7783-86-0Relevant academic research and scientific papers
The use of trimethylsilyl iodide as a synthon in coordination chemistry
Leigh,Sanders,Hitchcock, Peter B.,Fernandes, Jaisa Soares,Togrou, Maria
, p. 197 - 212 (2002)
Trimethylsilyl iodide is shown to be an efficient metathetical reagent for preparing transition-metal iodides from the corresponding chlorides, though often complications can cause problems. These include reduction of the starting metal chloride when its oxidation state is high, due to the reaction of iodide, and even oxidation of low-oxidation-state compounds, presumably by incipient silyl cations. Finally, some very inert chlorides, such as of iridium(III), react too slowly with the iodide under the experimental conditions, and simple reaction with solvent becomes predominant.
New high-spin iron complexes based on bis(imino)acenaphthenes (BIAN): Synthesis, structure, and magnetic properties
Fedushkin,Skatova,Khvoinova,Lukoyanov,Fukin,Ketkov,Maslov,Bogomyakov,Makarov
, (2013)
The reactions of iron diiodide with one and two equivalents of the monopotassium salt of 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene (dpp-BIAN) in diethyl ether gave the com-plexes [(dpp-BIAN)FeI]2 (1) and (dpp-BIAN)2Fe (2), re
High-Purity Iron(II) Iodide: Preparation, Vapor Pressure, and Vapor Composition, 792 to 1138 K
Mucklejohn, S. A.,O'Brien, N. W.,Brumleve, T. R.
, p. 2409 - 2415 (1985)
The preparation of hogh-purity iron(II) iodide from metallic iron and elemental iodine is described.The product is shown to have extremely low levels of hydrogen- and oxygen-containing impurities and is primarily intended for use in discharge lamps.The results of a high-temperature mass spectrometric study of iron(II) iodide are outlined.The vapor pressure above iron(II) iodide has been measured in the range 792-1138 K by the quasistatic method.The partial pressures of I2, FeI2, and Fe2I4 were derived from the vapor pressure and the corresponding mole fractions.The molar enthalpies of sublimation and evaporation for the vaporization of iron(II) iodide to FeI2(g) and Fe2I4(g) are calculated by the second-law and third-law methods.The uncertainties associated with these quantities are discussed.From the second-law treatment: FeI2(s) = FeI2(g), ΔHmo(298.15 K) = 209 +/- 6 kJ/mol; 2FeI2(s) = Fe2I4(g), ΔHmo(298.15 K) = 321 =+/- 12 kJ/mol; FeI2(l) + FeI2(g), ΔHmo(295.15 K) = 150 +/- 2 kJ/mol; 2FeI2(l) = Fe2I4(g),ΔHmo(298.15) = 201 +/-2 kJ/mol
Insights into the naphthalenide-driven synthesis and reactivity of zerovalent iron nanoparticles
Donsbach, Carsten,Feldmann, Claus,Rei?, Andreas
, p. 16343 - 16352 (2021/11/27)
The chemical and thermal stability of alkali metal naphthalenides as powerful reducing agents are examined, including the type of alkali metal ([LiNaph] and [NaNaph]), the type of solvent (THF, DME), the temperature (-30 to +50 °C), and the time of storage (0 to 12 hours). The stability and concentration of [LiNaph]/[NaNaph] are quantified via UV-Vis spectroscopy and the Lambert-Beer law. As a result, the solutions of [LiNaph] in THF at low temperature turn out to be most stable. The decomposition can be related to a reductive polymerization of the solvent. The most stable [LiNaph] solutions in THF are exemplarily used to prepare reactive zerovalent iron nanoparticles, 2.3 ± 0.3 nm in size, by reduction of FeCl3 in THF. Finally, the influence of [LiNaph] and/or remains of the starting materials and solvents upon controlled oxidation of the as-prepared Fe(0) nanoparticles with iodine in the presence of selected ligands is evaluated and results in four novel, single-crystalline iron compounds ([FeI2(MeOH)2], ([MePPh3][FeI3(Ph3P)])4·PPh3·6C7H8, [FeI2(PPh3)2], and [FeI2(18-crown-6)]). Accordingly, reactive Fe(0) nanoparticles can be obtained in the liquid phase via [LiNaph]-driven reduction and instantaneously reacted to give new compounds without remains of the initial reduction (e.g. LiCl, naphthalene, and THF). This journal is
Catalytic reduction of N2 to NH3 by an Fe-N 2 complex featuring a C-atom anchor
Creutz, Sidney E.,Peters, Jonas C.
