Ligand control in the photochemical generation of high-valent porphyrin-iron–oxo derivatives

Chen, Tse-Hong; Asiri, Nawras; Kwong, Ka Wai; Malone, Jonathan; Zhang, Rui

doi:10.1039/c5cc02852c

Cited by 16 publications

(8 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In photolysis experiments of 4 , there are two possible sites at which bonds could break homolytically: (a) the Ru–ONO 2 bond or (b) the RuO–NO 2 bond (Scheme ). Previous studies have indicated that either site is possible. ,, Heterolytic RuO–NO 2 bond cleavage is another possible pathway (pathway c in Scheme ), which has been demonstrated for perchlorate compounds . Both pathways b and c would explain our mass spectrometry results.…”

Section: Resultsmentioning

confidence: 89%

See 1 more Smart Citation

A Synthetic Oxygen Atom Transfer Photocycle from a Diruthenium Oxyanion Complex

et al. 2016

View full text Add to dashboard Cite

Three new diruthenium oxyanion complexes have been prepared, crystallographically characterized, and screened for their potential to photochemically unmask a reactive Ru–Ru=O intermediate. The most promising candidate, Ru2(chp)4ONO2 (4, chp = 6-chloro-2-hydroxypyridinate), displays a set of signals centered around m/z = 733 amu in its MALDI-TOF mass spectrum, consistent with the formation of the [Ru2(chp)4O]+ ([6]+) ion. These signals shift to 735 amu in 4*, which contains 18O-labeled nitrate. EPR spectroscopy and headspace GC-MS analysis indicate that NO2• is released upon photolysis of 4, also consistent with the formation of an Ru2(chp)4O species. Photolysis of 4 in CH2Cl2 at room temperature in the presence of excess PPh3 yields OPPh3 in 173% yield; control experiments implicate Ru2(chp)4O (6), NO2•, and free NO3− as the active oxidants. Notably, Ru2(chp)4Cl (3) is recovered after photolysis. Since 3 is the direct precursor to 4, the results described herein constitute the first example of a synthetic cycle for oxygen atom transfer that makes use of light to generate a putative metal oxo intermediate.

show abstract

Section: Resultsmentioning

confidence: 89%

“…Previous studies have indicated that either site is possible. 11a,11b,29 Heterolytic RuO–NO 2 bond cleavage is another possible pathway (pathway c in Scheme 4), which has been demonstrated for perchlorate compounds. 11b Both pathways b and c would explain our mass spectrometry results.…”

Section: Resultsmentioning

confidence: 91%

A Synthetic Oxygen Atom Transfer Photocycle from a Diruthenium Oxyanion Complex

et al. 2016

View full text Add to dashboard Cite

show abstract

“…44 The photolysis reaction is proposed to go through the heterolytic cleavage of the O-Br bond, forming a putative Fe V (O) complex which then relaxes to an Fe IV (O)(porphyrin •+ ). This was observed in electron-rich porphyrins such as TMP and TPP.…”

Section: Metal-oxo Porphyrinoid Complexes As Models For Biological Oxmentioning

confidence: 99%

Biomimetic Reactivity of Oxygen-Derived Manganese and Iron Porphyrinoid Complexes

2017

View full text Add to dashboard Cite

Heme proteins utilize the heme cofactor, an iron porphyrin, to perform a diverse range of reactions including dioxygen binding and transport, electron transfer, and oxidation/oxygenations. These reactions share several, key metalloporphyrin intermediates, typically derived from dioxygen and its congeners such as hydrogen peroxide, and which are comprised of metal-dioxygen, metal-superoxo, metal-peroxo, and metal-oxo adducts. A wide variety of synthetic metalloporphyrinoid complexes have been synthesized to generate and stabilize these intermediates, and then employed to determine the spectroscopic features, structures, and reactivities of such species in controlled and well-defined environments. In this review, we summarize recent findings on the reactivity of these species with common porphyrinoid scaffolds employed for biomimetic studies. The proposed mechanisms of action are emphasized. The review is organized by structural type of metal-oxygen intermediate, and broken into subsections based on the metal (manganese, iron) and porphyrinoid ligand (porphyrin, corrole, corrolazine).

show abstract

“…[44] As thermodynamically favored in the less electron-demanding TPC system, iron(V)oxo species 5 might relax to radical cation species 6 by internal electron transfer (ET) from the corrole ligand to the iron. [47] In contrast, the electron-deficient Fe III (TPFC) 1b (λ max = 404 nm) was quantitatively converted by excess PhI(OAc) 2 (5 to 20 equivalents) to a stable compound with clearly resolved isosbestic points (Fig. 2B).…”

Section: Comparison Of Various Oxygen Sources In the Catalytic Oxidatmentioning

confidence: 98%

Highly efficient and chemoselective oxidation of sulfides catalyzed by iron(III) corroles with iodobenzene diacetate

Chen

Kwong

Lee

et al. 2016

Inorganica Chimica Acta

Self Cite

View full text Add to dashboard Cite

Iron(III) corrole complexes catalyze the highly chemoselective oxidation of sulfides to sulfoxides with iodobenzene diacetate [PhI(OAc) 2 ] as a mild oxygen source. Various substituted thioanisoles, vinyl sulfides, and hydroxyl sulfides can be efficiently oxidized to sulfoxides with quantitative conversions (up to 5000 TONs) and excellent selectivies without over-oxidation to sulfones. The remarkably enhanced catalytic activity and stability against degradation is ascribed to the slow and steady-state formation of PhIO from highly soluble PhI(OAc) 2 in the presence of a small amount of water. On the basis of Hammett correlation and mixing UV-vis spectral studies, a putative high-valent iron(V)-oxo species is likely generated as a short-lived active intermediate.

show abstract

Ligand control in the photochemical generation of high-valent porphyrin-iron–oxo derivatives

Abstract: Visible-light irradiation of photo-labile bromate porphyrin-iron(III) salts gave iron(IV)-oxo porphyrin radical cations (compound I model) or the neutral iron(IV)-oxo porphyrin (compound II model), depending on the electronic structure of porphyrin ligands.

Cited by 16 publications

References 37 publications

A Synthetic Oxygen Atom Transfer Photocycle from a Diruthenium Oxyanion Complex

A Synthetic Oxygen Atom Transfer Photocycle from a Diruthenium Oxyanion Complex

Biomimetic Reactivity of Oxygen-Derived Manganese and Iron Porphyrinoid Complexes

Highly efficient and chemoselective oxidation of sulfides catalyzed by iron(III) corroles with iodobenzene diacetate

Contact Info

Product

Resources

About