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1998[X]
201Author    Z. NaturforschRequires cookie*
 Title    Ag+ als Substituent eines Alkalimetalls in Ag2SrMnV20 8  
 Abstract    Single crystals of Ag2 SrM nV20 8 have been prepared by reactions of metallic silver and a mixture of S rC 0 3, M nC 03 HoO and V ?0 5. X-Ray investigations showed monoclinic symmetry, space group Cfh-C2/c, a = 9.7022(9), b = 5.5882(5), c = 13.894(1), ß = 90.41(1)°, Z = 4. The crystal structure is isotypic to N a2BaCuV20 8 and includes V 0 4 tetrahedra, M n 0 6 octahedra as well as irregular A g 0 8 and S rO !0 polyhedra. Ag2SrM nV20 8 is characterized by a [MnV20 8] network incorporating Ag+ and S r + or a [Ag2V 2Ö 8] frame incorporating Mn2+ and Sr2+ ions. Ag+ is able to replace an alkali ion in the cationic part of the crystal structure. 
  Reference    Z. Naturforsch. 53b, 279—282 (1998); eingegangen am 17. November 1997 
  Published    1998 
  Keywords    Silver, Strontium, Manganese, Vanadium Oxide 
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 Identifier    ZNB-1998-53b-0279 
 Volume    53 
202Author    Hk Wulff, Müller-BuschbaumRequires cookie*
 Title    Isolierte trigonale S r 0 6-Prismen verknüpfen Kagome-Netze im Strontium-Manganat(I V)-Tellurat( VI): SrMnTe06 Kagome Layers Connected by Isolated Trigonal Sr06 Prisms in the Strontium Manganate(IV) Tellurate(VI): SrMnTe06 L  
 Abstract    Single crystals of the hitherto unknown compound SrM nT e06 have been prepared from Sr(0H)2-8H20 , M n C 0 3(aq) and T e 0 2 in air by crystallization below the melt range. X-ray in­ vestigations showed hexagonal symmetry, space group D3h-P62m, lattice constants a = 5.143(1), c = 5.384(2) A, Z = 1. SrM nTe06 is characterized by staggered [(Mn/Te)60 18] Kagome layers along [001]. These layers are connected by Sr2+ ions, resulting in S r0 6 prisms isolated from each other. The structure is discussed with respect to the connection of Kagome nets in the quaternary oxides of the Ba3Ln40 9 type. 
  Reference    Z. Naturforsch. 53b, 283—286 (1998); eingegangen am 7. November 1997 
  Published    1998 
  Keywords    Strontium, Manganese, Tellurate, Crystal Structure 
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 Identifier    ZNB-1998-53b-0283 
 Volume    53 
203Author    B. Wedel, L. Wulff, Hk Müller-BuschbaumRequires cookie*
 Title    Isolierte ^[TeOs]-Oktaederketten im Bleitellurat Pb2T e05 Isolated ^ [Te05] Chains of Octahedra in the Lead Tellurate Pb2T e05  
 Abstract    Single crystals of Pb2T e0 5 have been prepared by flux techniques. X-ray investigations showed a new crystal structure with monoclinic symmetry, space group Cj-Cc, a = 13.099(3), b = 5.714(1), c = 7.520(2) Ä, ß = 123,80(3)°, Z = 4. Pb2T e 0 5 is characterized by o[o[Te05] chains of octahedra isolated from each other and incorporated into an edge, corner and face connected frame of P b 0 7 polyhedra. Possible positions o f the lone pair o f electrons of Pb2+ are estimated by calculations of Coulomb terms of lattice energy. 
