Institute For Anorganische Und Analytische Chemie

Bad Münster am Stein-Ebernburg, Germany

Institute For Anorganische Und Analytische Chemie

Bad Münster am Stein-Ebernburg, Germany
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Wachtler E.,TU Bergakademie Freiberg | Wachtler E.,University of Zaragoza | Oro L.A.,University of Zaragoza | Iglesias M.,University of Zaragoza | And 4 more authors.
Chemistry - A European Journal | Year: 2017

The paddlewheel-shaped complex [Sb(μ-pyS)4Rh]2 (1) (pyS−= 2-S-C5H4N−) was synthesized from [Rh(pyS)(cod)]2 (cod=1,5-cyclooctadiene) and Sb(pyS)3. Upon oxidation with ONMe3, the complex [(μ-O)Sb(μ-pyS)3Rh(κ2-pyS)]2 (2) is formed. Both 1 and 2 form dimers and feature short Rh−Sb bonds and bridging pyS ligands. 121Sb Mössbauer spectro- scopy and computational studies were employed to elucidate the Rh−Sb bonding in 1 and 2. Both covalent (Rh−Sb, X-type Sb ligand) and dative (Rh→Sb, Z-type; Rh←Sb L-type Sb ligand) interactions have to be considered for the description of their bonding situations. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim


Fohlmeister L.,Monash University | Vignesh K.R.,Indian Institute of Technology Bombay | Winter F.,Institute For Anorganische Und Analytische Chemie | Moubaraki B.,Monash University | And 4 more authors.
Dalton Transactions | Year: 2015

Three neutral bis(μ-chalcogenido)diiron(iii) complexes, [{(N,N′-Pipiso)Fe(μ-E)}2] (Pipiso- = [(DipN)2C(cis-2,6-Me2NC5H8)]-, (Dip = C6H3Pri 2-2,6; E = O, S or Se) have been prepared by reactions of the iron(i) dimer [{(μ-N,N′-Pipiso)Fe}2] with O2, S8 or Se∞. Treating the μ-selenido compound [{(N,N′-Pipiso)Fe(μ-Se)}2] with O2 cleanly generated its μ-oxo counterpart, [{(N,N′-Pipiso)Fe(μ-O)}2]. X-ray crystallographic analyses of the compounds showed them to possess Fe2(μ-E)2 core structures with distorted square planar (E = O) or tetrahedral (E = S or Se) iron coordination geometries. Magnetic, 57Fe Mössbauer spectroscopic and computational studies indicate medium to strong antiferromagnetic coupling between the two high-spin FeIII ions in all three compounds. © 2015 The Royal Society of Chemistry.


Burchner M.,Institute For Anorganische Und Analytische Chemie | Burchner M.,Freiburg Institute of Advanced Studies FRIAS IK | Burchner M.,Albert Ludwigs University of Freiburg | Erle A.M.T.,Institute For Anorganische Und Analytische Chemie | And 8 more authors.
Chemistry - A European Journal | Year: 2012

Straightforward access to hydridoborate-based ionic liquids (BILs) is provided. They fall into a barely developed area of research and are of interest as, for example, reagents for organic synthesis. A series of pure [BH 4]- ILs with 1-butyl-2,3-dimethylimidazolium (BMMIM), 1-ethyl-3-methylimidazolium (EMMIM), 1-propyl-1-methylpiperidinium (PropMPip), and1-butyl-1-methylpyrrolidinium (BMP) cations were prepared. All synthesized ILs are well soluble in CH2Cl2. We developed a procedure that gives clean products with correct elemental analyses. In contrast to earlier reports, which when conducted by us yielded only mixtures of the boranate anion with major halide contamination (maximum [BH4] - content: 77.5 %). These materials can be viewed as the starting material for the (hypothetical) hydrogen-storage redox shuttling sequence between [BH4]- and [B12H12] 2-, in which the triboranate anion [B3H8] - is a formal intermediate. Here we also developed a facile route to [B3H8]- ILs with [BMMIM]+, [EMMIM]+, [PropMPip]+, and [NBu4]+, in which Na[BH4] reacts in situ (enhanced by ultrasound) with the solvent CH2Cl2 as the oxidizing agent to give the triboranate IL in high yield and purity according to the equation: 3 [BH 4]-+2 CH2Cl2+[Cat] +→[B3H8]-[Cat] ++H2+2 CH3Cl+2 Cl-. We further investigated this reaction path by additional NMR spectroscopic experiments, powder-XRD analysis, and quantum chemical DFT calculations. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Zeng Z.,Institute For Physikalische Chemie | Matuschek D.,Organisch Chemisches Institute | Studer A.,Organisch Chemisches Institute | Schwickert C.,Institute For Anorganische Und Analytische Chemie | And 2 more authors.
Dalton Transactions | Year: 2013

