Journal articles: 'Fe2+ complexes'

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De, Rajib Lai, and Heinrich Vahrenkamp. "Synthesen neuer Fe–P-Käfigverbindungen / Syntheses of New Fe–P Cage Compounds." Zeitschrift für Naturforschung B 41, no. 3 (March 1, 1986): 273–82. http://dx.doi.org/10.1515/znb-1986-0302.

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Four reaction types were used with the aim of obtaining new cage compounds of composition Fex(CO)y(PR)z- with R = Me, Ph, Tol: oxidation of the compounds Fe2(CO)6(PHR)2, photolysis thereof, reaction between RPCF and Fe2(CO)82- . and reaction between P-Cl containing iron complexes and Fe(CO)42_. Besides several known products, e.g. Fe3(CO)9(PR)2 or Fe4(CO)11(PR)2, and derivatives of the Fe2(CO)6(PRX)2 butterfly type complexes, the new octabisvalene shaped compounds Fe4(CO)2(PR)4 with R = Me, Ph, Tol were obtained and confirmed by a crystal structure analysis for R = Me, Side products of the oxidative conversions were Fe4(CO)12(P2Me2)(MeP-C2H4-PMe) and Fe4(CO)12(P2Tol2)(PHTol)2 which can be derived from the octabisvalene type. Side products of the irradiative conversions were Fe3(CO)8(PPh)(PHPh)2 and (CO)3Fe(μ-PHPh)2Fe(CO)(C6H8). the structure of the latter being proved crystallographically.

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Hasinoff, Brian B. "Oxyradical production results from the Fe3+–doxorubicin complex undergoing self-reduction by its α-ketol group." Biochemistry and Cell Biology 68, no. 12 (December 1, 1990): 1331–36. http://dx.doi.org/10.1139/o90-195.

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A variety of different measures have been used to compare the self-reduction of the Fe3+ complexes of doxorubicin and daunorubicin. The Fe3+ –doxorubicin complex exhibited a much faster rate of (i) O2 consumption, (ii) self-reduction under Ar to the Fe2+ complex, (iii) aerobic reduction of ferricytochrome c, (iv) scavenging of Fe2+ by bipyridine, (v) hydroxyl radical production measured by electron paramagnetic resonance spin-trapping experiments, and (vi) inactivation of the cytochrome c oxidase activity of beef heart submitochondrial particles, than did the corresponding Fe3+ –daunorubicin complex. In contrast to Fe3+ –doxorubicin, the Fe3+ –daunorubicin complex displayed only a fast phase of inhibition of the cytochrome c oxidase activity, indicating that the initial binding of these two Fe3+ –drug complexes is very similar. All of these results indicate that Fe3+ –doxorubicin undergoes a much faster self-reduction to the Fe2+ complex and hence a much greater rate of production of damaging oxyradicals when the Fe2+ is reoxidized by O2 or H2O2. The addition of the α-ketol acetol to Fe3+–daunorubicin resulted in greately increased rates of (i) ferricytochrome c reduction, (ii) Fe2+ production, and (iii) hydroxyl radical production. These results support the hypothesis that the α-ketol functional group of doxorubicin (which is not present on daunorubicin and is the only structural difference between these two compounds) reduces the Fe3+ while undergoing oxidation itself.Key words: doxorubicin, adriamycin, iron, self-reduction, oxyradical.

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Herberhold, Max, Wolfgang Feger, and Ulf Thewalt. "Umsetzungen von Ferrocenyl-lithium mit Carbonyleisen-Komplexen / Reactions of Ferrocenyl Lithium with Carbonyliron Complexes." Zeitschrift für Naturforschung B 45, no. 4 (April 1, 1990): 447–56. http://dx.doi.org/10.1515/znb-1990-0407.

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The reaction of cis-Fe(CO)4Br, with ferrocenyl lithium, FcLi, leads to the binucleara hexacarbonyldiiron complexes Fe2,(CO)6(μ-Br)(μ-CFc) (7), Fe,(CO)6(μ-COFc)2 (8) and Fe2(CO)6(μ-C2Fc2O) (9)b. Addition of FcLi to Fe(CO)5 gives the ferrocenoyl tetracarbonylferrate anion which was characterized as the salt NEt4+[Fe(CO)4(FcCO)]- (10); 9 is obtained after reaction of the anion with Meerwein’s salt, Me3O+BF4-.The reaction of Fe2(CO)9 with FcLi, followed by methylation with Me3O+BF4-, results in the formation of Fe2(CO)8[μ2-C(OMe)Fc] (11) which can be extracted from the product mixture using pentane. Chromatography of the product mixture over silica, however, leads preferentially to the formation of trinucleara complexes of the type Fe3(CO)9(μ3-COMe)(μ3-CR) (R = Fc (12), OMe (13) and O(CH2)4OMe (14)) in addition to 9; the same products are obtained starting from Fe3(CO)12. No complexes could be isolated which contained a direct iron σ-ferrocenyl bond. The structures of the new complexes were deduced from their infrared, mass, 1H and 13C NMR spectra. The bis(ferrocenoyl)-bridged compound 8 was also characterized by an X-ray crystallographic structure analysis.

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Maxton, D. G., R. P. H. Thompson, and R. C. Hider. "Absorption of iron from ferric hydroxypyranone complexes." British Journal of Nutrition 71, no. 2 (February 1994): 203–7. http://dx.doi.org/10.1079/bjn19940127.

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The absorption of 59Fe from preparations of FeSO4 and the ferric hydroxypyranone complexes maltol and ethyl maltol was studied by whole-body counting in normal subjects and patients with Fe deficiency. Fe in the Fe3+ complexes was in general absorbed almost as well as Fe2+. It is concluded that the absorption of Fe3+ from hydroxypyranone complexes is much greater than that from simple Fe3+ salts; this may prove an efficient and less toxic form of Fe for the treatment of deficiency.

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Hamdan, lmad I., and Motasem Taha. "Spectrophotometric and Conductometric Study of the Complexation of Ranitidine to Fez+, Fe3+, Al*, Mg*+, Cu", Ni2+ and PtP+ Metal Ions: Pharmaceutical Implications." Scientia Pharmaceutica 68, no. 4 (October 12, 2000): 357–67. http://dx.doi.org/10.3797/scipharm.aut-00-33.

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Complexation properties of ranitidine (Ran) with Fe2+, Fe3+, A13+, Mg2+, Cu2+, Ni2+ and Pb2+ were studied using UV/V|S spectroscopy and conductometric titrations respectively. Ranitidine was found to form 1:1 complexes in methanol or aqueous buffer (pH 6.5) with all cations except magnesium. In case of Fe3+ complexes of the formula [(Fe3+)2Ran] were evident.

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Lindenberger, Heide, Reiner Birk, Olli Orama, Gottfried Huttner, and Heinz Berke. "Ketenylidentriphenylphosphoran-Komplexe / Ketenylidenetriphenylphosphorane Complexes." Zeitschrift für Naturforschung B 43, no. 6 (June 1, 1988): 749–57. http://dx.doi.org/10.1515/znb-1988-0619.

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AbstractKetenylidenetriphenylphosphorane complexes of the type LnMC(CO)PPh3 LnM = CpMn(CO)2 (2a), CpRe(CO)2 (2b) and Fe(CO)4 (3) are obtained by CO substitution reactions. The synthesis of 3 at 80 °C is accompanied by the formation of a Fe2(CO)6 compound with a bridging α-metallated formyl(triphenylphosphane)carbido ligand. From ethylation of 3 arises an Fe2(CO)6 ferrol-type complex 5.

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7

Hassan, Kamaledin. "Characterization of granites by 57Fe Mössbauer spectroscopy." Mineralogia 40, no. 1-4 (January 1, 2009): 95–106. http://dx.doi.org/10.2478/v10002-009-0008-x.

