Artículos de revistas: "Complexes de Fe(III)"

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Rai, Dhanpat, Mikazu Yui y Dean A. Moore. "Isosaccharinate Complexes of Fe(III)". Journal of Solution Chemistry 41, n.º 11 (7 de noviembre de 2012): 1906–21. http://dx.doi.org/10.1007/s10953-012-9911-7.

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Chen, Shangjun, Lu An y Shiping Yang. "Low-Molecular-Weight Fe(III) Complexes for MRI Contrast Agents". Molecules 27, n.º 14 (18 de julio de 2022): 4573. http://dx.doi.org/10.3390/molecules27144573.

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Fe(III) complexes have again attracted much attention for application as MRI contrast agents in recent years due to their high thermodynamic stability, low long-term toxicity, and large relaxivity at a higher magnetic field. This mini-review covers the recent progress on low-molecular-weight Fe(III) complexes, which have been considered as one of the promising alternatives to clinically used Gd(III)-based contrast agents. Two kinds of complexes including mononuclear Fe(III) complexes and multinuclear Fe(III) complexes are summarized in sequence, with a specific highlight of the structural relationships between the complexes and their relaxivity and thermodynamic stability. In additional, the future perspectives for the design of low-molecular-weight Fe(III) complexes for MRI contrast agents are suggested.

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3

Xue, Xiao Fei, Yan Xiang Liu, Yan Qing Shao y Nan Sheng Deng. "Rapid Decolorization of Rhodamine B by UV/Fe(III)-Penicillamine Process under Neutral pH: Compared with UV/Fe(III)-Oxalate". Advanced Materials Research 183-185 (enero de 2011): 130–34. http://dx.doi.org/10.4028/www.scientific.net/amr.183-185.130.

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This study investigated the decolorization of Rhodamine B by the UV/Fe(III)-Oxalate and UV/Fe(III)-Penicillamine process under neutral pH. Fe(III)-Penicillamine complexes showed much higher photoactivity than that of Fe(III)-Oxalate complexes. The efficiency for decolorization of Rhodamine B at pH 5.0 was 59% and 88% in Fe(III)-Oxalate and Fe(III)-Penicillamine complexes aqueous solution after 60 min irradiation, respectively, whereas, 35% and 57% was achieved at pH 7.0. Compared to the Fe(III)/Oxalate system, the kinetic constants kapp (min-1) for Rhodamine B decolorization in Fe(III)/Penicillamine system increased 2.4 and 2.0 times at pH 5.0 and 7.0, respectively. According to the obtained results, it was quite reasonable to conclude that penicillamine should play a similar role in Fe(III)-Penicillamine aqueous solution as oxalate did in Fe(III)-Oxalate solution. The results obtained indicated that the UV/Fe(III)-Penicillamine process was probably an alternative method to treat dye pollutant at neutral pH condition.

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4

Hassen, Jasim y Jack Silver. "Stability of Fe(III) and Sn(IV) Metalloporphyrins Adsorbed on Cation-Exchanged Montmorillonite". Trends in Sciences 19, n.º 8 (27 de marzo de 2022): 3426. http://dx.doi.org/10.48048/tis.2022.3426.

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The iron(III)tetraphenylporphyrin chloride Fe(III)TPPCl, iron(III)tetra-naphthylporphyrin Fe(III)TNPCl, μ-oxo-bis[tetraphenylporphyriniron(III)] [(Fe(III)TPP)2O], μ-oxo-bis[tetranaphthylporphyriniron(III)] [(Fe(III)TNP)2O], tin(IV)tetraphenylporphyrin chloride Sn(IV)TPPCl2 and tin(IV)tetra-naphthylporphyrin Sn(IV)TNPCl2 complexes were all found to be adsorbed onto the montmorillonite MMT clay without demetallation. The evidence from the visible absorption and diffuse reflectance spectra all showed that the species present on the montmorillonite are the metallated form. Also the evidence from Mossbauer spectroscopy confirm these findings. The only process that occurs is that the dimeric form of the iron complexes underwent transformation to the monomeric form. The clay-complex systems were characterized using visible absorption spectra, diffuse reflectance spectra, X-ray diffraction, Mossbauer spectra and Electron microscopy. HIGHLIGHTS Fe(III)TPPCl, Fe(III)TNPCl, Sn(IV)TPPCl2, and Sn(IV)TNPCl2 porphyrin complexes adsorbed onto the montmorillonite clay without demetallation The dimeric forms of iron porphyrin complexes [(Fe(III)TPP)2O] and [(Fe(III)TNP)2O are converted to the monomeric form when adsorbed on montmorillonite clay The weak acidity of montmorillonite clay does not have the ability to cause demetallation of the metallo complexes of porphyrin

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5

Ansari, Khairul I., Sahba Kasiri, James D. Grant y Subhrangsu S. Mandal. "Fe(III)-Salen and Salphen Complexes Induce Caspase Activation and Apoptosis in Human Cells". Journal of Biomolecular Screening 16, n.º 1 (2 de noviembre de 2010): 26–35. http://dx.doi.org/10.1177/1087057110385227.

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To explore the apoptotic and antitumor activities of metallo-salens, the authors have synthesized several Fe(III)-salen and salphen complexes and analyzed their effects on human cancer and noncancer cells. Their results demonstrated that Fe(III)-salen and salphen complexes affect cell viability and induce nuclear fragmentation and apoptosis in breast cancer (MCF7) cells. The IC50 values for the active metallo-salen complexes ranged between 0.3 and 22 µM in MCF7 cells. Biochemically active Fe(III)-salen and salphen complexes induced caspase-3/7 activation and release of cytochrome c from the mitochondria to cytosol, suggesting the involvement of the mitochondrial pathway of apoptosis. Comparison of IC50 values toward 3 different cell lines demonstrated that selected Fe(III)-salen complexes induce tumor cell-selective apoptosis in cultured cells. Overall, the studies demonstrated that Fe(III)-salen and salphen complexes induced efficient apoptosis in cultured human cells. The nature of the substituents and the bridging spacer between diamino groups play critical roles in determining the apoptotic activities of Fe(III)-salen and salphen complexes.

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6

Manimaran, P. y S. Balasubramaniyan. "Synthesis, Characterization and Biological Evaluation of Fe(III) and Cu(II) Complexes with 2,4-Dinitrophenyl hydrazine and Thiocyanate Ions". Asian Journal of Chemistry 31, n.º 4 (27 de febrero de 2019): 780–84. http://dx.doi.org/10.14233/ajchem.2019.21719.

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The metal complexes of Fe(III) and Cu(II) were prepared by using 2,4-dinitrophenyl hydrazine (DNPH) and thiocyanate (SCN) with stirrer refluxed for about 6 h. The prepared Fe(III) and Cu(II) complexes were characterized by elemental analysis, molar conductance, magnetic susceptibility and electronic spectrum, FT-IR spectral studies. The result suggested the octahedral geometry for Fe(III) and Cu(II) complexes. Powder X-ray diffraction indicate the crystalline nature of the metal complexes. The antimicrobial activities of the Fe(III) and Cu(II) complexes were tested with various micro organisms by disc diffusion method. The antimicrobial results indicate that the metal complexes are highly active with compared to the free ligand. The in vitro antioxidant activity of the free ligand and its metal complexes was assayed by radical scavenging activity (DPPH). The result proposed that Fe (III) and Cu(II) complexes exhibited strong antioxidant activity than that of the ligand.

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7

K. Dideriksen, J. A. Baker y S. L. S. Stipp. "Fe isotope fractionation between inorganic aqueous Fe(III) and a Fe siderophore complex". Mineralogical Magazine 72, n.º 1 (febrero de 2008): 313–16. http://dx.doi.org/10.1180/minmag.2008.072.1.313.

