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1994[X]
201Author    Andreas HammRequires cookie*
 Title    T h e In flu e n c e o f N o ise on F ra c ta ls  
 Abstract    The weak-noise asymptotics of the blurring effect of noise on fractals can be described by scaling laws. It does not only depend on the geometric properties of the fractals but also on their generating dynamics. This is illustrated with the example of the Feigenbaum attractor. 
  Reference    Z. Naturforsch. 49a, 1238—1240 (1994); received October 12 1994 
  Published    1994 
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 TEI-XML for    default:Reihe_A/49/ZNA-1994-49a-1238.pdf 
 Identifier    ZNA-1994-49a-1238 
 Volume    49 
202Author    G. Zumofen3, J. KlafterbRequires cookie*
 Title    F ro m D isp ersio n to L a m in a rity in D y n a m ic a l System s  
 Abstract    We study transport in dynamical systems characterized by intermittent chaotic behavior with coexistence of dispersive motion due to periods of localization, and of enhanced diffusion due to periods of laminar motion. This transport is discussed within the continuous-time random walk approach which applies to both dispersive and enhanced motions. We analyze the coexistence for the standard map and for a one-dimensional map. 
  Reference    Z. Naturforsch. 49a, 1241—1247 (1994); received December 9 1994 
  Published    1994 
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 TEI-XML for    default:Reihe_A/49/ZNA-1994-49a-1241.pdf 
 Identifier    ZNA-1994-49a-1241 
 Volume    49 
203Author    Peter ReimannRequires cookie*
 Title    N o is y M a p s near C rises  
 Abstract    We address the escape rate for single-humped maps near a boundary crisis multiplicatively coupled to weak uncorrelated noise. A scaling law for the rate is derived predicting a stabilization of deterministic transient chaos by noise. Generalizations to maps near interior crises and band merging points are given. 
  Reference    Z. Naturforsch. 49a, 1248—1250 (1994); received October 12 1994 
  Published    1994 
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 TEI-XML for    default:Reihe_A/49/ZNA-1994-49a-1248.pdf 
 Identifier    ZNA-1994-49a-1248 
 Volume    49 
204Author    Lutz Schäfer, Alfred KlemmRequires cookie*
 Title     
 Abstract    h e o ry o f lin e a r response a p p lie d to th e lith iu m isotope effects on th e m o b ilitie s in m o lte n L iC l Expressions in terms of group-velocity time-correlation functions for the ionic mobilities of molten 6LiCl,7 LiCl and (6Li,7 Li)Cl are derived, taking the time-averaged zero momentum of inertia of each of the three groups of ions into account. MD-simulations have been performed for 6LiCl and 7 LiCl, yielding agreement between the simulated and the published experimental reduced isotope effect, although the temperature -volume conditions of the simulations did not conform with natural LiCl. 
  Reference    Z. Naturforsch. 49a, 1251—1255 (1994); received October 31 1994 
  Published    1994 
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 TEI-XML for    default:Reihe_A/49/ZNA-1994-49a-1251.pdf 
 Identifier    ZNA-1994-49a-1251 
 Volume    49 
205Author    G. Drechsler, C. Bäßmann, U. Boesl, E. W. SchlagRequires cookie*
 Title    Mass Selected ZEKE-Spectra of FeC2-Anions: A Spectroscopic Access to Intermediates in Catalytic Reactions of Hydrocarbons on Metal Surfaces  
 Abstract    Zero-kinetic-energy (ZEKE) photoelectron spectra of metalcarbide anions are presented, allowing a high resolu­ tion spectroscopic access to intermediates in catalytic reac­ tions of hydrocarbons on metal surfaces. As a first compound, FeC2 (an intermediate of the iron/acetylene system) has been chosen. Important for successful ZEKE spectroscopy was a special anion source and the selection by time-of-flight mass spectrometry. In addition, conventional laser induced photo­ detachment photoelectron spectroscopy in combination with our anion source and mass analyzer delivered valuable new information. 
  Reference    Z. Naturforsch. 49a, 1256—1258 (1994); received December 12 1994 
  Published    1994 
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 TEI-XML for    default:Reihe_A/49/ZNA-1994-49a-1256_n.pdf 
 Identifier    ZNA-1994-49a-1256_n 
 Volume    49 
206Author    Ewald WickeRequires cookie*
 Title    No Decelerated /J-Decay of Tritium Solved in Titanium  
 Abstract    Experimental results on the interaction of tritium with fine particles of titanium, published in Phys. Lett. A and attrib­ uted to decelerated ß-deca.y of tritium solved in titanium, are instead explained by adsorption of tritium on the surface of the particles, formation of tritium oxide when oxygen is pres­ ent, and normal ß-decay. 
  Reference    Z. Naturforsch. 49a, 1259—1261 (1994); received December 13 1994 
  Published    1994 
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 TEI-XML for    default:Reihe_A/49/ZNA-1994-49a-1259_n.pdf 
 Identifier    ZNA-1994-49a-1259_n 
 Volume    49 
207Author    Crystal Structure, Sbcl4fR. Olf, M. Inkwitz, D. Etlef, K. Onikow Ski, H. Ans PreuRequires cookie*
 Title    Kristallstruktur von SbCl4F  
 Abstract    The crystal structure of SbCl4F is reported. SbCl4F crystallizes in the tetragonal space group 14 with a = 1278.4(6), c = 774.1(5) pm, V = 1265(1) • 106 pm3 and Z = 8. Four SbCl4F units are linked via symmetric Sb-F-contacts forming an eight-membered heterocycles. 
