Synthetic iron-oxo “diamond core” mimics structure of key intermediate in methane monooxygenase catalytic cycle

Deciphering the origin of million-fold reactivity observed for the open core diiron [HO–FeIII–O–FeIVO]2+species towards C–H bond activation: role of spin-states, spin-coupling, and spin-cooperation

“…27,[38][39][40] The high-valent intermediate Q of soluble methane monooxygenase (sMMO) is a two-electron oxidant that effects the hydroxylation of methane. [41][42][43][44][45][46][47] For these reasons, complexes based on high-valent iron have been proved to be a compelling tool in the activation of inert C-H bonds, both in biochemical and synthetic oxidation processes. [48][49][50] The active site structure of the sMMO possesses an [Fe IV 2 (m-O 2 )] diamond core motif, 45,[51][52][53][54][55][56] and this unit is known to be responsible for the activation of inert C-H bonds such as those of methane.…”

“…[41][42][43][44][45][46][47] For these reasons, complexes based on high-valent iron have been proved to be a compelling tool in the activation of inert C-H bonds, both in biochemical and synthetic oxidation processes. [48][49][50] The active site structure of the sMMO possesses an [Fe IV 2 (m-O 2 )] diamond core motif, 45,[51][52][53][54][55][56] and this unit is known to be responsible for the activation of inert C-H bonds such as those of methane. 57 This has inspired several groups to utilise both heme 50,[58][59][60] and non-heme 61 ligand frameworks to synthesise biomimetic models, which are both structural and functional mimics of the enzyme.…”

“…The active site structure of the sMMO possesses an [FeIV2(μ-O 2 )] diamond core motif, 45 , 51 – 56 and this unit is known to be responsible for the activation of inert C–H bonds such as those of methane. 57 This has inspired several groups to utilise both heme 50 , 58 – 60 and non-heme 61 ligand frameworks to synthesise biomimetic models, which are both structural and functional mimics of the enzyme.…”

Isolation and Characterization of a Dihydroxo-Bridged Iron(III,III)(μ-OH)2 Diamond Core Derived from Dioxygen

“…The reduced binuclear Fe(II) 2 active site of methane monooxygenase (MMO) 1,10,18–21 and ribonucleotide reductase (RNR) 10,22–25 react with O 2 to afford highly reactive oxidized binuclear Fe(IV) 2 (μ-O) 2 (A) or M(III)(μ-O)(μ-OH)M'(IV) (M, M'= Mn, Fe; B) diamond cores 26–28 , respectively, (Scheme 1) which abstract H-atoms from either CH 4 or TyrOH, respectively, to afford Fe(III)(μ-OH)(μ-O)Fe(IV) (B) or M(III)(μ-OH) 2 M'(III) (C) species. 3,19,21,25,29,30 The highly reactive nature of these enzymatic intermediates has prompted numerous investigations aimed at establishing benchmark structural, spectroscopic, and reactivity properties of these species. 1,4,10–12,16,18–28,31–36 With RNR, the introduction of an electron along with O 2 affords structure B (Scheme 1), which in Chlamydia tranchomatis has been shown to contain an oxo/hydroxo bridged Fe(III)Mn(IV) dimer based on Mn and Fe K-edge EXAFS and DFT calculations.…”

Metallomics Using Inductively Coupled Plasma Mass Spectrometry

“…For instance, metalloenzymes perform the most industrially relevant, energetically challenging, and arguably most interesting reactions in all biology. Nitrogen fixation (catalyzed by nitrogenase) (Schwarz et al, 2009), the interconversion of CO and CO 2 (carbon monoxide dehydrogenase) (Ragsdale, 2009), photolysis of water (oxygen-evolving complex) (Guskov et al, 2010), hydrogen production (hydrogenase) (Lubitz et al, 2007), C-H activation (methane monooxygenase and cytochrome P450s) (Brunhold, 2007), radicalbased chemistry (radical SAM enzymes and cobalamin) (Matthews, 2001;Frey et al, 2008), and electron transport (Paquete and Louro, 2010) are all carried out biologically using metal centers. These are reactions with applications in agriculture, environmental remediation, biofuels, and synthetic chemistry.…”