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Characterization of granites by 57Fe Mössbauer spectroscopyTwo granite complexes in Egypt, a sodic type and an aluminous type are characterized by Mössbauer spectroscopy. Mössbauer spectra (MS) of the sodic granite show a major doublet of ferric (Fe3+) iron that is attributable to octahedral coordination (M1) sites plus/minus a tetrahedron Fe3+ doublet plus/minus a doublet of ferrous (Fe2+) iron on the M1 sites plus/ minus another Fe2+ (M1) doublet and a sextet of Fe3+. The sextet is attributed to α-Fe2O3 (hematite) and the other Fe components are due to NaCaFeSi2O6 (aegirine-augite) plus/minus minor contributions from (Ca2(Mg, Fe)5(Si, Al)8O22(OH)2 (magnesium-hornblende). Changes in the quadrupole splitting and width line of Fe2+ ions are likely composition-related. The MS of the aluminous-type granite, on the other hand, shows evidence only of single doublets containing Fe2+ or Fe3+ in the octahedral M1 sites, with parameters that remain almost constant. This consistency implies that the existing minerals - K(Mg, Fe2+)3 (Al, Fe3+)Si3O10(OH, F)2 (biotite), (Mg, Fe)6(Si, Al)4O10(OH)8 (clinochlore), (Na, K)Ca2(Fe, Mg)5(Al, Si)8O22(OH)2 (ferrohornblende and magnesiohornblende) - have similar iron positions. The intensity of iron oxidized (Fe3+/ΣFe) for the sodic granite is 79.1 to 100% and for the aluminous granite, 28.4 to 38.2%. The observed Fe3+/ΣFe differences between the two granites are source-related and consistent with distributions of other redox-sensitive elements.

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8

De Grave, E., J. Vandenbruwaene, and E. Elewaut. "An 57Fe Mossbauer effect study on glauconites from different locations in Belgium and Northern France." Clay Minerals 20, no. 2 (June 1985): 171–79. http://dx.doi.org/10.1180/claymin.1985.020.2.02.

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AbstractSixteen glauconite samples from different locations in Belgium and Northern France were investigated by 57Fe Mössbauer spectroscopy at room temperature. The spectra were fitted with three Fe3+ and two Fe2+ doublets, both Fe species occupying M1(trans) and M2(cis) sites in the T-O-T layers. The third Fe3+ doublet was assigned to interlayer ferric complexes. The observed Mössbauer parameters did not show significant variations from sample to sample. No direct relation between K and Fe content was observed, although within some distinct groups (e.g. Bande Noire, Cenomanian) the amount of Fe2+ increased with increasing K content.

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9

Kneifel, Charles L., Harold L. Friedman, and Marshall D. Newton. "Calculation of the Thermodynamic Solvent Isotope Effect for Ferrousand FerricIons in Water." Zeitschrift für Naturforschung A 44, no. 5 (May 1, 1989): 385–94. http://dx.doi.org/10.1515/zna-1989-0506.

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Molecular dynamics simulations of molecular models of Fe2+ and Fe3+ in water (L2O = H2O or D2O) are used to generate various correlation functions that characterize the respective hexaaquo hydration complexes. The static Fe2+-oxygen and Fe2+-hydrogen correlation functions are compared in detail with the first difference neutron diffraction results of Enderby et al. for Ni2+ . Velocity autocorrelation functions and corresponding power spectra are generated and analyzed for those modes of hydration shell water molecules whose reduced masses are most sensitive to the changes from H2O to D2O. Various approximations are applied to these data to calculate the solvent isotope effect on the difference in hydration free energies for Fe2+ and Fe3+ . These different approximations all lead to the qualitative conclusion that the net solvent isotope effect reflects a large degree of cancellation between the OL stretching modes and the librational modes. The simulation results generally agree with the results of earlier quantum chemical calculations applied to the same system, but in some respects the new results are not as realistic as the earlier ones. It is proposed that the agreement with experiment would be improved by changes in the model potential which are motivated by other, independent considerations.

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10

Shoukry, Mohamed, and Safaa Hassan. "Thermodynamic investigation of the binary and ternary complexes involving 1-aminocyclopropane carboxylic acid with reference to plant hormone." Open Chemistry 12, no. 3 (March 1, 2014): 318–24. http://dx.doi.org/10.2478/s11532-013-0374-5.

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AbstractComplex formation equilibria of 1-aminocyclopropane carboxylic acid (ACC) and 3,3-bis(1-methylimidazol-2-yl) propionic acid (BIMP) with metal ions Cu2+, Ni2+, Co2+, Zn2+, Mn2+ and Fe2+ were investigated. ACC forms 1:1 and 1:2 complexes in addition to the hydrolysed form of the 1:1 complex, except in the case of Mn2+ and Fe2+, where the hydrolysed complex is not formed. BIMP forms 1:1 and 1:2 complexes in addition to the hydrolsed form of the 1:1 complex in the case of Mn2+ and Cu2+, however the hydrolysed complex is not detected for Ni2+, Co2+, Zn2+ and Fe2+. The concentration distribution diagrams of the complexes were determined. The Fe2+-complex with BIMP is exothermic and the thermodynamic parameters were calculated. The effect of organic solvent on the acid dissociation constants of 1-aminocyclopropane carboxylic acid (ACC) and 3,3-bis(1-methylimidazol-2-yl) propionic acid (BIMP) and the formation constants of Fe2+ complexes were investigated. Fe2+ forms a mixed-ligand complex with ACC and BIMP with stoichiometric coefficients 1:1:1. The formation constant was determined. The ternary complex is enhanced by back donation from the negatively charged 1-aminocyclopropane carboxylate to the π-system of BIMP. From the concentration distribution diagram, the ternary complex prevails in the physiological pH range.

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11

Przybylski, Piotr, Grzegorz Wojciechowski, Bogumil Brzezinski, Halina Kozubek, Bronisław Marciniak, and Stefan Paszyc. "Spectroscopic and semiempirical studies of gossypol complexes with Fe2+ and Fe3+ cations." Journal of Molecular Structure 569, no. 1-3 (July 2001): 147–55. http://dx.doi.org/10.1016/s0022-2860(01)00431-8.

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12

Alorabi, Ali Q., Mohamed Abdelbaset, and Sami A. Zabin. "Colorimetric Detection of Multiple Metal Ions Using Schiff Base 1-(2-Thiophenylimino)-4-(N-dimethyl)benzene." Chemosensors 8, no. 1 (December 18, 2019): 1. http://dx.doi.org/10.3390/chemosensors8010001.

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In this paper, a Schiff base ligand 1-(2-thiophenylimino)-4-(N-dimethyl)benzene (SL1) bearing azomethine (>C=N-) and thiol (-SH) moieties capable of coordinating to metals and forming colored metal complexes was synthesized and examined as a colorimetric chemosensor. The sensing ability toward the metal ions of Cu2+, Cr3+, Fe2+ Ni2+, Co2+, Mg2+, Zn2+, Fe2+, Fe3+, NH4VO3 (V5+), Mn2+, Hg2+, Pb2+, and Al3+ was investigated in a mixture of H2O and dimethylformamide (DMF) solvent using the UV–Visible spectra monitoring method. The synthesized Schiff base ligand showed colorimetric properties with Cr3+, Fe2+, Fe3+, and Hg2+ ions, resulting in a different color change for each metal that could be identified easily with the naked eye. The UV–Vis spectra indicated a significant red shift (~69–288 nm) from the origin after the addition of the ligand to these metal ions, which may be due to ligand-to-metal charge-transfer (LMCT). On applying Job’s plot, it was indicated that the ligand binds to the metal ions in a 2:1 ligand-to-metal molar ratio. SL1 behaves as a bidentate ligand and binds through the N atom of the imine group and the S atom of the thiol group. The results indicate that the SL1 ligand is an appropriate coordination entity and can be developed for use as a chemosensor for the detection of Cr3+, Fe2+, Fe3+, and Hg2+ ions.