  Reference    Z. Naturforsch. 53b, 287—290 (1998); eingegangen am 17. November 1997 
  Published    1998 
  Keywords    Lead, Tellurate, Crystal Structure 
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 Identifier    ZNB-1998-53b-0287 
 Volume    53 
204Author    R. Rettich, Hk Müller-BuschbaumRequires cookie*
 Title    Zur Kristallchemie der Silber-Mangan-Oxovanadate Ag2BaMnV20 8 und (AgCa2)Mn2(V 04)3 On the Crystal Chemistry of the Silver Manganese Oxovanadates Ag?BaMnV?Oo and (AgCa2)Mn2(V 0 4)3  
  Reference    Z. Naturforsch. 53b, 291—295 (1998); eingegangen am 12. Januar 1998 
  Published    1998 
  Keywords    Barium, Calcium, Manganese, Vanadium Oxide, Crystal Structure 
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 Identifier    ZNB-1998-53b-0291 
 Volume    53 
205Author    CyanhydrineRequires cookie*
 Title    Zur Synthese fluororganischer 0-(Trimethylsilyl)-cyanhydrine  
 Abstract    [ 1 ] sind wertvolle Ausgangsverbin­ dungen zur Synthese von z.B. Wirkstoffen. An­ dererseits sind zahlreiche halogen-, insbesondere fluorsubstituierte Substanzen als pharmakologisch spezifisch wirksam erkannt worden [ 2 -4 ] , Deren Cyanhydrine sind jedoch oftmals -ebenso wie bei sterisch gehinderten Ausgangsverbindungen -nicht direkt aus Aldehyden oder Ketonen und Cyanwas­ serstoff erhältlich, da das Gleichgewicht der Cyan-hydrinbildung weitgehend oder ganz auf der Sei­ te der Edukte liegt. Das gilt auch für aliphatische, mehr noch für aromatische Ketone. Wird der Bin­ dungsgrad der C =0-G ruppe durch fluororganische Reste erhöht, sind klassische Carbonylreaktionen überhaupt nicht mehr beobachtbar. Im Gegensatz dazu verläuft die Reaktion solcher Carbonylgruppen mit Trimethyl-silylcyanid (TM ­ SCN) in der Regel problemlos zu den 0-(Trim ethyl-silyl)-cyanhydrinen [5], wie es gleichzeitig und un­ abhängig auch für "normale" Aldehyde und Ke­ tone [6 , 7] sowie für Epoxide, Säurechloride und Chlorkohlensäureester [8] gezeigt werden konnte. Entgegen älteren Literaturangaben [6 , 9] können auf diesem Umweg aus den O-Silylcyanhydrinen durch Hydrolyse mit verdünnter Salzsäure die auf * Sonderdruckanforderungen an Prof. Dr. W. Sundermeyer. 
  Reference    Z. Naturforsch. 53b, 296 (1998) 
  Published    1998 
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 Identifier    ZNB-1998-53b-0296 
 Volume    53 
206Author    Hans-Friedrich Klein, Alexandra Brand, Gerhard CordierRequires cookie*
 Title    Synthesis and Reactions with CO and C2H4 of Cobalt(I) Complexes Containing Trimethylphosphine and Chelating o-Diphenylphosphanyl- phenolate Ligands  
 Abstract    In tetracoordinate cobalt(I) halide compounds CoX(Ph2P ^ O H)(P M e3)2 (X = CI, Br) o-phos-phanylphenols PhaP^O H are coordinated as phosphane ligands. In the presence o f base chelat­ ing anions Ph2P ^ O _ give rise to pentacoordinate com plexes Co(Ph2 P ^ O)(P M e3)3. M olec­ ular structures are presented for both types o f compounds. The five-membered chelate ring in Co(Ph2P ^ O)(P M e3)3 is resistant to protonation, and ring-opening is not observed in the presence o f CO or C2H4. Replacing one o f the trimethylphosphanes by one o f the 7r-acceptor ligands affords fiuxional com plex m olecules which upon cooling attain definite ground-state geometries out o f a multitude o f possible isomers. 
