Generation of trans-dioxoruthenium(VI) porphyrins: A photochemical approach

Zhang, Rui; Huang, Yong; Abebrese, Chris; Thompson, Helen; Vanover, Eric; Webb, Cathleen

doi:10.1016/j.ica.2011.06.002

Cited by 13 publications

(4 citation statements)

References 41 publications

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“…Notably, we have discovered a new photosynthetic entry to the well-known trans -dioxoruthenium(VI) porphyrins as a result of the simultaneous cleavages of two X-O bonds from ruthenium(IV) dichlorates or dibromates. 44, 45 In this work, we have also extended the so called photo-induced ligand cleavage reactions 20 for the generation of the ruthenium(V)-oxo species. Instead of the homolysis of the Cl-O in ruthenium(IV) dichlorates that gave an one-electron oxidation, we expected a two-electron oxidation through heterolysis of the O-X bond in the oxygen-containing ligands to produce the ruthenium(V)-oxo species (Figure 5).…”

Section: Resultsmentioning

confidence: 99%

Photochemical generation and kinetic studies of a putative porphyrin-ruthenium(v)-oxo species

et al. 2014

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Photo-disproportionation of a bis-porphyrin-diruthenium(IV) μ-oxo dimer gave a porphyrin-ruthenium(III) species and a putative poprhyrin-ruthenium(V)-oxo species that can be detected and studied in real time via laser flash photolysis methods. As determined by its spectral and kinetic behavior, the same oxo transient was also formed by photolysis of a porphyrin-ruthenium(III) N-oxide adduct. Second-order rate constants for reactions with several substrates at 22 °C were determined; representative values of rate constants were kox = 6.6 × 103 M−1 s−1 for diphenylmethanol, kox = 2.5 × 103 M−1 s−1 for styrene, and kox = 1.8 × 103 M−1 s−1 for cyclohexene. The putative porphyrin-ruthenium(V)-oxo transient reacted 5–6 orders of magnitude faster than the corresponding trans-dioxoruthenium(VI)-oxo porphyrins, and the rate constants obtained in this work were similar to those of corrole-iron(V)-oxo derivative. The high reactivity for the photochemically generated ruthenium-oxo species in comparison to other poprhyrin-metal-oxo intermediates suggests it is a true ruthenium(V)-oxo species.

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Section: Resultsmentioning

confidence: 99%

Photochemical generation and kinetic studies of a putative porphyrin-ruthenium(v)-oxo species

et al. 2014

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“…Cl and Br) complexes was also reported to produce trans-dioxoruthenium(VI) species through analogous homolytic cleavage of the O-X bond. [37,38] Clearly, visible light irradiation of bromates 3 represents the same homolysis manifold that results in one-electron photo-oxidation to afford corrole-manganese(V)-oxo species 4. Of note, we found that photochemical cleavages of the bromate complexes were considerably more efficient and faster than cleavages of chlorate complexes (see Fig S2 in the Supplementary Material).…”

Section: Visible Light Formation Of Corrole-manganese(v)-oxo Complexesmentioning

confidence: 99%

“…In addition, the kinetics of oxidation reactions by photo-generated metal-oxo species are not convoluted with the rate constants for formation of the reactive transients by reaction of the excess sacrificial oxidant with the low-valent metal species. [35] As our ongoing efforts to explore photochemical approaches to access high-valent metal-oxo species, we have utilized photo-induced ligand cleavage reactions to produce trans-dioxoruthenium (VI) porphyrins [37,38] as well as a putative ruthenium(V)-oxo species [39] that was also found in a photo-disproportionation of the bis-porphyrin-ruthenium(IV) µ-oxo dimer. [40] Very recently, we communicated a photo-induced entry to iron(IV)-oxo porphyrin radical cations (compound I models) or iron(IV)-oxo porphyrin (compound II models) as controlled by the electronic nature of porphyrin ligands.…”

Section: Introductionmentioning

confidence: 99%

Visible light-induced formation of corrole-manganese(V)-oxo complexes: Observation of multiple oxidation pathways

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Ranburger

et al. 2016

Journal of Inorganic Biochemistry

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Two manganese(V)-oxo corroles [Mn(Cor)O] that differ in their electronic environments were produced by visible light irradiation of highly photo-labile corrole-manganese(IV) bromates. The corrole ligands under study include 5,10,15-tris(pentafluorophenyl)corrole (TPFC), and 5,10,15-triphenylcorrole (TPC). The kinetics of oxygen transfer atom (OAT) reactions with various organic reductants by these photo-generated Mn(Cor)O were also studied in CHCN and CHCl solutions. Mn(Cor)O exhibits remarkable solvent and ligand effect on its reactivity and spectral behavior. In the more electron-deficient TPFC system and in the polar solvent CHCN, Mn(Cor)O returned Mn corrole in the end of oxidation reactions. However, in the less polar solvent CHCl or in the less electron-deficient TPC system, Mn product was formed instead of Mn. Furthermore, with the same substrates and in the same solvent, the order of reactivity of Mn(Cor)O was TPC>TPFC, which is inverted from that expected based on the electron-demand of corrole ligands. Our spectral and kinetic results in this study provide compelling evidence in favor of multiple oxidation pathways, where Mn(Cor)O may serve as direct two-electron oxidant or undergo a disproportionation reaction to form a manganese(VI)-oxo corrole as the true oxidant. The choice of pathways is strongly dependent on the nature of the solvent and the corrole ligand.

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“…13,14,26,27 In this regard, the photoinduced ligand cleavage reactions have been developed to generate a variety of high-valent metal-oxo species in porphyrin and corrole systems. 28 In addition, we extended photo-induced ligand cleavage reactions to generate trans-dioxoruthenium(VI) porphyrins in sterically bulky and non-bulky porphyrins 29,30 and a highly reactive ruthenium-oxo species 31 that was also found in the photo-disproportionation of the bis-porphyrin-ruthenium(IV) m-oxo dimer. 32 In this work, we report a new photochemical access to compound I and II model complexes, depending on the electronic nature of porphyrin ligands.…”

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confidence: 99%

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

et al. 2015

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Generation of trans-dioxoruthenium(VI) porphyrins: A photochemical approach

Cited by 13 publications

References 41 publications

Photochemical generation and kinetic studies of a putative porphyrin-ruthenium(v)-oxo species

Photochemical generation and kinetic studies of a putative porphyrin-ruthenium(v)-oxo species

Visible light-induced formation of corrole-manganese(V)-oxo complexes: Observation of multiple oxidation pathways

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

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