Hybrid materials, in which stable organic radical cations are intercalated into layered inorganic host materials, can be successfully synthesized via an ion exchange reaction in a layered fluoromica clay, to yield recyclable heterogeneous catalysts for oxidation of various alcohols. We have conducted systematic synthetic and structural studies on the intercalation of the radical cations 4-(diethylmethylammonium)-2,2,6,6-tetramethylpiperidin-1-oxyl (DEMTEP), 1-[2-(4-amino-2,2,6,6-tetramethyl-1-piperidinyloxyl)-2-oxoethyl] -1′-methyl-4,4′-bipyridinium (VIOTEP), and 2-(3-N-methylpyridinium)- 4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazol-1-oxyl-3-N-oxide (m-MPYNN) into a synthetic fluoromica clay named Somasif® ME 100, Na2xMg 3.0-xSi4O10(FyOH1-y) 2 (x = 0.33, y = 0.98). The guest-host interactions in these intercalation compounds have been characterized by X-ray powder diffraction and solid-state NMR of the constituent nuclei (23Na, 19F, and 29Si) of the Somasif structure. The intercalation process can be conveniently monitored using 23Na MAS-NMR. Guest-guest interactions have been probed by magnetic susceptibility measurements as well as EPR and 1H MAS NMR experiments. The 1H MAS-NMR line widths and chemical shifts probe modifications in the electron spin density distributions and/or intermolecular interactions between the electron spins of the guest species. Despite these indications of weakly interacting spins, magnetic susceptibility measurements are consistent with the near-absence of cooperative magnetism. The VIOTEP and DEMTEP inclusion compounds demonstrate catalytic activity for the oxidation of benzyl alcohol, using NaOCl as a co-oxidant. Although the radical ion species is partially leached out under these conditions (ionic exchange with Na+ in solution) the catalytic activity remains for up to 40 subsequent cycles. Fully leached materials can be regenerated by catalyst re-loading and this process can be conveniently monitored by X-band EPR spectroscopy. © 2013 The Royal Society of Chemistry.


Erdmann M.,University of Munster | Rosener C.,Institute For Anorganische Und Analytische Chemie | Holtrichter-Rossmann T.,University of Munster | Daniliuc C.G.,University of Munster | And 5 more authors.
Dalton Transactions | Year: 2013

The vicinal frustrated P/B Lewis pair (FLP) Mes2PCH 2CH2B(C6F5)2 reacts with 9-borabicyclo[3.3.1]nonane (9-BBN) by C6F5vs. H exchange at boron to give the new [B]-H functionalized FLP Mes2PCH 2CH2B(H)(C6F5) (4) and 9-C 6F5-BBN. The latter was characterized as an isonitrile adduct by X-ray diffraction. The new FLP 4 forms an adduct with pyridine and it undergoes clean hydroboration reactions with 1-pentyne or added styrene or dimesitylvinylphosphane. The products formed stable adducts with pyridine; two such examples were also characterized by X-ray crystal structure analysis. A similar alkyl vs. hydrogen exchange was observed upon treatment of an Al/N based Lewis pair, iBu2Al-(Me3Si)C=C(H)-N(CH2CH 2)2NMe (14), with 9-BBN. © 2013 The Royal Society of Chemistry.


Plonczak P.,Technical University of Denmark | Joost M.,Institute For Anorganische Und Analytische Chemie | Hjelm J.,Technical University of Denmark | Sogaard M.,Technical University of Denmark | And 2 more authors.
Journal of Power Sources | Year: 2011

Abstract: A multiple spin-coating deposition procedure of Ce 0.9Gd0.1O1.95 (CGO) for application in solid oxide fuel cells (SOFCs) was developed. The thin and dense CGO layer can be employed as a barrier layer between yttria stabilised zirconia (YSZ) electrolyte and a (La, Sr)(Co, Fe)O3 based cathode. The decomposition of the polymer precursor used in the spin-coating process was studied. The depositions were performed on anode supported half cells. By controlling the sintering temperature between each spin-coating process, dense and crack-free CGO films with a thickness of approximately 1 μm were obtained. The successive steps of dense layer production was investigated by scanning electron microscopy. X-ray diffraction was employed to monitor the crystal structure of the CGO layer sintered at different temperatures. The described spin coated barrier layer was evaluated using an anode supported cell with a composite cathode made of La 0.58Sr0.4Co0.2Fe0.8O3 (LSCF) and Ce0.9Gd0.1O1.95. The developed CGO layer, was sufficient to restrain reactions between the perovskite based electrode and the electrolyte. © 2010 Elsevier B.V.


