations prompted us to prepare and explore the properties of a coordination polymer with with the cyclic azobenzene 1 and Ag + ions.…”

“…Scaiano and Santer's groups have reported the enhanced photoswitching rate of acyclica zobenzene systemsi np resence of AuNPs (Figure 1B). [53,54] These observations prompted us to prepare and explore the properties of ac oordination polymer with with the cyclic azobenzene 1 and Ag + ions. The [Ag + -1]C P-2 was prepared by the addition of silver nitrate (AgNO 3 )s alt dissolved in methanolt oas olution of the 1 in acetonitrile, followed by continuous stirring of the mixture at room temperature for 48 hours in dark conditions (Figure 2A).…”

Heterogeneous photocatalytic C–C coupling: mechanism of plasmon-mediated reductive dimerization of benzyl bromides by supported gold nanoparticles

“…The catalyst is clearly reusable for this purpose, although some variability is observed; this is not uncommon with nanostructured catalysts. 37 The decrease on the yield of the reaction can be related to the growth of the particles (from 2.5 nm to 4.1 nm, see SI) and is reasonable after the catalyst has been reused three times. • Low concentrations and modest reactivity for any other free radical traps, and likely the reason why DIPEA gives better yield than the more reactive TEA.…”

“…38 . 37 It is interesting that these unusual criteria are all met in the current system making radical-radical reactions the preferred process. Finally, the catalyst showed an acceptable stability and reusability.…”