- Iodide-conducting polymer electrolytes based on poly-ethylene glycol and MgI2: Synthesis and structural characterization
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A major obstacle for a viable technological development of dye sensitized solar cells (DSSCs) is still the synthesis of a high performance iodide-conducting polymer electrolyte. Here we present a series of eight electrolytic complexes with formula PEG1000/(MgI2)x(I 2)y (0.0038 ≤ x ≤ 0.5801, 0 ≤ y ≤ 0.0636). The synthesis involves the preparation of a disordered form of MgI2 by a metallorganic route, which enables us to dissolve high amounts of salt in the chosen polymer host. The thermal analysis of the resulting polymer electrolytes was performed using modulated differential scanning calorimetry measurements. Vibrational studies were carried out using medium FT-IR, far FT-IR and FT-Raman. The variation of the CO and OH stretching modes in the medium infrared, as a function of the mole-to-mole ratio nMg/nO, was investigated by Gaussian decomposition to provide insight into the polymer-polymer and salt-polymer interactions in these materials. The FT-Raman spectra confirmed and complemented the vibrational assignment. The conductivity study of these systems was performed by electrical spectroscopy in the frequency interval 10 mHz-10 MHz. The direct current conductivity (σDC) profiles versus the reciprocal temperature exhibited a Vo?gel-Tamman-Fu?lcher (VTF) behavior. The best σDC at 50°C was 5 × 10-5 S cm-1. The overall results indicate the presence of bivalent, monovalent and neutral species, Mg2+, [MgI]+ and MgI2, respectively, which participate in the conduction process. These results are consistent with what was previously observed in PEG400-based systems doped with δ-MgCl2. The presence of at least one Mg site containing a distribution in parameters was observed using 25Mg solid state magic angle spinning nuclear magnetic resonance (MAS NMR) spectroscopy. The site has been assigned to a Mg complex involving the coordination by oxygen atoms of the polymer backbone.
- Vittadello, Michele,Waxman, David I.,Sideris, Paul J.,Gan, Zhehong,Vezzù, Keti,Negro, Enrico,Safari, Ahmad,Greenbaum, Steve G.,Di Noto, Vito
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- Intramolecular Alkene Hydroamination with Hybrid Catalysts Consisting of a Metal Salt and a Neutral Organic Base
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Hybrid catalysts consisting of alkaline earth iodides (AeI2) and the Schwesinger base tBuP4 catalyse the intramolecular alkene hydroamination of H2C=CHCH2CR2CH2NH2 [CR2/sub
- Fischer, Christian A.,Harder, Sjoerd,Langer, Jens,Nguyen, D. Thao,Penafiel, Johanne,R?sch, Andreas,Stegner, Philipp C.,Wiesinger, Michael
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- A rechargeable non-aqueous Mg-O2 battery
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We propose a catalytic cycle using the iodine-dimethylsulfoxide (I 2-DMSO) complex for the realization of secondary Mg-O2 batteries. We have demonstrated that the Mg-O2 battery incorporating an I2-DMSO complex electrolyte showed evidence of being rechargeable.
- Shiga, Tohru,Hase, Yoko,Kato, Yuichi,Inoue, Masae,Takechi, Kensuke
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- Total Synthesis of Actinorhodin
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The enantioselective total synthesis of actinorhodin (1) is described. The synthesis features 1) dual benzyne reactions en route to the monomer, 2) the trans-selective installation of the side chain, and 3) a regioselective oxidative dimerization.
- Ninomiya, Mamiko,Ando, Yoshio,Kudo, Fumitaka,Ohmori, Ken,Suzuki, Keisuke
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- Proton NMR Characterization of the Ferryl Group in the Model Heme Complexes and Hemoproteins: Evidence for the FeIV=O Group in Ferryl Myoglobin and Compound II of Horseradish Peroxidase
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The proton NMR spectra of model porphyrin complexes possessing the ferryl, FeIV=O group are reported and assigned.The only resonance shifted well outside the diamagnetic region is that of the meso protons.Moreover, these model compounds exhibit
- Mar, Gerd N. La,Ropp, Jeffrey S. de,Latos-Grazynski, Lechoslaw,Balch, Alan L.,Johnson, R. B.,et al.