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Hamad Al-Dabbagh, Shahinaz A. "Synthesis and characterization of ligands derived 2-hydroxy-1- naphthaldehyde and their complexes with divalent metal ions (Mn+2, Fe+2, Ni +2)." Iraqi Journal of Physics (IJP) 16, no. 37 (September 11, 2018): 79–87. http://dx.doi.org/10.30723/ijp.v16i37.79.

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In this work, Schiff base ligands L1: N, N-bis (2-hydroxy-1-naphthaldehyde) hydrazine, L2: N, N-bis (salicylidene) hydrazine, and L3:N –salicylidene- hydrazine were synthesized by condensation reaction. The prepared ligands were reacted with specific divalent metal ions such as (Mn2+, Fe2+, Ni2+) to prepare their complexes. The ligands and complexes were characterized by C.H.N, FT-IR, UV-Vis, solubility, melting point and magnetic susceptibility measurements. The results show that the ligands of complexes (Mn2+, Fe2+) have octahedral geometry while the ligands of complexes (Ni2+) have tetrahedral geometry.

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Kłos-Witkowska, Aleksandra, and Vasyl Martsenyuk. "Investigation of Biosensor Potential Component Stability Caused by Influence of External Condition." Ecological Chemistry and Engineering S 26, no. 4 (December 1, 2019): 665–74. http://dx.doi.org/10.1515/eces-2019-0048.

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Abstract The analysis of UV-VIS spectrum was used for testing changes through 36 days and the impact of external conditions (reduced temperature (R), microwave radiation (M) and normal conditions (NC) for comparisons) on the stability of: BSA and BSA-Fe2+ complexes after different treating procedure. The increase of BSA absorption with increasing concentration of Fe2+ was observed. Increased absorption of BSA, and BSA-Fe2+ with time, related probably to conformational changes present in the protein and changes in electrostatic reactions within the BSA-Fe2+ complexes. Examination of the impact of an external factor on stabilization of the protein and complexes showed a tendency to keep the stability under reduced temperature and a trend with accelerated protein and complex aging under microwave radiation. The observed tendencies to changes under the influence of external factors became more significant in time. These effects were most probably related to changes of the protein structure and time, while the observed trend of accelerating the changes was impacted by the applied external factors.

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Davies, K. J. A., A. Sevanian, S. F. Muakkassah-Kelly, and P. Hochstein. "Uric acid-iron ion complexes. A new aspect of the antioxidant functions of uric acid." Biochemical Journal 235, no. 3 (May 1, 1986): 747–54. http://dx.doi.org/10.1042/bj2350747.

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In order to survive in an oxygen environment, aerobic organisms have developed numerous mechanisms to protect against oxygen radicals and singlet oxygen. One such mechanism, which appears to have attained particular significance during primate evolution, is the direct scavenging of oxygen radicals, singlet oxygen, oxo-haem oxidants and hydroperoxyl radicals by uric acid. In the present paper we demonstrate that another important ‘antioxidant’ property of uric acid is the ability to form stable co-ordination complexes with iron ions. Formation of urate-Fe3+ complexes dramatically inhibits Fe3+-catalysed ascorbate oxidation, as well as lipid peroxidation in liposomes and rat liver microsomal fraction. In contrast with antioxidant scavenger reactions, the inhibition of ascorbate oxidation and lipid peroxidation provided by urate's ability to bind iron ions does not involve urate oxidation. Association constants (Ka) for urate-iron ion complexes were determined by fluorescence-quenching techniques. The Ka for a 1:1 urate-Fe3+ complex was found to be 2.4 × 10(5), whereas the Ka for a 1:1 urate-Fe2+ complex was determined to be 1.9 × 10(4). Our experiments also revealed that urate can form a 2:1 complex with Fe3+ with an association constant for the second urate molecule (K'a) of approx. 4.5 × 10(5). From these data we estimate an overall stability constant (Ks approximately equal to Ka × K'a) for urate-Fe3+ complexes of approx. 1.1 × 10(11). Polarographic measurements revealed that (upon binding) urate decreases the reduction potential for the Fe2+/Fe3+ half-reaction from −0.77 V to −0.67 V. Thus urate slightly diminishes the oxidizing potential of Fe3+. The present results provide a mechanistic explanation for our previous report that urate protects ascorbate from oxidation in human blood. The almost saturating concentration of urate normally found in human plasma (up to 0.6 mM) represents 5-10 times the plasma ascorbate concentration, and is orders of magnitude higher than the ‘free’ iron ion concentration. These considerations point to the physiological significance of our findings.

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Osella, Domenico, Olimpia Gambino, Carlo Nervi, and Mauro Ravera. "HPLC studies of Fe2(CO)6(ligand) complexes." Journal of Organometallic Chemistry 433, no. 3 (July 1992): 287–94. http://dx.doi.org/10.1016/0022-328x(92)80154-p.

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17

Albano, Vincenzo G., Luigi Busetto, Fabio Marchetti, Magda Monari, Stefano Zacchini, and Valerio Zanotti. "Synthesis and Characterization of New Diiron and Diruthenium μ-Aminocarbyne Complexes Containing Terminal S-, P- and C-Ligands." Zeitschrift für Naturforschung B 62, no. 3 (March 1, 2007): 427–38. http://dx.doi.org/10.1515/znb-2007-0317.

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The diiron aminocarbyne complexes [Fe2{μ-CN(Me)(R)}(μ-CO)(CO)(NCMe)(Cp)2][SO3CF3] (R = Xy1, 1a; R = Me, 1b; R = CH2Ph, 1c; Xy1 = 2,6-Me2C6H3) undergo replacement of the coordinated nitrile by halides, diethyldithiocarbamate, and dicyanomethanide to give [Fe2{μ-CN(Me) (R)}(μ-CO)(CO)(X)(Cp)2] complexes (R = Me, X = Br, 4a; R = Me, X = I, 4b; R = CH2Ph, X = Cl, 4c; R = CH2Ph, X = Br, 4d; R = CH2Ph, X = I, 4e; R = Xy1, X = SC(S)NEt2, 5a; R = Me, X = SC(S)NEt2, 5b; R = Xy1, X = CH(CN)2, 7), in good yields. The molecular structure of 5a shows an unusual η1 coordination mode of the dithiocarbamate ligand. Similarly, treatment of [M2{μ-CN(Me) (R)}(μ-CO)(CO)(NCMe)(Cp)2][SO3CF3] (M = Fe, R = Xy1, 1a; M = Fe, R = Me, 1b; M = Ru, R = Xy1, 2a; M = Ru, R = Me, 2b) with a series of phosphanes generates the cationic complexes [M2{μ- CN(Me)(R)}(μ-CO)(CO)(P)(Cp)2][SO3CF3] (M = Fe, R = Xy1, P = PPh2H, 6a; M = Fe, R = Xy1, P = PPh3, 6b; M = Fe, R = Xy1, P = PMe3, 6c; M = Fe, R = Me, P = PMe2Ph, 6d; M = Fe, R = Me, P = PPh3, 6e; M = Fe, R = Me, P = PMePh2, 6f; M = Ru, R = Xy1, P = PPh2H, 6g; M = Ru, R = Me, P = PPh2H, 6h), in high yields. The molecular structure of 6a has been elucidated by an X-ray diffraction study. The reactions of [Fe2{μ-CN(Me)(Xyl)}(μ-CO)(CO)(NCR′)(Cp)2][SO3CF3] [R′ = Me, 1a; R′ = tBu, 3] with PhLi and PPh2Li yield [Fe2{μ-CN(Me)(Xy1)}(μ-CO)(CO)(Ph)(Cp)2] (8) and [Fe2{μ-CN(Me)(Xy1)}(μ-CO)(CO)(PPh2)(Cp)2] (9), respectively. The molecular structure of 8 has been ascertained by X-ray diffraction. Conversely, the reaction of 1a with MeLi generates the aminoalkylidene compound [Fe2{C(Me)N(Me)(Xy1)}(μ-CO)2(CO)(Cp)2] (10).Finally, the acetone complex [Fe2{μ-CN(Me)(Xy1)}(μ-CO)(CO)(OCMe2)(Cp)2][SO3CF3] (12) reacts with lithium acetylides to give complexes [Fe2{μ-CN(Me)(Xy1)}(μ-CO)(CO)(C≡CR)(Cp)2] (R = p-C6H4Me, 11a; R = Ph, 11b; R = SiMe3, 11c), in high yields. Filtration through alumina of a solution of 11a in CH2Cl2 results in hydration of the acetylide group and C-Si bond cleavage, affording [Fe2{μ-CN(Me)(Xy1)}(μ-CO)(CO){C(O)Me}(Cp)2] (12).

