Models of the Cytochromes b

Walker, F. Ann; Barry, Judith; Balke, Virginia L.; McDermott, Gregory A.; Wu, Michael; Linde, Peter F.

doi:10.1021/ba-1982-0201.ch017

Cited by 23 publications

(21 citation statements)

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“…It is well documented that the addition of nitrogen bases to iron() tetraphenylporphyrins in non-polar solvents generally leads to a bis-ligated, low-spin iron() complex. [22][23][24][25][26][27][28] The equilibria involved are such that the second equilibrium constant for formation of the bis-complex is larger than that of the first for mono-ligation and consequently iron() porphyrins prefer to be bis-ligated. For this reason it is probable that the amino acid complexes in this study are also bis-ligated (not shown in Scheme 5) and low spin.…”

Section: Methodsmentioning

confidence: 99%

Photo-decarboxylation of iron(III) porphyrin–amino acid complexes in aqueous solution

Gilbert¹,

Smith²,

Parsons³

et al. 1997

J. Chem. Soc., Perkin Trans. 2

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Section: Methodsmentioning

confidence: 99%

Photo-decarboxylation of iron(III) porphyrin–amino acid complexes in aqueous solution

Gilbert¹,

Smith²,

Parsons³

et al. 1997

J. Chem. Soc., Perkin Trans. 2

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“…Oligonucleotides have been synthesized by the phosphotriester approach. 16 The oligomers have been sampled directly from their water solution into the glycerol layer present on the tip of FAB probe. Spectra have been recorded in a double-focusing mass spectrometer VG ZAB equipped with a commercial FAB gun.…”

Section: Methodsmentioning

confidence: 99%

Electrochemical and spectral characterization of iron mono- and dinitrosyl porphyrins

Lançon¹,

Kadish²

1983

J. Am. Chem. Soc.

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The electrochemistry of (TPP)Fe"(NO) and (OEP)Fe"(NO) was investigated in nine nonaqueous solvents. In weakly binding solvents, such as dichloromethane or benzonitrile, five diffusion-controlled electron-transfer reactions were observed. Three of these reactions were oxidations. The remaining two reactions involved reversible electroreductions, either at the Fe(I1) center or at the porphyrin ring. In strongly binding solvents, such as Me2S0 or pyridine, similar redox reactions were observed, but a number of chemical reactions were coupled to the electron-transfer steps. Formation of dinitrosyl complexes from either the unnitrosylated or mononitrosyl Fe(I1) and Fe(II1) complexes was characterized, and several stability constants measured. Finally, competitive ligation between different solvents and NO as axial ligand in each solvent system was studied along the series of oxidized, neutral, and reduced complexes.

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“…Expressing equation [8] in the form of equation [4] yields the following equation: [9 ] where EO' is EO for unsubstituted tetraphenylporphyrin. The artificial photosynthesis project supported by this work is designed to fabricate a device in which porphyrin molecules are assembled into a polymeric film.…”

Section: Linear Free Energy Relationshipsmentioning

confidence: 99%

“…Expressing equation [8] in the form of equation [4] yields the following equation: [9 ] where EO' is EO for unsubstituted tetraphenylporphyrin. Model Porphryins For Thin-Film Membranes…”

mentioning

confidence: 99%

Solvent and Substituent Effects on the Redox Potentials of Several Substituted Tetraphenylporphyrins

Ransdell

2000

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Some specific conclusions are summarized. 1.The usefulness of linear free energy relationships in correlating variations in redox potentials with changes in substituent was confirmed with two exceptions. Two of the porphyrins were shown to undergo a different electrochemical oxidation mechanism than the remaining porphyrins, and another porphyrin was shown to be more difficult to reduce than predicted on the basis of its substituent constant. 2.Solvent effects, here investigated as the effect of added water on the reduction potential of tetraaminophenylporphyrin in DMSO, were demonstrated to correlate with the Dimroth-Reichardt solvent parameter, E T , determined experimentally for each water-DMSO mix. 2. LIST OF TABLES 3.4. 5.6. 7.8. 9.10. 11.12. can be used to drive the photochemical splitting of water into hydrogen gas and oxygen gas. This is illustrated in Figure 1, where S is an absorbing chromophore, A is an electron acceptor, and 0 is an electron donor. Figure 3), the resultant straight line can be written as: LIST OF FIGURESwhere p is the slope of the plot and A is the Y-intercept, which is equal to log k h '. As before, k h ' is the value of k h for the unsubstituted ethyl benzoate. This notation is used instead of that of Hammett, who used Ki 0 and k h 0 in their place, in order to avoid confusion when correlating EO values.Hammett then proposed choosing one system as the reference K or k, and recommended using Ki for substituted benzoic acids since at the time those constants were readily available and easily measured with good precision. A general relationship between a given rate or equilibrium constant k and the reference system Ki can be described using the equation below: [ 2] Hammett then went on to define C1 (x), the substituent constant for substituent X, as below:log KjK' Ionization Figure 3. Comparison of hydrolysis rates of esters with ionization constant~of acids for m-and pbenzoic acid derivatives.[ 3 ]Substituting equation [3] into equation [2] relating the generic k to Ki for benzoic acids yields the following equation:or,[5 ] Given the existence of a quantitative correlation, the fact that it is linear in the logarithms can be no mere accident; for the linear relationship between the logarithms of the constants is equivalent to a relationship between the quantities -RT In k, which are the free energies of reaction or of activation. From the definition of an equilibrium constant, we know that~Go = -RTeln K =.-nFEo. From this it follows that:In K = (nF/RT)eEO or converting to base 10, log K = (nF/2.303RT)eEO [7] [ 8 ] 8Expressing equation [8] in the form of equation [4] yields the following equation: [9 ] where EO' is EO for unsubstituted tetraphenylporphyrin. Model Porphryins For Thin-Film MembranesThe assembly of molecular components into photochemical molecular devices is the goal of a new field of research. 11Many useful applications are possible, such as photochemical synthesis, photochromism, and photodecomposition. Applications such as these may not require an organiz...

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Models of the Cytochromes b

Cited by 23 publications

References 0 publications

Photo-decarboxylation of iron(III) porphyrin–amino acid complexes in aqueous solution

Photo-decarboxylation of iron(III) porphyrin–amino acid complexes in aqueous solution

Electrochemical and spectral characterization of iron mono- and dinitrosyl porphyrins

Solvent and Substituent Effects on the Redox Potentials of Several Substituted Tetraphenylporphyrins

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