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- Crystal structures of hydrates of simple inorganic salts. I. Water-rich magnesium halide hydrates MgCl2·8H2O, MgCl 2·12H2O, MgBr2·6H2O, MgBr2·9H2O, MgI2·8H2O and MgI2·9H2O
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The previously reported structures of the hydrates of simple inorganic salts that crystallize at room temperature are generally well determined. This is not true for water-rich hydrates, which crystallize at temperatures below 273 K. In this series, investigations of the crystal structures of water-rich hydrates crystallized from aqueous solutions at low temperatures are presented. Reported herein are the structures of a set of magnesium salts. Crystals of MgCl2·8H2O (magnesium dichloride octahydrate), MgCl2·12H2O (magnesium dichloride dodecahydrate), MgBr2·6H2O (magnesium dibromide hexahydrate), MgBr2·9H2O (magnesium dibromide nonahydrate), MgI2·8H2O (magnesium diiodide octahydrate) and MgI2·9H2O (magnesium diiodide nonahydrate) were grown from their aqueous solutions at temperatures below 298 K according to the solid-liquid phase diagrams. All structures are built up from Mg(H 2O)6 octahedra. Dimensions and angles in the hexaaqua cation complexes are very similar and variation is not systematic. The anions are incorporated into a specific network of O-H...X hydrogen bonds.
- Hennings, Erik,Schmidt, Horst,Voigt, Wolfgang
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- Redox active aluminium(iii) complexes convert CO2 into MgCO 3 or CaCO3 in a synthetic cycle using Mg or Ca metal
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Redox-active Group 13 molecules possess the unusual combination of concomitant redox and acid-base reactivity. These combined properties enable regeneration of a metal hydroxide complex in a cycle for conversion of CO 2 into carbonate salts. Reaction of (IP-) 2Al(OH) (M = Al, Ga) with 1 atm of CO2 affords [(IP -)2Al]2(μ2κ1: κ2-OCO2). Subsequent reduction affords MgCO 3 or CaCO3 and two equivalents of [(IP2-) 2Al]-, which can be reoxidized to (IP-) 2Al(OH) to close a cycle.
- Myers, Thomas W.,Berben, Louise A.
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- Total Synthesis of Gukulenin B via Sequential Tropolone Functionalizations
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The synthesis of functionalized aromatic compounds is a central theme of research for modern organic chemistry. Despite the increasing finesse in the functionalization of five- and six-membered aromatic rings, their seven-membered-ring sibling, tropolone (2-hydroxy-2,4,6-cycloheptatrien-1-one), remains a challenging target for synthetic derivatization. This challenge primarily emanates from the unique structural and chemical properties of tropolonoid compounds, which often lead to unexpected and undesired reaction outcomes under conditions developed for the functionalizations of other aromatic moieties. Herein, we describe the total synthesis of one of the most complex natural tropolonoids, gukulenin B. Our synthetic route features a series of site-selective aromatic C-H bond functionalizations and C-C bond formations, whose reaction conditions are judiciously tuned to allow uncompromised performance on the tropolone nucleus. The flexibility and modularity of our synthesis are expected to facilitate further synthetic and biological studies of the gukulenin family of cytotoxins. In addition, the methods and tactics developed herein for the functionalization of the tropolone moiety could inspire and enable chemists of multiple disciplines to take advantage of this privileged yet underexplored structural motif.
- Nicolaou,Yu, Ruocheng,Lu, Zhaoyong,Alvarez, Fernando G.
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supporting information
p. 5190 - 5196
(2022/03/27)
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- Efficient demethylation of aromatic methyl ethers with HCl in water
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A green, efficient and cheap demethylation reaction of aromatic methyl ethers with mineral acid (HCl or H2SO4) as a catalyst in high temperature pressurized water provided the corresponding aromatic alcohols (phenols, catechols, pyrogallols) in high yield. 4-Propylguaiacol was chosen as a model, given the various applications of the 4-propylcatechol reaction product. This demethylation reaction could be easily scaled and biorenewable 4-propylguaiacol from wood and clove oil could also be applied as a feedstock. Greenness of the developed methodversusstate-of-the-art demethylation reactions was assessed by performing a quantitative and qualitative Green Metrics analysis. Versatility of the method was shown on a variety of aromatic methyl ethers containing (biorenewable) substrates, yielding up to 99% of the corresponding aromatic alcohols, in most cases just requiring simple extraction as work-up.
- Bomon, Jeroen,Bal, Mathias,Achar, Tapas Kumar,Sergeyev, Sergey,Wu, Xian,Wambacq, Ben,Lemière, Filip,Sels, Bert F.,Maes, Bert U. W.