  Reference    Z. Naturforsch. 53b, 307 (1998); received November 28 1997 
  Published    1998 
  Keywords    Cobalt, o-Phosphanylphenolate Complexes, Synthesis, Structure, Fluxionality 
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 Identifier    ZNB-1998-53b-0307 
 Volume    53 
207Author    N. Sauerwalda, M. Schwenka, J. Polster3, E. BengschbRequires cookie*
 Title    Spectrometric pK Determination of Daphnetin, Chlorogenic Acid and Quercetin  
 Abstract    Daphnetin, Chlorogenic Acid, Quercetin Polyphenols play an important role in the 'immune system ' of plants. Since their charge is important for their physiological effect it is important to know their pKj values. Therefore, the pKj values of some plant contents such as daphnetin (pK = 7.36), chlorogenic acid (pK « 8.5), and quercetin (pKi = 7.03, pfro = 9 .1 5) were determined in the pH range 7 -1 0 using UV/VIS spectroscopy. The decomposition kinetics of quercetin in alkaline solutions was taken into consideration by extrapolating the absorbance time curves to time zero (t = 0). The graphic method of absorbance (A) diagrams was used to determine the pKi values. In the case of quercetin the method of linear regression was also used for the determination. 
  Reference    Z. Naturforsch. 53b, 315—321 (1998); received September 15 1997 
  Published    1998 
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 Identifier    ZNB-1998-53b-0315 
 Volume    53 
208Author    Z. NaturforschRequires cookie*
 Title    Bonding in an Unusual Nickel Carbide  
 Abstract    The bonding in an unusual nickel carbide polymer network synthesized by Musanke and Jeitschko is analyzed using qualitative, band-structure calculations in the framework of extended Hiickel tight-binding theory. The carbide features infinite, one-dimensional, vertex-sharing chains of Ni squares. Each square is centered by a carbon and flanked by C: units. -In this electron-rich polymer, the Ni atoms act as electron acceptors through their s and p orbitals. The orbital interaction schemes reveal that there is little Ni-Ni bonding and essentially no Ni to C2 back-donation. Molecular orbital interaction diagrams of some molecular models are used to describe the bonding in ^[N i^C s]8 -. We also discuss the stability of the planar building block of the polymer, (CNi.;)4"' (which resembles planar CH4) with respect to a "tetrahedral" alternative and we do so for the extended ^ [ N i3C]4-and ^[Ni.^C?]8-chains. In each model case the tetrahedral alternative is favored, and there is no sign of stabilization of a crucial C L4 orbital. Such stabilization is partially achieved through bonding to two Ca axial to the C in the center of the Ni4 ring, but it takes the entire inter-chain calcium network to effect the observed stabilization. 
  Reference    Z. Naturforsch. 53b, 322—332 (1998); received November 4 1997 
  Published    1998 
  Keywords    Carbides, Molecular Orbitals, Electronic Structure, Metal Carbides, Square-Planar Carbon 