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Pajoudoro, Djafarou Ngouh, Daniel Lissouck, Baruch Ateba Amana, Joseph Zobo Mfomo, A. E. B. Abdallah, Alfred Aristide Flavien Toze, and Désiré Bikele Mama. "Antioxidant Properties of Lapachol and Its Derivatives and Their Ability to Chelate Iron (II) Cation: DFT and QTAIM Studies." Bioinorganic Chemistry and Applications 2020 (March 31, 2020): 1–10. http://dx.doi.org/10.1155/2020/2103239.

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The elucidation of the complexation of lapachol and its derivatives to Fe2+ cation has been done using the density functional theory (DFT). This complexation has been limited to bidentate and tridentate to Fe2+ cation. Geometry optimizations have been implemented in gas and solution phase (water, acetonitrile, chlorobenzene, benzene, and toluene) for ligands at B3LYP/6-311++G (d,p) level of theory using B3LYP/6-31+G(d,p) optimized data as starting point. But, the geometrical optimizations in solution phase of the 22 complexes analyzed of lapachol and its derivatives to Fe2+ cation were restricted to acetonitrile and benzene. The complexation energy and the metal ion affinity (MIA) have also been calculated using the B3LYP method. The results obtained indicated a proportionality between the MIA values and the retained charge on Fe2+ cation for k2-(O1,O2) modes. But, an inverse proportionality has been yielded between these two parameters for k3-(O2, C=C) tridentate modes. For k3-(O3,C=C) tridentate mode coordination, the higher stability has been obtained. In this latter tridentate coordination in gas phase, the topological analysis of complexes exhibits the fact that the electron density is concentrated between the O3 oxygen atom of the ligand attached to Fe2+ and this metal cation. Moreover, the hydrogen bond strength calculated for isolated ligands (situated between 23.92 and 30.15 kJ/mol) is in the range of normal HBs. Collectively, all the complexation processes have shown to be highly exothermic. Our results have also shown that the electron extraction from Fe2+...Lai complexes is more difficult compared to that from free ligands.

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Isupova, Zalina Yu, S. Yu Khashirova, A. A. Kyarov, S. M. Balaeva, Galina M. Danilova-Volkovskaya, and M. T. Bashorov. "Metal Complex Polymers of Guanidine Polymetacrylate with Fe²⁺- Ions and their Properties." Key Engineering Materials 816 (August 2019): 33–36. http://dx.doi.org/10.4028/www.scientific.net/kem.816.33.

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Metal complex polymers of polymethacrylate guanidine with Fe2 + ions were studied. The optimal concentration of Fe2+-ions to obtain water-soluble polymers has been determined. Their thermal properties were investigated, it was found that the obtained metal complexes exhibit bactericidal properties with respect to gram-positive and gram-negative bacterial strains.

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Lenis-Rojas, Oscar A., Sandra Cordeiro, Marta Horta-Meireles, Jhonathan Angel Araujo Fernández, Sabela Fernández Vila, Juan Andrés Rubiolo, Pablo Cabezas-Sainz, Laura Sanchez, Alexandra R. Fernandes, and Beatriz Royo. "N-Heterocyclic Carbene Iron Complexes as Anticancer Agents: In Vitro and In Vivo Biological Studies." Molecules 26, no. 18 (September 12, 2021): 5535. http://dx.doi.org/10.3390/molecules26185535.

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Cisplatin and its derivatives are commonly used in chemotherapeutic treatments of cancer, even though they suffer from many toxic side effects. The problems that emerge from the use of these metal compounds led to the search for new complexes capable to overcome the toxic side effects. Here, we report the evaluation of the antiproliferative activity of Fe(II) cyclopentadienyl complexes bearing n-heterocyclic carbene ligands in tumour cells and their in vivo toxicological profile. The in vitro antiproliferative assays demonstrated that complex Fe1 displays the highest cytotoxic activity both in human colorectal carcinoma cells (HCT116) and ovarian carcinoma cells (A2780) with IC50 values in the low micromolar range. The antiproliferative effect of Fe1 was even higher than cisplatin. Interestingly, Fe1 showed low in vivo toxicity, and in vivo analyses of Fe1 and Fe2 compounds using colorectal HCT116 zebrafish xenograft showed that both reduce the proliferation of human HCT116 colorectal cancer cells in vivo.

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Herberhold, Max, Uwe Bertholdt, and Wolfgang Milius. "Hexacarbonyldieisen-stabilisierte Sulfimid-Derivate, Fe2(CO)6(μ-SNR) / Hexacarbonyl Diiron Stabilized Sulfimide Derivatives, Fe2(CO)6(μ-SNR)." Zeitschrift für Naturforschung B 50, no. 8 (August 1, 1995): 1252–56. http://dx.doi.org/10.1515/znb-1995-0820.

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Hexacarbonyl diiron complexes of N-substituted sulfimides (SNR) have been obtained from the parent tetrahedrane, Fe2(CO)6(μ-SNH) (1), by deprotonation to give the anion Fe2(CO)6(μ-SN-) (2) and subsequent reaction with either trialkyloxonium or carbenium tetrafluoroborates. The new aza-diferra-thia-tetrahedranes, Fe2(CO)6(μ-SNR) (R = CH3 (3a), C2H5 (3b), CPh3 (3c), cyclo-C3Ph3 (3d), cyclo-C7H7 (3e), and cyclo-(C7H7)M (CO)3 with M = Cr (3f), Mo (3g), W (3h)) were characterized by their 1H and 13C NMR as well as their IR and MS spectra. The molecular structure of Fe2(CO)6[SN-cyclo-C7H7Mo(CO)3] (3g) has been determined by X-ray diffraction.

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22

Macdonald, R., and H. E. Belkin. "Compositional variation in minerals of the chevkinite group." Mineralogical Magazine 66, no. 6 (December 2002): 1075–98. http://dx.doi.org/10.1180/0026461026660078.

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Abstract The composition of chevkinite and perrierite, the most common members of the chevkinite group, is closely expressed by the formula A4BC2D2Si4O22, where A = (La,Ce,Ca,Sr,Th), B = Fe2+, C = (Fe2+,Fe3+,Ti,Al,Zr,Nb) and D = Ti. The A site is dominated by a strong negative correlation between (Ca+Sr) and the REE. Chondrite-normalized REE patterns are very variable, e.g. in LREE/HREE and Eu/Eu*. The C site is dominated by Ti, Al and Fe2+, in very variable proportions. Most chevkinites and perrierites are close to stoichiometric, with cation sums between 12.9 and 13.5, compared to the theoretical 13. There is no single, generally applicable charge balancing substitution scheme in the group; however, the general relationship defines a linear array with r2 = 0.91. Chevkinite and perrierite are shown to be compositionally distinct on the basis of CaO, FeO*, Al2O3 and Ce2O3 abundances. Chevkinite forms mainly in chemically evolved parageneses, such as syenites, rhyolites and fenites associated with carbonatite complexes. Perrierite is more commonly recorded from igneous rocks of mafic to intermediate composition. The compositional characteristics and possible structural formulae of other members of the chevkinite group are reviewed briefly.