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AbstractIn oxic waters, dissolved Fe exists dominantly as Fe(III) complexes with strongly coordinating, siderophore-like ligands. In this study, we have determined an equilibrium Fe isotope fractionation of 0.6% (∆56Fe) between inorganic Fe(III) and Fe(III) siderophore complexes using the siderophore desferrioxamine B as a model compound. The 57Fe tracer experiments show that the Fe isotopes ofthe siderophores exchange readily with dissolved inorganic Fe. The results indicate that organic ligands are likely to be important in the generation ofFe isotope signatures in oxic environments. For example, the isotopic composition ofmarine Fe-Mn nodules may largely be due to the presence of strongly coordinating ligands.

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8

Melník, Milan y Marian Koman. "Pyridine-2,6-dicarboxylates in monomeric iron complexes – structural aspects". Reviews in Inorganic Chemistry 40, n.º 2 (25 de junio de 2020): 75–89. http://dx.doi.org/10.1515/revic-2019-0017.

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AbstractThis review includes 70 monomeric high-spin complexes of the following general compositions: [Fe(II)(η3-pdc)(L)3], [Fe(III)(η3-pdc)(L)3]+, [Fe(II)(η3-pdc)2]2− and [Fe(III)(η3-pdc)2]− (pdc = pyridine-2,6-dicarboxylate (−2)). Each Fe(II) atom has a distorted octahedral geometry. The Fe(III) atoms have a distorted octahedral geometry (most common) and in some examples have a distorted pentagonal-bipyramidal geometry. The chelating donor ligands create varieties of n-membered metallocyclic rings: ONO, OCO, NC2N, OC2N, OC2NO and OC3O. Some cooperative effects between Fe(II) and Fe(III) complexes were found and discussed. There are complexes that are examples of distortion isomerism.

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9

Monreal-Corona, Roger, Jesse Biddlecombe, Angela Ippolito y Nelaine Mora-Diez. "Theoretical Study of the Iron Complexes with Lipoic and Dihydrolipoic Acids: Exploring Secondary Antioxidant Activity". Antioxidants 9, n.º 8 (28 de julio de 2020): 674. http://dx.doi.org/10.3390/antiox9080674.

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The thermodynamic stability of twenty-nine Fe(III) complexes with various deprotonated forms of lipoic (LA) and dihydrolipoic (DHLA) acids, with coordination numbers 4, 5 and 6, is studied at the M06(SMD)/6-31++G(d,p) level of theory in water under physiological pH conditions at 298.15 K. Even though the complexes with LA- are more stable than those with DHLA−, the most thermodynamically stable Fe(III) complexes involve DHLA2−. The twenty-four exergonic complexes are used to evaluate the secondary antioxidant activity of DHLA and LA relative to the Fe(III)/Fe(II) reduction by O2•− and ascorbate. Rate constants for the single-electron transfer (SET) reactions are calculated. The thermodynamic stability of the Fe(III) complexes does not fully correlate with the rate constant of their SET reactions, but more exergonic complexes usually exhibit smaller SET rate constants. Some Cu(II) complexes and their reduction to Cu(I) are also studied at the same level of theory for comparison. The Fe(III) complexes appear to be more stable than their Cu(II) counterparts. Relative to the Fe(III)/Fe(II) reduction with ascorbate, DHLA can fully inhibit the formation of •OH radicals, but not by reaction with O2•−. Relative to the Cu(II)/Cu(I) reduction with ascorbate, the effects of DHLA are moderate/high, and with O2•− they are minor. LA has minor to negligible inhibition effects in all the cases considered.

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10

Rastogi, Raj Kamal, Sonu Sharma, Gulshan Rastogi y Alok K. Singh. "SYNTHESIS AND CHARACTERIZATION OF TI (III), V (III),VO (IV), MOO (V),FE (II) AND FE (III) COMPLEXES OF BENZIL- 2,4-DINITROPHENYL HYDRAZONE P-BROMO ANILINE". Green Chemistry & Technology Letters 2, n.º 4 (14 de diciembre de 2016): 177. http://dx.doi.org/10.18510/gctl.2016.242.

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The complexes of Benzil-2, 4-dinitrophenyl hydrazone-p- bromo aniline with Ti(III),V(III), VO(IV),MoO (V), Fe(II), Fe(III) have synthesized and characterized by elemental analysis, magnetic measurement data, molar conductance, TGA,UV-visible and IR spectra data. The complexes of Ti (III), V (III), Fe (II) and Fe (III) have octahedral geometry while VO (IV) and MoO(V) have distorted octahedral geometry due to the presence of M=O moiety.

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11

Patel, Akanksha, Didar Asik, Eric M. Snyder, Joseph A. Spernyak, Paul J. Cullen y Janet R. Morrow. "Saccharomyces cerevisiae and Candida albicans Yeast Cells Labeled with Fe(III) Complexes as MRI Probes". Magnetochemistry 6, n.º 3 (4 de septiembre de 2020): 41. http://dx.doi.org/10.3390/magnetochemistry6030041.

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The development of MRI probes is of interest for labeling antibiotic-resistant fungal infections based on yeast. Our work showed that yeast cells can be labeled with high-spin Fe(III) complexes to produce enhanced T2 water proton relaxation. These Fe(III)-based macrocyclic complexes contained a 1,4,7-triazacyclononane framework, two pendant alcohol groups, and either a non-coordinating ancillary group and a bound water molecule or a third coordinating pendant. The Fe(III) complexes that had an open coordination site associated strongly with Saccharomyces cerevisiae upon incubation, as shown by screening using Z-spectra analysis. The incubation of one Fe(III) complex with either Saccharomyces cerevisiae or Candida albicans yeast led to an interaction with the β-glucan-based cell wall, as shown by the ready retrieval of the complex by the bidentate chelator called maltol. Other conditions, such as a heat shock treatment of the complexes, produced Fe(III) complex uptake that could not be reversed by the addition of maltol. Appending a fluorescence dye to Fe(TOB) led to uptake through secretory pathways, as shown by confocal fluorescence microscopy and by the incomplete retrieval of the Fe(III) complex by the maltol treatment. Yeast cells that were labeled with these Fe(III) complexes displayed enhanced water proton T2 relaxation, both for S. cerevisiae and for yeast and hyphal forms of C. albicans.

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Singh, Dharam Pal, Vandna Malik y Ramesh Kumar. "Synthesis and Characterization of Biologically Active 10-Membered Tetraazamacrocyclic Complexes of Cr(III), Mn(III), and Fe(III)". Research Letters in Inorganic Chemistry 2009 (26 de abril de 2009): 1–4. http://dx.doi.org/10.1155/2009/824561.

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A new series of macrocyclic complexes of type [M(TML)X]X2; where M = Cr(III), Mn(III), or Fe(III); TML is tetradentate macrocyclic ligand and X = Cl−1, NO3−1, CH3COO−1 for Cr(III), Fe(III), and X = CH3COO−1 for Mn(III) has been synthesized by template condensation of succinyldihydrazide and glyoxal. The complexes have been formulated as [M(TML)X]X2 due to 1:2 electrolytic natures of these complexes as shown by conductivity measurements. The complexes have been characterized with the help of elemental analyses, molar conductance, electronic, infrared, far infrared spectral studies and magnetic susceptibilities. On the basis of these studies, a five-coordinate distorted square-pyramidal geometry, in which two nitrogens and two carbonyl oxygen atoms are suitably placed for coordination toward the metal ion, has been proposed for all the complexes. The complexes were tested for their in vitro antibacterial activity. Some of the complexes showed remarkable antibacterial activities against some selected bacterial strains. The minimum inhibitory concentration shown by these complexes was compared with minimum inhibitory concentration shown by some standard antibiotics like linezolid and cefaclor.

