Effects of electron-withdrawing substituents on the electrochemical oxidation of porphyrins

Giraudeau, A.; Callot, H. J.; Gross, Maurice

doi:10.1021/ic50191a042

Cited by 138 publications

(77 citation statements)

References 11 publications

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“…A comparison of the electrochemical behaviour with other reported data 30,31 leads us to suppose that the redox reactions of the nitro-porphyrins reported here also involve the porphyrin π-ring system. Considering the predominant effect of the nitro groups on the electrochemical properties, all results were analysed as a function of the number of these groups.…”

Section: Electrochemical Characterizationsupporting

confidence: 75%

Synthesis and characterization of a novel series of meso (nitrophenyl) and meso (carboxyphenyl) substituted porphyrins

Schiavon¹,

Iwamoto²,

Ferreira³

et al. 2000

J. Braz. Chem. Soc.

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As porfirinas aniônicas 5,10,15-tris(4-carboxifenil), 20-mono(2-nitrofenil) porfirina (1), 5,10(ou 15)-bis(4-carboxifenil), 15(or 10),20-bis(2-nitrofenil)porfirina (2) and 5-mono(4-carboxifenil), 10,15,20-tris(2-nitrofenil)porfirina (3), foram sintetizadas diretamente através da reação de pirrol com os benzaldeídos substituídos em meio de ácido propiônico/nitrobenzeno. A relação molar dos benzaldeídos foi controlada para otimizar a síntese e purificação das porfirinas desejadas. Esta nova série de porfirinas foi caracterizada por cromatografia em camada delgada, espectrometria de massas (FAB MS), RMN 1 H, UV/Vis, IV e eletroquímica. As porfirinas 5,10,15,20-tetrakis(4-carboxifenil)porfirina (4) e 5,10,15,20-tetrakis(2-nitrofenil)porfirina (5) também foram estudadas para comparação, tornando a série completa. A redução eletroquímica das porfirinas base livre e correspondentes ferro(III) porfirinas foi investigada em eletrodos de carbono e mercúrio. Os potenciais de redução mostraram a dependência esperada do número de grupos nitro, fortemente retirador de elétrons, presentes no anel porfirínico, fornecendo evidências adicionais para a caracterização dos compostos sintetizados.The anionic 5,10,15-tris(4-carboxyphenyl), 20-mono(2-nitrophenyl) porphyrin (1), 5,10(or 15)-bis(4-carboxyphenyl), 15(or 10),20-bis(2-nitrophenyl)porphyrin (2) and 5-mono(4-carboxyphenyl), 10,15,20-tris(2-nitrophenyl)porphyrin (3) were sinthesized directly by reaction of pyrrole with substituted benzaldehydes in nitrobenzene/propionic acid media. The benzaldehydes molar ratio was controlled to optimize the synthesis and purification of the desired porphyrins. This new series of porphyrins was characterised by TLC, mass spectrometry (FAB MS), 1 H NMR, UV/Vis, IR and electrochemistry. 5,10,15,10,15,porphyrin (5) were also characterised for comparative purposes, completing the series The electrochemical reduction was investigated for the free base and corresponding iron(III) porphyrins on glassy carbon and mercury electrodes. The reduction potentials showed the expected dependence on the number of electron-withdrawing nitro groups present on the porphyrin ring providing additional evidences for the characterisation of the synthesised compounds.

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Section: Electrochemical Characterizationsupporting

confidence: 75%

Synthesis and characterization of a novel series of meso (nitrophenyl) and meso (carboxyphenyl) substituted porphyrins

Schiavon¹,

Iwamoto²,

Ferreira³

et al. 2000

J. Braz. Chem. Soc.

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“…On the other hand, the substitution of electron withdrawing bromo groups at the pyrole positions of porphyrins was found to cause an anodic shift in the ring oxidation and reduction potentials [33,34]. Octabromotetraphenylphorphyrin and its metal derivatives are highly soluble in organic solvents and are stable toward acids [29].…”

Section: Resultsmentioning

confidence: 99%

Thiocyanate-Selective Membrane Electrode Based on (Octabromotetraphenylporphyrinato)manganese(III) Chloride

Shamsipur¹,

Khayatian

Tangestaninejad

1999

Electroanalysis

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The response characteristics of a new solvent-polymeric membrane electrode with unique selectivity and detection limit toward SCN À ion are reported. The electrode is prepared by incorporating (octabromotetraphenylporphyrinato)manganese(III) chloride into a plasticized PVC-membrane. The resulting sensor exhibits anti-Hofmeister selectivity pattern with high speci®city for thiocyanate over other anions, including lipophilic inorganic anions. The electrode has a linear dynamic range between 1.0 and 4.8610 À7 M, with a Nernstian slope of 58.3 AE 0.8 mVadecade and a detection limit of 3.2610 À7 M. The electrode can be used for at least 3 months without any considerable divergence in potential. It was used as an indicator electrode in potentiometric titration of SCN À ion and in direct determination of thiocyanate in urine samples.

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“…52 whereas those of HBNDI are unknown. However, as the redox properties of the core-substituted NDIs have been shown to be correlated with their S 1 ' S 0 energy gap, the redox potentials of HBNDI can be expected to be close to those of a blue NDI with two amino core substituents and with similar S 1 ' S 0 gap (compound 17 in ref.…”

Section: Discussionmentioning

confidence: 99%

Ultrafast excited-state dynamics of strongly coupled porphyrin/core-substituted-naphthalenediimide dyads

Banerji

Bhosale

Petkova

et al. 2011

Phys. Chem. Chem. Phys.

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The photophysics and excited-state dynamics of two dyads consisting of either a free-base or a zinc-tetraphenylporphyrin linked through a rigid bridge to a core-substituted naphthalenediimide (NDI) have been investigated by femtosecond-resolved spectroscopy. The absorption and fluorescence spectra differ substantially from those of the individual units, pointing to a substantial coupling and to a delocalisation of the excitation over the whole molecule, as confirmed by quantum chemistry calculations. A strong dependence of their excited-state dynamics on the solvent polarity has been observed. In toluene, the fluorescence quantum yield of the dyads is of the order of a few percent and the main decay channel of the emitting state is proposed as intersystem-crossing to the triplet state. However, in a medium polarity solvent like dichloromethane, the emitting state undergoes charge separation from the porphyrin to the NDI unit within 1-3 ps, and the ensuing charge-separated state recombines in about 10-20 ps. This solvent dependence can be explained by the weak driving force for charge separation in polar solvents and the large electronic coupling between the porphyrin and NDI moieties, making charge separation a solvent-controlled adiabatic process.

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Effects of electron-withdrawing substituents on the electrochemical oxidation of porphyrins

Cited by 138 publications

References 11 publications

Synthesis and characterization of a novel series of meso (nitrophenyl) and meso (carboxyphenyl) substituted porphyrins

Synthesis and characterization of a novel series of meso (nitrophenyl) and meso (carboxyphenyl) substituted porphyrins

Thiocyanate-Selective Membrane Electrode Based on (Octabromotetraphenylporphyrinato)manganese(III) Chloride

Ultrafast excited-state dynamics of strongly coupled porphyrin/core-substituted-naphthalenediimide dyads

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