Solvation chemistry of water-soluble thiol-protected gold nanocluster Au102 from DOSY NMR spectroscopy and DFT calculationsElectronic supplementary information (ESI) available: Synthesis scheme and details, analytical methods and details, UV-Vis spectra, NMR spectra (1H and 2D DOSY) and snapshots from MD simulations of a pMBA−/NH4+ ion pair in water. See DOI: 10.1039/c4nr01255k

The hydrodynamic diameter of Au m ( p MBA) n [( m , n ) = (102, 44) and (144, 60)] clusters in aqueous media was determined via DOSY NMR spectroscopy. The apparent size of the same ( n , m ) cluster depends on the counter ion of the deprotonated p MBA − ligand as explained by the competing ion-pair strength and hydrogen bonding interactions studied in DFT calculations. The choice of the counter ion affects the surface chemistry and molecular structure at the organic/water interface, which is relevant for biological applications. The hydrodynamic diameter of Au m ( p MBA) n clusters in aqueous media was determined by DOSY NMR spectroscopy. The apparent size of the cluster was shown to depend on the counter ion of the deprotonated p MBA − ligand.