(AuAg)144(SR)60 alloy nanomolecules.

(Au-Ag)(144)(SR)(60) alloy nanomolecules were synthesized and characterized by ESI mass spectrometry to atomic precision. The number of Ag atoms can be varied by changing the incoming metal ratio and plateaus at ∼60. UV-vis data demonstrates that the electronic structure of the nanomolecules can be tuned by incorporation of silver atoms. Based on the proposed 3-shell structure of Au(144)(SR)(60), we hypothesize that the Ag atoms are selectively incorporated in to the symmetry equivalent 60-atom shell-having Au(12), Au(42), Ag(60) concentric shells with 30 -SR-Au-SR- protecting units. This journal is © The Royal Society of Chemistry 2011