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Download fileSingle Open Sites on FeII Ions Stabilized by Coupled Metal Ions in CN-Deficient Prussian Blue Analogues for High Catalytic Activity in the Hydrolysis of Organophosphates
journal contribution
posted on 2020-10-20, 05:14 authored by Mari Yamane, Hiroyasu Tabe, Masami Kawakami, Hisashi Tanaka, Tohru Kawamoto, Yusuke YamadaCN-deficient Prussian blue analogues
(PBAs), [MN(H2O)x]y[FeII(CN)5(NH3)] (MN =
CuII, CoII, or GaIII), were synthesized
and examined as a new class of heterogeneous catalysts for hydrolytic
decomposition of organophosphates often used as pesticides. The active
species of the CN-deficient PBAs were mainly C-bound FeII ions with only single open sites generated by liberation of the
NH3 ligand during the catalytic reactions. [CuII(H2O)8/3]3/2[FeII(CN)5(NH3)] showed higher catalytic activity than [CoII(H2O)8/3]3/2[FeII(CN)5(NH3)] and [GaIII(H2O)][FeII(CN)5(NH3)], although N-bound
CuII species has been reported as less active than CoII and GaIII species in conventional PBAs. IR measurements
of a series of the CN-deficient PBAs after the catalytic reactions
clarified that a part of the NH3 ligands remained on [CoII(H2O)8/3]3/2[FeII(CN)5(NH3)] and that hydrogen phosphate formed
as a product strongly adsorbed on the FeII ions of [GaIII(H2O)][FeII(CN)5(NH3)]. Hydrogen phosphate also adsorbed, but weakly, on the FeII ions of [CuII(H2O)8/3]3/2[FeII(CN)5(NH3)]. These
results suggest that heterogeneous catalysis of the FeII ions with single open sites were tuned by the MN ions
through metal–metal interaction.