, p. 1105 - 1115 (2014/02/14)
While recent spectroscopic studies have established the presence of an interstitial carbon atom at the center of the iron-molybdenum cofactor (FeMoco) of MoFe-nitrogenase, its role is unknown. We have pursued Fe-N2 model chemistry to explore a
Room-temperature synthesis, hydrothermal recrystallization, and properties of metastable stoichiometric FeSe
Nitsche,Goltz,Klauss,Isaeva,Mueller,Schnelle,Simon,Doert, Th.,Ruck
, p. 7370 - 7376 (2012/07/28)
Room-temperature precipitation from aqueous solutions yields the hitherto unknown metastable stoichiometric iron selenide (ms-FeSe) with tetragonal anti-PbO type structure. Samples with improved crystallinity are obtained by diffusion-controlled precipitation or hydrothermal recrystallization. The relations of ms-FeSe to superconducting η-FeSe1-x and other neighbor phases of the iron-selenium system are established by high-temperature X-ray diffraction, DSC/TG/MS (differential scanning calorimetry/ thermogravimetry/mass spectroscopy), 57Fe Moessbauer spectroscopy, magnetization measurements, and transmission electron microscopy. Above 300 °C, ms-FeSe decomposes irreversibly to η-FeSe1-x and Fe7Se8. The structural parameters of ms-FeSe (P4/nmm, a = 377.90(1) pm, c = 551.11(3) pm, Z = 2), obtained by Rietveld refinement, differ significantly from literature data for η-FeSe1-x. The Moessbauer spectrum rules out interstitial iron atoms or additional phases. Magnetization data suggest canted antiferromagnetism below TN = 50 K. Stoichiometric non-superconducting ms-FeSe can be regarded as the true parent compound for the 11 iron-chalcogenide superconductors and may serve as starting point for new chemical modifications.
Ferromagnetic coupling in hexanuclear gadolinium clusters
Sweet, Lucas E.,Roy, Lindsay E.,Meng, Fanqin,Hughbanks, Timothy
, p. 10193 - 10201 (2007/10/03)
The magnetic susceptibilities of hexanuclear gadolinium clusters in the compounds Gd(Gd6Zl12) (Z = Co, Fe, or Mn) and CsGd(Gd 6Col12)2 are reported and subjected to theoretical analysis with the help of density functional theory (DFT) computations. The single-crystal structure of Gd(Gd6Col12) is reported here as well. We find that the compound with a closed shell of cluster bonding electrons, Gd(Gd6Col12), exhibits the effects of antiferromagnetic coupling over the entire range of temperatures measured (4-300 K). Clusters with unpaired, delocalized cluster bonding electrons (CBEs) exhibit enhanced susceptibilities consistent with strong ferromagnetic coupling, except at lower temperatures (less than 30 K) where intercluster antiferromagnetic coupling suppresses the susceptibilities. The presence of two unpaired CBEs, as in [Gd6Mnl12] 3-, yields stronger coupling than when just one unpaired CBE is present, as in [Gd6Fel12]3- or [Gd 6Col12]2-. DFT calculations on model molecular systems, [Gd6Col12](OPH3)6 and [Gd6Col12]2(OPH3)10, indicate that the delocalized cluster bonding electrons are highly effective at mediating intracluster ferromagnetic exchange coupling between the Gd atom 4f7 moments and that intercluster coupling is expected to be antiferromagnetic. The DFT calculations were used to calculate the relative energies of various 4f7 spin patterns and form the basis for construction of a simple spin Hamiltonian describing the coupling within the [Gd6Col12] cluster.
