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Abstract
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The oxo-bridged hexanuclear iron cluster formulated [FeIII
6 (μ4-O)2(edteH)2( piv)4(SCN)4]·2MeCN·2H2O (1)
(where edteH = N,N,N’,N’-tetrakis(2-hydroxyethyl)ethylenediamine; piv = pivalic acid) has been synthesized
by the reaction of FeCl2·4H2O with edteH4 and piv in the presence of KSCN in CH2Cl2/MeCN.
The single crystal X-ray measurements indicated that the cluster is centrosymmetric in structure. The
magnetic study demonstrated the presence of very strong antiferromagnetic coupling between the iron
centers and the Brillouin fitting showed the best fit with S = 5/2 and g = 1.87. In addition, the water oxidation
activity of the cluster has been studied by electrochemical techniques. Electrochemical experiments
revealed that the electrode modified by 1 has high efficiency for the oxidation of water and needs
an overpotential of 484 mV under a constant current density of 15 mA cm−2 with a Tafel slope of 114 mV
dec−1 in neutral media. Experiments indicated that in the presence of 1, a yellow solid film was formed on
the electrode surface under the applied electrochemical conditions. This yellow material is likely a compound
of iron and oxygen and has a crystalline nature. Our findings revealed that along with the cluster,
this compound is active in water oxidation reactions.
Introduction
Polynuclear coordination clusters have gained interest in bioinorganic,
molecular magnetism, and redox chemistry.1–4 The
Lewis acidity
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