Coinage metal nanoparticles

The reaction was studied for all coinage metal nanoparticles. In the case of GMEs the rate follows zero-order kinetics with IT for all the coinage metal cases. The observed IT for the Cu catalyzed reaction was maximum but its rate of reduction was found to be minimum. Just the reverse was the case for Au and an intermediate value was obtained for the Ag catalyzed reaction (Figure 7). The adsorption of substrates is driven by chemical interaction between the particle surface and the substrates. Here phe-nolate ions get adsorbed onto the particle surface when present in the aqueous medium. This caused a blue shift of the plasmon band. A strong nucleophile such as NaBH4, because of its diffusive nature and high electron injection capability, transfers electrons to the substrate via metal particles. This helps to overcome the kinetic barrier of the reaction. 

Pradhan N, Pal A, Pal T (2001) Catalytic Reduction of Aromatic Nitro Compounds by Coinage Metal Nanoparticles. Langmuir 17 1800-1802... 

Coinage metal nanoparticles (Au, Ag and Cu) have been particularly popular in nanoparticle research because of their easy synthesis, the high intensity of their surface plasmon band and the ease of functionalising the metal surface with ligands such as thiolates. Gold nanoparticles are prepared... 

Pradhan, N., A. Pal and T. Pal (2001). Catalytic reduction of aromatic nitro compounds by coinage metal nanoparticles. Langmuir, 17(5), 1800-1802. 

Bunge, S.D., Boyle, T.J., and Headley, T.J. 2003. Synthesis of coinage-metal nanoparticles from mesityl precursors. Nano Letters, 3 901-5. 

When thiols with varying chain lengths, such as Cg-, Cio-, Ci2- and Ci6- are used, we observe very interesting trends [47]. First, all the colloids under reflux conditions display a strong reddish color. Nanoparticles, especially those of coinage metals like gold and silver, display striking colors... 

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