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supporting information
p. 1995 - 2009
(2021/03/26)
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- Highly Active Superbulky Alkaline Earth Metal Amide Catalysts for Hydrogenation of Challenging Alkenes and Aromatic Rings
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Two series of bulky alkaline earth (Ae) metal amide complexes have been prepared: Ae[N(TRIP)2]2 (1-Ae) and Ae[N(TRIP)(DIPP)]2 (2-Ae) (Ae=Mg, Ca, Sr, Ba; TRIP=SiiPr3, DIPP=2,6-diisopropylphenyl). While monomeric 1-Ca was already known, the new complexes have been structurally characterized. Monomers 1-Ae are highly linear while the monomers 2-Ae are slightly bent. The bulkier amide complexes 1-Ae are by far the most active catalysts in alkene hydrogenation with activities increasing from Mg to Ba. Catalyst 1-Ba can reduce internal alkenes like cyclohexene or 3-hexene and highly challenging substrates like 1-Me-cyclohexene or tetraphenylethylene. It is also active in arene hydrogenation reducing anthracene and naphthalene (even when substituted with an alkyl) as well as biphenyl. Benzene could be reduced to cyclohexane but full conversion was not reached. The first step in catalytic hydrogenation is formation of an (amide)AeH species, which can form larger aggregates. Increasing the bulk of the amide ligand decreases aggregate size but it is unclear what the true catalyst(s) is (are). DFT calculations suggest that amide bulk also has a noticeable influence on the thermodynamics for formation of the (amide)AeH species. Complex 1-Ba is currently the most powerful Ae metal hydrogenation catalyst. Due to tremendously increased activities in comparison to those of previously reported catalysts, the substrate scope in hydrogenation catalysis could be extended to challenging multi-substituted unactivated alkenes and even to arenes among which benzene.
- Eyselein, Jonathan,F?rber, Christian,Grams, Samuel,Harder, Sjoerd,Knüpfer, Christian,Langer, Jens,Martin, Johannes,Thum, Katharina,Wiesinger, Michael
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supporting information
p. 9102 - 9112
(2020/03/30)
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- Weak Coordination Promoted Regioselective Oxidative Coupling Reaction for 2,2′-Difunctional Biaryl Synthesis in Hexafluoro-2-propanol
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An unprecedented weak coordination promoted dehydrogenative cross-coupling reaction has been developed by palladium catalysis, which provides a convenient access to a wide range of 2,2′-difunctional biaryls from easily accessible substrates. Both HFIP solvent and oxidants serve as the critical factors in this new reaction. A plausible mechanism involving Pd(II)/Pd(IV) is proposed. The reaction demonstrates excellent reactivity, broad functional-group tolerance and high yields.
- Zhang, Chao,Rao, Yu
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supporting information
p. 4456 - 4459
(2015/09/28)
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- Methods for producing trialkyl gallium
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The present invention provides method 1 for producing a trialkyl gallium comprising the steps of reacting gallium, magnesium, and an alkyl halide in an ether, and diluting during the reaction the reaction system with an ether; method 2 for producing a trialkyl gallium comprising the steps of heating in a vacuum a mixture of magnesium and molten gallium, and reacting the mixture with an alkyl halide in a solvent; and method 3 for producing a trialkyl gallium comprising the step of reacting an alkyl metal with an alkylgallium halide compound represented by the formula ???????? Ga2RmX6-m wherein R is a methyl or ethyl group, X is a halogen atom, and m is an integer from 1 to 5.
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- Synthesis, structure, and reactivity of (tBu2PC2H4PtBu 2)Ni(CH3)2 and {(tBu2PC2H4PtBu 2)Ni}2(μ-H)2
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Oxidative addition of CH3I to (dtbpe)Ni(C2H4) (dtbpe = tBu2PC2H4PtBu 2) affords (dtbpe)-Ni(I)CH3 (1). The reaction of (dtbpe)NiCl2 or 1 with the stoichiometric quantity of (tmeda)-Mg(CH3)2 yields (dtbpe)Ni(CH3)2 (2). (dtbpe)Ni(I)CD3 (1-d3) and (dtbpe)Ni(CD3)2 (2-d6) have been prepared analogously. Thermolysis of 2 in benzene affords {(dtbpe)Ni}2(μ-η2:η 2-C6H6) (4). The reaction of either 2 or 4 with hydrogen (H2, HD, D2) gives {(dtbpe)Ni}2(μ-H)2 (3) and the isotopomers {(dtbpe)Ni}2(μ-H)(μ-D) (3-d) and {(dtbpe)Ni}2(μ-D)2 (3-d2). According to the NMR spectra, the structure of 3 is dynamic in solution. The crystal structures of 2 and 3 have been determined by X-ray crystallography. Solution thermolysis of 2 or reduction of (dtbpe)NiCl2 with Mg* in the presence of alkanes probably involves σ-complex-type intermediates [(dtbpe)Ni(η2-R′H)] (R′ = e.g. C2H5, A). While the nonisolated [(dtbpe)Ni0] σ-complexes A are exceedingly reactive intermediates, isolated 3 and 4 represent easy to handle starting complexes for [(dtbpe)Ni0] reactions. Partial protolysis of 2 with CF3SO3H affords (dtbpe)Ni(CH3)(OSO2CF3) (5). Complex 5 reacts slowly with 2 equiv of ethene to give equimolar amounts of [(dtbpe)Ni(C2H5)]+(OSO 2CF3-) (6) and propene. The reaction is thought to be initiated by an insertion of ethene into the Ni-CH3 bond of 5 to form the intermediate [(dtbpe)Ni(C3H7)(OSO2CF 3)] (G), followed by elimination of propene to give the hydride intermediate [(dtbpe)Ni(H)(OSO2CF3)] (H), which on insertion of ethene into the Ni-H bond affords 6.
