Nitrosyl and carbene iron complexes bearing a κ3-SNS thioamide pincer type ligand

2015 ◽  
Vol 44 (3) ◽  
pp. 1017-1022 ◽  
Author(s):  
Tatsuya Suzuki ◽  
Jun Matsumoto ◽  
Yuji Kajita ◽  
Tomohiko Inomata ◽  
Tomohiro Ozawa ◽  
...  
Keyword(s):  
Iron Complexes ◽  
Iron Complex ◽  
Substitution Reactions ◽  
Pincer Ligand

The monochelate iron complex with κ3-SNS thioamide pincer ligand, [Fe(THF)2(κ3-LDPM)], gave novel complexes, [Fe(NHC)(κ3-LDPM)] and [Fe(NO)2(κ3-LDPM)], by substitution reactions with N heterocyclic carbene and NO molecules, respectively.

scholarly journals Neutrophil Gelatinase-Associated Lipocalin Expresses Antimicrobial Activity by Interfering with l-Norepinephrine-Mediated Bacterial Iron Acquisition

2010 ◽  
Vol 54 (4) ◽  
pp. 1580-1589 ◽  
Author(s):  
Marcus Miethke ◽  
Arne Skerra
Keyword(s):  
Iron Acquisition ◽  
Primary Source ◽  
Iron Complexes ◽  
Iron Complex ◽  
Immune Defense ◽  
Uptake System ◽  
Iron Chelate ◽  
Neutrophil Gelatinase Associated Lipocalin ◽  
Bacterial Uptake ◽  
Neutrophil Gelatinase

ABSTRACT l-norepinephrine (NE) is a neuroendocrine catecholamine that supports bacterial growth by mobilizing iron from a primary source such as holotransferrin to increase its bioavailability for cellular uptake. Iron complexes of NE resemble those of bacterial siderophores that are scavenged by human neutrophil gelatinase-associated lipocalin (NGAL) as part of the innate immune defense. Here, we show that NGAL binds iron-complexed NE, indicating physiological relevance for both bacterial and human iron metabolism. The fluorescence titration of purified recombinant NGAL with the FeIII·(NE)3 iron complex revealed high affinity for this ligand, with a K D of 50.6 nM. In contrast, the binding protein FeuA of Bacillus subtilis, which is involved in the bacterial uptake of triscatecholate iron complexes, has a K D for FeIII·(NE)3 of 1.6 μM, indicating that NGAL is an efficient competitor. Furthermore, NGAL was shown to inhibit the NE-mediated growth of both E. coli and B. subtilis strains that either are capable or incapable of producing their native siderophores enterobactin and bacillibactin, respectively. These experiments suggest that iron-complexed NE directly serves as an iron source for bacterial uptake systems, and that NGAL can function as an antagonist of this iron acquisition process. Interestingly, a functional FeuABC uptake system was shown to be necessary for NE-mediated growth stimulation as well as its NGAL-dependent inhibition. This study demonstrates for the first time that human NGAL not only neutralizes pathogen-derived virulence factors but also can effectively scavenge an iron-chelate complex abundant in the host.

Nucleophilic addition to di- and poly-iron arene complex cations

1996 ◽  
Vol 74 (11) ◽  
pp. 2073-2082 ◽  
Author(s):  
Alaa S. Abd-Ei-Aziz ◽  
Debbie A. Armstrong ◽  
Shelly Bernardin ◽  
Harold M. Hutton
Keyword(s):  
Nucleophilic Addition ◽  
Iron Complexes ◽  
Iron Complex ◽  
Cyanide Anion ◽  
Meta Position ◽  
Arene Complex ◽  
Nmr Techniques ◽  
Cyano Groups ◽  
Predominant Effect

Hydride and cyanide addition to a series of di- and polycyclopentadienyliron arene complex cations with etheric bridges is described. Reaction of the di-iron complexes with sodium borohydride resulted in the formation of a number of adducts.p-Methyl- and o,o-dimethylphenoxybenzene cyclopentadienyliron complexes were used as models in this study to allow for the characterization of the analagous di-iron complexes. The use of HH COSY and CH COSY NMR techniques enabled us to identify the isomeric nature of these adducts. The hydride addition results indicated that the etheric substituent had the predominant effect over the methyl group, leading to a higher addition ratio to the meta-, followed by the ortho-, then the para-positions. It was also clear that in the di-iron system, the hydride addition to each complexed arene ring took place independently. The addition of the cyanide anion to di- and poly-iron arene systems was more selective than that of the hydride anion. Reaction of sodium cyanide with p-methyl- or o-methyl-substituted arene complexes led to the formation of one adduct, with the cyanide being added to the meta position to the etheric bridges. However, cyanide addition to the di-iron complex, with a methyl substituent attached at the meta position of each complexed arene, led to the formation of a mixture of adducts. Cyanide addition to the poly-iron system with p-substituted arenes proved to be very selective, allowing for the formation of one adduct. Oxidative demetallation with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) produced the uncomplexed polyaromatic ethers with cyano groups in a very good yield. Key words: cyclopentadienyliron, arene, nucleophilic addition, hydride, cyanide.

