X-ray Crystallographic Structure of (<i>meso</i>-Tetraphenylporphinato)bis(phenylphosphinic methyl ester)iron(III) Perchlorate:  A New High-Spin Six-Coordinate Ferric Porphyrin

Guillemot, Maud; Toupet, Loı̈c; Simonneaux, Gérard

doi:10.1021/ic960338n

“…Actually three major difficulties that we have encountered in preparing phosphonite ferric derivatives have been (i) autoreduction to the ferrous state, (ii) the necessity to add a large excess of the ligand to assure full complexation, and (iii) the partial hydrolysis of the phosphonite to the phosphinic ester in the presence of traces of acidic water. In the latter case the product was the perchlorato derivative of bis(phenylphosphinic methyl ester) (tetraphenylporphyrinato)iron III , which is a new high-spin six-coordinate ferric porphyrin . When these problems are controlled, addition under argon of 8 equiv of dimethyl phenylphosphonite to [Fe(TPP)]ClO 4 in dichloromethane affords the hexacoordinated complex [(P(OMe) 2 Ph) 2 Fe(TPP)]ClO 4 with 74% yield.…”

Section: Resultsmentioning

confidence: 99%

“…In order to characterize the iron bis-phosphonite electronic structure, the isotropic shifts were calculated for 2 by using (P(OMe) 2 Ph) 2 Fe(TPP) and related para and meta -methyl substituted diamagnetic complexes as references .…”

Section: Resultsmentioning

confidence: 99%

Effect of Phosphorus Axial π-Acceptors in Iron(III) Porphyrinates: Characterization of Low-Spin Complexes [(PPh(OMe)₂)₂Fe(T(p-Me)PP)]CF₃SO₃ and [(PPh(OEt)₂)₂Fe(T(p-Me)PP)]CF₃SO₃

Pilard

¹

,

Guillemot

²

,

Toupet

³

et al. 1997

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The synthesis and characterization of the trifluoromethanesulfonato derivatives of bis(dimethyl phenylphosphonite)(tetrakis(p-methylphenyl)porphyrinato)ironIII, 1, and bis(diethyl phenylphosphonite)(tetrakis(p-methylphenyl)porphyrinato)ironIII, 2, are reported: [(PPh(OMe)2)2Fe(T(p-Me)PP)]CF3SO3, 1, and [(PPh(OEt)2)2Fe(T(p-Me)PP)]CF3SO3, 2, (T(p-Me)PP = tetrakis(p-methylphenyl)porphyrinato). The crystal structure of complexes 1 and 2 have been determined. Both X-ray structures show that the porphyrinate rings are strongly ruffled. The equatorial Fe−N bond distances average to 1.971 (6) Å for 1 and to 1.969 (7) Å for 2, which is a quite short distance for low-spin ironIII porphyrinate derivatives. The 1H NMR isotropic shifts at 20 °C of the pyrrole protons of the two complexes, varied from −2 ppm for 2 to +3 ppm for 1 rather than the expected −20 to −30 ppm, based on previously studied bis-ligated complexes of low-spin ferric porphyrins. The electron paramagnetic resonance spectra of [(PPh(OMe)2)2Fe(T(p-Me)PP)]CF3SO3, 1, and [(PPh(OEt)2)2Fe(T(p-Me)PP)]CF3SO3, 2, in solution are axial, with g ⊥ = 2.36 and g ∥ = 1.87−1.91 at 4 K, Σg 2 = 14.7. The Mössbauer spectra of 1 and 2 at 70 K have isomer shifts of 0.35 and 0.37 mm/s and quadrupole splittings of 1.23 and 1.66 mm/s, respectively. All physical properties are consistent with a low-spin ironIII with an unusual ground-state configuration (d xz ,d yz )4(d xy )1, as recently reported for [(4-CN−Py)2Fe(TPP)]ClO4 Safo, (M. K.; Walker, F. A.; Raitsimring, A. M.; Walters, W. P.; Dolata, D. P.; Debrunner P. G.; Scheidt, W. R. J. Am. Chem. Soc. 1994, 116, 7760−7770). Crystal data for [(PPh(OMe)2)2Fe(T(p-Me)PP)]CF3SO3, 1: a = 16.611(3) Å, c = 20.722(4) Å, trigonal, space group P32, V = 4951(2) Å3, Z = 3. Crystal data for [(PPh(OEt)2)2Fe(T(p-Me)PP)]CF3SO3, 2: a = 24.017(2) Å, b = 14.380(9) Å, c = 18.702(4) Å, monoclinic, space group P21/a, V = 6457(6) Å3, Z = 4.

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Iron Porphyrin Chemistry

Walker¹,

Simonis²

2005

Encyclopedia of Inorganic Chemistry

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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

Iron Porphyrin Chemistry

Walker

¹

,

Simonis

²

2005

Encyclopedia of Inorganic and Bioinorganic 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.

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X-ray Crystallographic Structure of (meso-Tetraphenylporphinato)bis(phenylphosphinic methyl ester)iron(III) Perchlorate: A New High-Spin Six-Coordinate Ferric Porphyrin

Cited by 8 publications

References 19 publications

Effect of Phosphorus Axial π-Acceptors in Iron(III) Porphyrinates: Characterization of Low-Spin Complexes [(PPh(OMe)₂)₂Fe(T(p-Me)PP)]CF₃SO₃ and [(PPh(OEt)₂)₂Fe(T(p-Me)PP)]CF₃SO₃

Effect of Phosphorus Axial π-Acceptors in Iron(III) Porphyrinates: Characterization of Low-Spin Complexes [(PPh(OMe)₂)₂Fe(T(p-Me)PP)]CF₃SO₃ and [(PPh(OEt)₂)₂Fe(T(p-Me)PP)]CF₃SO₃

Iron Porphyrin Chemistry

Iron Porphyrin Chemistry

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X-ray Crystallographic Structure of (meso-Tetraphenylporphinato)bis(phenylphosphinic methyl ester)iron(III) Perchlorate: A New High-Spin Six-Coordinate Ferric Porphyrin

Cited by 8 publications

References 19 publications

Effect of Phosphorus Axial π-Acceptors in Iron(III) Porphyrinates: Characterization of Low-Spin Complexes [(PPh(OMe)2)2Fe(T(p-Me)PP)]CF3SO3 and [(PPh(OEt)2)2Fe(T(p-Me)PP)]CF3SO3

Effect of Phosphorus Axial π-Acceptors in Iron(III) Porphyrinates: Characterization of Low-Spin Complexes [(PPh(OMe)2)2Fe(T(p-Me)PP)]CF3SO3 and [(PPh(OEt)2)2Fe(T(p-Me)PP)]CF3SO3

Iron Porphyrin Chemistry

Iron Porphyrin Chemistry

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Effect of Phosphorus Axial π-Acceptors in Iron(III) Porphyrinates: Characterization of Low-Spin Complexes [(PPh(OMe)₂)₂Fe(T(p-Me)PP)]CF₃SO₃ and [(PPh(OEt)₂)₂Fe(T(p-Me)PP)]CF₃SO₃

Effect of Phosphorus Axial π-Acceptors in Iron(III) Porphyrinates: Characterization of Low-Spin Complexes [(PPh(OMe)₂)₂Fe(T(p-Me)PP)]CF₃SO₃ and [(PPh(OEt)₂)₂Fe(T(p-Me)PP)]CF₃SO₃