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 Identifier    ZNB-1998-53b-0322 
 Volume    53 
209Author    Nils Wiberg, Kerstin Amelunxen, Hans-Wolfram Lemer, Heinrich Nöth, Jörg Knizek, Ingo KrossingRequires cookie*
 Title    Supersilylverbindungen der Borgruppenelemente  
 Abstract    , IV [1]. Supersilylelementhalogenide fBu3SiEX2 und (fBu3Si)2EX mit E = Al, Ga, In: Synthesen, Eigenschaften, Strukturen [2] Supersilylated Compounds of the Thirteenth Group, IV [I]. Supersilylelement Halides rBu3SiEX2 and (/Bu3Si)2EX with E = Al, Ga, In: Syntheses, Properties, Structures [2] Water and oxygen sensitive compounds (rBu3SiEX2)2, fBu3SiEX2 Do and (rBu3Si)2EX (E = AI, Ga, In; X = (F), Cl, Br; Do = OR2, NR3) have been synthezised by reaction of EX3 with rBu3SiNa in the absence or presence of donors. In addition, (?Bu3Si)AlBr2, (fBu3Si)2InF and rBu3SiInBr2 were prepared by reaction of AlBr3 with (rBu3Sij2Zn or of (/Bu3Si)2In-In(Si/Bu3)2 with AgF2 and HBr, respectively. The adduct [rBu3SiAlBr2 AlBr3 '/ 2M gBr2]2 is formed from AlBr3 and (fBu3Si)2Mg(THF)2. Thermal decomposition of the compounds in solution or in the gas phase leads to the formation of ?Bu3SiEX2 (from the dimers or the donor adducts) and of fBu3SiX. The Lewis acidity of ?Bu3SiEX2 against donors incre­ ases in the direction Do = Et20 < THF < NEtM e2. Dehalogenation of (/Bu3Si)2ECl with /Bu3SiNa(THF)2 in pentane at room temperature leads to clusters (rBu3Si)4Al2, (fBu3Si)3Ga2*, (fBu3Si)4In2 and (rBu3Si)3Ga2Na(THF)3, reduction of rBu3SiGaCl2 with Na or K in heptane at 100°C to the tetrahedran (rBu3Si)4Ga4. The structures of (rBu3SiGaCl2)2, (fBu3Si)2GaCl, and [/Bu3SiAlBr2 AlBr3-'/2MgBr2]2 have been determined by X-ray structure analysis. 
  Reference    Z. Naturforsch. 53b, 333—348 (1998); eingegangen am 7. November 1997 
  Published    1998 
  Keywords    Supersilylaluminum Halides, Supersilylgallium Halides, Supersilylindium Halides, Acid-base Reactions, Redox-Reactions, X-Ray Data 
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 Identifier    ZNB-1998-53b-0333 
 Volume    53 
210Author    Anja Loose, WilliamS. SheldrickRequires cookie*
 Title    Solventothermal Synthesis of the Lamellar Selenidostannates(IV) A2Sn4Se9*H20 (A = Rb, Cs) and Cs2Sn2Se6  
 Abstract    Reaction of A 2C O 3 with Sn and Se in an H 2O /CH 3OH mixture at 115 -130°C affords the isotypic lamellar selenidostannates A2Sn4Se9-H20 1 (A = Rb) and 2 (A = Cs). The polyanions ^ [Sn4Se92~] exhibit S ^ S e s molecular building units, in which two adjacent Sn(IV) atoms of an Sn4Se4 8-membered ring are bridged by an additional Se atom. These units connect through (SnSe)2 4-mem bered rings to afford a 44 anionic net with 16-membered cavities. Cs2Sn2Se6 (3) may be prepared by methanolothermal reaction of CstCO^ with SnSe and Se at 130°C and contains porous 2 [SnTSeö2 -] sheets in which [SnSes--] ribbons are linked through Se-Se bonds. The resulting 4 net displays 14-membered pores in which the Cs cations reside. 
