Keynote
POLYOXOMETALATE COMPLEXES OF METAL-OXIDE CORES

Building on our use of polyoxometalate (POM) cluster-anions as ligands for gold-nanoparticle catalysts and building blocks [1], we show how POMs can serve as covalently attached ligands for reactive metal-oxide nanocrystals, providing soluble and isolable assemblies uniquely positioned between molecular macroanions and traditional colloids. For example, covalently coordinated redox-active POMs serving as ligands for individual anatase titanium-dioxide nanocrystals [2] control hydrogen formation by rationally tuning rates of visible-light driven electron injection into the TiO₂ cores, while soluble POM complexes of α-Fe₂O₃ serve as well-behaved homogeneous catalysts for visible-light driven water oxidation. By harnessing the reactivity of these and other metal-oxide nanocrystals within inherently stable nano-structures, reactions of the catalytically active metal-oxide cores can be investigated using solution-state methods traditionally reserved for molecular complexes.

[1] (a) Zhang, M.; Hao, J.; Neyman, A; Wang, Y.; Weinstock, I. A. Inorg. Chem., 2017, 56, 2400-2408 (Front cover); (b) Wang, Y.; Raula, M.; Wang, Y.; Zeiri, O.; Chakraborty, S.; Gan-Or, G.; Gadot, E.; Weinstock, I. A. Ang. Chem. Int. Ed. 2017,56, 7083-7087; (c) Wang, Y.; Zeiri, O.; Raula, M.; Le Ouay, B.; Stellacci, F.; Weinstock, I. A. Nature Nanotech. 2017, 12, 170-176.

[2] M. Raula, G. Gan Or, M. Saganovich, O. Zeiri, Y. Wang, M. R. Chierotti, R. Gobetto, I. A. Weinstock, Angew. Chem. Int. Ed. 2015, 54, 12416 –12421 (“Hot paper”).