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Lan, Wenlong, Xiaoyun Hao, Yong Dou, Zhen Zhou, Lu Yang, Hui Liu, Dacheng Li, Yunhui Dong, Lingqian Kong y Daopeng Zhang. "Various Structural Types of Cyanide-Bridged FeIII–MnIII Bimetallic Coordination Polymers (CPs) and Polynuclear Clusters Based-on A New mer-Tricyanoiron(III)Building Block: Synthesis, Crystal Structures, and Magnetic Properties". Polymers 11, n.º 10 (27 de septiembre de 2019): 1585. http://dx.doi.org/10.3390/polym11101585.

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Four cyanide-bridged FeIII–MnIII complexes {[Fe(qxcq)(CN)3][Mn(L1)(H2O)]}[Mn(L1)(H2O)(CH3OH)](ClO4)·1.5MeOH·0.5H2O (L1 = N,N′-bis(3-methoxy-5-bromosalicylideneiminate) (2), {[Fe(qxcq)(CN)3][Mn(L2)]}2·0.5H2O (L2 = N,N′-ethylene-bis(3-ethoxysalicylideneiminate)) (3), [Fe(qxcq)(CN)3][Mn(L3)] (L3 = bis(acetylacetonato)ethylenediimine) (4), [Fe(qxcq)(CN)3][Mn(L4)]·1.5MeOH·0.5CH3CN·0.25H2O (L4 = N,N′-(1,1,2,2-tetramethylethylene)bis(salicylideneiminate)) (5), were prepared by assembling a new structurally characterized mer-tricyanoiron(III) molecular precursor (Ph4P)[Fe(qxcq)(CN)3]·0.5H2O (qxcq− = 8-(2-quinoxaline-2-carboxamido)quinoline anion) (1) and the corresponding manganese(III) Schiff base compound. Complexes 2and 3containa cyanide-bridged heterobimetallic dinuclear entity, which can be further dimerized by self-complementary H-bond interactions through the coordinated water molecule from one complex and the free O4unit from the adjacent complex. Complexes 4 and 5 area one-dimensional coordination polymer (CP) comprised of the repeated [Mn(Schiffbase)-Fe(qxcq)(CN)3] units. Complex 4 shows a linear-chain conformation with two trans-located cyano groups bridgingthe neighboring Mn units, while complex 5 is a zigzag-like 1D CP, where the two cyano groups in cis configurationfunction as bridges. In bothcomplexes 4 and 5, the inter-chain π–πstack interactions within the aromaticrings of cyanide precursor extend the 1D chain into the supermolecular 2D networks. The magnetic property has been experimentally studied and theoretically fitted over the four Fe(III)-Mn(III) complexes, revealing the antiferromagnetic interaction in complexes 2 and 4 and the unusual ferromagnetic coupling in complexes 3 and 5 between the Fe(III) ion and the Mn(III) ion bridged by the cyano group. Furthermore, the different magnetic coupling nature has been analyzed on the basis of the magneto-structure correlation of the mer-tricyanometallate-based Fe(III)-Mn(III) magnetic system.

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14

Rashid, K. K. Abdul, Jacob Chacko y P. N. K. Nambisan. "Complexes of embelin with Cr(III) and Fe(III)". Inorganica Chimica Acta 151, n.º 1 (enero de 1988): 1–3. http://dx.doi.org/10.1016/s0020-1693(00)83472-6.

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Cooper, Rebecca Elizabeth, Karin Eusterhues, Carl-Eric Wegner, Kai Uwe Totsche y Kirsten Küsel. "Ferrihydrite-associated organic matter (OM) stimulates reduction by <i>Shewanella oneidensis</i> MR-1 and a complex microbial consortia". Biogeosciences 14, n.º 22 (20 de noviembre de 2017): 5171–88. http://dx.doi.org/10.5194/bg-14-5171-2017.

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Abstract. The formation of Fe(III) oxides in natural environments occurs in the presence of natural organic matter (OM), resulting in the formation of OM–mineral complexes that form through adsorption or coprecipitation processes. Thus, microbial Fe(III) reduction in natural environments most often occurs in the presence of OM–mineral complexes rather than pure Fe(III) minerals. This study investigated to what extent does the content of adsorbed or coprecipitated OM on ferrihydrite influence the rate of Fe(III) reduction by Shewanella oneidensis MR-1, a model Fe(III)-reducing microorganism, in comparison to a microbial consortium extracted from the acidic, Fe-rich Schlöppnerbrunnen fen. We found that increased OM content led to increased rates of microbial Fe(III) reduction by S. oneidensis MR-1 in contrast to earlier findings with the model organism Geobacter bremensis. Ferrihydrite–OM coprecipitates were reduced slightly faster than ferrihydrites with adsorbed OM. Surprisingly, the complex microbial consortia stimulated by a mixture of electrons donors (lactate, acetate, and glucose) mimics S. oneidensis under the same experimental Fe(III)-reducing conditions suggesting similar mechanisms of electron transfer whether or not the OM is adsorbed or coprecipitated to the mineral surfaces. We also followed potential shifts of the microbial community during the incubation via 16S rRNA gene sequence analyses to determine variations due to the presence of adsorbed or coprecipitated OM–ferrihydrite complexes in contrast to pure ferrihydrite. Community profile analyses showed no enrichment of typical model Fe(III)-reducing bacteria, such as Shewanella or Geobacter sp., but an enrichment of fermenters (e.g., Enterobacteria) during pure ferrihydrite incubations which are known to use Fe(III) as an electron sink. Instead, OM–mineral complexes favored the enrichment of microbes including Desulfobacteria and Pelosinus sp., both of which can utilize lactate and acetate as an electron donor under Fe(III)-reducing conditions. In summary, this study shows that increasing concentrations of OM in OM–mineral complexes determines microbial Fe(III) reduction rates and shapes the microbial community structure involved in the reductive dissolution of ferrihydrite. Similarities observed between the complex Fe(III)-reducing microbial consortia and the model Fe(III)-reducer S. oneidensis MR-1 suggest electron-shuttling mechanisms dominate in OM-rich environments, including soils, sediments, and fens, where natural OM interacts with Fe(III) oxides during mineral formation.

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16

Ouyang, Zhi-Jian, Xiao-Ying Mo, Jia-Qi Ye, Xiao-Xuan Yu, Shu-Yuan Huang, Xiao-Ling Liu, Wen-Bin Chen, Song Gao y Wen Dong. "High temperature anionic Fe(iii) spin crossover behavior in a mixed-valence Fe(ii)/Fe(iii) complex". Dalton Transactions 50, n.º 17 (2021): 5960–67. http://dx.doi.org/10.1039/d1dt00111f.

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Two ion-pair complexes (PPh₄)[Fe^III(HATD)₂]·2H₂O (1) and [Fe^II(phen)₃][Fe^III(HATD)₂]₂·3DMA·3.5H₂O (2) have been synthesized and high temperature Fe(iii) spin crossover behaviour has been observed in 2.

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17

Abraham, Michael H., William E. Acree, Anthony F. Fucaloro y Andrew W. Zanella. "Determination of molar refractions and Abraham descriptors for tris(acetylacetonato)chromium(iii), tris(acetylacetonato)iron(iii) and tris(acetylacetonato)cobalt(iii)". New Journal of Chemistry 41, n.º 23 (2017): 14259–65. http://dx.doi.org/10.1039/c7nj02102j.