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23

Krznarić, D., and I. Ciglenečki. "Voltammetric study of an FeS layer on a Hg electrode in supersaturated FeS chloride solution." Environmental Chemistry 12, no. 2 (2015): 123. http://dx.doi.org/10.1071/en14016.

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Environmental context During the electrochemical analysis of natural waters, the Hg electrode could become the site for surface metal sulfide formation, such as FeS, which can have significant influence on the voltammetric determination of FeII. Reduction of FeII in such conditions can occur both on the bare Hg surface and on the FeS-modified Hg surface. Until recently, measurements of FeII have considered only the signal obtained from reduction on the bare Hg surface, and hence may have underdetermined the true FeII content of natural samples. Abstract Cyclic voltammetry at a Hg electrode was used for the study of an FeS layer formed on the electrode surface during scanning potential in a saturated FeS suspension containing FeS nanoparticles in chloride electrolyte. Newly presented results as a part of comprehensive study on FeS electrochemistry in model and natural samples confirm that the voltammetric peak at –1.1V, which can often be recorded in anoxic waters containing Fe and sulfide species, represents reduction of Fe2+ on the Hg electrode surface modified by the FeS layer. Fe0 deposited on such a modified Hg surface is reoxidisable, often producing two oxidation peaks situated between –0.8 and –0.6V (v. Ag/AgCl). These peaks represent two different Fe0 oxidation products, free Fe2+ and Fe2+ chloro complexes, FeCl+. By scanning the potential from –0.75V in the positive direction, an oxidation exchange peak of Hg and FeS at ~–0.45V occurs, which can be taken as a measure for FeS nanoparticles from bulk solution.

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24

Cooper, B., J. M. Creeth, and A. S. Donald. "Studies of the limited degradation of mucus glycoproteins. The mechanism of the peroxide reaction." Biochemical Journal 228, no. 3 (June 15, 1985): 615–26. http://dx.doi.org/10.1042/bj2280615.

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The reaction between ovarian-cyst glycoproteins and H2O2 was investigated in the presence of a number of inhibitors and catalysts. Azide and 2H2O were separately found to have little effect, implying that singlet oxygen was not involved. Superoxide dismutase was destroyed by H2O2, but mannitol had no effect: thus generalized attack by OH., whether originating from HO2.- or more directly, is not indicated. The glycoproteins contained trace quantities of Cu and Fe, amounting to about 2 atoms of metal per glycoprotein molecule. Treatment of the glycoproteins with the strong chelator DETAPAC (diethylenetriaminepenta-acetic acid) or Chelex resin eliminated the reaction with H2O2; activity could be restored by addition of Cu2+ or Fe2+ in millimolar quantities. It was concluded that metal-ion catalysis is an essential step in the attack of H2O2 on glycoproteins. Spectroscopic and other evidence showed that Cu2+ (and probably Fe2+) complexes strongly with poly-L-histidine, and implies that the Cu2+ or Fe2+ in the glycoproteins is complexed with some of the histidine residues in the glycosylated backbone. Neither polyhistidine nor polyproline reacted with H2O2 in the absence of metal ions, but small quantities of Cu2+ or Fe3+ caused degradation. This was rapid with polyhistidine, which was converted largely into aspartic acid, but slower with polyproline, where limited conversion into glutamic acid occurs. These findings confirm the original hypothesis that peroxide attack on glycoproteins occurs largely at the histidine residues, with simultaneous peptidolysis. The mechanism most probably involves the liberation of OH. by an oxidation-reduction cycle involving, e.g. Cu+/Cu2+: specificity of attack at histidine is due to the location of the metal at these residues only.

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25

Inoue, Haruhiko, Sakiko Yamashita-Muraki, Kanako Fujiwara, Kayoko Honda, Hiroki Ono, Takamasa Nonaka, Yuichi Kato, et al. "Fe2+ Ions Alleviate the Symptom of Citrus Greening Disease." International Journal of Molecular Sciences 21, no. 11 (June 4, 2020): 4033. http://dx.doi.org/10.3390/ijms21114033.

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Citrus greening (CG) is among the most devastating citrus diseases worldwide. CG-infected trees exhibit interveinal chlorotic leaves due to iron (Fe) deficiency derived from CG; thus, Fe content is lower in infected leaves than in healthy leaves. In this study, we demonstrated that the foliar application of Fe2+ relieves the symptom of CG infection in citrus trees. We applied Fe2+ and citrate to the leaves of infected rough lemon plants. Following this treatment, a reduction in the number of yellow symptomatic leaves was observed, and their growth was restored. Using chlorophyll content as an index, we screened for effective Fe complexes and found that a high ratio of citrate to Fe2+ in the applied solution led to effects against CG in Shikuwasa trees. A high proportion of Fe2+ to total Fe was another key factor explaining the effectiveness of the solution in CG infection, indicating the importance of Fe2+ absorption into plant cells. We confirmed the proportion of Fe2+ to total Fe through the high correlation of reflectometry data via a triazine reaction and X-ray absorption fine structure analysis. These results demonstrate that the foliar application of a high-Fe2+ citrate solution can restore the growth of CG diseased trees.

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26

Przewloka, S. R., and B. J. Shearer. "The Further Chemistry of Ellagic Acid II. Ellagic Acid and Water-Soluble Ellagates as Metal Precipitants." Holzforschung 56, no. 1 (February 6, 2002): 13–19. http://dx.doi.org/10.1515/hf.2002.003.

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Summary Preparations of the previously unreported, water-soluble, tetraguanidinium, tetracholine and tetrakisbenzyltrimethylammonium ellagates are outlined. Ellagic acid and these water-soluble salts remove Mg2+, Ca2+ and Mn2+ ions from dilute aqueous solutions at pH greater than 7. The salts also remove Fe2+, Fe3+, Co2+ and Cu2+ between pH 3 and pH 6. At pH 1 the water-soluble ellagates underwent hydrolysis, resulting in the precipitation of free ellagic acid in preference to the formation of metal-ellagate complexes. These trends were also observed when mixtures of metal ions were applied.

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27

Grigor’ev, T. E., Kim Hung Nguen, I. V. Skryabina, E. E. Makhaeva, and A. R. Khokhlov. "Formation of Fe2+-phenanthroline complexes in the volume of hydrogel." Polymer Science Series A 50, no. 1 (January 2008): 68–73. http://dx.doi.org/10.1134/s0965545x08010112.

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28

Shaker, Shayma A. "Synthesis, Spectral and Magnetic Studies of Newly Mixed-Ligand Complexes of 4-Formyl-Acetanilide Thiosemicarbazone and 3,4-Dihydrocinnamic Acid with Some Metal Ions." E-Journal of Chemistry 7, s1 (2010): S594—S600. http://dx.doi.org/10.1155/2010/307842.

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New complexes with thiosemicarbazone derivative and 3, 4-dihydrocinnamic acid were prepared and characterized by elemental analysis, determination of metal, IR,1H NMR, electronic spectroscopy and magnetic measurements. The thiosemicarbazone derivative forms bidentate ligand complexes of the general formula, [M(Thz)(Caf)] where Thz = 4-formyl- acetanilide thiosemicarbazone, Caf = 3,4-dihydrocinnamic acid and M=Mn2+, Fe2+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+and Pb2+. The IR and1H NMR spectra indicates that the (Thz) was coordinated with the metal ions through the N and S atoms and the (Caf) was negatively charged bidentat ligand and was coordinated with the metal ions through the two O atoms. Electronic spectra and magnetic susceptibility measurements of the solid complexes indicates the tetrahedral geometry around the Mn2+, Fe2+, Co2+, Ni2+, Zn2+, Cd2+and irregular tetrahedral geometry around Pb2+ion while the Cu2+complex has squar planer geometry.