  Reference    Z. Naturforsch. 53b, 349—354 (1998); received December 29 1997 
  Published    1998 
  Keywords    Tin, Selenium, Selenidostannates(IV), Lamellar Structures, Solventothermal Synthesis 
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 Identifier    ZNB-1998-53b-0349 
 Volume    53 
211Author    Uwe Klingebiel, Brigitte Tecklenburg, Mathias Noltemeyer, Dieter Schmidt-Bäse, Regine Herbst-IrmerRequires cookie*
 Title    Cyclodisilazane in cis-Konformation -eine einfache Synthese Cyclodisilazanes in cis Conformation -a Facile Synthesis  
 Abstract    Dilithium derivatives of bis(silylamino)fluorosilanes (1-3) react with chlorotrimethylsilane to give dilithium derivatives of the corresponding bis(silylamino)chlorosilanes and Me3SiF. LiCl-elimination in the presence of THF leads to the formation of silaamidides, which are 
  Reference    Z. Naturforsch. 53b, 355—360 (1998); eingegangen am 14. Januar 1998 
  Published    1998 
  Keywords    Silicon, Lithium, Silylamide, Silaamidide, Cyclodisilazane 
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 Identifier    ZNB-1998-53b-0355 
 Volume    53 
212Author    Oppermann, S. Herrera, DaoQuoc HuongRequires cookie*
 Title    Untersuchungen zum chemischen Transport von YX3 mit A1X3 und zur Existenz von gasförmigen und festen Komplexen YA13 X12 (X = Br, I) Investigations on the Chemical Transport Reaction of YX3 with A1X3 and on the Existence of Gaseous and Solid Complexes YA13 X 12 (X = Br, I) H  
 Abstract    The dominant gaseous complexes YAl3B r12 and YA13I 12 were generated in the chemical trans­ port reactions of YBr3 with AlBr3 and YI3 with A1I3. The enthalpy of formation Z\H£(YAl3B r12,gi298) = -484,5 ± 6 kcal/mol and the standard entropy S°(YA13B 12 g 298) = 290,0 ± 7,5 cal/K mol have been calculated. It follows from total pressure measurements of mixtures of YBr3 s with AlBr3 1 and YI3 s with A1I3 b respectively, that complexes YAl3B r12 s and YA13I 12 s do not exist up to the boiling points of the aluminium trihalides. 
  Reference    Z. Naturforsch. 53b, 361—366 (1998); eingegangen am 1. Dezember 1997 
  Published    1998 
  Keywords    Chemical Transport Reaction, Yttrium Aluminium Halides, Enthalpy of Formation, Standard Entropy, Total Pressure Measurements 
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 Identifier    ZNB-1998-53b-0361 
 Volume    53 
213Author    C. Aguilera, M. Parra, G. FuentesRequires cookie*
 Title    Synthesis and Mesomorphic Properties of Polymethylene-a,u;-bis [2-thio- 5-(4',4"n-alcoxybenzoyIoxy)phenyl]-l,3,4-oxadiazole  
 Abstract    Three homologous series of polymethylene-a,i<;-bis[2-thio-5(4',4''n-alkoxybenzoyloxy)-phenyl]-l,3,4-oxadiazole (series 5 a, b, c), are reported.The compounds have identical meso-genic units at both ends of a spacer (i.e. they are twins). These twins possess a spacer of 6, 8 and 10 carbon atoms joined directly to the oxadiazole ring through sulphur atoms. The lateral alkylic chains vary between 6 and 10 carbon atoms.The presence of enantiotropic and m onotropic nematic phase is related to the length of the spacer group. The influence of molecular structure on the mesomorphic properties has been studied. Me­ somorphic properties and phase transitions have been determined using polarizing hot-stage microscopy and differential scanning calorimetry. 
  Reference    Z. Naturforsch. 53b, 367—370 (1998); received May 15 1997 
  Published    1998 
  Keywords    Liquid Crystal, Twin Mesogens, Oxadiazole, M esomorphic Properties 
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 Identifier    ZNB-1998-53b-0367 
 Volume    53 
214Author    Requires cookie*
 Title    Syntheses and Structures of Cyclopentadienyl Arsenic (III) Compounds Part IIIa: Tetraisopropylcyclopentadienyl Arsenic (III) Dibromide and Tetraisopropyl- cyclopentadienyl Arsenic (III) Diiodide (TipCpAsBr2, TipCpAsI2)  
  Reference    Z. Naturforsch. 53b, 371 (1998) 
  Published    1998 
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 Identifier    ZNB-1998-53b-0371 
 Volume    53 
215Author    Z. NaturforschRequires cookie*
 Title    Kristallstruktur  
 Abstract    von [Mo(CO)3(NCMe)(SrBu)]2 C ry stal S tru c tu re o f [M o (C O)3(N C M e)(S rB u)]2 M ike R. K opp, B e rn h a rd N eu m ü ller* Single crystals of [M o(CO)3(NCM e)(S'Bu)]2 (1) and [{Mo(CO)3}2{Mo(CO)2}{S'Bu}4] (2) were obtained by the reaction of [M o(CO)3(NCM e)3] with [(PhCH2)2GaS'Bu]2 in 1,4-dio-xane. The X-ray structure determination of 1 showed the presence of a Mo2S2 four-membe-red ring with a Mo-Mo bond length of 296,7(1) pm. Space group Pbca, Z = 4, lattice dim en­ sions at -80 °C: a = 1588,2(3), b = 905,8(1), c = 1676,0(1) pm, R y = 0,0555. 
