- Observation of Single-Ion. Transitions in the Ordered States of FeBr2
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By utilizing a far infrared laser operating in the THz range, we have observed new electron spin resonance (ESR) lines in the ordered states of a layered antiferromagnet with strong uniaxial anisotropy, FeBr2. We interpret these ESR lines as arising from transitions within the lowest triplet state of single Fe2+ ions. Good agreement between theory and experiment is obtained without any adjustable parameters.
- Yamaguchi, Hideki,Katsumata, Koichi
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- LABORATORY SYNTHESIS OF FERROUS BROMIDE
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A laboratory method is presented for the preparation of ferrous bromide by heating ferric bromide or its crystal hydrate in toluene or xylene at reflux for 3-4 h.The yield is quantitative.The FeBr2 or 57FeBr2 sample thereby obtained may be used in the synthesis of iron porphyrin complexes. Keywords: ferrous bromide, reduction, porphyrins, laboratory method.
- Mikhal'tseva, I. S.,Gridnev, A. A.
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- Neutron-scattering studies of a phase transition in the metamagnet FeBr2 under external magnetic fields
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Neutron-scattering experiments have been performed on the metamagnet FeBr2 under external magnetic fields. We find an anomaly in the temperature (T) and magnetic-field (H) dependences of the intensity of the (2,0,1/2) antiferromagnetic Bragg scattering at the temperature T1(H) at which an anomaly in specific heat has been observed in addition to the anomaly at the Neel temperature TN(H). We argue that our results are consistent with the theoretical H-T phase diagram of a metamagnet in which the tricritical point decomposes into a critical end point and a bicritical end point. We locate the latter point at Tcr? 10.8 K and Hcr? 1.4 T in this compound.
- Katsumata,Aruga Katori,Sharpiro,Shirane
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- Spectroscopic Investigations of [FeFe] Hydrogenase Maturated with [57Fe2(adt)(CN)2(CO)4]2-
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The preparation and spectroscopic characterization of a CO-inhibited [FeFe] hydrogenase with a selectively 57Fe-labeled binuclear subsite is described. The precursor [57Fe2(adt)(CN)2(CO)4]2- was synthesized from the 57Fe metal, S8, CO, (NEt4)CN, NH4Cl, and CH2O. (Et4N)2[57Fe2(adt)(CN)2(CO)4] was then used for the maturation of the [FeFe] hydrogenase HydA1 from Chlamydomonas reinhardtii, to yield the enzyme selectively labeled at the [2Fe]H subcluster. Complementary 57Fe enrichment of the [4Fe-4S]H cluster was realized by reconstitution with 57FeCl3 and Na2S. The Hox-CO state of [257Fe]H and [457Fe-4S]H HydA1 was characterized by M?ssbauer, HYSCORE, ENDOR, and nuclear resonance vibrational spectroscopy. (Chemical Equation Presented).
- Gilbert-Wilson, Ryan,Siebel, Judith F.,Adamska-Venkatesh, Agnieszka,Pham, Cindy C.,Reijerse, Edward,Wang, Hongxin,Cramer, Stephen P.,Lubitz, Wolfgang,Rauchfuss, Thomas B.
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- How Inert, Perturbing, or Interacting Are Cryogenic Matrices? A Combined Spectroscopic (Infrared, Electronic, and X-ray Absorption) and DFT Investigation of Matrix-Isolated Iron, Cobalt, Nickel, and Zinc Dibromides
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The interactions of FeBr2, CoBr2, NiBr2, and ZnBr2 with Ne, Ar, Kr, Xe, CH4, and N2 matrices have been investigated using IR, electronic absorption, and X-ray absorption spectroscopies as well as DFT calculations. ZnBr2 is linear in all of the matrices. NiBr2 is linear in all but N2 matrices, where it is severely bent. For FeBr2 and CoBr2 there is a more gradual change, with evidence of nonlinearity in Xe and CH4 matrices as well as N2. In the N2 matrices, the presence of νNN modes blue-shifted from the "free" N2 values indicates the presence of physisorbed species, and the magnitude of the blue shift correlates with the shift in the ν3 mode of the metal dibromide. In the case of NiCl2 and NiBr2, chemisorbed species are formed after photolysis, but only if deposition takes place below 10 K. There was no evidence for chemisorbed species for NiF2 and FeBr2, and in the case of CoBr2 the evidence was not strong.
- Wilkin, Owen M.,Harris, Neil,Rooms, John F.,Dixon, Emma L.,Bridgeman, Adam J.,Young, Nigel A.