Crystal growth and properties of PbI2 doped with Fe and Ni
Rybak,Lun',Bordun,Omelyan
, p. 1124 - 1127 (2008/10/09)
A procedure is described for doping PbI2 single crystals with Fe and Ni during vapor-phase growth in a closed system in the presence of excess iodine. The rate of mass transport in the system and the doping level of the crystals are shown to be governed by the dopant content in the source material and the source temperature. The effect of Fe and Ni doping on the low-temperature (5 K) exciton photoluminescence spectrum of PbI2 is discussed.
Pressure-induced structural transformations in the Mott insulator FeI 2
Rozenberg, G. Kh.,Pasternak, M. P.,Xu, W. M.,Dubrovinsky, L. S.,Osorio Guillen, J. M.,et al.
, p. 1 - 9 (2008/10/08)
A full-profile refinement of the layered antiferromagnetic FeI2 crystallographic structures at pressures up to 70 GPa were performed combined with ab initio calculations to particularly elucidate the structural aspects of the recently observed pressure-induced quenching of the orbital term of the Fe2+ moment and of the Mott transition. Synchrotron powder XRD diffraction studies have shown that at ～17 GPa a substantial alteration of the lattice parameters takes place which is attributed to the quenching of the orbital term. Starting at P ～20 GPa and completed at ～35 GPa, a sluggish structural phase transition takes place which can be attributed to the onset of a Mott transition as has been previously observed by resistance and MS studies. In agreement with ab initio calculations, the doubling of lattice parameters and the formation of a new Fe sublattice replacing the original CdI2-type structure, can explain this structural transition. The latter alterations in the Fe sublattice may indicate a trend of the Fe sites to disorder in the new high pressure phase. This first-order phase transition is characterized by a significant change of the unit cell parameters, a reduction in volume, and a change of the Fe-I distances. The substantial reduction of the Fe-I distances with minimal changes in the Fe-Fe bond lengths at the transition, suggests a charge-transfer-type gap closure mechanism involving the Ip-Fed bands. At P>40 GPa a overturn of the structural transition is observed resulting in the return of the original, CdI2-type structure.
Pressure-induced magnetic and electronic transitions in the layered Mott insulator FeI2
Pasternak, M. P.,Xu, W. M.,Rozenberg, G. Kh.,Taylor, R. D.,Hearne, G. R.,Sterer, E.
, p. 1 - 6 (2008/10/08)
Powder x-ray diffraction, electrical resistance, and 57Fe Mo ssbauer spectroscopy at pressures to at least 40 GPa in diamond anvil cells have been employed to investigate the pressure evolution of the structural, electrical-transport, and magnetic properties of the antiferromagnetic insulator FeI2. Up to 18 GPa, the volume decreases by 25%, the resistivity decreases by eight orders of magnitude, TN increases 16-fold to 150 K, and the Fe2+ moments remain parallel to the c axis. The change in the isomer shift (IS), which is negatively proportional to the change in the s-electron density at the Fe nucleus, follows the volume reduction by continuously decreasing from 1.0 to 0.8 mm/s, the quadrupole splitting (QS) increases monotonically from 0.6 mm, peaking at 0.85 mm/s by 12 GPa, and decreases to 0.75 at 18 GPa, and the magnetic hyperfine field Hhf composed of spin and orbital terms with opposite signs increases from 8 to 12 T. At ～18 GPa the orbital term quenches, as is evident from a Mo ssbauer component characterized by Hhf=32 T and e2qzzQ(3 cos2 θ-1)=0, where the moments tilt to 55°, and TN increases to 260 K. At 20 GPa an isostructural first-order phase transition occurs, accompanied by a discontinuous ～5% decrease in volume and a considerably lower QS and IS. The c axis decreases by 5% with no decrease in the a axis, suggesting a considerable contraction of the Fe-I bond lengths. The high-pressure phase (HP) is diamagnetic, as characterized by a pure quadrupole-split spectrum to the lowest temperature of 5 K. The abundance of this diamagnetic phase increases with rising pressure reaching 100% by ～38 GPa. The HP phase is also metallic, as shown by R(P,T) data. The observation of diamagnetism, metallic behavior, and the considerable reduction in volume distances establishes that-a Mott or charge-transfer transition has occurred, resulting in the total collapse of any electron correlation. The coexistence of several phases and their respective abundances were determined from the Mo ssbauer data.
