title: Syntheses, Structural Characterization, and Catalytic Properties of Di- and Trinickel Polyoxometalates.
abstract: The syntheses, structural characterization, and catalytic properties of two different nickel-containing polyoxometalates (POMs) are presented. The dinickel-containing sandwich-type POM [Ni2(P2W15O56)2](20-) (Ni2) exhibits an unusual αααα geometry. The trinickel-containing Wells-Dawson POM [Ni3(OH)3(H2O)3P2W16O59](9-) (Ni3) shows a unique structure where the [α-P2W15O56](12-) ligand is capped by a triangular Ni3O13 unit and a WO6 octahedron. Ni3 shows a high catalytic activity for visible-light-driven hydrogen evolution, while the activity for Ni2 is minimal. An analysis of the structures of multinickel-containing POMs and their hydrogen evolution activity is given.
authors.affiliation: Department of Chemistry and ‡X-ray Crystallography Center, Emory University , 1515 Dickey Drive, Atlanta, Georgia 30322, United States.
authors.forename: Weiwei
authors.initials: W
authors.lastname: Guo
authors.affiliation: Department of Chemistry and ‡X-ray Crystallography Center, Emory University , 1515 Dickey Drive, Atlanta, Georgia 30322, United States.
authors.forename: Hongjin
authors.initials: H
authors.lastname: Lv
authors.affiliation: Department of Chemistry and ‡X-ray Crystallography Center, Emory University , 1515 Dickey Drive, Atlanta, Georgia 30322, United States.
authors.forename: John
authors.initials: J
authors.lastname: Bacsa
authors.affiliation: Department of Chemistry and ‡X-ray Crystallography Center, Emory University , 1515 Dickey Drive, Atlanta, Georgia 30322, United States.
authors.forename: Yuanzhe
authors.initials: Y
authors.lastname: Gao
authors.affiliation: Department of Chemistry and ‡X-ray Crystallography Center, Emory University , 1515 Dickey Drive, Atlanta, Georgia 30322, United States.
authors.forename: Je Seong
authors.initials: JS
authors.lastname: Lee
authors.affiliation: Department of Chemistry and ‡X-ray Crystallography Center, Emory University , 1515 Dickey Drive, Atlanta, Georgia 30322, United States.
authors.forename: Craig L
authors.initials: CL
authors.lastname: Hill