Redox- and EPR-Active Graphene Diiron Complex Nanocomposite

David P. de Sousa, Jeffrey Huijie Yu, Christopher J. Miller, Yingyue Chang, Christine J. McKenzie, T. David Waite

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

19 Downloads (Pure)

Abstrakt

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 FeIIFeII → FeIIFeIII (+0.56 V vs NHE), FeIIFeIII → FeIIIFeIII (+0.73 V), and FeIIIFeIII → FeIIIFeIV (+0.95 V) redox processes accessible, with an estimated surface coverage of 58 pmol cm-2 established from the electrochemical measurements.

OriginalsprogEngelsk
TidsskriftLangmuir : the ACS journal of surfaces and colloids
Vol/bind35
Udgave nummer38
Sider (fra-til)12339-12349
Antal sider11
ISSN0743-7463
DOI
StatusUdgivet - 24. sep. 2019

Fingeraftryk Dyk ned i forskningsemnerne om 'Redox- and EPR-Active Graphene Diiron Complex Nanocomposite'. Sammen danner de et unikt fingeraftryk.

Citationsformater