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Микоян, В. Д., Е. Н. Бургова, Р. Р. Бородулин, and А. Ф. Ванин. "ДИНИТРОЗИЛЬНЫЕ КОМПЛЕКСЫ ЖЕЛЕЗА C ТИОЛСОДЕРЖАЩИМИ ЛИГАНДАМИ ПРЕДСТАВЛЕНЫ В ЖИВЫХ ОРГАНИЗМАХ В ОСНОВНОМ ИХ БИЯДЕРНОЙ ФОРМОЙ." Биофизика 65, no. 6 (2020): 1142–53. http://dx.doi.org/10.31857/s0006302920060149.

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The number of mononitrosyl iron complexes with diethyldithiocarbamate, formed in the liver of mice in vivo and in vitro after intraperitoneal injection of binuclear dinitrosyl iron complexes with N-acetyl-L-cysteine or glutathione, S-nitrosoglutathione, sodium nitrite or the vasodilating drug Isoket® was assessed by electron paramagnetic resonance (EPR). The number of the said complexes, in contrast to the complexes, formed after nitrite or Isoket administration, the level of which sharply increased after treatment of liver preparations with a strong reducing agent - dithionite, did not change in the presence of dithionite. It was concluded that, in the first case, EPR-detectable mononitrosyl iron complexes with diethyldithiocarbamate in the absence and presence of dithionite appeared as a result of the reaction of NO formed from nitrite with Fe2+-dieth- yldithiocarbamate and Fe3+-diethyldithiocarbamate complexes, respectively. In the second case, mononitrosyl iron complexes with diethyldithiocarbamate appeared as a result of the transition of iron-mononitosyl fragments from ready-made iron-dinitrosyl groups of binuclear dinitrosyl complexes, which is three to four times higher than the content of the mononuclear form of these complexes in the tissue...

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30

Bitterer, Frank, David J. Brauer, Frank Dörrenbach, Jörg Fischer, and Othmar Stelzer. "Synthese von Phosphaalkenclustern durch reduktive Phosphinidenfragmentierung zweizähniger Halogenphosphane RXP— CH2 — PXR mit Fe2(CO)9 / Synthesis of Phosphaalkene Clusters by Reductive Phosphinidene Fragmentation of Bidentate Halogenphosphines RXP—CH2—PXR with Fe2(CO)9." Zeitschrift für Naturforschung B 47, no. 11 (November 1, 1992): 1529–40. http://dx.doi.org/10.1515/znb-1992-1105.

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Reaction of halogen functional methylenebisphosphines 1 XRP–CH2–PRX (X = Cl, Br) with excess Fe2(CO)9 affords μ3-phosphinidene clusters (5) containing phosphaalkene ligands R–P=CH2. The fragmentation of the P–C–P skeletons in 1 proceeds stepwise, phosphide complexes 2 and novel Fe3 clusters 3 with RP–CH2–PR bridging units being formed as intermediates of the oxidative addition reductive elimination process. The X-ray structural analysis for 5b (R = NEt2) reveals an Fe3(CO)9PR butterfly core to which the phosphaalkene ligand R–P=CH2 (P=C bond length 1.766(4) A) is coordinated in a μ3,η2-manner. In case of methylenebisphosphines 1 with bulky substituents (R = 2,4,6-iPr3C6H2) the phosphinidene fragmentation of the P–C–P skeleton is accompanied by the formation of 2,3-dihydrobenzo[b]-phosphole ligands.

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31

Gervasio, Giuliana, Domenica Marabello, Enrico Sappa, and Andrea Secco. "Reactions of Fe3(CO)12 and Fe(CO)5 with functionalized alkynes in CH3OHKOH solution The crystal structure of Fe2(CO)6(PPh3)[µ-η3-(H2CCCH2)]." Canadian Journal of Chemistry 84, no. 2 (February 1, 2006): 337–44. http://dx.doi.org/10.1139/v05-252.

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The complex Fe2(CO)7(H2CCCH2) (1) is obtained starting from a variety of functionalized alkynes that can release C3 fragments during the reactions with Fe3(CO)12 or Fe(CO)5 in CH3OHKOH solutions. Owing to the oily nature of 1, it was reacted with triphenylphosphine, and the structure of the resulting title compound (1a) has been determined by X-ray analysis. Complex 1a shows a new coordination mode of a H2C=C=CH2 ligand to a diiron centre and is, to our knowledge, unprecedented. We have also found that 1 (and 1a) are by-products, and not intermediates in the formation of complex 3. A discussion of the possible reaction pathways is given.Key words: iron carbonyls, alkynols, CO and methanol activation, acetyl and acetate complexes, allenyl iron complexes, crystal structure.

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32

Boeré, René T., Klaus H. Moock, Vicki Klassen, Joel Weaver, Dieter Lentz, and Heike Michael-Schulz. "Electrochemistry of methylidyne and 1,2,3,5-dithiadiazole complexes of iron and nickel and a reinterpretation of the composition of "PhCN2S2Fe2(CO)6"." Canadian Journal of Chemistry 73, no. 9 (September 1, 1995): 1444–53. http://dx.doi.org/10.1139/v95-179.

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The title compounds have been studied in CH2Cl2 by cyclic voltammetry. Nonacarbonyldi(μ3-methylidyne)triiron, [Fe3(CO)9(μ3-CX)2] (X = F, Cl, Br, H), undergo chemically reversible 1e− reduction (−0.72 to −0.88 V vs. SCE) and irreversible oxidation (+1.59 to +1.72 V); the compound for which X = F displays a second, irreversible reduction (−1.96 V). Using reduction potentials of comparable μ3-E (E = S, Se, NPh, PPh) clusters, μ3-methylidyne ligands are shown to be strongly basic, comparable to PPh and NPh and more basic than S or Se. The methylidyne clusters are both more difficult to oxidize and reduce than isomeric alkyne clusters [Fe3(CO)9(C2R2)], indicative of greater thermodynamic stability. The complexes previously formulated as [Fe2(CO)6(S2N2CC6H4X)] (X = H, CF3, OCH3) are reversibly reduced (−1.59 to −1.70 V) and irreversibly oxidized (+1.0 to 1.3 V), unlike free dithiadiazole radicals, which are reversibly oxidized around +0.8 V. This behaviour is not consistent with the ring-centered free radical claimed for the case where X = H; instead we find conclusive evidence that these are diamagnetic complexes of the 3-H-1,2,3,5-dithiadiazolines, [Fe2(CO)6(S2N{NH}CC6H4X)] (νNH = 3376−3381 cm−1;δNH = 6.55−7.1 ppm). Dicyclopentadienyl-dithiadiazoledinickel, [Ni2Cp2(S2N2CC6H5)], is both reversibly reduced (−0.79 V) and oxidized (+0.45 V); and irreversibly oxidized at +1.9 V. This is consistent with an unpaired electron, and only the nickel cluster has an ESR signal (g = 2.0410, no resolved hyperfine splitting). Extended Hückel theory locates the free electron in a SOMO restricted to Ni, C, and S atoms. Keywords: electrochemistry, organometallic, methylidyne, dithiadiazole, dithiadiazoline.

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33

Wang, Zuo Hua, Jia Hui Zhang, Hua Zong, Wei Wang, and Hong Bo Fang. "Study on the Mechanism between HPAM and Metal Ions by UV Spectrophotometry." Applied Mechanics and Materials 333-335 (July 2013): 1979–83. http://dx.doi.org/10.4028/www.scientific.net/amm.333-335.1979.

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Hydrolyzed polyacrylamide (HPAM) has been widely used for enhanced oil recovery in oil production. However, metal ions existed may reduce the system viscosity and further impact the displacement efficiency. Thus, it is of importance to know the mechanism between HPAM and metal ions. UV spectrophotometry method can be effectively applied in this work. It is suggested that the extent of various metal ions on HPAM viscosity is in the order of Fe2+ >Ca2+>Na+. By shielding effect, the presence of large amount of Na+ reduces HPAM solution viscosity. The result also demonstrates that multivalent cations can form polyion-metal complexes which affect the solution viscosity. The viscosity degraded by Fe2+ is attributed to its reducing action. With oxygen in sewage, Fe2+ initiates a free radical reaction and causes the disintegration of the polymer.

