[{Ni4(OH)3AsO4}4(B‐α‐PW9O34)4]28−: A New Polyoxometalate Structural Family with Catalytic Hydrogen Evolution Activity

E-ISSN： 1521-3765|21|48|17363-17370

ISSN： 0947-6539

Source： CHEMISTRY - A EUROPEAN JOURNAL, Vol.21, Iss.48, 2015-11, pp. : 17363-17370

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Abstract

AbstractA new structural polyoxometalate motif, [{Ni4(OH)3AsO4}4(B‐α‐PW9O34)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)12O4(AsO4)4} core shows dominant ferromagnetic exchange interactions, with maximum χmT of 69.21 cm3 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.