β-Acylvinyl-dicarbonyl-η5-cyclopentadienyl-eisen-Komplexe / β-Acylvinyl-dicarbonyl-η5-cyclopentadienyl-iron Complexes

1990 ◽  
Vol 45 (6) ◽  
pp. 833-847 ◽  
Author(s):  
Rudolf Gompper ◽  
Eduard Kottmair
Keyword(s):  
Spectral Data ◽  
Oxalyl Chloride ◽  
Iron Complexes ◽  
Iron Complex ◽  
Cyclopentadienyliron Complexes ◽  
Binuclear Iron

Reactions of β-chlorovinylcarbonyl compounds 10, 14, 16, 18, 20, 22, with sodium dicarbonyl-η5-cyclopentadienyl-ferrate (NaFp) furnish β-acylvinyl-dicarbonyl-η5-cyclopentadienyliron complexes 15, 17, 19, 21, 23 and binuclear iron complexes 26-29. Spectral data demonstrate the donor effect of the Fp group. Irradiation of these complexes in the presence of triphenylphosphane delivers β-acylvinyl-carbonyl-η5-cyclopentadienyl-triphenylphosphane-iron complexes 34, 35. Reaction of glutarimides with oxalyl chloride gives rise to oxazolo-[3,2 a]pyridines 13. Benzylidenemalonyl chloride reacts with FpCS2Na to form benzylidenethietane-2,4-dione (32). A β-acylethinyl-carbonyl-η5-dicyclopentadienyl-iron complex 43 has been prepared.

scholarly journals Low-molecular-mass iron complexes in blood plasma of iron-deficient pigs do not originate directly from nutrient iron

Metallomics ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1900-1911 ◽  
Author(s):  
Nathaniel Dziuba ◽  
Joanne Hardy ◽  
Paul A. Lindahl
Keyword(s):  
Blood Plasma ◽  
Molecular Mass ◽  
Iron Complexes ◽  
Iron Complex ◽  
Iron Deficient ◽  
In Blood Plasma

This study aims to detect a nutrient-derived iron complex called NTBI in blood but detected complexes originate from internal stores.

scholarly journals Reaktive π-Komplexe der elektronenreichen Übergangsmetalle, 11. Mitteilung/ Reactive π-Complexes of the Electron Rich Transition Metal Complexes, Part 11

1991 ◽  
Vol 46 (6) ◽  
pp. 729-737 ◽  
Author(s):  
Catherine Tolxdorff ◽  
Dongqi Hu ◽  
Bernhard Höferth ◽  
Hartmut Schaufele ◽  
Hans Pritzkow ◽  
...  
Keyword(s):  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Coordination Sphere ◽  
Room Temperature ◽  
Iron Complexes ◽  
Iron Complex

The highly reactive arene iron complex [(η4-toluene)(η6-toluene)iron] allows the formation of C4-units from alkynes below room temperature. By this route butadiene-, cyclobutadiene-, and ferracyclopentadiene(arene)iron complexes are accessible. Synthesis, structure and the properties of one example each are reported. Ferracyclopentadienes are potential intermediates for the catalytic cyclotrimerization of alkynes in the coordination sphere of arene iron complexes.

Synthesis and Structures of μ3-Oxo-centered Mixed-valent Trinuclear Iron Complexes with 1-Methyl-imidazole Ligands

2007 ◽  
Vol 62 (9) ◽  
pp. 1117-1122 ◽  
Author(s):  
Ji-Xiang Dai ◽  
Fang-Hui Wu ◽  
Alexander Rothenberger ◽  
Qian-Feng Zhang
Keyword(s):  
Single Crystal ◽  
Crystal Structures ◽  
Iron Complexes ◽  
Iron Complex ◽  
Methanol Solution ◽  
X Ray Diffraction ◽  
X Ray ◽  
Elemental Analyses ◽  
Methyl Imidazole ◽  
Imidazole Ligands

