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Feng Li, Stephanie H Carpenter, Robert F Higgins, Mark G Hitt, William W Brennessel, Maryline G Ferrier, Samantha K Cary, Juan S Lezama-Pacheco, Joshua T Wright, Benjamin W Stein, Matthew P Shores, Michael L Neidig, Stosh A Kozimor, Ellen M Matson
Inspired by the multielectron redox chemistry achieved using conventional organic-based redox-active ligands, we have characterized a series of iron-functionalized polyoxovanadate-alkoxide clusters in which the metal oxide scaffold functions as a three-dimensional, electron-deficient metalloligand. Four heterometallic clusters were prepared through sequential reduction, demonstrating that the metal oxide scaffold is capable of storing up to four electrons. These reduced products were characterized by cyclic voltammetry, IR, electronic absorption, and (1)H NMR spectroscopies...
May 26, 2017: Inorganic Chemistry
Min Wang, Yushi Yang, Xiaobo Liu, Zonghua Pu, Zongkui Kou, Peipei Zhu, Shichun Mu
Fe-N-C series catalysts are always attractive for their high catalytic activity towards the oxygen reduction reaction (ORR). However, they usually consist of various components such as iron nitrides, metallic iron, iron carbides, N-doped carbon and Fe-N4 moieties, leading to controversial contributions of these components to the catalysis of the ORR, especially iron nitrides. In this work, to investigate the function of iron nitrides, FexN nanoparticles (NPs) embedded in mesoporous N-doped carbon without Fe-N4 moieties are designed and constructed by a simple histidine-assisted method...
May 25, 2017: Nanoscale
William P Clark, Simon Steinberg, Richard Dronskowski, Catherine McCammon, Ilya Kupenko, Maxim Bykov, Leonid Dubrovinsky, Lev G Akselrud, Ulrich Schwarz, Rainer Niewa
The combination of laser-heated diamond anvil cells and synchrotron Mössbauer source spectroscopy were used to investigate high-temperature high-pressure chemical reactions of iron and iron nitride Fe2 N with nitrogen. At pressures between 10 and 45 GPa, significant magnetic hyperfine splitting indicated compound formation after annealing at 1300 K. Subsequent in situ X-ray diffraction reveals a new modification of FeN with NiAs-type crystal structure, as also rationalized by first-principles total-energy and chemical-bonding studies...
May 18, 2017: Angewandte Chemie
Wasinee Phonsri, David S Macedo, Casey G Davies, Guy N L Jameson, Boujemaa Moubaraki, Keith S Murray
The influence of the halogen substituent on the qsal moiety of iron(iii) heteroleptic compounds with the formulae [Fe(qsal-X)(thsa)]·nMeCN, where qsal-X(-) = X-substituted quinolylsalicylaldimine; thsa(2-) = thiosemicarbazone-salicylaldiminate; X = F; n = 2.5, 1·2.5MeCN and X = Cl 2, Br 3 and I 4, n = 1 (labelled 2·MeCN, 3·MeCN and 4·MeCN, respectively) has been systematically investigated. Magnetic studies on solid samples show incomplete spin crossover in 1-3 which can be related to MeCN solvent loss...
May 17, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Ahmed S Abouelwafa, Andreas Hauser, Valeriu Mereacre, Yanhua Lan, Gary J Long, Fernande Grandjean, Gernot Buth, Christopher E Anson, Annie K Powell
K3Fe(CN)6 reacts with the viologen 1,1'-bis(2,4-dinitrophenyl)-4,4'-bipyridinium dication, (DNP)(2+), to form a supramolecular complex, (DNP)3[Fe(CN)6]2·10H2O (1). The crystal structure of 1 reveals that there are two [Fe(CN)6](3-) anions within an organic framework of three (DNP)(2+) cations with the shortest Fe(III)···Fe(III) distances of ca. 9.8 Å, distances that minimize extensive long-range magnetic exchange coupling interactions between the [Fe(CN)6](3-) anions, and, thus, 1 is paramagnetic above ca...