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Pozdnyakov, Ivan P., Alexander V. Kolomeets, Victor F. Plyusnin, Alexey A. Melnikov, Victor O. Kompanets, Sergey V. Chekalin, Nikolai Tkachenko y Helge Lemmetyinen. "Photophysics of Fe(III)–tartrate and Fe(III)–citrate complexes in aqueous solutions". Chemical Physics Letters 530 (marzo de 2012): 45–48. http://dx.doi.org/10.1016/j.cplett.2012.01.051.

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19

Vranovičová, Beata y Roman Boča. "MAGNETOSTRUCTURAL J-CORRELATIONS IN Fe(III) COMPLEXES – A REVISION". Nova Biotechnologica et Chimica 12, n.º 2 (1 de diciembre de 2013): 70–74. http://dx.doi.org/10.2478/nbec-2013-0008.

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Abstract The magnetostructural correlations in Fe(III) complexes, originally outlined by Gorun and Lippard has been revised. Other correlation variants have been tested and the dataset enlarged for more recent entries possessing the Fe-O-Fe bridge including dinuclear, tetranuclear and hexanuclear Fe(III) complexes. The resulting relationships confirm that instead of the original suggestions, the correlation could stay as a linear relationship which covers the possibilities of positive values of exchange coupling constants.

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Xu,, Zhijie, Shuo Meng, Tong Cao, Yu Xin, Mingjian Zhang, Xiaoyi Duan, Zhen Zhou y Daopeng Zhang. "The Paramagnetic or Spin Crossover Iron(III) Complexes Based-on Pentadentate Schiff Base Ligand: Crystal Structure, and Magnetic Property Investigation". Acta Chimica Slovenica 69, n.º 4 (15 de diciembre de 2022): 896–904. http://dx.doi.org/10.17344/acsi.2022.7680.

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A series of bi- or mononuclear hexacoordinate iron(III) complexes, [Fe(L)][Fe(bpb)(CN)2]·CH3OH·0.5H2O (1), [Fe(L)] [Co(bpb)(CN)2]·CH3OH (2) [(Fe (L))2(4,4’-bipy)](BPh4)2 (3), [Fe(L)(py)](BPh4) (4) and [Fe(L)(dmap)](BPh4) (5) (bpb = 1,2-bis(pyridine-2-carboxamido)benzenate, L = N,N’-bis(2-hydroxybenzyliden)-1,7-diamino-4-azaheptane, dmap = 4-dimethylaminopyridine), have been prepared with the pentadentate Schiff base iron(III) compound as assemble precursor and characterized by element analysis, IR and X-ray diffraction. Single crystal structural determination revealed the neutral cyanide-bridged binuclear entity for complexes 1 and 2 and the cationic di- or mononuclear structure for complexes 3–5 with the positive charge(s) balanced by BPh4 – ion(s). The experimental study and theoretical simulation of the magnetic property discovered the ferromagnetic coupling between the Fe(III) ions bridged by cyanide group in complex 1 and the always high spin state of the Fe(III) ion coordinated to the Schiff base ligand in both complexes 1 and 2. The temperature dependent magnetic susceptibility investigation over complexes 3–5 showed the occurrence of the thermo-induced gradual complete spin crossover (SCO) property at about 115, 170 and 200 K, respectively.

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Nguyen, Quang Trung, Phuong Nam Pham Thi y Van Tuyen Nguyen. "Synthesis, Characterization, and In Vitro Cytotoxicity of Unsymmetrical Tetradentate Schiff Base Cu(II) and Fe(III) Complexes". Bioinorganic Chemistry and Applications 2021 (3 de mayo de 2021): 1–10. http://dx.doi.org/10.1155/2021/6696344.

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Unsymmetrical tetradentate Schiff base Fe(III) and Cu(II) complexes were prepared by the coordination of some unsymmetrical tetradentate Schiff base ligands with CuCl2·2H2O or FeCl3·6H2O. The obtained complexes were characterized by ESI-MS, IR, and UV-Vis. The spectroscopic data with typical signals are in agreement with the suggested molecular formulae of the complexes. Their cyclic voltammetric studies in acetonitrile solutions showed that the Cu(II)/Cu(I) and Fe(III)/Fe(II) reduction processes are at (−)1.882–(−) 1.782 V and at (−) 1.317–(−) 1.164 V, respectively. The in vitro cytotoxicity of obtained complexes was screened for KB and Hep-G2 human cancer cell lines. The results showed that almost unsymmetrical tetradentate Schiff base complexes have good cytotoxicity. The synthetic complexes bearing the unsymmetrical tetradentate Schiff base ligands with different substituted groups in the salicyl ring indicate different cytotoxicity. The obtained Fe(III) complexes are more cytotoxic than Cu(II) complexes and relative unsymmetric Schiff base ligands.

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22

Xia, Y. M., P. G. Debrunner, S. S. David y L. Que. "The phosphate adduct of uteroferrin: Mössbauer results on the spin-coupled Fe(III)-Fe(II) and Fe(III)-Fe(III) complexes". Journal of Inorganic Biochemistry 36, n.º 3-4 (agosto de 1989): 262. http://dx.doi.org/10.1016/0162-0134(89)84341-7.

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23

Sreerama, Subramanya Gupta, Abhik Mukhopadhyay y Samudranil Pal. "Dinuclear triple helical Mn(III), Fe(III) and Co(III) complexes". Polyhedron 26, n.º 15 (septiembre de 2007): 4101–6. http://dx.doi.org/10.1016/j.poly.2007.05.004.

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24

Musa, Shuaibu, Iyun J F y Shuaibu Musa Abubakar. "Synthesis and characterization of iron (III) complexes of l-leucine and l-methionine". International Journal of Advanced Chemistry 7, n.º 1 (27 de mayo de 2019): 73–76. http://dx.doi.org/10.14419/ijac.v7i1.16098.

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The resulted complexes produced between Fe (III) and biological molecules like amino acids play an important role in human life. Fe (III) complexes are synthesized with l-Leucine and l-Methionine. The complexes were characterized by elemental analysis (AAS), molar conductance, melting point, infrared and uv-visible spectrophotometry analyses. The elemental analyses were used to determine the chelation ratio, 1:3(metal: ligands). The molar conductivity of the complexes show that the complexes are not electrolytic in nature. Moreover, the melting point of the tris (l-Leucine) iron (III) and tris (l-Methionine) iron (III) are 2390C and 210oC respectively.Â Â

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Davlatshoeva, Jahongul, Mubashira Rakhimova y Gulrukhsor Eshova. "Study of the Composition and Model Parameters of Complexes Formed in Fe(II)-Fe(III)-Ascorbic Acid-Water Systems". E3S Web of Conferences 401 (2023): 03046. http://dx.doi.org/10.1051/e3sconf/202340103046.

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The redox system Fe(II)-Fe(III)-ascorbic acid-water at 298.16 K and 0.5 mol/l solution ionic strength was studied by the Clark-Nikolsky redox potential method. It was found that five complexes of Fe(III) composition are formed in the system: [Fe(HAsc)]2+; [Fe(HAsc)]+; [FeIIFeIII(HAsc)2(OH)2]+; [FeAsc]+; [Fe(Asc)2]-and four coordination compounds Fe(II)-[Fe(HAsc)]+; [FeIIFeIII(HAsc)2(OH)2]+[Fe(HAsc)2]0; [Fe(Asc)]0. Models of ionic equilibria have been compiled, and the domination areas of the complexes have been determined.

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26

Wang, Zhaohui, Dongxue Xiao y Jianshe Liu. "Diverse redox chemistry of photo/ferrioxalate system". RSC Adv. 4, n.º 84 (2014): 44654–58. http://dx.doi.org/10.1039/c4ra07153k.

