title: Role of the alkali-metal cation size in the self-assembly of polyoxometalate-monolayer shells on gold nanoparticles.
abstract: Polyoxometalate (POM)-monolayer stability constants, K, for three POM anions  vary with the cation size, in the same order as that for increasing ion-pair formation with α-SiW(11)O(39)(8-) (1) in the early nucleation phase of monolayer self-assembly: Li(+) < Na(+) < K(+) < Cs(+). Cryo-TEM images demonstrating the use of the cation size to rationally control monolayer formation provide definitive evidence that the POM monolayers are electrostatically stabilized (ionic) shells, analogous in that respect to the monolayer walls of "hollow" POM-macroanion vesicles.
authors.affiliation: Department of Chemistry and the Ilse Katz Institute for Nanoscale Science & Technology, Ben Gurion University of the Negev, Beer Sheva 84105, Israel.
authors.forename: Yifeng
authors.initials: Y
authors.lastname: Wang
authors.forename: Offer
authors.initials: O
authors.lastname: Zeiri
authors.forename: Shelly
authors.initials: S
authors.lastname: Sharet
authors.forename: Ira A
authors.initials: IA
authors.lastname: Weinstock
mesh_terms: D002412:Cations / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D008672:Metals, Alkali / Q000737:chemistry*; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D010316:Particle Size; D013499:Surface Properties; D017973:Tungsten Compounds / Q000737:chemistry*; D000099294:Polyoxometalates
chemical_list: D002412:Cations; D006046:Gold; D008672:Metals, Alkali; D009942:Organometallic Compounds; D017973:Tungsten Compounds; C102296:polyoxometalate I; D000099294:Polyoxometalates