May 16, 2017: Inorganic Chemistry
Ondřej Lhotský, Eva Krákorová, Pavel Mašín, Radim Žebrák, Lucie Linhartová, Zdena Křesinová, Josef Kašlík, Jana Steinová, Torgeir Rødsand, Alena Filipová, Klára Petrů, Kristýna Kroupová, Tomáš Cajthaml
This study was performed to test the feasibility of several decontamination methods for remediating heavily contaminated groundwater in a real contaminated locality in the Czech Republic, where a pharmaceuticals plant has been in operation for more than 80 years. The site is polluted mainly by recalcitrant psychopharmaceuticals and monoaromatic hydrocarbons, such as benzene, toluene and chlorobenzene. For this purpose, an advanced oxidation technique employing UV radiation with hydrogen peroxide dosing was employed, in combination with simple aeration pretreatment...
April 30, 2017: Water Research
Xuewu Sui, Andrew C Weitz, Erik R Farquhar, Mohsen Badiee, Surajit Banerjee, Johannes von Lintig, Gregory Tochtrop, Krzysztof Palczewski, Michael P Hendrich, Philip D Kiser
Carotenoid cleavage oxygenases (CCOs) are non-heme iron enzymes that catalyze scission of alkene groups in carotenoids and stilbenoids to form biologically important products. CCOs possess a rare 4-His iron center whose resting-state structure and interaction with substrates are incompletely understood. Here, we address this knowledge gap through a comprehensive structural and spectroscopic study of three phyletically diverse CCOs. The crystal structure of a fungal stilbenoid-cleaving CCO, CAO1, reveals strong similarity between its iron center and those of carotenoid-cleaving CCOs, but with a markedly different substrate-binding cleft...
May 11, 2017: Biochemistry
Young Rang Uhm, Jae Cheong Lim, Sang Mu Choi
Antianemic medicament ferrous gluconate, ferrous fumarate, and a Dynabi tablet with a basic iron bearing ingredient were studied with the use of Mössbauer spectroscopy. Room temperature spectra of ferrous gluconate gave clear evidence that the two phases of iron were present: ferrous (Fe(2+)) as a major one with a contribution at and above 91 a.u.% and ferric (Fe(3+)) whose contribution was found to be ~9 a.u.%. In the case of ferrous fumarate, a single phase was measured corresponding to ferrous (Fe(2+)) state...
2017: International Journal of Analytical Chemistry
Ningsi Zhang, Yongsheng Guo, Xin Wang, Shiying Zhang, Zhaosheng Li, Zhigang Zou
Since Fe2O3 is a promising photoanode material for water splitting, it has attracted much attention, while other phases of ferric oxide are ignored. Here, β-Fe2O3 was used as a photoanode material for solar water splitting. The crystal structure and phase of β-Fe2O3 were characterized by using X-ray diffraction, X-ray photoelectron spectroscopy, Raman scattering, Mössbauer spectra and a superconducting quantum interference device. The photocurrent density of the β-Fe2O3 photoanode at 1.6 VRHE was 0.12 mA·cm(-2) under the illumination of simulated sunlight (AM1...
May 5, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Alexey Sobolev, Vyacheslav Rusakov, Alexander Moskvin, Alexei Gapochka, Alexei Belik, Iana Glazkova, Alena Akulenko, Gerard Demazeau, Igor Presniakov
We report new results of a <sup>57</sup>Fe Mössbauer study of hyperfine magnetic interactions in the layered multiferroic 3<i>R</i>-AgFeO<sub>2</sub> demonstrating two magnetic phase transitions at <i>T</i><sub>N1</sub> and <i>T</i><sub>N2</sub>. The asymptotic value <i>β</i>* ≅ 0.34 for the critical exponent obtained from the temperature dependence of the hyperfine field <i>H</i><sub>hf</sub>(<i>T</i>) at <sup>57</sup>Fe the nuclei below <i>T</i><sub>N1</sub> ≅ 14 K indicates that 3<i>R</i>-AgFeO<sub>2</sub> shows quasi-three-dimensional critical behavior...