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27

Kocot, Przemysław, Andrzej Karocki y Zofia Stasicka. "Photochemistry of the Fe(III)–EDTA complexes". Journal of Photochemistry and Photobiology A: Chemistry 179, n.º 1-2 (abril de 2006): 176–83. http://dx.doi.org/10.1016/j.jphotochem.2005.08.016.

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28

Nemec, Ivan, Roman Boča, Radovan Herchel, Zdeněk Trávníček, Milan Gembický y Wolfgang Linert. "Dinuclear Fe(III) complexes with spin crossover". Monatshefte für Chemie - Chemical Monthly 140, n.º 7 (4 de diciembre de 2008): 815–28. http://dx.doi.org/10.1007/s00706-008-0096-0.

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29

Nguyen, Quang Trung, Phuong Nam Pham Thi y Nguyen Van Tuyen. "Synthesis, Spectral Characterization, and In Vitro Cytotoxicity of Some Fe(III) Complexes Bearing Unsymmetrical Salen-Type Ligands Derived from 2-Hydroxynaphthaldehyde and Substituted Salicylaldehydes". Journal of Chemistry 2021 (19 de junio de 2021): 1–9. http://dx.doi.org/10.1155/2021/8028064.

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Six Fe(III) complexes bearing unsymmetrical salen-type ligands derived from 2-hydroxynaphthaldehyde and substituted salicylaldehydes were synthesized by coordinating the unsymmetrical salen-type ligands with FeCl3.6H2O. The synthetic complexes were characterized by electrospray ionization mass spectra (ESI-MS), effective magnetic moments (μeff), and infrared (IR) and ultraviolet-visible (UV-Vis) spectra. The spectroscopic data are in good agreement with the suggested molecular formulae of the complexes. Their cyclic voltammetric studies in acetonitrile solutions showed that the Fe(III)/Fe(II) reduction processes are electrochemically irreversible. The in vitro cytotoxicity of the obtained complexes was screened on human cancer cell lines KB (a subline of Hela tumor cell line) and HepG2 (a human liver cancer cell line) and a normal human cell line HEK-293 (Human Embryonic Kidney cell line). The results showed that the synthetic Fe(III) complexes are highly cytotoxic and quite selective. The synthetic complexes bearing unsymmetrical salen-type ligands with different substituted groups in the salicyl ring indicate different cytotoxicity.

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30

Muthu, S. Esakki, Suban K. Sahoo, Minati Baral y B. K. Kanungo. "Studies of Binary Complexes of Tripodal Ligandcis,cis-1,3,5-tris(methylamino)cyclohexane with Cr(III) and Fe(III)". E-Journal of Chemistry 2, n.º 1 (2005): 52–57. http://dx.doi.org/10.1155/2005/830389.

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The formation of binary complexes of Cr(III) and Fe(III) with a tripodal ligandcis,cis-1,3,5-tris(methylamino)cyclohexane (tmach) (L) has been investigated in solution. The overall stability constants oftmachwith Cr(III) and Fe(III) were determined by potentiometric method at an ionic strength of 0.1 M NaClO4at 25±1°C in aqueous medium. The formation of species like MLH25+, MLH4+, ML3+, ML(OH)2+and ML(OH)3were observed. Fe(III) was found to form more stable complexes than Cr(III). Molecular mechanics calculations were performed to explain the mode of coordination in solution.

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31

Kumar, Gajendra, Dharmendra Kumar, Shoma Devi, Amit Kumar y Rajeev Johari. "Synthesis, Physical Characterization and Biological Evaluation of Schiff BaseCr(III), Mn(III) and Fe(III) Complexes". E-Journal of Chemistry 7, n.º 3 (2010): 813–20. http://dx.doi.org/10.1155/2010/623915.

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M(III) complexes with Cr, Mn and Fe with Schiff base derived from 2-amino-4-ethyl-5-hydroxy benzaldehyde and oxocarbohydrazide were synthesized and characterized by several techniques using elemental analysis (C, H, N), molar conductance measurements, magnetic measurements, electronic, mass and IR spectral studies. On the bases of these studies, a five coordinated square pyramidal geometry for all these complexes has been proposed and found to be potential antimicrobial agent. The Schiff base ligand and complexes were also tested for their antimicrobial activity (against the bacteriaEscherichia coli, Staphylococcus aureus, Pseudomonas aeruginosaandBacillus megateriumand the fungiKluyveromyces fragilis, Rhodotorula rubra, Candida albicansandTrichoderma reesei) to assess their inhibiting potential. An attempt is also made to correlate the antimicrobial activity with geometry of the complexes. All complexes were found to be less active against the pathogensE.coli, S.aureusandP.aeruginosa. Cr(III) complex showed the best antimicrobial activity, but ligand alone was found to be active against the fungusT.reesei.

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32

Hoshikawa, Ryusei, Kosuke Yoshida, Ryoji Mitsuhashi, Masahiro Mikuriya, Takashi Okuno y Hiroshi Sakiyama. "Structure Controlling Factors of Oxido-Bridged Dinuclear Iron(III) Complexes". Molecules 26, n.º 4 (8 de febrero de 2021): 897. http://dx.doi.org/10.3390/molecules26040897.

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Oxido bridges commonly form between iron(III) ions, but their bond angles and symmetry vary with the circumstances. A large number of oxido-bridged dinuclear iron(III) complexes have been structurally characterized. Some of them belong to the C2 point group, possessing bent Fe–O–Fe bonds, while some others belong to the Ci symmetry, possessing the linear Fe–O–Fe bonds. The question in this study is what determines the structures and symmetry of oxido-bridged dinuclear iron(III) complexes. In order to gain further insights, three oxido-bridged dinuclear iron(III) complexes were newly prepared with 2,2′-bipyridine (bpy) and 1,10-phenanthroline (phen) ligands: [Fe2OCl2(bpy)4][PF6]2 (1), [Fe2O(NO3)2(bpy)4][PF6]2·0.6MeCN·0.2(2-PrOH) (2), and [Fe2OCl2(phen)4][PF6]2·MeCN·0.5H2O (3). The crystal structures of 1, 2, and 3 were determined by the single-crystal X-ray diffraction method, and all of them were found to have the bent Fe–O–Fe bonds. Judging from the crystal structure, some intramolecular interligand hydrogen bonds were found to play an important role in fixing the structures. Additional density functional theory (DFT) calculations were conducted, also for a related oxido-bridged dinuclear iron(III) complex with a linear Fe–O–Fe bond. We conclude that the Fe–O–Fe bridge tends to bend like a water molecule, but is often stretched by interligand steric repulsion, and that the structures are mainly controlled by the intramolecular interligand interactions.

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33

Avdeev, Ya G. "Some thermodynamic and kinetic properties of H2SO4–H3PO4–H2O–Fe(III) system". Corrosion: Materials, Protection, n.º 12 (diciembre de 2021): 1–9. http://dx.doi.org/10.31044/1813-7016-2021-0-12-1-9.

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The values of the electrode potentials of the redox couple Fe(III) / Fe(II) and the half-wave potentials of the reactions Fe3+ + e– = Fe2+ и Fe2+ — e– = Fe3+ on the cyclic voltammogram of a platinum electrode in acid solutions containing Fe(III) salts have been measured to characterize the oxidizing ability of the H2SO4—H3PO4—H2O—Fe(III) system. The values of these experimentally obtained parameters are close. A decrease in the oxidizing ability of H2SO4 and H3PO4 mixtures containing Fe(III) with an increase in the molar fraction of H3PO4 in them occurs due to the formation of Fe(III) complexes with phosphate anions which are inferior to their hydrate and sulfate complexes in the oxidizing ability. The temperature coefficients of the electrode potential (dE / dt) of the redox couple Fe(III) / Fe(II) in the H2SO4—H2O, H2SO4—H3PO4—H2O and H3PO4–H2O systems were determined experimentally. The diffusion coefficients of Fe(III) in the studied solutions were calculated based on the Randles—Shevchik equation. The temperature dependence of the diffusion coefficients of Fe(III) cations is satisfactorily described by the Arrhenius equation. The parameters of this equation are calculated.

