Ca2+‐Induced Oxygen Generation by FeO42− at pH 9–10 |
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Authors: | Dr Li Ma Dr William W Y Lam Dr Po‐Kam Lo Dr Kai‐Chung Lau Prof Tai‐Chu Lau |
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Institution: | Department of Biology and Chemistry and Institute of Molecular Functional Materials, City University of Hong Kong, Hong Kong, China |
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Abstract: | Although FeO42? (ferrate(IV)) is a very strong oxidant that readily oxidizes water in acidic medium, at pH 9–10 it is relatively stable (<2 % decomposition after 1 h at 298 K). However, FeO42? is readily activated by Ca2+ at pH 9–10 to generate O2. The reaction has the following rate law: dO2]/dt=kCaCa2+]FeO42?]2. 18O‐labeling experiments show that both O atoms in O2 come from FeO42?. These results together with DFT calculations suggest that the function of Ca2+ is to facilitate O–O coupling between two FeO42‐ions by bridging them together. Similar activating effects are also observed with Mg2+ and Sr2+. |
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Keywords: | calcium dioxygen generation iron(VI) Lewis acid |
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