  Reference    Z. Naturforsch. 53b, 378—380 (1998); eingegangen am 8. Dezember 1997 
  Published    1998 
  Keywords    Molybdenum Carbonyl Complex, Thiolato Complex, Crystal Structure 
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 Identifier    ZNB-1998-53b-0378 
 Volume    53 
216Author    Requires cookie*
 Title    The Molecular Structures and Conformational Preferences of Bis(dimethylstibyl)-Sulfane and -Tellurane, E(SbMe2)2? E = S or Te, Me = CH3, by Density Functional Theory Calculations and Gas Electron Diffraction  
  Reference    Z. Naturforsch. 53b, 381 (1998) 
  Published    1998 
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 Identifier    ZNB-1998-53b-0381 
 Volume    53 
217Author    Z. NaturforschRequires cookie*
 Title    Experimental and Computational Studies on Aminoguanidine Free Base, Monocation and Dication. Part III: Proton Affinities of Guanidine, Aminoguanidine and Glyoxal Bis(amidinohydrazone)  
 Abstract    The structures of glyoxal bis(amidinohydrazone) (GBG) free base and glyoxal bis(amidi-nohydrazonium) monocation and dication were calculated quantum chemically by using the density functional hybrid method B3-LYP with the standard basis set 6 -3 1 G (d). Proton affinities calculated from these data are 246.4 kcal/mol for the free base and 176.0 kcal/mol for the monocation. The proton affinities of guanidine free base (246.2 kcal/mol), am inogua­ nidine free base (242.9 kcal/mol), aminoguanidinium monocation (88.6 kcal/mol) were calcu­ lated for reference. The B3-LYP functional overestimates the proton affinities for all the species studied. For example, for guanidine the proton affinity at the M P2/6-31G (d) level is 238.3 kcal/mol, the experimental reference value being 233 kcal/mol. However, from the B3-LYP values it can be concluded that in the gas phase all the three bases are nearly equally basic. On the other hand, it is known that in aqueous solution guanidine is a much stronger base than aminoguanidine and glyoxal bis(amidinohydrazone). The results are discussed from the point of view of molecular size, shape and symmetry, and hydrogen bonding in solution. 
  Reference    Z. Naturforsch. 53b, 386—392 (1998); received November 21 1997 
  Published    1998 
  Keywords    Proton Affinity, Gas Phase Basicity, Acid Dissociation Constant 
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 Identifier    ZNB-1998-53b-0386 
 Volume    53 
218Author    Z. NaturforschRequires cookie*
 Title    R eaction o f 9-B orabicyclo[3.3.1]nonane with N-Trim ethylsilylam ines -C leavage o f the N-Si or N -H Bond  
 Abstract    The reaction of dimeric 9-borabicyclo[3.3.1]no-nane 1 with N-trimethylsilyl-aniline 2 affords 9-anilino-9-borabicyclo[3.3.1]nonane 5 by elimina­ tion of trimethylsilane. In contrast, 1 reacts with the N-trimethylsilyl-2-aminopyridines 3 and 4 se­ lectively by elimination of H 2 to give the corre­ sponding N-trimethylsilyl-aminoboranes 6 and 7. The latter reactions proceed via formation of bo-rane-pyridine adducts. 
