title: [{Ni4 (OH)3 AsO4 }4 (B-α-PW9 O34 )4 ](28-) : A New Polyoxometalate Structural Family with Catalytic Hydrogen Evolution Activity.
abstract: A new structural polyoxometalate motif, [{Ni4 (OH)3 AsO4 }4 (B-α-PW9 O34 )4 ](28-) , which contains the highest nuclearity structurally characterized multi-nickel-containing polyanion to date, has been synthesized and characterized by single-crystal X-ray diffraction, temperature-dependent magnetism and several other techniques. The unique central {Ni16 (OH)12 O4 (AsO4 )4 } core shows dominant ferromagnetic exchange interactions, with maximum χm T of 69.21 cm(3)  K mol(-1) at 3.4 K. Significantly, this structurally unprecedented complex is an efficient, water-compatible, noble-metal-free catalyst for H2 production upon visible light irradiation (photosensitizer=[Ir(ppy)2 (dtbbpy)][PF6 ]; sacrificial electron donor=triethylamine or triethanolamine). The highest turnover number of approximately 580, corresponding to a best quantum yield of approximately 4.07 %, is achieved when using triethylamine as electron donor in the presence of water. The mechanism of this photodriven process has been probed by time-solved luminescence and by static emission quenching.
authors.affiliation: Department of Chemistry and X-ray Crystallography Center, Emory University, 1515 Dickey Dr., Atlanta, Georgia 30322 (USA).
authors.forename: Hongjin
authors.initials: H
authors.lastname: Lv
authors.affiliation: Department of Chemistry and X-ray Crystallography Center, Emory University, 1515 Dickey Dr., Atlanta, Georgia 30322 (USA).
authors.forename: Yingnan
authors.initials: Y
authors.lastname: Chi
authors.affiliation: Institut für Anorganische Chemie, RWTH Aachen University, 52074 Aachen (Germany).
authors.forename: Jan
authors.initials: J
authors.lastname: van Leusen
authors.affiliation: Institut für Anorganische Chemie, RWTH Aachen University, 52074 Aachen (Germany).
authors.forename: Paul
authors.initials: P
authors.lastname: Kögerler
authors.affiliation: Department of Chemistry and X-ray Crystallography Center, Emory University, 1515 Dickey Dr., Atlanta, Georgia 30322 (USA).
authors.forename: Zheyuan
authors.initials: Z
authors.lastname: Chen
authors.affiliation: Department of Chemistry and X-ray Crystallography Center, Emory University, 1515 Dickey Dr., Atlanta, Georgia 30322 (USA).
authors.forename: John
authors.initials: J
authors.lastname: Bacsa
authors.affiliation: Department of Chemistry and X-ray Crystallography Center, Emory University, 1515 Dickey Dr., Atlanta, Georgia 30322 (USA).
authors.forename: Yurii V
authors.initials: YV
authors.lastname: Geletii
authors.affiliation: Department of Chemistry and X-ray Crystallography Center, Emory University, 1515 Dickey Dr., Atlanta, Georgia 30322 (USA).
authors.forename: Weiwei
authors.initials: W
authors.lastname: Guo
authors.affiliation: Department of Chemistry and X-ray Crystallography Center, Emory University, 1515 Dickey Dr., Atlanta, Georgia 30322 (USA).
authors.forename: Tianquan
authors.initials: T
authors.lastname: Lian
authors.affiliation: Department of Chemistry and X-ray Crystallography Center, Emory University, 1515 Dickey Dr., Atlanta, Georgia 30322 (USA). chill@emory.edu.
authors.forename: Craig L
authors.initials: CL
authors.lastname: Hill
keywords: hydrogen production; nickel; photocatalysis; polyoxometalates; temperature-dependent magnetism