Chemical and heating treatments of ionic monolayer-protected clusters (IMPCs) with different surface counter anions.

This paper shows an in-depth study on the chemical and thermal responses of two ionic monolayer-protected gold clusters (Oct(4)N(+-)Br- and Oct(4)N(+-)O(3)SS-IMPCs). Two IMPCs displayed completely different phase-transfer behaviors when the solutions were in contact with the aqueous solution containing N-(2-mercaptopropionyl)glycine (tiopronin). Not Oct(4)N(+-)O(3)SS-IMPCs but Oct(4)N(+-)Br-IMPCs experienced a facile phase transfer from the organic layer to the aqueous layer, which was resulted from the displacement of ionic ligands by tiopronin monolayers on the gold nanoparticle surface.