Barriers to Inversion of Nonplanar Ferric Porphyrin Radical Cations:  Comparison with the Corresponding Neutral Complexes

Nakamura, Mikio; Yamaguchi, Tatsuya; Ohgo, Yoshiaki

doi:10.1021/ic990139e

Cited by 19 publications

(18 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Fig. 2(a) shows the 1 H NMR spectra of [Fe(OETPP•)Cl](SbCl 6 ) reported previously [28]. The signals were unambiguously assinged by the spectral comparison with the phenyl perdeuterated complexes as shown in the inset of Fig.…”

Section: Resultsmentioning

confidence: 58%

“…complexes, where Ar is substituted or unsubstituted phenyl group at the meso positions and axial ligands are imidazole, tert-butylisocyanide, substituted and unsubstituted pyridine N-oxides, DMSO, DMF, THF, chloride, perchlorate, etc. [18,28,40,43]. As clearly seen from Fig.…”

Section: Resultsmentioning

confidence: 62%

“…Fe(T i PrP)Cl and Fe(OETPP)Cl thus formed showed the same 1 H NMR and UV-visible (UV-Vis) data as those reported previously [26,27]. One-electron oxidized products of iron(III) chloride such as [Fe(T i PrP•)Cl](SbCl 6 ) and [Fe(OETPP•)Cl](SbCl 6 ) were prepared by the addition of phenoxathiinylium hexachloroantimonate to the CH 2 Cl 2 solutions of Fe(T i PrP)Cl and Fe(OETPP)Cl [28,29]. The radical cations thus formed were purified by the recrystallization from CH 2 Cl 2 -hexane.…”

Section: Methodsmentioning

confidence: 89%

“…[10,11]. For comparison, the chemical shifts of the parent complexes such as Fe(T i PrP)X and Fe(TPP)X (X is Cl − or ClO 4 − ) are also listed [19,26,28,30,31].…”

Section: Methodsmentioning

confidence: 99%

See 3 more Smart Citations

Spin–spin interactions in iron(III) porphyrin radical cations with ruffled and saddled structure

Kouno¹,

Ikezaki²,

Ikeue³

et al. 2011

Journal of Inorganic Biochemistry

Self Cite

View full text Add to dashboard Cite

Section: Resultsmentioning

confidence: 58%

Section: Resultsmentioning

confidence: 62%

Section: Methodsmentioning

confidence: 89%

“…[10,11]. For comparison, the chemical shifts of the parent complexes such as Fe(T i PrP)X and Fe(TPP)X (X is Cl − or ClO 4 − ) are also listed [19,26,28,30,31].…”

Section: Methodsmentioning

confidence: 99%

See 2 more Smart Citations

Spin–spin interactions in iron(III) porphyrin radical cations with ruffled and saddled structure

Kouno¹,

Ikezaki²,

Ikeue³

et al. 2011

Journal of Inorganic Biochemistry

Self Cite

View full text Add to dashboard Cite

“…Curie plots of the signals for 1 – 3 exhibited a good linearity, as shown in the Supporting Information, which suggests that these complexes maintain a single spin state in the temperature range 298–173 K. The negative δ ( meta )− δ ( para ) values, together with the negative Curie slopes of the meta signals, indicate that the meso carbon atoms have negative spin,7, 8 which in turn indicates that 1 – 3 adopt the S =3/2 state; the S =5/2 Fe III complexes have positive spin at the meso carbon atoms and thus give positive δ ( meta )− δ ( para ) values, as in the case of [Fe(oetpp)]Cl 6. 9 The solution magnetic moment of 2 determined by the Evans method was 4.2 μ B at 298 K and was invariant down to 173 K. This value is close to the spin‐only value expected for the S =3/2 state.…”

Section: Structural Comparison Of Five‐coordinate Iron(iii) Porphyrinmentioning

confidence: 99%

Models for Cytochromes c′: Observation of an Extremely Labile Spin State in Monoimidazole Complexes of Saddle‐Shaped Iron(III) Porphyrinates

