Electrocatalysis of oxygen reduction. 5. Oxygen to hydrogen peroxide conversion by cobalt(II) tetrakis(N-methyl-4-pyridyl)porphyrin

Chan, Ray J.H.; Su, Yuhlong Oliver; Kuwana, Theodore

doi:10.1021/ic00217a017

Cited by 87 publications

(55 citation statements)

References 8 publications

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“…are found for cis-(NPh)PhBPyP (16) (medium intensGy) and cis-B(NPh)BPyP (17) (very strong) within the nitro porphyrins, and peaks at around 1618 cm-' (BNH (13b)) are seen for aminoporphyrins. The intensity of the ~C N band found for the pyrrole and pyridyl rings at -1595 cm-' (29,30) naturally increases with increasing pyridyl content.…”

Section: Uv-vis Infrared and Mass Spectramentioning

confidence: 95%

Porphyrin chemistry pertaining to the design of anti-cancer drugs; part 1, the synthesis of porphyrins containing meso-pyridyl and meso-substituted phenyl functional groups

Meng¹,

James²,

Skov³

1994

Can. J. Chem.

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Condensation of pyrrole with a benzaldehyde and 4-pyridinecarboxaldehyde mixture yields the six possible meso-substituted phenyl or pyridyl porphyrins. Nitration of four of these has yielded 13 other porphyrins containing one to four 4-nitrophenyl moieties, and SnCl2 reduction of eight of these nitrophenylporphyrins gives the corresponding 4-aminophenyl(phenyl)- or 4-aminophenyl(phenyl)(4-pyridyl)-porphyrins. Twelve of the porphyrins are new, but all 27 are fully characterized by 1H NMR; resonances for every proton within each of the phenyl, pyridyl, and pyrrole rings are assigned. Trends in UV–VIS data are discussed, while IR and mass spectral data are noted for selected porphyrins.

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Section: Uv-vis Infrared and Mass Spectramentioning

confidence: 95%

Porphyrin chemistry pertaining to the design of anti-cancer drugs; part 1, the synthesis of porphyrins containing meso-pyridyl and meso-substituted phenyl functional groups

Meng¹,

James²,

Skov³

1994

Can. J. Chem.

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“…46,47,61 Although Co II P in acidic media was thought to be a diaqua adduct, 62 there is no detailed information in the literature on the pH-dependent structure of Co II P ligated species. At low pH in aerobic conditions, efficient Co II P oxidation occurs, which makes the investigation of ligated species difficult.…”

Section: Background: Axial Ligation Of Co II Tmpyp(4) and Co Iii Tmpymentioning

confidence: 99%

Resonance Raman characterization of cationic Co(II) and Co(III) tetrakis(N‐methyl‐4‐pyridinyl)porphyrins in aqueous and non‐aqueous media

Терехов

Kruglik

Malinovskii

et al. 2003

J Raman Spectroscopy

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Resonance Raman (RR) spectra of Co(II) and Co(III) complexes of the water-soluble cationic tetrakis(Nmethyl-4-pyridinyl)porphyrin [Co II TMpyP(4), Co III TMpyP (4)] were obtained in aqueous and non-aqueous media, using both B-and Q-band excitation wavelengths. RR spectra of Co II TMpyP(4) are observed for the first time, and they are compared with those of Co III TMpyP(4). Wavenumbers of the n 2 , n 4 , n 8 and n 6 oxidation state-sensitive bands depend on pH in aqueous solution and on the nature of the solvent ( methanol, ethanol, DMF, DMSO): they lie in distinct spectral ranges for Co(II) vs Co(III) porphyrins. In addition, wavenumber shifts induced by axial ligation cover regions twofold broader for Co III TMpyP(4) than for Co II TMpyP(4). This shows that the electronic influence of axial ligands on the p-system of the macrocycle is more effective when cobalt is in a higher oxidation state. This can be due to (i) smaller axial bond lengths of Co(III) porphyrin and, hence, more efficient cobalt-axial ligand interaction as compared with Co(II) complexes, and (ii) Co III TMpyP(4) being involved in bis-adducts whereas Co II TMpyP(4) ismainly bound with only one axial ligand. The response of the porphyrin ring to the binding of axial ligands having various electron-donating-withdrawing properties was monitored by the behaviour of these oxidation-state sensitive RR bands: their shifts observed in a series of solvents were compared with Gutmann donor and acceptor numbers (DN, AN) of the solvents. A linear positive correlation was observed between Gutmann AN and n 2 , n 4 , n 8 and n 6 band wavenumbers for Co III TMpyP(4), whereas a linear negative correlation was observed for the same bands of Co II TMpyP(4) when DN increases. This means that enhanced electron-accepting properties of axial ligand result in a scarcity of cobalt d p -orbitals, which in turn leads to a decrease in p back-donation from cobalt to the porphyrin macrocycle.

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“…UV-Visible spectra of nonmetallated SiTiP/TmPyP (A) and metallated SiTiP/CoTmPyP (B), suspended in liquid paraffin. solutions (5,(39)(40)(41)(42)(43)(44). In our case, when varying the solution pH between 1.6 and 6.8 the potential is only slightly changed staying between −0.22 and −0.29 V. Reduction of O 2 by the metal porphyrin on a rough electrode surface and that occurring on a very porous material surface can be quite different.…”

Section: Dioxygen Reduction On the Electrode Surfacementioning

confidence: 57%

Electrochemical Properties of a Porphyrin-Cobalt (II) Adsorbed on Silica–Titania–Phosphate Composite Surface Prepared by the Sol–Gel Method

Castellani

Gushikem

2000

Journal of Colloid and Interface Science

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Electrocatalysis of oxygen reduction. 5. Oxygen to hydrogen peroxide conversion by cobalt(II) tetrakis(N-methyl-4-pyridyl)porphyrin

Cited by 87 publications

References 8 publications

Porphyrin chemistry pertaining to the design of anti-cancer drugs; part 1, the synthesis of porphyrins containing meso-pyridyl and meso-substituted phenyl functional groups

Porphyrin chemistry pertaining to the design of anti-cancer drugs; part 1, the synthesis of porphyrins containing meso-pyridyl and meso-substituted phenyl functional groups

Resonance Raman characterization of cationic Co(II) and Co(III) tetrakis(N‐methyl‐4‐pyridinyl)porphyrins in aqueous and non‐aqueous media

Electrochemical Properties of a Porphyrin-Cobalt (II) Adsorbed on Silica–Titania–Phosphate Composite Surface Prepared by the Sol–Gel Method

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