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34

Huang, Caoxing, Yuheng Tao, Min Li, Weiyu Zhang, Yimin Fan y Qiang Yong. "Synthesis and Characterization of an Antioxidative Galactomannan–Iron(III) Complex from Sesbania Seed". Polymers 11, n.º 1 (25 de diciembre de 2018): 28. http://dx.doi.org/10.3390/polym11010028.

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Galactomannan, a water-soluble polymer in the cell wall of leguminous plants, has been proven to possess anticancer and antioxidative activity. In this work, galactomannan with different molecular weights (GM-40 and GM-65) was obtained from Sesbania seeds and synthesized into galactomannan–iron(III) complexes, which are termed as GM-40-Fe and GM-65-Fe, respectively. These galactomannan–iron(III) complexes are intended to function as organic iron supplements to treat iron deficiency with the added benefit of antioxidative activity. The prepared galactomannan–iron(III) complexes were characterized for chemical composition, morphology, antioxidant capacity, and bioavailability in vitro. The results showed that galactomannan–iron(III) complexes could be produced with iron contents as high as 65.4 mg/g. Antioxidant assays indicated that both GM-40-Fe and GM-65-Fe exhibited antioxidant activities for scavenging radicals in vitro. The iron release/bioavailability assays showed that the iron was easily released into artificial gastric and intestinal juices, resulting in iron release rates of 88–94% over 300 min. These results suggest that galactomannan–iron(III) complexes synthesized from Sesbania seed polysaccharides are capable of being administered as organic iron supplements to patients with iron deficiency.

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35

Gruzdev, Matvey, Ulyana Chervonova y Valerya Vorobeva. "The Branched Schiff Base Cationic Complexes of Iron(III) with Different Counter-Ions". Symmetry 14, n.º 6 (1 de junio de 2022): 1140. http://dx.doi.org/10.3390/sym14061140.

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The Fe(III) complexes of branched asymmetric dendrimers were obtained by a one-step reaction as the second-generation architectures. Mesomorphic behavior was found for complexes with PF6− and BF4− counter-ions. To obtain knowledge about the existence of HS and LS fractions of iron(III) ion and their evolution with temperature, EPR methods were used. It was demonstrated that compounds contain one low-spin (LS, S = 1/2) and two HS-spin (HS, S = 5/2) of Fe(III) centers and are packed into two magnetic sub-lattices. A floating layers of Fe(III) complexes and Langmuir–Blodgett films on their base were formed and investigated in the presence of a magnetic field.

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36

Wang, Yong, Chensheng Lin, Xiao Ma, Zhenzhen Xue, Xiaoquan Zhu, Wenhai Cao, Shengmin Hu, Tianlu Sheng y Xintao Wu. "Influence of the central diamagnetic cyanidometal on the distant magnetic interaction in cyanide-bridged Fe(iii)–M(ii)–Fe(iii) complexes". Dalton Transactions 44, n.º 16 (2015): 7437–48. http://dx.doi.org/10.1039/c5dt00383k.

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This work shows that for the investigated Fe^III–NC–M^II–CN–Fe^III complexes the magnetic coupling strength between the distant Fe^III ions increases with the diamagnetic cyanidometal bridge in the order of Fe < Ru < Os.

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37

Kalinowska, Monika, Kamila Gryko, Ewelina Gołębiewska, Grzegorz Świderski, Hanna Lewandowska, Marek Pruszyński, Małgorzata Zawadzka, Maciej Kozłowski, Justyna Sienkiewicz-Gromiuk y Włodzimierz Lewandowski. "Fe(III) and Cu(II) Complexes of Chlorogenic Acid: Spectroscopic, Thermal, Anti-/Pro-Oxidant, and Cytotoxic Studies". Materials 15, n.º 19 (1 de octubre de 2022): 6832. http://dx.doi.org/10.3390/ma15196832.

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Complexes of chlorogenic acid (5-CQA) with copper(II) and iron(III) were synthesized in a solid state and examined by means of FT-IR, thermogravimetric, and elemental analyses. The molar stoichiometric ratios of metal:ligand for the solid forms of the complexes were established as Cu(II):L = 1:2 and Fe(III):L = 2:3 (L: 5-CQA), with the possible coordination through the carboxylate group and the hydroxyl group from the catechol moiety. In an aqueous solution at pH = 7.4, the composition of the complexes was Cu(II):L = 1:1, and Fe(III):L = 1:1 and 1:2. The Cu(II) and Fe(III) complexes with 5-CQA showed lower antioxidant properties, as estimated by the spectrophotometric methods with DPPH•, ABTS•+, and HO• radicals, than the ligand alone, whereas in the lipid peroxidation inhibition assay, the metal complexes revealed a higher antioxidant activity than 5-CQA. Cu(II) 5-CQA showed the highest pro-oxidant activity in the Trolox oxidation assays compared to the other studied compounds. The lipophilic parameters of the compounds were estimated using the HPLC method. 5-CQA and its complexes with Fe(III) and Cu(II) were not toxic to HaCaT cells in a tested concentration range of 0.15–1000 nM after a 24 h incubation time.

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38

Junghare, Nilesh V., Shrikant B. Jagtap, Rahul R. Jadhav y Jyoti P. Jadhav. "Synthesis, Spectral Characterization and Bioactivity of Co(II), Mn(II), Fe(II) and Fe(III) Complexes of Bidentate N,S Schiff Base of S-Benzyl Dithiocarbazate with p-(Dimethylamino)benzaldehyde". Asian Journal of Chemistry 34, n.º 3 (2022): 657–62. http://dx.doi.org/10.14233/ajchem.2022.23572.

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Metal complexes of (ML2)X2 type (X = H2O) of Co(II), Mn(II), Fe(II) and Fe(III) (X is NO3 – and H2O) were synthesized using Schiff base, S-benzyl-β-N-(p-dimethylaminophenyl)methylene dithiocarbazate (HL), which was synthesized by the condensation of equimolar concentrations of p-(dimethylamino)benzaldehyde and S-benzyldithiocarbazate. The metal complexes and dithiocarbazate ligands were confirmed by elemental study and spectroscopic techniques such as 1H and 13C NMR, electronic absorption spectroscopy, molar conductance, infrared techniques. The magnetic susceptibility and UV-vis spectral data suggest that the metal complexes (ML2)X2 show octahedral geometry. The bioactivity of ligand and its metal complexes were investigated by the well diffusion method against one fungus (Candida albicans) and three pathogenic bacteria (E. coli and B. cereus and S. aureus). Bioactivity analysis revealed that the (ML2)X2 complex of Fe(II) and Fe(III) shows enhanced antibacterial activity than free ligand. Comparatively, among all metal complexes, the Fe(III) complex shows higher antibacterial activity and moderate antifungal activity.

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39

Gaillard, Michel, Hussein Kanso, Franck Denat, Carole Calas-Blanchard, Nicolas Inguimbert y Thierry Noguer. "Fe(III)-DOTA/Fe(III)-NOTA Complexes: Attractive Alternative Markers for Future Electrochemical Biosensors". Journal of The Electrochemical Society 167, n.º 11 (30 de junio de 2020): 117502. http://dx.doi.org/10.1149/1945-7111/ab9e80.