2009

Self Cite

View full text Add to dashboard Cite

Saddle in a spin: The saddle‐shaped octaethyltetraphenylporphyrin–imidazole complex [FeIII(oetpp)(HIm)]+ adopts an essentially pure intermediate‐spin state between 298 and 173 K in CD2Cl2 solution, the conditions under which the NMR spectra are recorded. This complex has shown, however, a novel spin transition from S=3/2 to S=5/2 and S=1/2 below 70 K. Thus, the complex exists as an equilibrium mixture of three spin isomers at 4 K.

show abstract

Iron Porphyrin Chemistry

Walker¹,

Simonis²

2005

Encyclopedia of Inorganic Chemistry

View full text Add to dashboard Cite

This article reviews most aspects of the chemistry of iron porphyrins, from Fe(0) to Fe(V), including occurrence and roles of natural iron porphyrins (hemes) and their synthetic analogs, structures and electron configurations of iron porphyrins of all oxidation and spin states, π electron configuration of the porphyrin ring, synthesis of metal‐free porphyrins and other related macrocycles, insertion of iron into free‐base porphyrins and related macrocycles, the properties, reactions, uses and biological relevance of iron(0), ‐(I), ‐(II) porphyrins (the latter with S = 0, 1, and 2 spin state possibilities), of iron(II) porphyrin π‐cation radicals, of iron(III) porphyrins (with S = 1/2, 3/2, and 5/2 spin state possibilities), of iron(III) porphyrin and corrole π‐cation radicals, of iron(IV) porphyrins (including five‐ and six‐coordinate ferryl (FeO) 2+ , iron(IV) phenyl, carbene and hydrazine complexes, and the bis‐methoxide complex) and a comparison of iron(IV) porphyrins to iron(III) porphyrin π‐cation radicals, of iron(IV) porphyrin π‐cation radicals, and of the possible existence of iron(V) porphyrins. Included in the Fe(II) part are sections on addition of ligands to four‐coordinate iron(II) porphyrins, including equilibrium binding constants, photodissociation of ligands from PFeL 2 complexes, binding of small molecules (O 2 , CO, NO, HNO) to 5‐coordinate iron(II) porphyrins and design of porphyrin ligands that will mimic the active sites of heme proteins such as myoglobin and hemoglobin, the cytochromes P450 and nitric oxide synthases, and the nitrophorins and guanylyl cyclases. Included in the iron(III) part are sections on both 5‐ and 6‐coordinate high‐spin complexes and their similarities and differences, bridged or through‐space magnetically coupled complexes of high‐spin iron(III) porphyrins with other metal complexes as possible models for cytochrome oxidase and the assimilatory sulfite reductases, coupled oxidation of hemes by hydrogen peroxide or its equivalent, and the relationship of this reactivity to the reactions of heme oxygenase, iron(III) porphyrins as reduction catalysts, and photochemistry of iron(III) porphyrins, possible electron configurations of low‐spin iron(III) porphyrins, the phenomenon and possible electronic consequences of ruffling of the porphinato core in iron(III) porphyrins, the preferred orientation of planar axial ligands bound to low‐spin iron(III) porphyrins, NO complexes of iron(III) porphyrins, reduction potentials, equilibrium constants and rates of axial‐ligand addition and exchange, kinetics of axial‐ligand rotation and porphyrin ring inversion, kinetics of reduction and autoreduction of iron(III) porphyrins, electron self‐exchange between low‐spin iron(III) and iron(II) porphyrins, synthetic ferriheme proteins, and synthesis of five‐coordinate low‐spin iron(III) porphyrins having σ‐alkyl or σ‐aryl groups as axial ligands. The iron(IV) and iron(IV) cation radical sections discuss the high‐valent states of cytochromes P450 and related enzymes.

show abstract

Barriers to Inversion of Nonplanar Ferric Porphyrin Radical Cations: Comparison with the Corresponding Neutral Complexes

Cited by 19 publications

References 30 publications

Spin–spin interactions in iron(III) porphyrin radical cations with ruffled and saddled structure

Spin–spin interactions in iron(III) porphyrin radical cations with ruffled and saddled structure

Models for Cytochromes c′: Observation of an Extremely Labile Spin State in Monoimidazole Complexes of Saddle‐Shaped Iron(III) Porphyrinates

Iron Porphyrin Chemistry

Contact Info

Product

Resources

About