- Bach, Ingrid,Goddard, Richard,Kopiske, Carsten,Seevogel, Klaus,P?rschke, Klaus-Richard
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- N-derivatives of 1-deoxy nojirimycin
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This invention relates to novel N-derivatives of 1-deoxy nojirimycin, to the method for their preparation and to their use in the treatment of diabetes and the use against retro-viruses, particularly in the treatment of acquired immuno-deficiency syndrome
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- Structural studies of organometallic compounds in solution. II. Magnesium bromide and iodide in diethyl ether and tetrahydrofuran; an extended X-ray absorption fine structure (EXAFS) and large angle X-ray scattering(LAXS) study
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The structures of the magnesium iodide complexes formed in concentrated diethyl ether and tetrahydrofuran solutions have been determined by the large angle X-ray scattering (LAXS) technique.Those of the more dilute solutions of magnesium bromide in diethyl ether and tetrahydrofuran solutions have been determined by the extended X-ray absorption fine structure (EXAFS) method.The investigation of the MgI2 diethyl ether solution was carried out at 44 deg C since this solution cystallizes at about 30 deg C.This solution is probably best considered a melt, the structure of which can be regarded as a close-packing of iodide ions with magnesium ions occupying some of the holes.The coordination around a specific magnesium ion depends on whether it occupies a tetrahedral or an octahedral hole.The average Mg-I bond distance is 2.75 Angstroem.Solvated MgI+ is the dominating complex in MgI2-tetrahydrofuran solution.Magnesium is probably six-coordinate in this complex, and the Mg-I bond distance is 2.52(5) Angstroem.The Mg-Br bond distance is 2.49 and 2.66 Angstroem in diethyl ether and tetrahydrofuran, respectively.
- Wellmar, Agneta,Persson, Ingmar
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p. 143 - 153
(2007/10/02)
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- ε2-Coordination in pentacoordinate iron complexes
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The reactions of the dinitrogen complexes μ-N22 (L = P(OMe)3 1a; P(O-i-Pr)3, 1b; PEt3, 1c with diphenylketene diphenyl-p-tolylketene imine and propionitrile give the η2-C,O ketene compounds Fe(CO)2L2Ph2C2O (L = P(OMe)3, 2a; P(O-i-Pr)3, 2b; PEt3, 2c) a ketene imine system Fe(CO)22Ph2C2N-p-tolyl (3 and the propionitrile substitution derivatives Fe(CO)2L2EtCN (L = P(OMe)3 4; PEt3, 5), respectively.The structures of 2c, 3 and 5a have been determined by X-ray diffraction.
- Birk, Reiner,Berke, Heinz,Hund, Hans-Ulrich,Huttner, Gottfried,Zsolnai, Laszlo,et al.
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p. 397 - 410
(2007/10/02)
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- LABORATORY SCALE DEMONSTRATION OF THE Mg-S-I CYCLE FOR THERMOCHEMICAL HYDROGEN PRODUCTION
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The Mg-S-I water splitting cycle was demonstrated on a laboratory scale by constructing an apparatus for repeated operations of chemical reactions of the whole cycle and by the circulation of reactants through purely thermochemical proceses below 1000 deg C.Electric furnaces and quartz glass reactors were used.Sixteen times of cycle operations were performed in 16 h with production rates of 0.3 liter H2/h and 0.15 liter O2/h.
- Kumagai, Toshiya,Mizuta, Susumu
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p. 679 - 682
(2007/10/02)
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- THERMOCHEMICAL HYDROGEN PRODUCTION BY THE MAGNESIUM-SULFUR-IODINE CYCLE
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A new thermochemical cycle for hydrogen production is presented.It consists of (i) redox reaction of sulfur dioxide and iodine with magnesium oxide in an aquenous solution, (ii) hydrolysis of magnesium iodide, (iii) thermal decomposition of magnesium sulfate and (iv) thermal dissociation of hydrogen iodide.Key reaction (i) and (ii) were experimentally verified.
- Mizuta, Susuma,Kumagai, Toshiya
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