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40

Reddy, Vidyavati, Nirdosh Patil, Tukaram Reddy y S. D. Angadi. "Synthesis, Characterization and Biological Activities of Cu(II), Co(II), Ni(II), Mn(II) and Fe(III) Complexes with Schiff Base Derived from 3-(4-Chlorophenoxymethyl)-4-amino-5-mercapto-1,2,4-triazole". E-Journal of Chemistry 5, n.º 3 (2008): 529–38. http://dx.doi.org/10.1155/2008/690535.

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Coordination complexes of Cu(II),Co(II), Ni(II), Mn(II) and Fe(III)with Schiff bases derived from 3-(4-chlorophenoxymethyl)-4-amino-5-mercapto-1, 2, 4-triazole and substituted aldehydes have been synthesized. The complexes were characterized by elemental analysis, conductivity measurements, magnetic susceptibility data, electronic, IR, ESR and1H NMR spectral data. On the basis spectroscopic studies, the Schiff base is monobasic bidentate ligand having the composition ML2(2H2O) Where M = Cu(II), Co(II), Ni(II) ,Mn(II), ML2(H2O)Cl Where M = Fe(III). Various physicochemical data suggest a six coordinated octahedral geometry for Cu(II),Co(II), Ni(II), Mn(II) and Fe(III) complexes. The antibacterial activities of ligand and its complexes were screened by cup plate method.

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41

Ouyang, Zhi-Jian, Xiao-Ying Mo, Meng Yang, Li Zhong, Wen-Bin Chen, Song Gao y Wen Dong. "High temperature Fe(iii) spin crossover behaviours in three unprecedented FeIII–MII–FeIII (M = Fe, Cd) linear trinuclear complexes". Inorganic Chemistry Frontiers 7, n.º 7 (2020): 1526–31. http://dx.doi.org/10.1039/c9qi01560d.

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An azo-based ligand of azotetrazolyl-2,7-dihydroxynaphthalene (H₃ATD) was used to synthesize three Fe^III–M^II–Fe^III (M = Fe, Cd) linear trinuclear complexes with different high temperature spin crossover (SCO) behaviours for the terminal Fe^III ions.

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42

Kumar, J., J. Singh, A. Jangra, K. Rani y R. Kumar. "Trivalent Tetraazamacrocyclic Complexes of Cr(III) and Fe(III): Synthesis, Characterization and Antimicrobial Evaluation". Asian Journal of Chemistry 36, n.º 1 (31 de diciembre de 2023): 189–94. http://dx.doi.org/10.14233/ajchem.2024.30766.

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A novel series of macrocyclic compounds, [M(C37H36N4)X]X2; where M = Cr(III) and Fe(III); X = Clˉ, NO3ˉ, CH3COOˉ, have been synthesized by using the template condensation between 3,4-diaminotoluene, dibenzoyl methane and dimedone in the presence of chromium(III) and iron(III). Various physio-chemical studies were used to characterize these complexes including PXRD, magnetic susceptibility, elemental analysis, electronic, IR and mass spectroscopy. These studies suggested that all the metal complexes have a five-coordinated square pyramidal geometry around the metal ion. The molar conductance values of these complexes in the range of 168-140 ohm-1cm2mol-1 indicated the electrolytic nature of these complexes. Furthermore, the antibacterial and antifungal behavior of these complexes was also examined by using different microbial strains i.e. Bacillus subtilis, Escherichia coli and Candida albicans. In addition to this, the results of antibacterial and antifungal of complexes were compared with commercially available antibacterial and antifungal drug i.e. ciprofloxacin and Amphotericin B, respectively.

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43

Dick, Stefan, Armin Weiss, Ursel Wagner, Friedrich Wagner y Gerhard Große. "Einkernige und oxoverbrückte zweikernige Fe(III)-Komplexe von N-Alkyl-N,N-bis(2-pyridylmethyl)aminen / Mononuclear and Oxo-Bridged Binuclear Fe(III) Complexes of N-Alkyl-N,N-bis(2-pyridylmethyl)amines". Zeitschrift für Naturforschung B 52, n.º 3 (1 de marzo de 1997): 372–84. http://dx.doi.org/10.1515/znb-1997-0313.

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Abstract Tridentate amines of the type N-alkyl-N,N -bis(2-pyridylmethyl)amine with alkyl = methyl L1, benzyl L2 and adamantyl L3 form mononuclear Fe(III) complexes LFeCl3. In the presence of various carboxylates binuclear μ-oxo-bis(μ-carboxylato) Fe(III) complexes [L2Fe2O(RCO2)2]2+ are formed. These compounds can be synthesized from mono-, bi-, tri- and tetranuclear iron complexes as starting materials.The crystal structures of three mononuclear and four binuclear complexes show that the tridentate ligand is always facially coordinated to Fe. While in binuclear complexes of L1 and L2 the Namin-atom is trans to the oxo-bridge, in a complex of L3 a coordination with one Npyridin atom trans to that bridge is found. In all complexes the Fe-Namine distances increase with increasing space requirement of the alkyl substituent. The effects of different ligands trans to Namine and Npyridin are discussed.57Fe Mößbauer spectra show that the electric field gradient at Fe vanishes in L1FeCl3 and L2FeCl3 despite non-cubic ligand spheres. For both mono- and binuclear complexes a correlation between isomer shift δ and Fe-N distances exists. The strong increase of Lamb-Mößbauer factors on cooling to 4,2 K and the Goldanski-Karyagin effect observed for some complexes can be explained by the displacement parameters of the Fe-atoms obtained by X -ray structure analysis.

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44

Islam, Faridul, Jannat Al Foisal, Mahbubur Rahman, Md Zahidul Islam, Mst Afsana Mimi, Rasel Habib, Md Amran Hossain, Likson Chowdhury, Sreebash Chandra Bhattacharjee y Daxiang Cui. "Antimicrobial Activity of Cu(II) and Fe(III) with Pyridine Complexes as Ligands Contrary to Clinical Strains of Bacteria and Fungi Species". Asian Journal of Chemistry 31, n.º 10 (30 de agosto de 2019): 2323–26. http://dx.doi.org/10.14233/ajchem.2019.22096.

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In this study, green coloured Cu(II) and red coloured Fe(III) complexes of pyridine were prepared and the elemental characterization confirmed their composition. The pyridine complexes of Cu(II) and Fe(III) were found very interesting and attractive as potential candidates with antimicrobial activity. Along with this, melting point, molar conductivity measurement, magnetic moment determination, electronic and FTIR spectroscopy were also measured to characterize the prepared complexes. Pyridine acts as monodentate which resulted in formation of square planar and octahedral structure of Cu(II) and Fe(III) complexes, respectively with the nitrogen atom pyridine ring by coordination bond. For antimicrobial activity studies Alternaria alternata, Bacillus cerelus, Botrgodiplodia theobromal, Colletotrichums corcolei, Escherichia coli, Fusarium equiseti, Macrophomina phaseolina, Salmonell typhi and Shigella dysenteriae were used. The prepared complexes showed inhibition against mycelial growth. Although the complexes showed satisfactory inhibition against the tested bacteria and fungi species, both of the complexes were comparatively better against bacteria than fungi compared to ligand.

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45

Dömötör, Orsolya, Nóra V. May, G. Tamás Gál, Gabriella Spengler, Aliona Dobrova, Vladimir B. Arion y Éva A. Enyedy. "Solution Equilibrium Studies on Salicylidene Aminoguanidine Schiff Base Metal Complexes: Impact of the Hybridization with L-Proline on Stability, Redox Activity and Cytotoxicity". Molecules 27, n.º 7 (22 de marzo de 2022): 2044. http://dx.doi.org/10.3390/molecules27072044.