May 3, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
Ritambhara Gond, Sher Singh Meena, S M Yusuf, Vivekanand Shukla, Naresh K Jena, Rajeev Ahuja, Shigeto Okada, Prabeer Barpanda
Sodium-ion batteries are widely pursued as an economic alternative to lithium-ion battery technology, where Fe- and Mn-based compounds are particularly attractive owing to their elemental abundance. Pursuing phosphate-based polyanionic chemistry, recently solid-state prepared NaFe(PO3)3 metaphosphate was unveiled as a novel potential sodium insertion material, although it was found to be electrochemically inactive. In the current work, employing energy-savvy solution combustion synthesis, NaFe(2+)(PO3)3 was produced from low-cost Fe(3+) precursors...
May 2, 2017: Inorganic Chemistry
Y Friedman, I Nowik, I Felner, J M Steiner, E Yudkin, S Livshitz, H C Wille, G Wortmann, A I Chumakov
New results, additional techniques and know-how acquired, developed and employed in a recent HC-1898 experiment at the Nuclear Resonance Beamline ID18 of ESRF are presented, in the quest to explore the acceleration effect on time dilation. Using the specially modified Synchrotron Mössbauer Source and KB-optics together with a rotating single-line semicircular Mössbauer absorber on the rim of a specially designed rotating disk, the aim was to measure the relative spectral shift between the spectra of two states when the acceleration of the absorber is anti-parallel and parallel to the source...
May 1, 2017: Journal of Synchrotron Radiation
Holm Petzold, Paul Djomgoue, Gerald Hörner, Silvio Heider, Charles Lochenie, Birgit Weber, Tobias Rüffer, Dieter Schaarschmidt
Fe(2+) spin crossover complexes [Fe(L)2](2+) (L = 2-(6-R(1)-pyridin-2-yl)-1,10-phenanthroline with R(1) = H, methoxy, bromo, -(1H-pyrazol-1-yl) or L = 2-(3-methoxy-pyridin-2-yl)-1,10-phenanthroline) were prepared. These air stable and durable complexes show SCO behaviour with very different transition temperatures T1/2 ranging from 130 K to 600 K depending on the substitution pattern. The use of (1)H NMR spectroscopy to elucidate the thermodynamics and kinetics of SCO in a solution of this series is described in detail...
May 16, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Subramaniam Kuppuswamy, Joshua D Wofford, Chris Joseph, Zhu-Lin Xie, Azim K Ali, Vincent M Lynch, Paul A Lindahl, Michael J Rose
The syntheses, interconversions, and spectroscopic properties of a set of iron carbonyl clusters containing an interstitial carbide are reported. This includes the low temperature X-ray structures of the six-iron clusters (Y)2[Fe6(μ6-C)(μ2-CO)4(CO)12] (1a-c; where Y = NMe4, NEt4, PPh4); the five-iron cluster [Fe5(μ5-C)(CO)15] (3); and the novel formulation of the five-iron cluster (NMe4)2[Fe5(μ5-C)(μ2-CO)(CO)13] (4). Also included in this set is the novel charge-neutral cluster, [Fe6(μ6-C)(CO)18] (2), for which we were unable to obtain a crystallographic structure...
April 25, 2017: Inorganic Chemistry
Claudia Kleinlein, Shao-Liang Zheng, Theodore A Betley
Three ferric dipyrromethene complexes featuring different ancillary ligands were synthesized by one electron oxidation of ferrous precursors. Four-coordinate iron complexes of the type ((Ar)L)FeX2 [(Ar)L = 1,9-(2,4,6-Ph3C6H2)2-5-mesityldipyrromethene] with X = Cl or (t)BuO were prepared and found to be high-spin (S = (5)/2), as determined by superconducting quantum interference device magnetometry, electron paramagnetic resonance, and (57)Fe Mössbauer spectroscopy. The ancillary ligand substitution was found to affect both ground state and excited properties of the ferric complexes examined...
April 24, 2017: Inorganic Chemistry
Anna L Smith, Eric Colineau, Jean-Christophe Griveau, Karin Popa, Guilhem Kauric, Philippe Martin, Andreas C Scheinost, Anthony K Cheetham, Rudy J M Konings
The physicochemical properties of the potassium neptunate K2NpO4 have been investigated in this work using X-ray diffraction, X-ray absorption near edge structure (XANES) spectroscopy at the Np-L3 edge, and low-temperature heat capacity measurements. A Rietveld refinement of the crystal structure is reported for the first time. The Np(VI) valence state has been confirmed by the XANES data, and the absorption edge threshold of the XANES spectrum has been correlated to the Mössbauer isomer shift value reported in the literature...
