Binuclear Iron Complexes Research Articles

Structures of binuclear and tetranuclear iron(III) complexes as models for ferritin core formation

Determination des structures cristallines des 2 complexes [Fe 2 L(OH)(H 2 O) 2 ] et [Fe 4 L 2 O 2 (OH) 2 ][C 4 H 10 N] 4 avec L=N,N'-(hydroxy-2 methyl-5 xylylene-1,3) bis(N-carboxymethyl glycine)

M�ssbauer spectra of iron carbonyl complexes of aromatic azines and schiff bases

1. The nature of the substituents at the methylenimino group carbon atom does not have a significant effect on the Mossbauer spectral parameters of binuclear complexes of iron with nitrogen bridges not containing a nitrogen-nitrogen bond. 2. The ortho-metallated complexes obtained from Schiff bases and aromatic azines have two structurally nonequivalent iron atom positions.

Evidence for intramolecular pathways in carbon-carbon bond-forming reactions proceeding from binuclear iron complexes

Etude de la decomposition du complexe dinucleaire de fer-carbonyle, donnant 3 produits: octadecane, nonadecanone-10 et eicosadione; le principal produit organometallique est Fe(CO) 5 . Cinetique du 1er ordre. Reactivite vis-a-vis de l'iodure de methyle

A study of the complexes [η 5-C 5H 5Fe(CO) 2] 2{μ-(CH 2) n} (where n = 3–12) by mass spectrometry and differential scanning calorimetry

The new μ(1, n)-alkanediyl binuclear iron complexes [CpFe(Co) 2] 2{μ-(CH 2) n } (where n = 7–12; Cp = η 5-C 5H 5) have been prepared and fully characterized. The mass spectra of the complexes of this type where n = 3–12 are reported and discussed. Differential Scanning Calorimetry (DSC) has been used to study the effect of heat on this series of complexes. The organic products formed on decomposition of some of the compounds in the solid state are reported.

Active site structures of deoxyhemerythrin and oxyhemerythrin.

The physiologically active forms of the nonheme-iron, oxygen-transport protein hemerythrin have been studied by x-ray crystallographic techniques. At 3.9-A resolution, a difference electron-density map between the deoxy form and met form (methemerythrin) of the protein suggests only small differences in the binuclear iron complexes. The coordination of the iron atoms appears to be the same in both the deoxy and met forms, one iron of the complexes being pentacoordinate, the other iron being hexacoordinate. The iron atoms appear to be somewhat farther apart in the deoxy form. A 2.2-A resolution study of oxyhemerythrin shows that dioxygen binds to one iron atom--the pentacoordinate one in the met form of the protein, the same binding site found for azide in azidomethemerythrin.

Synthesis and reactivities of binuclear iron(III) complexes with ligands composed of two tridentate chelating groups

Abstract Several new binuclear iron( III ) complexes were prepared using the binucleating ligands in which two molecules of N,N-bis(2-benzimidazolymethyl)amine are linked by a polyatomic chain, such as-(CH 2 ) 4 (L-4), -(CH 2 ) 6 - (L-6), and -CH 2 CH(OH)CH 2 H(L-3), etc., and were characterized in terms of the magnetic measurements and cyclic voltammetry. The complexes, Fe 2 (L-3′0(NO 3 ) 5 showed subnormal magnetic moments, 4.10 BM at 299 K and 2.22 BM at 87 K, respectively, suggesting the presence of an alkoxo-bridge structure. This complex showed much higher catalytic activity for the O 2 oxidation of N, N, N′,N′-tetramethyl-1-1,4-diaminobenzene than those of the relevant mononuclear complexes and other binuclear complexes studied here which have no alkoxo-bridge. The complex reacts with catechol and hydrogen peroxide to form 1:1 adducts.

