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Hendrik Auerbach, Giuseppe E Giammanco, Volker Schünemann, Alexis D Ostrowski, Carl J Carrano
While polycarboxylates and hydroxyl-acid complexes have long been known to be photoactive, simple carboxylate complexes which lack a significant LMCT band are not typically strongly photoactive. Hence, it was somewhat surprising that a series of reports demonstrated that materials synthesized from iron(III) and polysaccharides such as alginate (poly[guluronan-co-mannuronan]) or pectate (poly[galacturonan]) formed photoresponsive materials that convert from hydrogels to sols under the influence of visible light...
September 15, 2017: Inorganic Chemistry
Kasibhatta J Datta, Anuj K Rathi, Pawan Kumar, Josef Kaslik, Ivo Medrik, Vaclav Ranc, Rajender S Varma, Radek Zboril, Manoj B Gawande
A facile approach for the synthesis of magnetite microspheres with flower-like morphology is reported that proceeds via the reduction of iron(III) oxide under a hydrogen atmosphere. The ensuing magnetic catalyst is well characterized by XRD, FE-SEM, TEM, N2 adsorption-desorption isotherm, and Mössbauer spectroscopy and explored for a simple yet efficient transfer hydrogenation reduction of a variety of nitroarenes to respective anilines in good to excellent yields (up to 98%) employing hydrazine hydrate. The catalyst could be easily separated at the end of a reaction using an external magnet and can be recycled up to 10 times without any loss in catalytic activity...
September 14, 2017: Scientific Reports
Hooman Yaghoobnejad Asl, Kartik Ghosh, Amitava Choudhury
Li5Fe2PO4F8, a new member of the family of alkali transition metal fluorophosphates, has been synthesized and characterized using single-crystal X-ray diffraction, (57)Fe Mössbauer spectroscopy and magnetic susceptibility measurements. The existence of an infinite {-[PO4(FeF4)2]-}∞ tetrahedral network in an inter-penetrated diamond lattice, along with the presence of seven unique Li sites, presents interesting structural features of this structure-type for energy storage applications. The initial results of (de)lithiation reveal that a relatively low fraction of theoretical capacity may be utilized reversibly (0...
September 14, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Sayed Muktar Hossain, Avinash Lakma, Rabindra Nath Pradhan, Serhiy Demeshko, Akhilesh Kumar Singh
A new unsymmetrical ditopic ligand H2L was used to synthesize two [2 × 2] grid type tetranuclear trivalent and mixed-valent Fe, FeFe complexes, respectively. Both complexes [Fe(L')4] (1) and [FeFe(L)4](BF4)2·2CH3CN (2) have been X-ray structurally characterized. The magnetic properties of complexes 1 and 2 show dominant antiferromagnetic coupling. Mössbauer studies were carried out to confirm the electronic states of the iron centres. The structural properties of the two complexes are diverse though they have been synthesized from the same ligand but under different conditions...
September 14, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Sandrine Ollagnier de Choudens, Frédéric Barras
FeS clusters containing proteins are structurally and functionally diverse and present in most organisms. Our understanding of FeS cluster production and insertion into polypeptides has benefited from collaborative efforts between in vitro and in vivo studies. The former allows a detailed description of FeS-containing protein and a deep understanding of the molecular mechanisms catalyzing FeS cluster assembly. The second allows to include metabolic and environmental constraints within the analysis of FeS homeostasis...
2017: Methods in Enzymology
G Aprilis, C Strohm, I Kupenko, S Linhardt, A Laskin, D M Vasiukov, V Cerantola, E G Koemets, C McCammon, A Kurnosov, A I Chumakov, R Rüffer, N Dubrovinskaia, L Dubrovinsky
A portable double-sided pulsed laser heating system for diamond anvil cells has been developed that is able to stably produce laser pulses as short as a few microseconds with repetition frequencies up to 100 kHz. In situ temperature determination is possible by collecting and fitting the thermal radiation spectrum for a specific wavelength range (particularly, between 650 nm and 850 nm) to the Planck radiation function. Surface temperature information can also be time-resolved by using a gated detector that is synchronized with the laser pulse modulation and space-resolved with the implementation of a multi-point thermal radiation collection technique...