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p. 1994 - 2029
(2018/03/09)
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- Processes and Systems for In-Line HBR Oxidation and Cyclic Oxygen Shuttle
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An embodiment relates to a process for converting lower molecular weight, gaseous alkanes to higher hydrocarbons, such as olefins, higher molecular weight hydrocarbons, or mixtures thereof, that may use in-line hydrogen bromide oxidation for capture of hydrogen bromide produced in the process. An embodiment may provide a process for producing elemental halogen comprising: providing a first stream comprising a hydrogen halide; contacting the first stream with a metal oxide to form water, elemental halogen, and at least some metal halide, wherein the metal oxide comprises a metal capable of forming a plurality of stable oxidation states; and contacting the metal halide with an oxygen source to produce a regenerated metal oxide, wherein the oxygen source contacts the metal halide under conditions sufficient to avoid release of elemental halogen.
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Paragraph 0045
(2015/06/24)
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- Microwave-assisted carbohydrohalogenation of first-row transition-metal oxides (M = V, Cr, Mn, Fe, Co, Ni, Cu) with the formation of element halides
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The anhydrous forms of first-row transition-metal chlorides and bromides ranging from vanadium to copper were synthesized in a one-step reaction using the relatively inexpensive element oxides, carbon sources, and halogen halides as starting materials. The reactions were carried out in a microwave oven to give quantitative yields within short reaction times.
- Berger, Matthias,Neumeyer, Felix,Auner, Norbert
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supporting information
p. 11691 - 11693
(2013/11/19)
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- Synthesis of anionic iron(II) complex bearing an n-heterocyclic carbene ligand and its catalysis for aryl grignard cross-coupling of alkyl halides
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The reaction of 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene (IPr) with one equivalent of a novel imidazolium salt of iron(II), [FeBr 3(C4H8O)](HIPr)·C4H 8O (1), afforded the anionic iron(II) comp
- Gao, Huan-Huan,Yan, Chun-Hui,Tao, Xue-Ping,Xia, Ying,Sun, Hong-Mei,Shen, Qi,Zhang, Yong
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p. 4189 - 4192
(2011/01/03)
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- NIOSOME HAVING METAL PORPHYRIN COMPLEX EMBEDDED THEREIN, PROCESS FOR PRODUCING THE SAME AND DRUG WITH THE USE THEREOF
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A niosome having a metalloporphyrin complex embedded therein comprising a cationized metalloporphyrin complex and a niosome-forming substance. The niosome having a metalloporphyrin complex embedded therein has an SOD activity, can interact with superoxide
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Page/Page column 5
(2008/06/13)
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- Metal-porphyrin-complex-embedded liposomes, production process thereof, and medicines making use of the same
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An metalloporphyrin-complex-embedded liposome, comprising a cationic metalloporphyrin complex and a lipid having liposome forming ability is disclosed. As metalloporphyrin-complex-embedded liposomes according to the present invention act on superoxide anion radicals (O2?), and can surely lower their concentration, they can exhibit superb effects for the treatment of cancers and have excellent characteristics as antioxidants.
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Page/Page column 5
(2010/02/10)
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- PORPHYRIN-METAL COMPLEXES AND OXYGEN INFUSIONS CONTAINING THE SAME
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A porphyrin metal complex that can form a stable oxygen complex and acts effectively as an oxygen infusion, which comprises:a transition metal ion M of period 4 or 5 coordinating to a porphyrin derivative represented by the following general formula [I] w
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- Reactivity of ammonium halides: Action of ammonium chloride and bromide on iron and iron(III) chloride and bromide
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Ammonium chloride and bromide, (NH4)Cl and (NH4)Br, act on elemental iron producing divalent iron in [Fe(NH3) 2]Cl2 and [Fe(NH3)2]Br2, respectively, as single crystals at temperatures around 450°C. Iron(III) chloride and bromide, FeCl3 and FeBr3, react with (NH 4)Cl and (NH4)Br producing the erythrosiderites (NH 4)2[Fe(NH3)Cl5] and (NH 4)2[Fe(NH3)Br5], respectively, at fairly low temperatures (350°C). At higher temperatures, 400°C, iron(III) in (NH4)2[Fe(NH3)Cl5] is reduced to iron(II) forming (NH4)FeCl3 and, further, [Fe(NH3)2]Cl2 in an ammonia atmosphere. The reaction (NH4)Br + Fe (4:1) leads at 500°C to the unexpected hitherto unknown [Fe(NH3)6]3[Fe 8Br14], a mixed-valent FeII/FeI compound. Thermal analysis under ammonia and the conditions of DTA/TG and powder X-ray diffractometry shows that, for example, FeCl2 reacts with ammonia yielding in a strongly exothermic reaction [Fe(NH3) 6]Cl2 that at higher temperatures produces [Fe(NH 3)]Cl2, FeCl2 and, finally, Fe3N.
