Analytical Evidence for the Monolayer-Protected Cluster Au_(225)[(S(CH_(2))_(5)CH_(3))]_(75)

摘要

The Brust synthesis of thiolate-protected gold clusters has been modified to produce identifiable proportions of a hexanethiolate-protected Au_(225) core nanoparticle that display quantized double layer charging voltammetry consistent with a Au_(225) core dimension. Transmission electron microscopy (TEM) and thermogravimetric results indicate an average nanoparticle formula of Au_(225)[(S(CH_(2))_(5)-CH_(3))]_(75). A simulated pulse voltammogram that accounts for the TEM nanoparticle dispersity matches reasonably well with that of the polydisperse synthetic sample containing the Au_(225) component. In confirmation of the size determination, an HPLC analysis using ratiometric absorbance and electrochemical detectors gives a core radius of 1.0 nm for the Au_(225) nanoparticle.