Crystal structures and magnetism of binuclear iron(III) complexes with a linear oxo-bridge, [Fe2O(bbimae)2X2][NO3]2{bbimae =2-[bis(benzimidazol-2-ylmethyl)amino]ethanol, X = Cl or NCS}

The crystal structures of the oxo-bridged binuclear iron(III) complexes [Fe2O(bbimae)2X2][NO3]2{X = Cl (1) or NCS (2); bbimae = 2-[bis(benzimidazol-2-ylmethyl)amino]ethanol} have been determined by X-ray diffraction methods. Crystals of (1) are monoclinic with a=11.949(3), b=15.901(4), c= 11.326(2)A, β=109.36(2)°, space group P21/n, and Z= 2. Crystals of (2) are orthorhombic with a=16.384(2), b=19.804(2), c=13.600(2)A, space group Pbca, and Z= 4. Both crystals are composed of centrosymmetric dimeric cations with a linear Fe–O–Fe bond and nitrate counter ions. The iron–iron and iron–oxo distances are 3.563(1) and 1.7816(7)A for (1) and 3.559(1) and 1.7795(8)A for (2). Mossbauer spectra reveal the presence of high-spin iron(III) atoms in both complexes. The magnetic moments of 1.81(295 K) and 0.73 B.M. (98 K) for (1) and 1.82 (295 K) and 0.89 B.M. (98 K) for (2) indicate an antiferromagnetic interaction between the two iron(III) atoms. The –J value was evaluated as 103 cm–1 for (1), which falls in the range (95–110 cm–1) of previously reported oxo-bridged complexes with Fe–O–Fe bond angles in the range 139–180°

Preparation and reactivity of the new cyclopentadienyl-bridged complex (Me 2SiCH 2CH 2SiMe 2)(C 5H 4Fe(CO) 2) 2

A new metal-metal bonded binuclear iron system [Me 2SiCH 2CH 2SiMe 2][η 5-C 5H 4Fe(CO) 2] 2 ( 2) has been prepared by treating two equivalents of NaCp with one equivalent of ClSi(Me) 2CH 2CH 2SiClMe 2 obtaining the intermediate (C 5H 5)Si(Me) 2CH 2CH 2Si(Me) 2(C 5H 5) which then is directly allowed to react with Fe(CO) 5 given 2 in 30% yield. From this cyclopentadienyldisilyl linked system three new binuclear irom complexes are formed. Treatment of 2 with Na/Hg in THF produced the dianion [Me 2SiCH 2CH 2SiMe 2][η 5-C 5H 4Fe(CO) 2 −] 2 which is quenched with CH 3I giving [Me 2SiCH 2CH 2SiMe 2][η 5-C 4H 4Fe(CO) 2CH 3] 2 ( 4) in 76% yield. Complex 2 is oxidized with 1.2 equivalent of I 2 to give [Me 2SiCH 2CH 2SiMe 2][η 5-C 5H 4Fe(CO) 2I] 2 ( 5) in 85% yield. Photolysis of 5 (1 equiv.) and PPh 3 (3 equiv.) results in the formation of the bis-substituted compound [Me 2SiCH 2CH 2SiMe 2][η 5-C 5H 4Fe(CO)(PPh 3)I] 2 ( 6). These four new binuclear iron complexes are characterized by 1H, 13C, and 31P NMR and IR spectroscopy.

The structure of the iron complex in metaquohemerythrin

The novel binuclear iron complex in metaquohemerythrin is described. One of the two iron atoms is octahedrally coordinated, the other being penta-coordinate. A number of questions concerning the structure of the metal complex in different forms of this nonheme iron oxygen transport protein have been clarified. The structure of the complex presented here differs from that of metazidohemerythrin in that the Fe atom providing the binding locus for azide ion is five-coordinate with no small molecule ligand bound to it. The coordination polyhedron of this Fe is best described as a trigonal bipyramid.

Amino(keto)carbene und Amino(phenyl)carbene als 1.4-dipolare Brückenliganden in einer Fe2(CO)6-Matrix / Amino(keto)carbenes and Amino(phenyl)carbenes as 1,4-Dipolar Bridging Ligands in a Fe2(CO)6 Matrix

Abstract Cyclohexylamino(keto)carbene complexes of group VI B metals which contain a terminally bound carbene ligand, on reaction with Fe2(C0)9 give binuclear oxallyl iron complexes 5, in which the carbene carbon and the keto function form a bridge consisting of three atoms bound to two iron atoms. From a single crystal structure analysis of the phenyl derivative 5b, the Fe-Fe distance was found to be 2.508 Å. The two C atoms are bridging the Fe2 group in a somewhat distorted manner (C(l)-Fe(l) 2.461, C(l)-Fe(2) 1.912, C(2)-Fe(l) 2.024, C(2)-Fe(2) 2.478 Å), whereas the bridging keto oxygen is symmetrically bound to both Fe (1.927 and 2.004 Å). Alkylamino(phenyl)carbene complexes like 11 react with Fe2(C0)9 to give a four atom bridging ligand by migration of a hydrogen atom from nitrogen and an ortho hydrogen from the phenyl group to the carbene carbon. Free or complexed alkylimines may be intermediates in this reaction.