Treatment of the μ3-oxo-centered mixed-valent trinuclear iron complex [Fe3(μ3-O)(μ-OAc)6- (H2O)3] (1) in methanol solution with one, two, or three equivalents of 1-methyl-imidazole (C4H6N2) afforded the substitution products [Fe3(μ3-O)(μ-OAc)6(H2O)2(C4H6N2)] (2), [Fe3(μ3-O)(μ-OAc)6- (H2O)(C4H6N2)2] (3), and [Fe3(μ3-O)(μ-OAc)6(C4H6N2)3] (4), respectively. Complexes 2 - 4 were characterized by spectroscopic and elemental analyses, and the crystal structures of complexes 3 · 1.5MeOH· 2H2O and 4 have been determined by single-crystal X-ray diffraction. The results indicate that in 2 - 4 the trinuclear core unit [Fe3(μ3-O)(μ-OAc)6] of 1 is preserved.

Density functional theory study of bis(imino) N-heterocyclic carbene iron(II) complexes

2014 ◽  
Vol 92 (10) ◽  
pp. 925-931 ◽  
Author(s):  
Jameel Al Thagfi ◽  
Gino G. Lavoie
Keyword(s):  
Density Functional Theory ◽  
Electron Density ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Iron Complexes ◽  
Relative Energy ◽  
Iron Complex ◽  
Geometrical Parameters ◽  
Functional Theory ◽  
Imine Group

Density functional theory calculations at the B3LYP/DGDZVP and UB3LYP/TZVP levels were performed on 1,3-bis[1-(2,6-dimethylphenylimino)ethyl]imidazolium and on the corresponding imidazol-2-ylidene iron(II) dichloride complex, respectively. The resulting geometrical parameters of the optimized structures were in good agreement with previously reported X-ray structures. The ground state for the high-spin (quintet multiplicity) iron complex is 82.4 kJ/mol lower in energy compared to the low-spin (triplet) configuration, in agreement with magnetic susceptibility measurements. Further calculations were carried out on related benzimidazol-2-ylidene and pyrimidin-2-ylidene ligands and on the corresponding iron complexes to gain insight into their electronic properties and reactivities. The energy of the highest occupied and lowest unoccupied molecular orbitals of all three carbenes suggests that the pyrimidin-2-ylidene and the benzimidazol-2-ylidene are the best σ-donor and best π-acceptor, respectively. Using those results, the metal center in the pyrimidin-2-ylidene iron dichloride complex was predicted to bear the highest electron density. This was supported by the high relative energy of its highest occupied molecular orbital compared to that of the corresponding imidazole-2-ylidene and benzimidazol-2-ylidene iron complexes. The electrostatic potential maps of all three metal complexes furthermore indicated a marked decrease in electron density for the coordinated imine group, supporting a greater reactivity towards nucleophiles.

Iron complexes of tris(4-nitrophenyl)corrole, with emphasis on the (nitrosyl)iron complex

2012 ◽  
Vol 16 (05n06) ◽  
pp. 663-673 ◽  
Author(s):  
Pinky Singh ◽  
Irena Saltsman ◽  
Atif Mahammed ◽  
Israel Goldberg ◽  
Boris Tumanskii ◽  
...  
Keyword(s):  
Iron Complexes ◽  
Iron Complex ◽  
Oxidation Products ◽  
Spectroscopic Techniques ◽  
X Ray ◽  
Nitrosyl Iron Complex ◽  
Reduction And Oxidation ◽  
Electron Reduction ◽  
The One ◽  
Redox Centre

The iron complexes of 5,10,15-tris(4-nitrophenyl)corrole have been prepared and characterized by various spectroscopic techniques. The (nitrosyl)iron complex is diamagnetic and its X-ray structure reveals an almost perfectly linear Fe–N–O bond. EPR spectroscopy in conjunction with 15N labelling were used to deduce the redox centre of the one-electron reduction and oxidation products of the (nitrosyl)iron corrole.

Three bonding modes of bis(2-picolyl)phenylphosphine at iron: isolation of a dinuclear iron complex featuring dearomatized pyridine moieties

2015 ◽  
Vol 44 (16) ◽  
pp. 7500-7505 ◽  
Author(s):  
G. Jin ◽  
L. Vendier ◽  
Y. Coppel ◽  
S. Sabo-Etienne ◽  
S. Bontemps
Keyword(s):  
Iron Complexes ◽  
Iron Complex ◽  
Coordination Modes ◽  
Dinuclear Iron

Three iron complexes displaying different coordination modes of the NPN ligand were isolated, including one dinuclear compound featuring dearomatized pyridine moieties.

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