May 15, 2017: Inorganic Chemistry
Erik Wächtler, Sven Wahlicht, Steven H Privér, Martin A Bennett, Birgit Gerke, Rainer Pöttgen, Erica Brendler, Robert Gericke, Jörg Wagler, Suresh K Bhargava
The tin(IV) compounds MexSn(2-C6F4PPh2)4-x (1, x = 1; 2, x = 2) and ClSn(2-C6F4PPh2)3 (3) were obtained from the reactions of 2-LiC6F4PPh2 with MeSnCl3 (3:1), Me2SnCl2 (2:1), or SnCl4 (3:1), respectively. The reactions of 2-LiC6F4PPh2 with SnCl4 in different stoichiometric ratios (4:1-1:1) gave 3 as the main product. Compound Cl2Sn(2-C6F4PPh2)2 (4) was formed in the transmetalation reaction of 3 and [AuCl(tht)] but could not be isolated. 1 and 2 react with palladium(0) sources {[Pd(PPh3)4] and [Pd(allyl)Cp]} by the oxidative addition of one of their Sn-CAryl bonds to palladium(0) with formation of the heterobimetallic complexes [MeSn(μ-2-C6F4PPh2)2Pd(κC-2-C6F4PPh2)] (5) and [Me2Sn(μ-2-C6F4PPh2)Pd(κ(2)-2-C6F4PPh2)] (6) featuring Sn-Pd bonds...
April 13, 2017: Inorganic Chemistry
B Pacakova, S Kubickova, G Salas, A R Mantlikova, M Marciello, M P Morales, D Niznansky, J Vejpravova
This work aims to emphasize that the magnetic response of single-domain magnetic nanoparticles (NPs) is driven by the NPs' internal structure, and the NP size dependencies of magnetic properties are overestimated. The relationship between the degree of the NPs' crystallinity and magnetic response is unambiguously demonstrated in eight samples of uniform maghemite/magnetite NPs and corroborated with the results obtained for about 20 samples of spinel ferrite NPs with different degrees of crystallinity. The NP samples were prepared by the thermal decomposition of an organic iron precursor subjected to varying reaction conditions, yielding variations in the NP size, shape and relative crystallinity...
April 20, 2017: Nanoscale
Matthew J Chalkley, Trevor J Del Castillo, Benjamin D Matson, Joseph P Roddy, Jonas C Peters
We have recently reported on several Fe catalysts for N2-to-NH3 conversion that operate at low temperature (-78 °C) and atmospheric pressure while relying on a very strong reductant (KC8) and acid ([H(OEt2)2][BAr(F)4]). Here we show that our original catalyst system, P3(B)Fe, achieves both significantly improved efficiency for NH3 formation (up to 72% for e(-) delivery) and a comparatively high turnover number for a synthetic molecular Fe catalyst (84 equiv of NH3 per Fe site), when employing a significantly weaker combination of reductant (Cp*2Co) and acid ([Ph2NH2][OTf] or [PhNH3][OTf])...
March 22, 2017: ACS Central Science
M Albino, L Clark, J Lhoste, C Payen, J-M Grenèche, P Lightfoot, V Maisonneuve, M Leblanc
A series of triazole fluoride weberites (M1-x(2+)Mx(3+))M(3+)F5(Htaz)1-x(taz)x is obtained by hydrothermal synthesis. All phases are found to be isostructural to ZnAlF5(Htaz) by powder X-ray diffraction. Weberite structures are prone to induce the magnetic frustration of antiferromagnetic interactions originating from the cationic topology of HTB layers. The (nD) magnetic properties of (0D) Co-Ga, (1D) Zn-Fe, (3D) Fe-Ga, Mn-Fe, Co-Fe and Co-V couples are thus reported. Co(2+) or Fe(2+) magnetic anisotropy induces a negative magnetisation below TN and compensation temperatures for Mn-Fe and Co-Fe couples...
April 19, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
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