Comment on “(Au–Ag)144(SR)60 alloy nanomolecules” by C. Kumara and A. Dass, Nanoscale, 2011, 3, 3064

Abstract

A recent paper in this journal reported the synthesis and characterization via electrospray ionization mass spectroscopy and UV-vis spectroscopy of (Au–Ag)₁₄₄(SR)₆₀ alloy nanomolecules with different compositions, ranging from 1 : 0 to 1 : 0.75 Au : Ag ratios. The UV-vis spectra of such systems were found to exhibit absorption peaks at 310 nm, 425 nm and 560 nm, interpreted as reminiscent of the silver surface plasmon resonance band due to simple atomic replacement of Au by Ag atoms in a fixed structural framework. On the basis of a comparison of experimentally observed and theoretically simulated optical absorption spectra, we conclude that the experimental situation must be more complicated, and that further work is needed to achieve atomistic insight into these fascinating systems.