August 2017: Review of Scientific Instruments
Wei-Min Ching, Ang Zhou, Johannes E M N Klein, Ruixi Fan, Gerald Knizia, Christopher J Cramer, Yisong Guo, Lawrence Que
Nonheme mononuclear hydroxoiron(III) species are important intermediates in biological oxidations, but well-characterized examples of synthetic complexes are scarce due to their instability or tendency to form μ-oxodiiron(III) complexes, which are the thermodynamic sink for such chemistry. Herein, we report the successful stabilization and characterization of a mononuclear hydroxoiron(III) complex, [Fe(III)(OH)(TMC-py)](2+) (3; TMC-py = 1-(pyridyl-2'-methyl)-4,8,11-trimethyl-1,4,8,11-tetrazacyclotetradecane), which is directly generated from the reaction of [Fe(IV)(O)(TMC-py)](2+) (2) with 1,4-cyclohexadiene at -40 °C by H-atom abstraction...
August 31, 2017: Inorganic Chemistry
Sebastian A Stoian, Yi-Ru Peng, Christopher C Beedle, Yi-Jung Chung, Gene-Hsiang Lee, En-Che Yang, Stephen Hill
The synthesis, X-ray crystal and electronic structures of [Fe3(μ3-O)(mpmae)2(OAc)2 Cl3], 1, where mpmae-H = 2-(N-methyl-N-((pyridine-2-yl)methyl)amino)ethanol, are described. This cluster comprises three high-spin ferric ions and exhibits a T-shaped site topology. Variable-frequency electron paramagnetic resonance measurements performed on single crystals of 1 demonstrate a total spin ST = 5/2 ground state, characterized by a small, negative, and nearly axial zero-field splitting tensor D = -0.49 cm(-1), E/D ≈ 0...
August 28, 2017: Inorganic Chemistry
Chao Wang, Hui Chen
AurF and CmlI are currently the only two known diiron arylamine oxygenases. On the basis of extensive quantum mechanical/molecular mechanical (QM/MM) spectroscopic and mechanistic modelings, here we predict that the key oxygenated intermediates in AurF and CmlI, so-called P, are uniformly hydroperoxo species having similar structures. As a basis for mechanistic unification in AurF and CmlI, the proposed diferric-hydroperoxo P is calculated to be able to promote the arylamine N-oxygenation with highly accessible kinetics...
September 8, 2017: Journal of the American Chemical Society
Rafał Grubba, Kinga Kaniewska, Łukasz Ponikiewski, Beata Cristóvão, Wiesława Ferenc, Alina Dragulescu-Andrasi, J Krzystek, Sebastian A Stoian, Jerzy Pikies
This work describes a series of iron(II) phosphanylphosphido complexes. These compounds were obtained by reacting lithiated diphosphanes R2PP(SiMe3)Li (R = t-Bu, i-Pr) with an iron(II) β-diketiminate complex, [LFe(μ2-Cl)2Li(DME)2] (1), where DME = 1,2-dimethoxyethane and L = Dippnacnac (β-diketiminate). While the reaction of 1 with t-Bu2PP(SiMe3)Li yields [LFe(η(1)-Me3SiPP-t-Bu2)] (2), that of 1 with equimolar amounts of i-Pr2PP(SiMe3)Li, in DME, leads to [LFe(η(2)-i-Pr2PPSiMe3)] (3). In contrast, the reaction of 1 with (i-Pr2N)2PP(SiMe3)Li provides not an iron-containing complex but 1-[(diisopropylamino)phosphine]-2,4-bis(diisopropylamino)-3-(trimethylsilyl)tetraphosphetane (4)...
August 25, 2017: Inorganic Chemistry
Shiliang Zhou, Erica S Howard, Jue Liu, Nicholas H Bashian, Kyle Nolan, Sankarganesh Krishnamoothy, Geovanni M Rangel, Moulay-Tahar Sougrati, G K Surya Prakash, Katharine Page, Brent C Melot
The development of functional materials based on Earth-abundant, environmentally benign compositions is critical for ensuring their commercial viability and sustainable production. Here we present an investigation into the crystal chemistry and electrochemical properties of the muscovite clay KFe2.75Si3.25O10(OH)2. We first report a low temperature hydrothermal reaction that allows for a significant degree of control over sample crystallinity, particle morphology, and cation distribution through the lattice...