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34

Wrackmeyer, Bernd, Ēriks Kupče, Berthold Distler, Klaus Dirnberger, and Max Herberhold. "57Fe-15N Spin-Spin Coupling at Natural Abundance of the Isotopes in Binuclear Complexes Fe2(CO)6(μ-RNS) Containing a Sulfimide Bridge." Zeitschrift für Naturforschung B 46, no. 12 (December 1, 1991): 1679–83. http://dx.doi.org/10.1515/znb-1991-1216.

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Complexes of the type Fe2(CO)6(μ-RNS) [R = H (la), tBu (lb), SiMe3 (lc), Si'BuMe2 (1d), SnMe3 (le)] have been studied by multinuclear magnetic resonance (1H13C, 14C, 14N, 15N, 17O, 29Si, 119Sn) with emphasis on natural abundance 15N NMR measurements. By application of various polarization transfer techniques 1J(57Fe15N) (6.1 Hz) in la has been determined for the first time, together with the isotope-induced shift 1Δ34/32S (-36 ppb). Compound ld has been prepared via the reaction between Me2tBuSiCl and Fe2(CO)6(μ-NaNS) (lf), available from la and sodium.

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35

Berezina, Nadezhda M., Do Ngoc Minh, Mikhail I. Bazanov, Aleksandr S. Semeikin, and Aleksandra A. Maksimova. "SYNTHESIS AND ELECTROCHEMICAL CHARACTERISTICS OF Fe (III)-ETIO PORPHYRIN II AND ITS 5,15-BIS(PYRID-3-YL) DERIVATIVE." IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENIY KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA 61, no. 2 (January 29, 2018): 29. http://dx.doi.org/10.6060/tcct.20186102.5652.

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In this work acetato(3,7,13,17-tetramethyl-2,8,12,18-tetraethylporphinato)iron(III) [(AcO)FeTMeTEtP] and acetato[5,15-bis(pyrid-3-yl)-3,7,13,17-tetramethyl-2,8,12,18-tetraethylporphinato)iron(III) [(OAc)OFe(Py-3)2TMeTEtP] have been synthesized and characterized. Electrochemical properties and electrocatalytic activity of complexes in oxygen electroreduction reaction in 0.1M KOH aqueous solution were studied by the cyclic voltammetry. The comparative analysis of the effect of complex formation, as well as functional substitution in the molecule (the introduction of one or two pyridyl fragments into meso-positions of the macrocycle) on the electrochemical parameters and activity of alkyl-substituted and pyridyl-substituted porphyrins in oxygen electroreduction reaction were carried out. The research of electrochemical behavior of complexes with close structure in experimental conditions has showed that a pyridyl substituent significantly affects the studied properties. The published data and obtained in our work have showed that (AcO)FeTMeTEtP and (AcO)Fe(Py-3)2TMeTEtP are characterized by redox processes involving both the porphyrin macrocycle (L ↔ Lˉ˙, Lˉ˙ ↔ L2ˉ), and metal (Fe3+ ↔ Fe2+, Fe2+ ↔ Fe+). It should be noted that the process of electroreduction of the central metal ion (Fe3+ ↔ Fe2+) proceeds under additional introduction of oxygen into the system for the (AcO)FeTMeTEtP, (Cl)Fe(Py-3)HMeDEtP and (AcO)Fe(Py-3)2TMeTEtP. The results of investigation of the electrocatalytic activity of tetrapyrrole compounds in an aqueous-alkaline medium allows one to make a conclusion about the positive effect of complexation and the introduction of electron-donor substitutes in the porphyrin macrocycle on the electroreduction process of molecular oxygen. The electrocatalytic activity of the studied compounds in the oxygen ionization reaction were increased, according to the decrease in the half-wave potential of O2 [E1/2(O2)] in the series: H2TMeTEtP < (AcO)FeTMeTEtP < (AcO)Fe(Py-3)2TMeTEtP.Forcitation:Berezina N.M., Do Ngoc Minh, Bazanov M.I., Semeikin A.S., Maksimova A.A. Synthesis and electrochemical characteristics of Fe (III) - etio porphyrin ii and its 5,15-bis(pyrid-3-yl) derivative. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2018. V. 61. N 2. P. 29-34

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Khan, Mateen A., William E. Walden, Dixie J. Goss, and Elizabeth C. Theil. "Direct Fe2+Sensing by Iron-responsive Messenger RNA·Repressor Complexes Weakens Binding." Journal of Biological Chemistry 284, no. 44 (August 31, 2009): 30122–28. http://dx.doi.org/10.1074/jbc.m109.041061.

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37

Weng, Jian, Weilin Sun, Liming Jiang, and Zhiquan Shen. "Synthesis and magnetic properties of novel poly(Schiff base)-Fe2+ complexes." Macromolecular Rapid Communications 21, no. 15 (October 1, 2000): 1099–102. http://dx.doi.org/10.1002/1521-3927(20001001)21:15<1099::aid-marc1099>3.0.co;2-6.

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38

Anderson, John S., and Jonas C. Peters. "Low-Spin Pseudotetrahedral Iron(I) Sites in Fe2(μ-S) Complexes." Angewandte Chemie International Edition 53, no. 23 (April 17, 2014): 5978–81. http://dx.doi.org/10.1002/anie.201401018.

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39

Anderson, John S., and Jonas C. Peters. "Low-Spin Pseudotetrahedral Iron(I) Sites in Fe2(μ-S) Complexes." Angewandte Chemie 126, no. 23 (April 17, 2014): 6088–91. http://dx.doi.org/10.1002/ange.201401018.

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40

Svoboda, Ladislav, Tomáš Šafařík, and Uwe Schmidt. "Separation of Lead, Cadmium, and Iron in Analyses of Soil Samples." Collection of Czechoslovak Chemical Communications 60, no. 6 (1995): 938–49. http://dx.doi.org/10.1135/cccc19950938.

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The conditions of sorption of chloride complexes of Pb2+, Cd2+, Fe2+, and Fe3+ ions from media of hydrochloric acid have been studied with a strongly basic anion exchanger - Ostion LG AT. The experiments used an exchanger microcolumn connected with atomic absorption spectrometer as a selective detector of metal ions. From the relation found between retention of the ions studied and hydrochloric acid concentration, conditions of separation have been suggested and used for separations of small amounts of lead and cadmium from many times higher amounts of iron and aluminium in soil extract before determination of both the foreign metals by means of AAS method. The yield of separation exceeded 95%.

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41

Varela, Elisa, and Ming Tien. "Effect of pH and Oxalate on Hydroquinone-Derived Hydroxyl Radical Formation during Brown Rot Wood Degradation." Applied and Environmental Microbiology 69, no. 10 (October 2003): 6025–31. http://dx.doi.org/10.1128/aem.69.10.6025-6031.2003.

