Solution characterization of copper(II) and silver(II) porphyrins and the one-electron oxidation products by nuclear magnetic resonance spectroscopy

Godziela, Gregory M.; Goff, Harold M.

doi:10.1021/ja00269a019

Cited by 79 publications

(48 citation statements)

References 2 publications

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“…In NMR spectroscopy, the reduction of 6 was accompanied by an additional line broadening and the entire loss of any residual signal fine structure, which was detected even in the spectrum of 6 for the most distant CH 3 groups only. [24] This observation is again indicative of the presence of a π-radical on 6 Ϫ· that has no magnetic coupling with the d-electron of the metal centre. [25] The EPR spectroscopic investigation of the reduction of 6 (X-band at 9.76 GHz, room temperature) gave the spectra depicted in Figure 7.…”

Section: Spectroelectrochemical Investigationsmentioning

confidence: 99%

Structural and Spectroelectrochemical Studies on (2,2′-Bidipyrrinato)copper(II) and -palladium(II) Complexes

Bröring

Brandt

Bley-Escrich³

et al. 2002

Eur. J. Inorg. Chem.

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Copper(II) and palladium(II) complexes of two 2,2′‐bidipyrrin ligands were prepared and examined, in comparison with the known nickel(II) complexes of these ligands, by means of X‐ray crystallography, cyclic voltammetry, and spectroelectrochemistry. All compounds are of helical geometry with coordination environments of the metal centres displaying very small tetrahedral distortions for palladium and very large ones for copper complexes. Porphyrinoid behaviour was found for the one‐ and two‐electron oxidations of all complexes studied, as well as for the reductions of the PdII species. On the other hand, the reduction of the CuII complexes shows some special features, which may be explained from the results of spectroelectrochemical studies as related to the particular non‐planarity of these compounds. (© Wiley‐VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)

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Section: Spectroelectrochemical Investigationsmentioning

confidence: 99%

Structural and Spectroelectrochemical Studies on (2,2′-Bidipyrrinato)copper(II) and -palladium(II) Complexes

Bröring

Brandt

Bley-Escrich³

et al. 2002

Eur. J. Inorg. Chem.

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“…Perhaps the most thoroughly studied example is that of the readily available horseradish peroxidase (HRP). 1 While optical absorption spectroscopy provides support for the existence of a ferryl porphyrin -cation radical in the case of the Compound I intermediate (HRP-I) (6), this technique does not permit a clear distinction between the 2 A 1u and 2 A 2u formulations (7)(8)(9)(10)(11)(12). The results of various magnetic resonance measurements are also conflicting.…”

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confidence: 99%

Resonance Raman Spectra of Native and Mesoheme-reconstituted Horseradish Peroxidase and Their Catalytic Intermediates

Kincaid

Zheng

Al-Mustafa

et al. 1996

Journal of Biological Chemistry

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Resonance Raman studies of native and mesohemereconstituted horseradish peroxidase and their catalytic intermediates, known as Compounds I and II, have been conducted using both near UV (ϳ350 nm) and visible (406.7 nm) excitation. Careful power studies indicate that the authentic Compound I spectra are obtainable using near UV excitation, but that use of visible excitation results in contamination of the Compound I spectrum with the spectrum of a Compound II-like photoproduct. Using H 2 18 O 2 , the (Fe‫؍‬O) stretching modes for both systems are unambiguously identified, for the first time, at ϳ790 cm ؊1 . The authentic Compound I spectra are indicative of an 2 A 1u -like ground state for both the native and the mesoheme-reconstituted proteins. Finally, the possible biological implications of such information are briefly discussed.

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“…(10,(17)(18)(19). The second oxidation results in removal of an electron from the porphyrin ring to produce the OEP'A~(III)'+ a-cation radical (10).…”

Section: Resultsmentioning

confidence: 99%

In situ Fourier transform infrared spectroelectrochemical studies of the oxidation of some octaethylporphyrin complexes

Hinman¹,

Olorunyolemi²

1993

Can. J. Chem.

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A. Scon HINMAN and TEMITAYO 01-ORUNYOLEMI. Can. J. Chem. 71, 1975Chem. 71, (1993.The oxidations of OEPNi(II), OEPCu(II), OEPFe(III)Cl, OEPMn(III)ClO,, OEPAg(II), OEPCo(II), and OEPZn(I1) (OEP = 2,3,7,8,12,13,17,18-octaethylporphyrin dianion) have been studied by in situ FTIR reflectance spectroelectrochemistry in dibromomethane. One-electron oxidation of the porphyrin ring to produce a =-cation radical results in the appearance of a strong new absorbance band near 1550 cm-I. Other features typical of =-cation radical formation are a strong absorbance increase near 1470 cm-I, and absorbance decreases near 1270 and 1018 cm-'. Oxidation of the metal centre, as observed for OEPCo(I1) in the presence of CH3CN, and for OEPAg(II), results in considerably less perturbation of the vibrational spectra of the complexes. For OEPCo(I1) in dry dibromomethane, initial oxidation at the porphyrin ligand is followed by a second oxidation at the metal centre. This order is reversed when acetonitrile is added to solution. Production of porphyrin T-dications was observed for OEPCu(I1) and OEPNi(I1). This results in a shift of the 1550 cm-' =-cation radical marker band to higher energy, and a strong absorbance increase near 1380 cm-I. Unusual spectral changes observed on one-electron oxidation of OEPZn(I1) are suggested to result from the formation of a dimer.A. Scon HINMAN et TEMITAYO OLORUNYOLEMI. Can. J. Chem. 71, 1975 (1993.

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Solution characterization of copper(II) and silver(II) porphyrins and the one-electron oxidation products by nuclear magnetic resonance spectroscopy

Cited by 79 publications

References 2 publications

Structural and Spectroelectrochemical Studies on (2,2′-Bidipyrrinato)copper(II) and -palladium(II) Complexes

Structural and Spectroelectrochemical Studies on (2,2′-Bidipyrrinato)copper(II) and -palladium(II) Complexes

Resonance Raman Spectra of Native and Mesoheme-reconstituted Horseradish Peroxidase and Their Catalytic Intermediates

In situ Fourier transform infrared spectroelectrochemical studies of the oxidation of some octaethylporphyrin complexes

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