title: Polyoxometalate complexes of anatase-titanium dioxide cores in water.
abstract: Polyoxometalate (POM) cluster anions are shown to serve as covalently coordinated ligands for anatase-TiO2 nanocrystals, giving isolable assemblies uniquely positioned between molecular macroanions and traditional colloidal nanoparticles. Na(+) salts of the water-soluble polyanionic structures are obtained by reacting amorphous TiO2 with the 1 nm lacunary ion, Na7 [α-XW11 O39 ] (X=P(5+) ), at 170 °C, after which an average of 55 α-PW11 O39 (7-) clusters are found as pentadentate ligands for Ti(IV) ions covalently linked to 6 nm single-crystal anatase cores. The attached POMs are reversible electron acceptors, the reduction potentials of which shift in a predictable fashion by changing the central heteroatom, X, directly influencing a model catalytic reaction. Just as POM cluster anions control the reactivities of metal centers in molecular complexes, directly coordinated POM ligands with tunable redox potentials now provide new options for rationally controlling the reactions of semiconductor nanocrystals.
authors.affiliation: Department of Chemistry, Ben Gurion University of the Negev and the Ilse Katz Institute for Nanoscale Science & Technology, Beer Sheva, 84105 (Israel) http://www.bgu.ac.il/∼iraw.
authors.forename: Manoj
authors.initials: M
authors.lastname: Raula
authors.affiliation: Department of Chemistry, Ben Gurion University of the Negev and the Ilse Katz Institute for Nanoscale Science & Technology, Beer Sheva, 84105 (Israel) http://www.bgu.ac.il/∼iraw.
authors.forename: Gal
authors.initials: G
authors.lastname: Gan Or
authors.affiliation: Department of Chemistry, Ben Gurion University of the Negev and the Ilse Katz Institute for Nanoscale Science & Technology, Beer Sheva, 84105 (Israel) http://www.bgu.ac.il/∼iraw.
authors.forename: Marina
authors.initials: M
authors.lastname: Saganovich
authors.affiliation: Department of Chemistry, Ben Gurion University of the Negev and the Ilse Katz Institute for Nanoscale Science & Technology, Beer Sheva, 84105 (Israel) http://www.bgu.ac.il/∼iraw.
authors.forename: Offer
authors.initials: O
authors.lastname: Zeiri
authors.affiliation: School of Chemistry and Chemical Engineering, Shandong University, Ji'nan 250100 (China).
authors.forename: Yifeng
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Chemistry and NIS Centre, University of Turin, Via P. Giuria n° 7, Torino, 10125 (Italy).
authors.forename: Michele R
authors.initials: MR
authors.lastname: Chierotti
authors.affiliation: Department of Chemistry and NIS Centre, University of Turin, Via P. Giuria n° 7, Torino, 10125 (Italy).
authors.forename: Roberto
authors.initials: R
authors.lastname: Gobetto
authors.affiliation: Department of Chemistry, Ben Gurion University of the Negev and the Ilse Katz Institute for Nanoscale Science & Technology, Beer Sheva, 84105 (Israel) http://www.bgu.ac.il/∼iraw. iraw@bgu.ac.il.
authors.forename: Ira A
authors.initials: IA
authors.lastname: Weinstock
keywords: electron transfer; hybrid materials; nanostructures; polyoxometalates; titanium dioxide