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The proton dissociation processes of two tridentate salicylidene aminoguanidine Schiff bases (SISC, Pro-SISC-Me), the solution stability and electrochemical properties of their Cu(II), Fe(II) and Fe(III) complexes were characterized using pH-potentiometry, cyclic voltammetry and UV-visible, 1H NMR and electron paramagnetic resonance spectroscopic methods. The structure of the proline derivative (Pro-SISC-Me) was determined by X-ray crystallography. The conjugation of L-proline to the simplest salicylidene aminoguanidine Schiff base (SISC) increased the water solubility due to its zwitterionic structure in a wide pH range. The formation of mono complexes with both ligands was found in the case of Cu(II) and Fe(II), while bis complexes were also formed with Fe(III). In the complexes these tridentate ligands coordinate via the phenolato O, azomethine N and the amidine N, except the complex [Fe(III)L2]+ of Pro-SISC-Me in which the (O,N) donor atoms of the proline moiety are coordinated beside the phenolato O, confirmed by single crystal X-ray crystallographic analysis. This binding mode yielded a stronger Fe(III) preference for Pro-SISC-Me over Fe(II) in comparison to SISC. This finding is also reflected in the lower redox potential value of the iron-Pro-SISC-Me complexes. The ligands alone were not cytotoxic against human colon cancer cell lines, while complexation of SISC with Cu(II) resulted in moderate activity, unlike the case of its more hydrophilic counterpart.

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46

Kaur, Kirandeep y Minati Baral. "Synthesis of Imine-Naphthol Tripodal Ligand and Study of Its Coordination Behaviour towards Fe(III), Al(III), and Cr(III) Metal Ions". Bioinorganic Chemistry and Applications 2014 (2014): 1–10. http://dx.doi.org/10.1155/2014/915457.

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A hexadentate Schiff base tripodal ligand is synthesized by the condensation of tris (2-aminoethyl) amine with 2-hydroxy-1-naphthaldehyde and characterized by various spectroscopic techniques like UV-VIS, IR, NMR, MASS, and elemental analysis. The solution studies by potentiometric and spectrophotometric methods are done at 25 ± 1°C,µ=0.1 M KCl, to calculate the protonation constants of the ligand and formation constants of metal complexes formed by the ligand with Fe(III), Al(III), and Cr(III) metal ions. The affinity of the ligand towards Fe(III) is compared with deferiprone (a drug applied for iron intoxication) and transferrin (the main Fe(III) binding protein in plasma). Structural analysis of the ligand and the metal complexes was done using semiempirical PM6 method. Electronic and IR spectra are calculated by semiempirical methods and compared with experimental one.

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47

Failes, Timothy W. y Trevor W. Hambley. "Crystal Structures of Tris(hydroxamato) Complexes of Iron(III)". Australian Journal of Chemistry 53, n.º 10 (2000): 879. http://dx.doi.org/10.1071/ch00118.

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The crystal structures of [Fe(aha)3]·1.5H2O and [Fe(bha)3]·3H2O (ahaH = acetohydroxamic acid, bhaH = benzohydroxamic acid) have been determined. [Fe(aha)3]·1.5H2O crystallizes in the monoclinic space group P21/ c (a 19.169(4), b 8.5738(3), c 12.257(3) Å, α = γ = 90°, β 92.255(4)°). The two isomeric forms (fac and mer) cocrystallize. The structure of [Fe(bha)3]·3H2O is as reported previously (monoclinic, P21/n, a 12.9998(16), b 13.2196(16), c 14.1154(17) Å, α = γ = 90°, β 90.809(2)°) but with improved refinement giving an R value of 0.03 compared to 0.12. In each complex the geometry of the Fe centre is octahedral but with significant distortion.

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48

Boča, Roman. "Thermodynamics and cooperativeness of the spin crossover". Nova Biotechnologica et Chimica 19, n.º 2 (1 de diciembre de 2020): 138–53. http://dx.doi.org/10.36547/nbc.v19i2.769.

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Spin transition – a passage from the low-spin electronic state to the high-spin one of Fe(III) and Fe(II) complexes is assessed from several points of view: theoretical modelling, magnetic susceptibility data, and calorimetric measurements. The concept of the cooperativeness in the solid state is discussed in detail. Thermodynamic parameters are mutually correlated for a set of analogous Fe(III) complexes by using modern statistical methods.

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49

Asik, Didar, Rachel Smolinski, Samira M. Abozeid, Travis B. Mitchell, Steven G. Turowski, Joseph A. Spernyak y Janet R. Morrow. "Modulating the Properties of Fe(III) Macrocyclic MRI Contrast Agents by Appending Sulfonate or Hydroxyl Groups". Molecules 25, n.º 10 (13 de mayo de 2020): 2291. http://dx.doi.org/10.3390/molecules25102291.

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Complexes of Fe(III) that contain a triazacyclononane (TACN) macrocycle, two pendant hydroxyl groups, and a third ancillary pendant show promise as MRI contrast agents. The ancillary group plays an important role in tuning the solution relaxivity of the Fe(III) complex and leads to large changes in MRI contrast enhancement in mice. Two new Fe(III) complexes, one with a third coordinating hydroxypropyl pendant, Fe(L2), and one with an anionic non-coordinating sulfonate group, Fe(L1)(OH2), are compared. Both complexes have a deprotonated hydroxyl group at neutral pH and electrode potentials representative of a stabilized trivalent iron center. The r1 relaxivity of the Fe(L1)(OH2) complex is double that of the saturated complex, Fe(L2), at 4.7 T, 37 °C in buffered solutions. However, variable-temperature 17O-NMR experiments show that the inner-sphere water of Fe(L1)(OH2) does not exchange rapidly with bulk water under these conditions. The pendant sulfonate group in Fe(L1)(OH2) confers high solubility to the complex in comparison to Fe(L2) or previously studied analogues with benzyl groups. Dynamic MRI studies of the two complexes showed major differences in their pharmacokinetics clearance rates compared to an analogue containing a benzyl ancillary group. Rapid blood clearance and poor binding to serum albumin identify Fe(L1)(OH2) for development as an extracellular fluid contrast agent.

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Xiu, Weiye, Xin Wang, Shiyou Yu, Zhiguo Na, Chenchen Li, Mengyuan Yang y Yongqiang Ma. "Structural Characterization, In Vitro Digestion Property, and Biological Activity of Sweet Corn Cob Polysaccharide Iron (III) Complexes". Molecules 28, n.º 7 (26 de marzo de 2023): 2961. http://dx.doi.org/10.3390/molecules28072961.

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This study aimed to enhance the utilization value of sweet corn cob, an agricultural cereal byproduct. Sweet corn cob polysaccharide-ron (III) complexes were prepared at four different temperatures (40 °C, 50 °C, 60 °C, and 70 °C). It was demonstrated that the complexes prepared at different temperatures were successfully bound to iron (III), and there was no significant difference in chemical composition; and SCCP-Fe-C demonstrated the highest iron content. The structural characterization suggested that sweet corn cob polysaccharide (SCCP) formed stable β-FeOOH iron nuclei with −OH and −OOH. All the four complexes’ thermal stability was enhanced, especially in SCCP-Fe-C. In vitro iron (III) release experiments revealed that all four complexes were rapidly released and acted as iron (III) supplements. Moreover, in vitro antioxidant, α-glucosidase, and α-amylase inhibition studies revealed that the biological activities of all four complexes were enhanced compared with those of SCCP. SCCP-Fe-B and SCCP-Fe-C exhibited the highest in vitro antioxidant, α-glucosidase, and α-amylase inhibition abilities. This study will suggest using sweet corn cobs, a natural agricultural cereal byproduct, in functional foods. Furthermore, we proposed that the complexes prepared from agricultural byproducts can be used as a potential iron supplement.

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