Table 1.

Visible-light driven water oxidation by 1^a

Entry	Oxidantb	Catalyst	Lightc	Solvent	O2 (μmol g−1)d
1	S2O82–	1	Visible	H2O	1025
2	IO4–	1	Visible	H2O	6300
3	None	1	Visible	H2O	0
4	IO4–	None	Visible	H2O	0
5	IO4–	1	Dark	H2O	0
6	IO4–	{[α-PW11O39Fe]2O}10– (2)e	Dark	H2O	60 ± 20
7	IO4–	{[α-PW11O39Fe]2O}10– (2)e	Visible	H2O	60 ± 20
8	IO4–	Fe3+ f	Visible	H2O	0
9	IO4–	1 g	Visible	Dry MeCN	0
10	IO4–	1 g	Visible	1:1 H2O:MeCN	1640

^aAll reactions were carried out at pH 8 for 8 h (40 ± 1 °C)

^bOxidant concentrations were 20 mM

^cLight source was a 150 W Xe lamp with a λ ≥ 420-nm cutoff filter

^dValues reported are per gram of the α-Fe₂O₃ cores, or of the catalysts listed in column three

^eThese two control experiments (entries 6 and 7) rule out oxygen evolution by reaction of periodate with the Fe(III) atoms complexed within the hematite-bound POM ligands. They were carried out at pH 5 to ensure integrity of the molecular dimer, 2. In 8 h at pH 5, 1 gave 3200 μmol O₂ g⁻¹

^fAfter air oxidation of FeSO₄ at pH 5 and 8

^gCarried out using an organic-solvent soluble form of 1, and R₄N⁺IO₄^– (R = n-butyl)