August 25, 2017: ACS Applied Materials & Interfaces
D M Bykov, R J M Konings, C Apostolidis, A Hen, E Colineau, T Wiss, P Raison
A new double neptunium zirconium phosphate of the type MxZr2(PO4)3 (M = Np), crystallizing in the structure type NaZr2(PO4)3 (NZP, NASICON), was synthesized by solid state reactions at high temperatures and characterized by X-ray diffraction, infrared spectroscopy and Mössbauer spectroscopy. The Rietveld refinement of the XRD pattern together with the analysis of the IR spectra of the sample confirmed the space group P3[combining macron]c, the same as that for the lanthanide analogues Ln0.33Zr2(PO4)3. However, Mössbauer studies revealed the presence of neptunium in the two oxidation states +3 and +4, indicating a two-phase NZP system with different crystallographic environments of the neptunium atoms...
September 12, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
R Mantovan, R Fallica, A Mokhles Gerami, T E Mølholt, C Wiemer, M Longo, H P Gunnlaugsson, K Johnston, H Masenda, D Naidoo, M Ncube, K Bharuth-Ram, M Fanciulli, H P Gislason, G Langouche, S Ólafsson, G Weyer
The underlying mechanism driving the structural amorphous-to-crystalline transition in Group VI chalcogenides is still a matter of debate even in the simplest GeTe system. We exploit the extreme sensitivity of (57)Fe emission Mössbauer spectroscopy, following dilute implantation of (57)Mn (T½ = 1.5 min) at ISOLDE/CERN, to study the electronic charge distribution in the immediate vicinity of the (57)Fe probe substituting Ge (FeGe), and to interrogate the local environment of FeGe over the amorphous-crystalline phase transition in GeTe thin films...
August 15, 2017: Scientific Reports
Peng Wang, Michelle M Killian, Mohamed R Saber, Tian Qiu, Glenn P A Yap, Codrina V Popescu, Joel Rosenthal, Kim R Dunbar, Thomas C Brunold, Charles G Riordan
The iron(II) semiquinonate character within the iron(III) catecholate species has been proposed by numerous studies to account for the O2 reactivity of intradiol catechol dioxygenases, but a well-characterized iron(II) semiquinonate species that exhibits intradiol cleaving reactivity has not yet been reported. In this study, a detailed electronic structure description of the first iron(II) o-semiquinonate complex, [PhTt(tBu)]Fe(phenSQ) [PhTt(tBu) = phenyltris(tert-butylthiomethyl)borate; phenSQ = 9,10-phenanthrenesemiquinonate; Wang et al...
August 15, 2017: Inorganic Chemistry
Natália S F Trotte, M Alzamora, D R Sánchez, Nakédia M F Carvalho
This study aims to prepare environmentally friendly iron catalysts supported on silica, using glycerol as green reducing and stabilizing agent, for application in heterogeneous Fenton degradation of the pollutant dye methyl orange. The catalysts were characterized by XRD, AAS, SEM, TEM, thermogravimetric analyses, Mössbauer and FTIR spectroscopies, which revealed the formation of iron(II)/(III) oxalates from the oxidation of glycerol by the iron(III) nitrate precursor. Besides, iron oxihydroxide nanoparticles with superparamagnetic behavior were also formed...
August 10, 2017: Environmental Technology
Nadia Soulmi, Damien Dambournet, Cécile Rizzi, Juliette Sirieix-Plénet, Mathieu Duttine, Alain Wattiaux, Jolanta Swiatowska, Olaf J Borkiewicz, Henri Groult, Laurent Gaillon
The potential application of high capacity Sn-based electrode materials for energy storage, particularly in rechargeable batteries, has led to extensive research activities. In this scope, the development of an innovative synthesis route allowing to downsize particles to the nanoscale is of particular interest owing to the ability of such nanomaterial to better accommodate volume changes upon electrochemical reactions. Here, we report on the use of room temperature ionic liquid (i.e., [EMIm(+)][TFSI(-)]) as solvent, template, and stabilizer for Sn-based nanoparticles...
