• 文献标题:   Redox- and EPR-Active Graphene Diiron Complex Nanocomposite
  • 文献类型:   Article
  • 作  者:   DE SOUSA DP, YU JH, MILLER CJ, CHANG YY, MCKENZIE CJ, WAITE TD
  • 作者关键词:  
  • 出版物名称:   LANGMUIR
  • ISSN:   0743-7463
  • 通讯作者地址:   Univ New South Wales
  • 被引频次:   0
  • DOI:   10.1021/acs.langmuir.9b01526
  • 出版年:   2019

▎ 摘  要

A mixed valence diiron(II/III) complex with the ligand 2,6-bis{bis[(2-pyridinylmethyl)amino]methyl}phenol (bppH) has been covalently anchored onto graphene using a mild in situ microwave-assisted diazonium coupling through an aryl amino precursor and isoamyl nitrite. A dinuclear iron complex is then formed by complexation of the grafted bppH-graphene material with iron(II) in the presence of dioxygen. X-ray photoelectron spectroscopy (XPS), atomic force microscopy, cyclic voltammetry, scanning transmission electron microscopy, energy-dispersive X-ray spectroscopy, and electron paramagnetic resonance (EPR) spectroscopy confirm the formation of the anchored ligand and derivative diiron complexes. Semiquantitative XPS analysis shows an average bppH ligand bulk loading of 0.33 mmol/g, corresponding to a significant 20.7 wt % of the functionalized material consisting of grafted moieties. EPR measurements reveal the existence of a strong isotropic S = 1/2 spin center associated with the graphene lattice, together with a much weaker S = 5/2 signal, associated with the iron(III) center of the grafted complex. The grafted complex is redox-active with surface-confined (FeFeII)-Fe-II -> (FeFeIII)-Fe-II (+0.56 V vs NHE), (FeFeIII)-Fe-II -> (FeFeIII)-Fe-III (+0.73 V), and (FeFeIII)-Fe-III -> (FeFeIV)-Fe-III (+0.95 V) redox processes accessible, with an estimated surface coverage of 58 pmol cm(-2) established from the electrochemical measurements.