Feldmann K.-O.,Institute For Anorganische Und Analytische Chemie | Schulz S.,Institute For Anorganische Und Analytische Chemie | Klotter F.,Institute For Anorganische Und Analytische Chemie | Weigand J.J.,Institute For Anorganische Und Analytische Chemie
ChemSusChem | Year: 2011

A convenient protocol for the smooth conversion of the resistant P-O bond in phosphane oxides into a reactive P-N bond of synthetically useful pyrazolylphosphonium salts is described. A highly charged, oxophilic, phosphorus-centered trication is employed and the reactions are conducted at room temperature with quantitative yields. The resulting pyrazolylphosphonium cations are valuable synthetic intermediates and are used for the synthesis of a variety of organophosphorus compounds. This represents a new approach towards the transformation of the rather inert phosphoryl group under very mild reaction and workup conditions and aims towards alternatives to existing reduction methods for phosphane oxide functionalization. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Feldmann K.-O.,Institute For Anorganische Und Analytische Chemie | Weigand J.J.,Institute For Anorganische Und Analytische Chemie
Angewandte Chemie - International Edition | Year: 2012

Accessible complexity: Polyphosphorus frameworks [R 4P 4pyr] + and [R 6P 7] + (R=Cy, Ph; pyr=3,5-dimethylpyrazolyl) were prepared from a P 1 source, R 2PH. In a one-pot reaction, eight P-P bonds are formed via a unique combination of substitution and base-induced reductive P-P coupling. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Weigand J.J.,Institute For Anorganische Und Analytische Chemie | Feldmann K.-O.,Institute For Anorganische Und Analytische Chemie | Echterhoff A.K.C.,Institute For Anorganische Und Analytische Chemie | Ehlers A.W.,VU University Amsterdam | Lammertsma K.,VU University Amsterdam
Angewandte Chemie - International Edition | Year: 2010

A door to new opportunities: The stepwise hydrolysis of a diphosphorus trication is an efficient method for the preparation of an unusual ligand-stabilized dication that contains a novel cationic [P4O4]2+ framework (see Scheme; gray C, blue N, red O, orange P). This approach demonstrates the potential of the diphosphorus trication as a source for phosphorus building blocks to be used in the construction of novel cationic ring and cluster systems. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.


Kahnes M.,Institute For Anorganische Und Analytische Chemie | Richthof J.,Institute For Anorganische Und Analytische Chemie | Gorls H.,Institute For Anorganische Und Analytische Chemie | Escudero D.,Institute For Physikalische Chemie | And 2 more authors.
Journal of Organometallic Chemistry | Year: 2010

The reaction of bis(2-pyridylmethyl)amine (II) with t-butylamine and dimethylzinc gives the heteroleptic [(MeZn)2{μ-N(H)tBu}{μ-N(CH2Py)2}] (1). Stoichiometric alcoholysis of 1 with methanol leads to the exchange of the μ-N(H)tBu moiety. Almost quantitatively the corresponding methoxide [(MeZn)2(μ-OMe){μ-N(CH2Py)2}] (2) is formed. Alternatively bis(alkylzinc)methoxide-bis(2-pyridylmethyl)amides (Alkyl = methyl (2), bis(trimethylsilyl)methyl) (3)) are also accessible by direct zincation of bis(2-pyridylmethyl)amine (II) and methanol with dialkylzinc regardless of the bulkiness of the alkyl groups. Extensive DFT calculations on the alcoholysis mechanism reveal the preferential insertion of methanol into a zinc amide bond rather than the cleavage of zinc carbon bonds. An intermediate with a Zn[μ-(MeO⋯H⋯NHR)]Zn functionality is predicted. Aminolyis of 1 with t-butylamine leads to intermediates with Zn[μ-(RNH ⋯ H ⋯ NHR)]Zn functionalities, respectively. We were able to detect the latter by 1H NMR spectroscopy. The aminolysis of 1 with an excess of phenylamine results in a partial decomposition of the complex leading to the hexanuclear amide [{Zn(μ-N(H)Ph)}{MeZn(μ-N(H)Ph)}2{μ-N(CH2Py)2}]2 (4). Compound 2 is able to cleave silicon grease when dissolved in t-butylamine yielding [(MeZn)2{μ-N(CH2Py)2}2Zn{μ-(OMe2Si)2O}] (5). The X-ray structures of complexes 1-5 are discussed. © 2009 Elsevier B.V. All rights reserved.

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