A new hexanuclear Fe(III) nanocluster: synthesis, structure, magnetic properties, and efficient activity as a precatalyst in water oxidation

Muhammad Nadeem Akhtar; Rahman Bikas; Murad A AlDamen; Zohreh Shaghaghi; M Shahid; Andrei Sokolov

doi:10.1039/d2dt01822e

A new hexanuclear Fe(III) nanocluster: synthesis, structure, magnetic properties, and efficient activity as a precatalyst in water oxidation

Dalton Trans. 2022 Aug 23;51(33):12686-12697. doi: 10.1039/d2dt01822e.

Authors

Muhammad Nadeem Akhtar¹, Rahman Bikas², Murad A AlDamen³, Zohreh Shaghaghi⁴, M Shahid⁵, Andrei Sokolov⁶

Affiliations

¹ Division of Inorganic Chemistry, Institute of Chemistry, The Islamia University of Bahawalpur, Bahawalpur, 63100, Pakistan. nadeemchem@yahoo.com.
² Department of Chemistry, Faculty of Science, Imam Khomeini International University, 34148-96818 Qazvin, Iran.
³ Department of Chemistry, School of Science, the University of Jordan, Amman 11942, Jordan. maldamen@ju.edu.jo.
⁴ Coordination Chemistry Research Laboratory, Department of Chemistry, Faculty of Basic Science, Azarbaijan Shahid Madani University, 5375171379, Tabriz, Iran.
⁵ Functional Inorganic Materials Lab (FIML), Department of Chemistry, Aligarh Muslim University, Aligarh 202002, India.
⁶ Department of Physics and Astronomy, University of Nebraska-Lincoln, Lincoln, NE 68588, USA.

PMID: 35939068
DOI: 10.1039/d2dt01822e

Abstract

The oxo-bridged hexanuclear iron cluster formulated [FeIII6(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.