Enzymatic haem and non-haem high-valent iron-oxo species are known to activate strong C-H bonds, yet duplicating this reactivity in a synthetic system remains a formidable challenge. Although instability of the terminal iron-oxo moiety is perhaps the foremost obstacle, steric and electronic factors also limit the activity of previously reported mononuclear iron(IV)-oxo compounds. In particular, although nature's non-haem iron(IV)-oxo compounds possess high-spin S = 2 ground states, this electronic configuration has proved difficult to achieve in a molecular species. These challenges may be mitigated within metal-organic frameworks that feature site-isolated iron centres in a constrained, weak-field ligand environment. Here, we show that the metal-organic framework Fe-2(dobdc) (dobdc(4-) = 2,5-dioxido-1,4-benzenedicarboxylate) and its magnesium-diluted analogue, Fe0.1Mg1.9(dobdc), are able to activate the C-H bonds of ethane and convert it into ethanol and acetaldehyde using nitrous oxide as the terminal oxidant. Electronic structure calculations indicate that the active oxidant is likely to be a high-spin S = 2 iron(IV)-oxo species.

Oxidation of ethane to ethanol by N2O in a metal-organic framework with coordinatively unsaturated iron(II) sites

BONINO, Francesca Carla;CROCELLA', VALENTINA;BORDIGA, Silvia;
2014-01-01

Abstract

Enzymatic haem and non-haem high-valent iron-oxo species are known to activate strong C-H bonds, yet duplicating this reactivity in a synthetic system remains a formidable challenge. Although instability of the terminal iron-oxo moiety is perhaps the foremost obstacle, steric and electronic factors also limit the activity of previously reported mononuclear iron(IV)-oxo compounds. In particular, although nature's non-haem iron(IV)-oxo compounds possess high-spin S = 2 ground states, this electronic configuration has proved difficult to achieve in a molecular species. These challenges may be mitigated within metal-organic frameworks that feature site-isolated iron centres in a constrained, weak-field ligand environment. Here, we show that the metal-organic framework Fe-2(dobdc) (dobdc(4-) = 2,5-dioxido-1,4-benzenedicarboxylate) and its magnesium-diluted analogue, Fe0.1Mg1.9(dobdc), are able to activate the C-H bonds of ethane and convert it into ethanol and acetaldehyde using nitrous oxide as the terminal oxidant. Electronic structure calculations indicate that the active oxidant is likely to be a high-spin S = 2 iron(IV)-oxo species.
2014
6
7
590
595
http://www.nature.com/nchem/journal/v6/n7/full/nchem.1956.html
2ND-ORDER PERTURBATION-THEORY; SPIN OXOIRON(IV) COMPLEX; NITROUS-OXIDE; DIOXYGEN ACTIVATION; DINITROGEN OXIDE; ENZYMES; REACTIVITY; iron(IV)–oxo species; iron–oxo; C-H bond activation; metal organic framework; MOF; high-spin; Fe(dobdc); Mg(dobdc); FeMg(dobdc); FTIR spectroscopy; Mossbauer spectroscopy
D. J. Xiao;E. D. Bloch;J. A. Mason;W. L. Queen;M. R. Hudson;N. Planas;J. Borycz;A. L. Dzubak;P. Verma;K. Lee;F. Bonino;V. Crocella;J. Yan...espandi
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2318/153276
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