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ABSTRACT The redox cycle of 2,5-dimethoxybenzoquinone (2,5-DMBQ) is proposed as a source of reducing equivalent for the regeneration of Fe2+ and H2O2 in brown rot fungal decay of wood. Oxalate has also been proposed to be the physiological iron reductant. We characterized the effect of pH and oxalate on the 2,5-DMBQ-driven Fenton chemistry and on Fe3+ reduction and oxidation. Hydroxyl radical formation was assessed by lipid peroxidation. We found that hydroquinone (2,5-DMHQ) is very stable in the absence of iron at pH 2 to 4, the pH of degraded wood. 2,5-DMHQ readily reduces Fe3+ at a rate constant of 4.5 × 103 M−1s−1 at pH 4.0. Fe2+ is also very stable at a low pH. H2O2 generation results from the autoxidation of the semiquinone radical and was observed only when 2,5-DMHQ was incubated with Fe3+. Consistent with this conclusion, lipid peroxidation occurred only in incubation mixtures containing both 2,5-DMHQ and Fe3+. Catalase and hydroxyl radical scavengers were effective inhibitors of lipid peroxidation, whereas superoxide dismutase caused no inhibition. At a low concentration of oxalate (50 μM), ferric ion reduction and lipid peroxidation are enhanced. Thus, the enhancement of both ferric ion reduction and lipid peroxidation may be due to oxalate increasing the solubility of the ferric ion. Increasing the oxalate concentration such that the oxalate/ferric ion ratio favored formation of the 2:1 and 3:1 complexes resulted in inhibition of iron reduction and lipid peroxidation. Our results confirm that hydroxyl radical formation occurs via the 2,5-DMBQ redox cycle.

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Mernissi-Arifi, K., C. Wehrer, G. Schlewer, and B. Spiess. "Complexation studies on inositol-phosphates. V. Cu2+, Zn2+, Fe2+ and Fe3+ complexes of some myo-inositol triphosphates." Journal of Inorganic Biochemistry 55, no. 4 (September 1994): 263–77. http://dx.doi.org/10.1016/0162-0134(94)85011-9.

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Kripli, Balázs, Gábor Baráth, É. Balogh-Hergovich, Michel Giorgi, A. Jalila Simaan, László Párkányi, József S. Pap, József Kaizer, and Gábor Speier. "Correlation between the SOD-like activity of hexacoordinate iron(II) complexes and their Fe3+/Fe2+ redox potentials." Inorganic Chemistry Communications 14, no. 1 (January 2011): 205–9. http://dx.doi.org/10.1016/j.inoche.2010.10.023.

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Xiang, Ying Hong, Yang Yang Zhong, and Chun Chen. "Study on Radioactive Organic Wastewater Treatment by Fenton Reagent." Applied Mechanics and Materials 685 (October 2014): 457–62. http://dx.doi.org/10.4028/www.scientific.net/amm.685.457.

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The radioactive organics in wastewater were removed by Fenton reagent. The optimum conditions determined by single-factor test and orthogonal experiment are as following: [H2O2] =1.0mol·L-1, [Fe2+] =6.00mmol·L-1 and 30min at pH=4.0. Under these conditions, the COD removal efficiency was 81%. The dosage of Fe2+ was the most influential factor on organic wastewater COD removal by Fenton and the following influential factors were the reaction time, H2O2 dosage and pH value. In the process of radioactive wastewater treatment by Fenton, the effect of molten iron complexes flocculation was bigger than hydroxyl radical oxidation on COD removal.

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Vekeman, Jelle, Javier Torres, Cristina Eugenia David, Els Van de Perre, Karl Martin Wissing, Emmanuel Letavernier, Dominique Bazin, Michel Daudon, Agnieszka Pozdzik, and Frederik Tielens. "In Search of an Efficient Complexing Agent for Oxalates and Phosphates: A Quantum Chemical Study." Nanomaterials 11, no. 7 (July 6, 2021): 1763. http://dx.doi.org/10.3390/nano11071763.

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Limiting gastrointestinal oxalate absorption is a promising approach to reduce urinary oxalate excretion in patients with idiopathic and enteric hyperoxaluria. Phosphate binders, that inhibit gastrointestinal absorption of dietary phosphate by the formation of easily excretable insoluble complexes, are commonly used as a treatment for hyperphosphatemia in patients with end-stage renal disease. Several of these commercially available phosphate binders also have affinity for oxalate. In this work, a series of metallic cations (Li+, Na+, Mg2+, Ca2+, Fe2+, Cu2+, Zn2+, Al3+, Fe3+ and La3+) is investigated on their binding affinity to phosphate and oxalate on one side and anionic species that could be used to administer the cationic species to the body on the other, e.g., acetate, carbonate, chloride, citrate, formate, hydroxide and sulphate. Through quantum chemical calculations, the aim is to understand the competition between the different complexes and propose possible new and more efficient phosphate and oxalate binders.

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46

Song, Li-Cheng, Qing-Mei Hu, and Xiang-Dong Qin. "Synthesis of (n5-R1C5H4)(CO)2Mo(n2-S2R) via Reaction of (μ-RS)(μ-p-MeC6H4SO2S)Fe2(CO)6 with Nucleophiles (n5-R1C5H4)(CO)3MoSeNa. Crystal Structure of (n5-MeO2CC5H4)(CO)2Mo(n2-S2But)." Journal of Chemical Research 23, no. 2 (February 1999): 84–85. http://dx.doi.org/10.1177/174751989902300209.

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The reaction of (μ-RS)(μ- p-MeC6H4SO2S)Fe2(CO)6 with ( n5-R1C5H4)(CO)3MoSeNa gave organomolybdenum complexes ( n5-R1C5H4)(CO)2Mo( n2-S2R) (3a R = Et, R1 = H; 3b R = But, R1 = MeO2C), the structure of 3b being determined by X-ray diffraction analysis.

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47

Prasad, G. Krishna, S. S. P. Prashanth, S. Srivastava, G. Nageswara Rao, and D. Rajesh Babu. "Synthesis, characterization, second and third order non-linear optical properties and luminescence properties of 1,10-phenanthroline-2,9-di(carboxaldehyde phenylhydrazone) and its transition metal complexes." Open Chemistry 15, no. 1 (December 13, 2017): 283–92. http://dx.doi.org/10.1515/chem-2017-0036.

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AbstractThe requirement for materials which exhibit good second and third order non-linear optical properties and also for materials which could sense metals in trace quantities has kindled renewed investigations. Organometallics and coordination compounds show a lot of promise as new NLO materials combining the variety of organic moieties with the strength and variable oxidation states of metals. Especially ligands which selectively detect industrial pollutants like Cd and biologically significant metals like Zn are necessary. In the current work the ligand 1,10-phenanthroline-2,9-di(carboxaldehyde phenylhydrazone) (L) and its Ni2+, Co2+, Fe2+, Zn2+, Cd2+ and Ir3+ complexes were synthesized. These were characterized by UV-Vis, FT-IR, 1H NMR, MS and CHN microanalysis techniques. The complexes were shown to have the formula [ML]2+. The second and third order NLO of the ligand and its complexes were recorded These new compounds were found to have same order of third order nonlinear optical susceptibility as that of CS2 and their second hyperpolarizability was an order of magnitude greater than that of C60. Furthermore the ligand also displays selective luminescence sensing of metals ions Fe2+ and Ir3+ even in the presence of other metal ions.

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48

Ai, Hongqi, Yuxiang Bu, Ping Li, Zhiqiang Li, Xiangquan Hu, and Zhida Chen. "Geometry and binding properties of different multiple-state glycine-Fe+/Fe2+ complexes." Journal of Physical Organic Chemistry 18, no. 1 (2004): 26–34. http://dx.doi.org/10.1002/poc.808.

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49

Seyferth, Dietmar, and Jeffrey B. Hoke. "Synthesis and characterization of (.mu.-R1C:NPh)(.mu.-RS)Fe2(CO)6 complexes." Organometallics 7, no. 2 (February 1988): 524–28. http://dx.doi.org/10.1021/om00092a045.

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Pokidova, O. V., N. A. Sanina, L. A. Syrtsova, B. L. Psikha, N. I. Shkondina, A. I. Kotelnikov, and S. M. Aldoshin. "Two decomposition mechanisms of nitrosyl iron complexes [Fe2(μ-SR)(NO)4]." Russian Chemical Bulletin 66, no. 3 (March 2017): 432–38. http://dx.doi.org/10.1007/s11172-017-1751-6.

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Journal articles on the topic 'Fe2+ complexes'

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