  Reference    Z. Naturforsch. 53b, 393—395 (1998); received December 29 1997 
  Published    1998 
  Keywords    Aminoborane, Aminosilane, Boron, Pyridine, NMR Data 
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 Identifier    ZNB-1998-53b-0393_n 
 Volume    53 
219Author    J. Feller3, H. Oppermann3, R. Kucharkowskib, S. DäbritzcRequires cookie*
 Title    Phasenbeziehungen und Chemischer Transport der Verbindungen im ternären System Re/Mo/O Phase Relations and Chemical Transport of the Compounds in the Ternary System Re/Mo/O  
 Abstract    In the ternary system Re/Mo/O four series of mixed oxides have been prepared by heating of powder samples and by transport reactions. The series are derived from the oxides R e 0 2, M o 0 2, 7 -Mo4O u und //-Mo40 |i and have compositions R e1_ vM ov0 2 (0 < x < 0.37), M o,_> .Re>0 2 (0 < v < 0 .4 2),7 -M o 4_-| Re-| 0 11 (0 < Zj < l),a n d /7-Mo4_.2Re-^Ö |, (0 < z 2 < 1). Contributions to the understanding of the transport mechanism were obtained from thermodynamic calculations. The composition of the mixed crystals obtained have been determined by EPM A and ICP-AES. 
  Reference    Z. Naturforsch. 53b, 397—104 (1998); eingegangen am 21. Januar 1998 
  Published    1998 
  Keywords    Rhenium Molybdenum Mixed Oxides, Chemical Transport Reaction, Phase Diagram 
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 Identifier    ZNB-1998-53b-0397 
 Volume    53 
220Author    Matthias Asbrand, Brigitte Eisenmann, Holger Engelhardt, Ute RößlerRequires cookie*
 Title    Dimere und polymere Pnictidostannat(IV)-Anionen -Darstellung und Kristallstrukturen von Na2K3[SnP3], Na2Cs3 [SnP3] und Na2K3[SnBi3] Dimeric and Polymerie Pnictidostannate(IV) Anions -Preparation and Crystal Structures of Na2K3[SnP3], Na2Cs3[SnP3] and Na2K3[SnBi3]  
 Abstract    Disodium Tripotassium Triphosphidostannate(IV), Disodium Tricesium Triphosphidostanna-te(IV), Disodium Tripotassium Tribismutidostannate(IV), Dimeric Tetrahedral Anions, Zweier Single Chains The metallic lustrous compounds Na2K3[SnP3], Na2Cs3[SnP3], and Na2K3[SnBi3] were pre­ pared from melts of mixtures of the elements. The isotypic compounds Na2K3[SnP3] and Na7Cs3[SnP3] crystallize in the orthorhombic system, space group Cmca (No 64), Z = 8, with lattice constants a = 1996.1 (4)/2047.9(4) pm, b = 669.5(1)/686.5(2) pm, c = 1494.5(2)/1617.8(3) pm. The structure is characterized by dimeric units [Sn2P6] l0_ of edge-sharing [SnP4] tetrahe­ dra, which are coordinated by the alkali cations. Na2K3[SnBi3] crystallizes in the orthorhombic system, space group Ibca (No 73), Z = 8, with lattice constants a = 718.2(1) pm , b -1692.6(2) pm, c = 2159.5(2) pm. In the anionic partial structure [SnBi4] tetrahedra are connected via common corners to infinite ^ [SnBi3]5_ Zweier single chains. The sodium and potassium cat­ ions separate the chains from each other. Neglecting the distortions caused by covalent bonding and different radii both structure types can be classified as superstructure defect variants of the Li3Bi structure. Different orderings in the occupation of the tetrahedral voids lead to the variants in the anionic assemblies. 
  Reference    Z. Naturforsch. 53b, 405—410 (1998); eingegangen am 26. Januar 1998 
  Published    1998 
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 Identifier    ZNB-1998-53b-0405 
 Volume    53 
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