Some aspects of the chemistry of binuclear bridging iron complexes

Formation de cyclopropane (n=3) et d'olefines (n=2,3,4) par photolyse de complexes de fer dinucleaires Cp(CO)(μ-CH 2 )Fe(CO)Cp, Cp(CO) 2 Fe(CH 2 ) 2 Fe(CO) 2 Cp (n=3,4). Mecanisme: mis en jeu d'especes metallocycliques

Binuclear Metal Complexes. LI. Synthesis and Characterization of the Tetrachloro-o-benzoquinone Adducts of Binuclear Iron(II) Complexes with 2-(Salicylideneamino)phenol and Its Substituted Homologs

Abstract Binuclear iron(III) complexes Fe2(R-R′-sap)2(tcoq) have been prepared by the oxidation of binuclear iron(II) complexes Fe2(R-R′-sap)2 with tetrachloro-o-benzoquinone (TCOQ), where H2(R-R′-sap) represents 2-(salicylideneamino) phenols with the substituent R on the salicylaldehyde ring and the R′ on the o-aminophenol ring. Magnetic measurements indicated the operation of an intramolecular antiferromagnetic spin-exchange interaction between the iron(III) ions, the exchange integrals being evaluated at −6–−10 cm−1. In both polarograms and cyclic voltammograms of these complexes, two redox processes attributable to Fe(III)–Fe(III)\ightleftharpoonsFe(III)–Fe(II)\ightleftharpoonsFe(II)–Fe(II) were observed.

Cytochrome oxidase models. 3. Spin coupling across imidazolate bridges in binuclear metalloporphyrin complexes of iron and copper

Cytochrome oxidase models. 3. Spin coupling across imidazolate bridges in binuclear metalloporphyrin complexes of iron and copper

The Validity of the Hartree-Fock (HF) Picture in Diamagnetic Binuclear Transition Metal Compounds: trans[(η5 -C5H5)Fe(CO)2]2

Abstract The Thouless instability conditions in the binuclear iron complex 1 have been investigated by means of a semiempirical INDO approach. The behaviour of the restricted Hartree-Fock (HF) wave function with respect to singlet, non-singlet and complex variations of the orbitals is studied. The existence of a spin decoupled solution near the diamagnetic closed shell groundstate is demonstrated. The nature of the correlation processes (angular vs left-right) for the various orbital fluctuations is discussed.

Transition-metal complexes of vitamin B6 related compounds. 3. X-ray, Moessbauer, and magnetic properties of a binuclear iron(III) complex containing an unusual pyridoxal derivative

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTransition-metal complexes of vitamin B6 related compounds. 3. X-ray, Moessbauer, and magnetic properties of a binuclear iron(III) complex containing an unusual pyridoxal derivativeGary J. Long, James T. Wrobleski, Raju V. Thundathil, Don M. Sparlin, and Elmer O. SchlemperCite this: J. Am. Chem. Soc. 1980, 102, 19, 6040–6046Publication Date (Print):September 1, 1980Publication History Published online1 May 2002Published inissue 1 September 1980https://doi.org/10.1021/ja00539a011RIGHTS & PERMISSIONSArticle Views149Altmetric-Citations30LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (837 KB) Get e-AlertsSupporting Info (1)»Supporting Information Supporting Information Get e-Alerts

Insertion photoinduite de soufre dans le cyclopentadiene fer-dicarbonyle-dimere et derives

In this paper octacyclic sulfur-(S 8)-photoinduced insertion in [η 5-C 5H 4RFe-(CO) 2] 2 (R  H, CH 3) is described. This reaction gives a series of new binuclear iron-sulfur complexes. They can be deduced one from the other by successive loss of bridged and then terminal carbonyl groups. A crystalline green compound [(η 5-C 5H 4R) 2Fe 2S 4CO] (R  H, CH 3) is obtained, whose structure has been determined by X-ray crystallographic technique. Its structure in solution has also been studied. Infrared studies in various solvents show that the bands of the terminal carbonyl group are very dependent on the polarity of the solvent. In solvents of low polarity and at low temperature (−20°C) the trans form predominates. An orange oily product of general formula [(η 5-C 5H 4R)Fe-(CO) 2] 2S 5 (R  H, CH 3) and two isomeric brown compounds without any carbonyl group of general formula [(η 5-C 5H 4R)FeS 2] 2 (R  H, CH 3) are also described based on their spectroscopic data. Photoinduced insertion of octacyclic sulfur into a binuclear iron complex containing two bridged, one terminal carbonyl group and an isocyanide substituent is also reported.