August 10, 2017: Inorganic Chemistry
Matthew J T Wilding, Diana A Iovan, Theodore A Betley
Reduction of previously reported ((Ar)L)FeCl with potassium graphite furnished a low-spin (S = 1/2) iron complex ((Ar)L)Fe which features an intramolecular η(6)-arene interaction and can be utilized as an Fe(I) synthon ((Ar)L = 5-mesityl-1,9-(2,4,6-Ph3C6H2)dipyrrin). Treatment of ((Ar)L)Fe with adamantyl azide or mesityl azide led to the formation of the high-spin (S = 5/2), three-coordinate imidos ((Ar)L)Fe(NAd) and ((Ar)L)Fe(NMes), respectively, as determined by EPR, zero-field (57)Fe Mössbauer, magnetometry, and single crystal X-ray diffraction...
August 18, 2017: Journal of the American Chemical Society
Crisanto A García-Ramos, María Retuerto, José Antonio Alonso
Four oxyfluorides of the title series (x = 0.00, 0.25, 0.50, 0.75) have been stabilized by topotactic treatment of perovskite precursors Sr1-xBaxFeO3-δ prepared by soft-chemistry procedures, yielding reactive materials that can easily incorporate a substantial amount of F atoms at moderate temperatures, thus avoiding the stabilization of competitive SrF₂ and BaF₂ parasitic phases. XRD and Neutron Powder Diffraction (NPD) measurements assess the phase purity and yield distinct features concerning the unit cell parameters' variation, the Sr and Ba distribution, the stoichiometry of the anionic sublattice and the anisotropic displacement factors for O and F atoms...
November 29, 2016: Materials
Miruna Silvia Stan, Ionela Cristina Nica, Anca Dinischiotu, Elena Varzaru, Ovidiu George Iordache, Iuliana Dumitrescu, Marcela Popa, Mariana Carmen Chifiriuc, Gratiela G Pircalabioru, Veronica Lazar, Eugenia Bezirtzoglou, Marcel Feder, Lucian Diamandescu
Our research was focused on the evaluation of the photocatalytic and antimicrobial properties, as well as biocompatibility of cotton fabrics coated with fresh and reused dispersions of nanoscaled TiO₂-1% Fe-N particles prepared by the hydrothermal method and post-annealed at 400 °C. The powders were characterized by X-ray diffraction (XRD), Mössbauer spectroscopy and X-ray photoelectron spectroscopy. The textiles coated with doped TiO₂ were characterized by scanning electron microscopy and energy dispersive X-ray analyses, and their photocatalytic effect by trichromatic coordinates of the materials stained with methylene blue and coffee and exposed to UV, visible and solar light...
September 21, 2016: Materials
Clara I R Magalhães, Ana C Gomes, André D Lopes, Isabel S Gonçalves, Martyn Pillinger, Eunyoung Jin, Ikjin Kim, Young Ho Ko, Kimoon Kim, Israel Nowik, Rolfe H Herber
Temperature-dependent (57)Fe Mössbauer effect (ME) spectroscopic studies were carried out on ferrocene (Fc), 1,1'-dimethylferrocene (1,1'(CH3)2Fc) and ferrocenium hexafluorophosphate (FcPF6) guest species in cucurbit[n]uril (n = 7, 8) inclusion complexes. The solid inclusion complexes were isolated by freeze-drying of dilute aqueous solutions and/or microwave-assisted precipitation from concentrated mixtures. The presence of genuine 1 : 1 (host : guest) inclusion complexes in the isolated solids was supported by liquid-state (1)H and solid-state (13)C{(1)H} MAS NMR, elemental and thermogravimetric analyses, powder X-ray diffraction, FTIR spectroscopy, and diffuse reflectance UV-Vis spectroscopy...
August 16, 2017: Physical Chemistry Chemical Physics: PCCP
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