The CHEMISTRY OF PORPHYRIN Π‐CATIONS*

Dolphin, David; Muljiani, Z.; Rousseau, Kathleen; Borg, Donald C.; Fajer, J.; Felton, R. H.

doi:10.1111/j.1749-6632.1973.tb43211.x

Cited by 122 publications

(55 citation statements)

References 27 publications

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“…Such ligand coordination induced ground state transitions were suggested previously for the Co1''(OEP) cation radicals (25), and such an explanation is strongly supported by the ruthenium data. The marked similarity of the spectra of the ruthenium(I1) cation radical species with those of the reported cobalt(ll1) analogues (5, 25) is in line with the general conclusion that such spectra are relatively insensitive to the nature of the cen- For personal use only.…”

supporting

confidence: 69%

“…ground state. Bromine oxidation of Col'(OEP) to Co"'(OEP)+'2Br-, however, gave a different optical spectrum for the cation-radical and that was considered to have a 'A,,, ground state (25). The two cobalt cation-radicals could be formed by the addition of >2 equiv.…”

Section: Resultsmentioning

confidence: 99%

“…Recent magnetic circular dichroism spectral data on the cobalt n-cation radical species mentioned above and on the cornpound 1 derivatives of horseradish peroxidase and catalase (27) have confirmed the iron(1V) n-cation radical nature of the enzyme cornpouncl 1 species (5,25).…”

mentioning

confidence: 96%

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Synthesis and redox chemistry of octaethylporphyrin complexes of ruthenium(II) and ruthenium(III)

Barley¹,

Becker²,

Domazetis³

et al. 1983

Can. J. Chem.

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. Can. J. Chem. 61, 2389Chem. 61, (1983.The syntheses and characterization of some ncw octaethylporphyrin complexes of ruthenium(l1) and ruthcnium(lll) are described; the complexes are Ru(OEP)(P"BU~)~. Ru(OEP)(CO)L (L = PPh3, PUBu3), [Ru(OEP)(P"BU,)~]B~, and Ru(0EP)-(PnBu3)Br, where OEP is the dianion of octaethylporphyrin. The Ru(OEP)(CO)EtOH complex, 1, which reversibly loscs the ethanol ligand in CHzC12 solution, undergoes a one-equivalent oxidation at the porphyrin ligand to gencratc the cation-radical [Ru(OEP)"(CO)]+; a purple species of 'Azu ground statc, produced electrochemically in perchlorate mcdia, can coordinate bromide to generate a green 'A,, ground state species that also results from oxidation of 1 using bromine. Coordination of pyridine to [Ru(OEP)'+CO]+ yields the Ru(OEP)"(CO)py species that can also be formcd by electrochemical oxidation of Ru(OEP)(CO)py. Addition of tertiary phosphines (PR3) to the cation-radical carbonyl spccics can lead to formation of [RU(OEP)(PR,)~]+, via an internal electron transfcr proccss from Ru(11) to the OEP" that appears to bc triggered by loss of the CO ligand. A reversible one-electron electrochemical oxidation of RU(OEP)(P"BU,)~ at 0.03 V (vs. Ag/AgCI) in CH2CIz also gives the ruthenium(Il1) biphosphine cation, while a furthcr onc-elcctron oxidation at 1.2 V generates [Ru(OEP)'+(P"BU,)~]'+, a ruthenium(lI1) n-cation radical characterized by esr. Thc [Ru(OEP)(P"Bu,),]Br complcx decomposes in the solid state to a mixture of Ru(OEP)(PUBu,)Br, formed together with free phosphine via an intramolecular ligand exchange, and RU(OEP)(P"BU~)~, formed by rcduction of the initial ionic ruthenium (lI1) [Traduit par le journal]

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supporting

confidence: 69%

Section: Resultsmentioning

confidence: 99%

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Synthesis and redox chemistry of octaethylporphyrin complexes of ruthenium(II) and ruthenium(III)

Barley¹,

Becker²,

Domazetis³

et al. 1983

Can. J. Chem.

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“…The oxidation of metalloporphyrins such as Zn or Mg have been characterized [10] as porphyrin ligand oxidations leading to 77-cation and 77-dications, the latter being good electrophiles react in nucleophilic solvents such as water or methanol, with the solvent yielding meso-substituted isoporphyrins. Such reactions would account for the irreversibility of the second oxidation waves in aqueous media.…”

Section: A Cyclic Voltammetrymentioning

confidence: 99%

“…Porphyrins are attractive as photosensitizers [4,6,10] due to their high light absorption in the visible region, long lifetime for their excited states and the ease with which they undergo photoredox reactions. Though the electrochemical studies of porphyrin redox chemistry have been rather extensive [6], they have almost exclusively been performed in non-aqueous aprotic media.…”

Section: Introductionmentioning

confidence: 99%

On the One and Two-Electron Oxidations of Water-Soluble Zinc Porphyrins in Aqueous Media

Neumann‐Spallart

Kalyanasundaram

1981

Zeitschrift Für Naturforschung B

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The one and two-electron oxidations of water soluble ionic zinc porphyrins (Zinctetra-methylpyridylporphyrin, ZnTMPyP, Zinc-tetra-p-sulfonato-phenyl-porphyrin, ZnTPPS, and Zinc-tetra-p-carboxy-phenylporphyrin, ZnTPPC) leading to the porphyrin Π-cations and Π-dications have been investigated in water by electrochemical (cyclic voltammetry and controlled potential electrolysis) and chemical methods. The half-wave potentials for the oxidation are shown to be markedly dependent on the charge on the β-substituents. While the one-electron oxidations for all these porphyrins are reversible, the dication formation leads to labile isoporphyrins as intermediates

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Formation and electronic properties of ring-oxidized and ring-reduced radical species of the phthalocyanines and porphyrins

Stillman

2000

J. Porphyrins Phthalocyanines

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The 18-π electron ring in the phthalocyanines and porphyrins largely controls their chemical and spectroscopic properties. It is the aim of this microsymposium to explore the formation and reactivities and the spectroscopic and theoretical properties of the ring-oxidized and ring-reduced phthalocyanines and porphyrins, essentially the π cation and π anion radical species. Redox chemistry of the ring, through ring oxidation and reduction to the radical species, offers powerful, new synthetic capabilities in which photochemical as well as electrochemical techniques may be used to effect highly localized reactions. The chemistry of these radical species can be moderated by control of the redox states of the central metal, the addition of electron-withdrawing or electron-donating peripheral substituents, and by the extent of intermolecular association applying both solvent polarity and peripheral substitution.

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The CHEMISTRY OF PORPHYRIN Π‐CATIONS*

Cited by 122 publications

References 27 publications

Synthesis and redox chemistry of octaethylporphyrin complexes of ruthenium(II) and ruthenium(III)

Synthesis and redox chemistry of octaethylporphyrin complexes of ruthenium(II) and ruthenium(III)

On the One and Two-Electron Oxidations of Water-Soluble Zinc Porphyrins in Aqueous Media

Formation and electronic properties of ring-oxidized and ring-reduced radical species of the phthalocyanines and porphyrins

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