- Bremm, Stephan,Meyer, Gerd
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p. 1875 - 1880
(2008/10/08)
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- The thermodynamic properties of iron(II) bromide and perchlorate complexes with 4-amino-1,2,4-triazole
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The heat capacity of iron(II) bromide and perchlorate complexes with 4-amino-1,2,4-triazole with the 1A1 ? 5T2 spin transition was studied in the temperature ranges 8-346 and 57-331 K, respectively. Measurements were performed on a vacuum adiabatic calorimeter. The thermodynamic parameters of the phase transition in the complexes were determined.
- Berezovskii,Bessergenev,Lavrenova,Ikorskii
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p. 1246 - 1250
(2007/10/03)
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- Iron-based catalyst composition for producing oligomers of conjugated dienes
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A catalyst composition that is the combination of or the reaction product of ingredients comprising (a) (i) a halogen-containing iron compound or (ii) an iron-containing compound and a halogen-containing compound, (b) a silyl phosphonate, and (c) an organoaluminum compound.
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- Preparation and spectroscopic characterization of strontium and barium tetrabromoferrate(III) and the crystal structure of Ba(FeBr4)2
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The synthesis of the hitherto unknown bromoferrates(III) of alkaline-earth metals was carried out by heating mixtures of the metals or the binary bromides together with bromine at temperatures of 450 °C and pressures of up to 1500 bar in closed quartz ampoules. The attempts have been successful only with the larger cations of Sr and Ba. In the case of Be, Mg, and Ca only mixtures of the binary bromides with FeBr3 could be received. By analysis of the Raman and electronic spectra the dark red compounds of Sr and Ba have been characterized as ternary tetrabromoferrates(III) containing tetrahedral FeBr4 anions. The composition M(FeBr4)2 (M = Sr, Ba) has been determined by potentiometric and titrimetric analysis and thermal degradation by thermogravimetry. A single crystal structure determination of Ba(FeBr4)2 confirmed the spectroscopic assignments. The orthorhombic crystal structure (space group Pbca; a = 13.054(3) A; b = 11.093(2) A; c = 21.764(4) A; Z = 8) consists of FeBr4 and BaBr9 polyhedra.
- Armbruster, Markus,Rotter, Heinz W.,Thiele, Gerhard
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p. 1697 - 1700
(2008/10/08)
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- Synthesis of some 3d-Metal Complexes of 2,6-Diacetylpyridine(benzyl and acetone)hydrazone
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2,6-Diacetylpyridine bis(benzyl and acetone)hydrazone and some 3d-metal complexes have been prepared. These complexes are five-coordinated trigonal bipyramidal. The ligand coordinates through the pyridine-N and amide-N. Formation of two chelate rings by one molecule of ligand, is a feature that undoubtedly enhances the stability of the complexes.
- Singh,Ansari,Rana
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p. 448 - 451
(2007/10/03)
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- Evidence for intermediate (S = 1) spin state stabilization in FeII(4,4′-dpb)2(NCS)2 and FeII(4,4′-dpb)2(NCSe)2 (dpb = diphenyl-2,2′-bipyridyl) from susceptibility, infrared, and 57Fe Mossbauer data
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Magnetic susceptibility, 57Fe Mossbauer spectroscopy, and variable-temperature FTIR spectroscopy have been used to characterize the spin states of FeII(4,4′-dpb)2X2 (dpb = diphenyl-2,2′-bipyridyl; X = NCS-, NCSe-) in the temperature range 6 ≤ T ≤ 460 K. Both complexes show a continuous variation of the field-dependent effective magnetic moment over this range. Below ～325 K, both the infrared and Mossbauer spectroscopic signatures are insufficient to permit characterization of the spin state(s) of the metal atom in these complexes, but at higher temperatures, the FTIR data can be accounted for by the increasing population of a high (S = 2) spin state, while the Mossbauer spectra can be accounted for by a rapid (on the Mossbauer time scale) relaxation between two spin states. The existence of an intermediate (S = 1) spin state for Fe(II) is a consequence of a major distortion from octahedral symmetry of the metal-based orbitals, permitting a (near) degeneracy of the dz2 and dxy levels around this atom.
- Figg,Herber,Felner
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p. 2535 - 2540
(2008/10/08)
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- Standard enthalpies of formation of crystalline iron bromides
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The enthalpies of the reactions of Br2(1), Fe(c), FeBr2(c), and FeBr3(c) with a solution of KBr*0.43Br2*0.12HBr*50.78H2O at 298.15 K have been measured in the dissolution calorimeter with isothermal jacket of the LKB-8700 apparatus.The following values have been calculated from the results: ΔfH0 (FeBr2, c, 298.15 K) = -244.74 +/- 0.22 kJ mol-1, ΔfH0 (FeBr3, c, 298.15 K) = -262.63 +/- 0.20 kJ mol-1.
- Efimov, M. E.,Evdokimova, V. P.
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p. 1224 - 1225
(2007/10/02)
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