Reduction of an acetylide CCr to an iminoethyl group CH 2 C(R)NR′ in a binuclear iron complex via hydrogen migration from nitrogen to carbon: x-ray structure of Fe 2(CO){ 6CH 2C(Ph)NMe}(PPh 2)

Primary amines RNH 2 effect reduction of the triple bond of the binuclear σπ-acetylide Fe 2(CO) 6(CCPh)(PPh 2) affording novel iminoethyl complexes Fe 2(CO) 6{CH 2C(Ph)NR}(PPh 2) via hydrogen migration from nitrogen to carbon. An X-ray analysis of the iminoalkyl derivative Fe 2(CO) 6{CH 2C(Ph)NMe}(PPh 2) shows the reduced ligand bonded as a bridging C(1e)N(2e) donor.

Synthesis of cationic iron complexes with the cyclobutenylidene ligand. The crystalline structure of 1-triphenylphosphonium-2-phenylvinyl-η 5-cyclopentadienyldicarbonylirontetrafluoroborate

Stable, cationic, binuclear iron complexes with a new cyclobutenylidene bridge ligand {[Cp(CO) 2Fe] 2(Ph 2C 4H)} + X − (X = ClO 4, BF 4) have been obtained by protonating the σ-phenylacetylide iron complex Cp(CO) 2FeCCPh with the strong protonic acids HClO 4 or HBF 4 in acetic anhydride. In the presence of PPh 3 this reaction results in the formation of metal—vinyl complexes containing the phosphonium cation {Cp(CO) 2Fe[C(PPh 3)CHPh]} + X − (X = ClO 4, BF 4). When Cp(CO) 2FeCCPh reacts with HClO 4 or HBF 4 in benzene, acetone or alcohol, [CpFe(CO) 3] + X − ionic complexes (X = ClO 4, BF 4) are formed. The structure of the above compounds has been confirmed by IR, 1H and 13C NMR spectra and X-ray analysis.

Synthesis of certain pyridinyl and diazinyl hydrazones containing one or more ferroin groups, and their chromogenic reactions with iron, copper, cobalt and nickel

Fifteen new hydrazones with one or more ferroin groups were prepared, and their chelation and chromogenic properties with iron(II), copper(I), cobalt(II) and nickel(II) were investigated. Improved sensitivity in the spectrophotometric determination of cobalt, copper, and nickel is provided by several of the new compounds. Several others are capable of forming unusually stable and interesting binuclear iron( II) complexes.

Electrochemical behaviour and chemical oxidation study of the thio- and phosphido-bridge binuclear iron complexes

The electrochemical behaviour of thio and phosphido complexes of iron(I): Fe 2XY(CO) 6 n L n (X = Y = SR, PR 2 and X = SR, Y = PR 2, L = PR 3) has been studied on platinum and mercury electrodes, in organic solvent. These complexes are reduced in a two-electron irreversible process. A large difference is observed between their oxidation potentials on mercury and platinum electrodes; this is ascribed to the formation of a mercury complex in which mercury is inserted into the metalmetal bond. In oxidation on platinum electrodes, two mono-electronic waves are observed. The influece of the ligand basicity on the cathodic E 1 2 values is discussed. A parallel shift is observed between the E 1 2 and the IR ν(CO) of the totally symmetrical mode. Chemical oxidation of the complexes shows that the dications cannot be isolated, and leads to isolation of the following species: [FeP(CH 3) 2(CO) 3] 2AgNO 3, [FeSCH 3(CO) 2P(CH 3) 3] 2(NO 3) 2, {[FeSCH 3(CO) 2P(CH 3) 3] 2F} PF 6, where NO 3 − and F − act as ligands.