Site-selective formation of an iron(<scp>iv</scp>)–oxo species at the more electron-rich iron atom of heteroleptic μ-nitrido diiron phthalocyanines

İşçi, Ümit; Faponle, Abayomi S.; Afanasiev, P.; Albrieux, Florian; Briois, Valérie; Ahsen, Vefa; Dumoulin, Fabienne; Sorokin, Alexander B.; Visser, Sam P. de

doi:10.1039/c5sc01811k

Cited by 76 publications

(45 citation statements)

References 111 publications

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“…Structurally all geometries look very similar especially regarding the ligand structure, and, for instance, all Pt–CH 3 distances are within 0.007 Å, which implicates a minor effect on the Pt binding properties upon changing the transition metals. Most optimized geometries give bond lengths as expected from calculations on analogous complexes [ 13 , 14 , 15 ]. In the case of A Fe,2CO a full geometry optimization without constraints led to hydrogen atom transfer from Fe to the carbene center, which implies a low-barrier process for hydrogen transfer.…”

Section: Resultssupporting

confidence: 55%

Alkyl Chain Growth on a Transition Metal Center: How Does Iron Compare to Ruthenium and Osmium?

Sainna

Visser

2015

IJMS

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Industrial Fischer-Tropsch processes involve the synthesis of hydrocarbons usually on metal surface catalysts. On the other hand, very few homogeneous catalysts are known to perform a Fischer-Tropsch style of reaction. In recent work, we established the catalytic properties of a diruthenium-platinum carbene complex, [(CpRu)2(μ2-H)(μ2-NHCH3)(μ3-C)PtCH3(P(CH3)3)2](CO)n+ with n = 0, 2 and Cp = η5-C5(CH3)5, and showed it to react efficiently by initial hydrogen atom transfer followed by methyl transfer to form an alkyl chain on the Ru-center. In particular, the catalytic efficiency was shown to increase after the addition of two CO molecules. As such, this system could be viewed as a potential homogeneous Fischer-Tropsch catalyst. Herein, we have engineered the catalytic center of the catalyst and investigated the reactivity of trimetal carbene complexes of the same type using iron, ruthenium and osmium at the central metal scaffold. The work shows that the reactivity should increase from diosmium to diruthenium to diiron; however, a non-linear trend is observed due to multiple factors contributing to the individual barrier heights. We identified all individual components of these reaction steps in detail and established the difference in reactivity of the various complexes.

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Section: Resultssupporting

confidence: 55%

Alkyl Chain Growth on a Transition Metal Center: How Does Iron Compare to Ruthenium and Osmium?

Sainna

Visser

2015

IJMS

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“…The corrolazine, in addition to the missing meso-CH group has the other three meso-CH groups replaced by nitrogen atoms. As a consequence, corrole and corrolazine ligands have an overall charge of +3, whereas heme, protoporphyrin IX and phthalocyanine rings only have a charge of +2 [ 79 ].…”

Section: Resultsmentioning

confidence: 99%

Challenging Density Functional Theory Calculations with Hemes and Porphyrins

Visser

Stillman

2016

IJMS

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In this paper we review recent advances in computational chemistry and specifically focus on the chemical description of heme proteins and synthetic porphyrins that act as both mimics of natural processes and technological uses. These are challenging biochemical systems involved in electron transfer as well as biocatalysis processes. In recent years computational tools have improved considerably and now can reproduce experimental spectroscopic and reactivity studies within a reasonable error margin (several kcal·mol−1). This paper gives recent examples from our groups, where we investigated heme and synthetic metal-porphyrin systems. The four case studies highlight how computational modelling can correctly reproduce experimental product distributions, predicted reactivity trends and guide interpretation of electronic structures of complex systems. The case studies focus on the calculations of a variety of spectroscopic features of porphyrins and show how computational modelling gives important insight that explains the experimental spectra and can lead to the design of porphyrins with tuned properties.

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“… 217 Under catalytic conditions, they were shown to activate C–H bonds of methane (BDE = 104 kcal/mol) to afford formic acid with total turnover numbers (TTN) up to ∼220. 218 Recent computational studies showed that the activation barriers of [(L)Fe IV =N–Fe IV (L •+ )=O] type intermediates for methane oxidation are over 10 kcal/mol lower than that of a model P450 cpd I. 219 The calculation also suggests that the donor properties of the bridged nitrido group dramatically increased the basicity of the oxo group, which is crucial for the high reactivity of this class of compounds.…”

Section: Key Intermediates Involved In O 2 Activatmentioning

confidence: 99%

Oxygen Activation and Radical Transformations in Heme Proteins and Metalloporphyrins

2017

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As a result of the adaptation of life to an aerobic environment, nature has evolved a panoply of metalloproteins for oxidative metabolism and protection against reactive oxygen species. Despite the diverse structures and functions of these proteins, they share common mechanistic grounds. An open-shell transition metal like iron or copper is employed to interact with O2 and its derived intermediates such as hydrogen peroxide to afford a variety of metal–oxygen intermediates. These reactive intermediates, including metal-superoxo, -(hydro)peroxo, and high-valent metal–oxo species, are the basis for the various biological functions of O2-utilizing metalloproteins. Collectively, these processes are called oxygen activation. Much of our understanding of the reactivity of these reactive intermediates has come from the study of heme-containing proteins and related metalloporphyrin compounds. These studies not only have deepened our understanding of various functions of heme proteins, such as O2 storage and transport, degradation of reactive oxygen species, redox signaling, and biological oxygenation, etc., but also have driven the development of bioinorganic chemistry and biomimetic catalysis. In this review, we survey the range of O2 activation processes mediated by heme proteins and model compounds with a focus on recent progress in the characterization and reactivity of important iron–oxygen intermediates. Representative reactions initiated by these reactive intermediates as well as some context from prior decades will also be presented. We will discuss the fundamental mechanistic features of these transformations and delineate the underlying structural and electronic factors that contribute to the spectrum of reactivities that has been observed in nature as well as those that have been invented using these paradigms. Given the recent developments in biocatalysis for non-natural chemistries and the renaissance of radical chemistry in organic synthesis, we envision that new enzymatic and synthetic transformations will emerge based on the radical processes mediated by metalloproteins and their synthetic analogs.

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Site-selective formation of an iron(iv)–oxo species at the more electron-rich iron atom of heteroleptic μ-nitrido diiron phthalocyanines

Abstract: A combination of MS and computation on μ-nitrido bridged diiron complexes reveals H2O2 binding to the complex and generates an oxidant capable of oxidizing methane.

Cited by 76 publications

References 111 publications

Alkyl Chain Growth on a Transition Metal Center: How Does Iron Compare to Ruthenium and Osmium?

Alkyl Chain Growth on a Transition Metal Center: How Does Iron Compare to Ruthenium and Osmium?

Challenging Density Functional Theory Calculations with Hemes and Porphyrins

Oxygen Activation and Radical Transformations in Heme Proteins and Metalloporphyrins

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