Synthetic model approach to the active site of cytochrome c oxidase: studies of a heterodinuclear iron(III) porphyrin-copper(II) tripeptide

Elliott, C. Michael; Jain, N. C.; Cranmer, Brian K.; Hamburg, Arlene W.

doi:10.1021/ic00269a008

Cited by 16 publications

(11 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Efforts in the synthesis of Fe III −X−Cu II model complexes include compounds with X = O 2- , ,,,,,− OH - , ,, CN - , − RC(O)O - , , F - , Cl - , S 2- , , and imidazolate groups. − Also, Boitrel and co-workers have recently described a nonbridged Fe III ···Cu II complex using a cyclam-strapped porphyrin binucleating ligand, where the Fe···Cu distance is 4.5 Å (as evaluated by EPR and NMR spesctroscopic methods), in the range of the known enzyme structures; this will not be further discussed. The model compounds could represent different states and situations for the enzyme.…”

Section: 2 Heme−copper Feiii−x−cuii Complexesmentioning

confidence: 99%

“…However, the desired μ-carboxylate compounds could be isolated as pure samples by multiple recrystallization 18 Carboxylate-bridged heme−copper model complexes: 33e , 33f , 44 , 45 . Under the formulas are indicated the bridge modalities.…”

Section: 23 Carboxylate-bridged Complexesmentioning

confidence: 99%

“…Carboxylate-bridged heme−copper model complexes: 33e , 33f , 44 , 45 . Under the formulas are indicated the bridge modalities.…”

Section: 23 Carboxylate-bridged Complexesmentioning

confidence: 99%

“…It was prepared by addition of 1 equiv of Cu III (aib 3 ) (aib 3 = tripeptide of α-aminoisobutyric acid) to a THF solution of Fe II (TPP). However, it could not be isolated as a solid because of the thermal, photochemical, and oxygen instability .…”

Section: 23 Carboxylate-bridged Complexesmentioning

confidence: 99%

See 3 more Smart Citations

Synthetic Models for Heme−Copper Oxidases

et al. 2004

View full text Add to dashboard Cite

show abstract

Section: 2 Heme−copper Feiii−x−cuii Complexesmentioning

confidence: 99%

Section: 23 Carboxylate-bridged Complexesmentioning

confidence: 99%

“…Carboxylate-bridged heme−copper model complexes: 33e , 33f , 44 , 45 . Under the formulas are indicated the bridge modalities.…”

Section: 23 Carboxylate-bridged Complexesmentioning

confidence: 99%

Section: 23 Carboxylate-bridged Complexesmentioning

confidence: 99%

See 2 more Smart Citations

Synthetic Models for Heme−Copper Oxidases

et al. 2004

View full text Add to dashboard Cite

show abstract

“…The design, isolation, and characterization of ligand-bound and bridged heme-copper model compounds may provide a necessary element in the completion of an accurate picture of C c O. Various groups have contributed significantly, by synthesizing and characterizing bridged heme-Cu multinuclear arrays. − Included are small-molecule analogues [(P)Fe III -X-Cu II (L)] (P = porphyrinate, L = copper-ligand), where X = O 2- (oxo) and OH - . , Among these from our laboratories is [(F 8 -TPP)Fe III -O-Cu II (TMPA)] + (see diagram) [F 8 -TPP = tetrakis(2,6-difluorophenyl)porphyrinate(2−); TMPA = tris(2-pyridylmethyl)amine] . The μ-oxo complex is notably basic and may be reversibly protonated to the hydroxo-bridged species [(F 8 -TPP)Fe III -OH-Cu II (TMPA)] 2+ 14b.…”

Section: Introductionmentioning

confidence: 99%

Synthesis, Structure, and Solution NMR Studies of Cyanide−Copper(II) and Cyanide-Bridged Iron(III)−Copper(II) Complexes

et al. 1999

View full text Add to dashboard Cite

A range of small molecules, such as cyanide, are known to bind and/or inhibit the active site of the heme-copper oxidase enzymes. As such, model studies are aimed at elucidating ligand binding modes and their subsequent impact on spectroscopic properties of derived complexes. We describe here the isolation and characterization of two compounds containing the Fe-CN-Cu moiety, [(py)(F(8)-TPP)Fe(III)-CN-Cu(II)(TMPA)](2+) (5) and [(F(8)-TPP)Fe(III)-(CN)(2)-{Cu(II)(TMPA)}(2)](3+) (6) [py = pyridine, TMPA = tris(2-pyridylmethyl)amine, and (F(8)-TPP) = tetrakis(2,6-difluorophenyl)porphyrinate(2-)]. [Cu(II)(TMPA)(CH(3)CN)](ClO(4))(2) and [(py)(F(8)-TPP)Fe(III)(CN)] (3) react to yield 5, while 6 is formed by combination of [Cu(II)(TMPA)(CN)]PF(6) (2-(PF(6))) and [(F(8)-TPP)Fe(III)(PF(6))] (4). Complex 2-(PF(6)) crystallizes in the orthorhombic space group Iba2 with a = 17.2269(5) Å, b = 17.3143(4) Å, and c = 14.4971(4) Å, Z = 8, complex (5-(Sb/P)F(6))(1.5)(ClO(4))(0.5) was obtained in the orthorhombic space group P222 with a = 17.9541(2) Å, b = 20.5359(1) Å, and c = 21.2023(2) Å, Z = 4, and 6-(PF(6))(3) crystallized in the monoclinic space group P2(1)/c with a = 15.318(4) Å, b = 33.921(2) Å, and c = 19.649(6) Å, beta = 109.69(2) degrees, and Z = 4. Compound 5 possesses a low-spin iron(III) center, bridged via cyanide to copper. The iron-cyanide vector deviates slightly from linearity (174.6(5) degrees ). The copper(II) ion is five-coordinated by the TMPA N-donor atoms and the cyanide carbon atom. The Cu(TMPA) moiety is bent with an angle of 163.8(5) degrees around the cyanide-copper vector. Compound 6 possesses a low-spin iron(III) atom axially coordinated by two cyanide ligands capped on either side by trigonally coordinated [Cu(TMPA)] moieties. The [Cu(1)(TMPA)] unit is twisted somewhat ( angleCu1-N&tbd1;C = 168 degrees ), whereas the [Cu(2)(TMPA)] unit is coordinated in a nearly linear fashion with respect to the cyanide-iron vector ( angleCu2-N&tbd1;C4 = 175 degrees ). (1)H and (2)H NMR spectroscopy on 5 and 6 confirmed the low-spin nature of these iron complexes (pyrrole resonance found at -11.1 and -8 ppm, respectively). The NMR data as well as observed solution magnetic moment (&mgr;(B) = 2.7 for 5; &mgr;(B) = 3.4 for 6) suggest ferromagnetic coupling between the paramagnetic metal ions. This gives rise to an enhancement of the electronic relaxation rate for Cu(II) in both 5 and 6 allowing for the observation of the sharp and downfield shifted TMPA ligand proton signals.

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

Synthetic model approach to the active site of cytochrome c oxidase: studies of a heterodinuclear iron(III) porphyrin-copper(II) tripeptide

Cited by 16 publications

References 0 publications

Synthetic Models for Heme−Copper Oxidases

Synthetic Models for Heme−Copper Oxidases

Synthesis, Structure, and Solution NMR Studies of Cyanide−Copper(II) and Cyanide-Bridged Iron(III)−Copper(II) Complexes

Iron Porphyrin Chemistry

Contact Info

Product

Resources

About