title: Assembled monolayers of Mo3S4(4+) clusters on well-defined surfaces.
abstract: A class of inorganic monolayers formed by assembling the molybdenum-sulfur cluster, Mo3S4(4+), onto a well-defined Au(111) surface is presented. The monolayers have been comprehensively characterized by electrochemistry, X-ray photoelectron spectroscopy (XPS), and in situ scanning tunneling microscopy (in situ STM). The voltammetric data show strong reductive and oxidative desorption signals from Au-S interactions, supported by the presence of both S and Mo signals in XPS. In situ STM shows many small pits in the dense adlayers uniformly spread over the surface, which is a typical feature of self-assembled monolayers (SAMs) of alkanethiols. The density of the pits is ca. 23 (+/-5)% and is significantly higher than for straight-chain alkanethiol SAMs with a single -SH group. The pit shapes are irregular, suggesting multiple Au-S interactions from Mo3S4(4+). High resolution images disclose bright round spots of ca. 8 A diameter representing individual molecules in the SAM. This is the first example of in situ monolayer formation by a metal-chalcogenide cluster directly anchored onto the gold surface through core ligands and offers a simple way to prepare a new class of functionalized inorganic monolayers.
authors.affiliation: Department of Chemistry, NanoDTU, Technical University of Denmark, Building 207, Kemitorvet, 2800, Lyngby, Denmark.
authors.forename: Jytte
authors.initials: J
authors.lastname: Kristensen
authors.forename: Jingdong
authors.initials: J
authors.lastname: Zhang
authors.forename: Ib
authors.initials: I
authors.lastname: Chorkendorff
authors.forename: Jens
authors.initials: J
authors.lastname: Ulstrup
authors.forename: Bee Lean
authors.initials: BL
authors.lastname: Ooi