  Reference    (Z. Naturforsch. 49b, 1—4 [1994]; eingegangen am 25. September 1993 Preparation Crystal Structure) 
  Published    1994 
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 TEI-XML for    default:Reihe_B/49/ZNB-1994-49b-0001.pdf 
 Identifier    ZNB-1994-49b-0001 
 Volume    49 
208Author    Lib, P. Eter, H., R. Üdiger, K. Niep, JoachimM. AierRequires cookie*
 Title    LiBa4[Mo2N7] und LiBa4[W2N7]: Neue Nitridomolybdate/wolframate(YI) mit dinieren Tetraeder-Anionen  
 Abstract    a4[M o2N 7] and LiB a4[W 2N 7]: New N itrid o m olybdates/tungstates(V I) w ith D im eric T etrahedral A nions Black crystals of the isotypic phases LiBa4[Mo2N7] and LiBa4[W2N7] (monoclinic, P2/n; a = 1552.2(3)/1555.2(4), b = 642.2(1)/644.4(1), c = 1039.9(2)/1042.4(2) pm; ß = 99.23(2)/99.30(3)°; Z = 4) were grown from the melt (Li, Ba3N2, MoAV; molar ratio 20:5:1; = 1323 K; re­ action with N2, 1 atm, 18 h) by cooling (20 K7h). The crystal structures contain two indepen­ dent dimeric units [ M O j N ^ / ^ N ,] 9-(staggered conformation; M o/W -N -M o/W : 173.6/173.7° and 180°/180°; " M o/W -N (term): 180(2)-185(1)/181(3)-185(1) pm; M o/W -N (bridg): 195(1)7194(1) pm and 193(1)/194(1) pm). 
  Reference    (Z. Naturforsch. 49b, 5—8 [1994]) 
  Published    1994 
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 TEI-XML for    default:Reihe_B/49/ZNB-1994-49b-0005.pdf 
 Identifier    ZNB-1994-49b-0005 
 Volume    49 
209Author    H. Einrich, N. Öth, M. Artina, T. Hom AnnRequires cookie*
 Title    Metal Tetrahydroborates and Tetrahydroboratometalates, 18 [1] Studies on the Formation of Cadmium(II)-tetrahydroborates with Tetrahydroborate and Iodide  
 Abstract    The structure of cadmium tetrahydroborate in THF solution is fluxional on the NMR time scale and best described as Cd[(a-H)2BH2]2-rcTHF as indicated by IR data. Reactions of LiBH4 with Cd(BH4)2 in THF yield the monoanion [Cd(BH4)3]_ exclusively, while a dilithium salt Li2[Cd(BH4)4] • 4 diglyme precipitates from diglyme solutions. Equilibria involving ICd(BH4), Cdl2, Cdl3~, [Cd(BH4)3]-and/or [ICd(BH4)2]~ result from Cd(BH4)2 and Lil in THF or diglyme. The solvent as well as the cation of the iodide (Cd2+ or Li+) influence the equilibria. This can be explained in terms of the different polarity and chelating ability of the solvents. 
  Reference    (Z. Naturforsch. 49b, 9—1 [1994]; received August 30 1993) 
  Published    1994 
  Keywords    Cadmium Bis(tetrahydroborate), Tris(tetrahydroborato)cadmate, Tetrakis(tetrahydroborato)cadmate, Iodo Tetrahydroborato Cadmates, nB NMR Spectra, U3Cd NMR Spectra 
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 Identifier    ZNB-1994-49b-0009 
 Volume    49 
210Author    Z. NaturforschRequires cookie*
 Title    Die isoelektronischen Molekülkomplexe TiCl3(NPPh3) und TiCl3(OSiPh3)  
 Abstract    The Isoelectronic M olecular C om plexes TiC l3(N P P h 3) and T iC l3(O SiPh3) Thilo R übenstahl, D o ro th ea W olff von G udenberg, F ra n k W eller, K u rt D ehnicke* TiCl3(NPPh3) and TiCl3(OSiPh3) have been prepared from titanium tetrachloride and Me3SiNPPh3 and HOSiPh3, respectively. Both complexes were characterized by IR spectrosco­ py and by crystal structure determmations. TiCl3(N PPhj): Space group R3, Z = 6, structure analysis with 959 observed unique reflec­ tions, R = 0.039. Lattice dimensions at -6 8 °C: a = b = 1370.5(7), c = 1845.9(9) pm. TiCl}(OSiPh3): Space group P2,/c, Z = 8, structure analysis with 4549 observed unique re­ flections, R = 0.049. Lattice dimensions at 19 °C: a = 2127.7(2), b = 947.2(1), c = 2136.8(1) pm, ß = 105.081(5)°. Both complexes form monomeric molecules in which the titanium atom is tetrahedrally coordinated by three chlorine atoms, the nitrogen atom of the phosphorone iminato ligand and the oxygen atom of the silyloxy group, respectively. The bond lengths TiN of 171.9(4) pm and TiO of 171.0(3) (in average) correspond to double bonds. 
  Reference    (Z. Naturforsch. 49b, 15—20 [1994]; eingegangen am 7. September 1993) 
  Published    1994 
  Keywords    Monomerie Titanium Complexes, Synthesis, Crystal Structure 
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 TEI-XML for    default:Reihe_B/49/ZNB-1994-49b-0015.pdf 
 Identifier    ZNB-1994-49b-0015 
 Volume    49 
211Author    W. Olfgang Eikens, P. Eter, G. Jones, Jü Rg, L. Au Tn Er, C. Arsten, ThöneRequires cookie*
 Title    Complexes of Copper, Silver, and Gold with Urea Homologues. Crystal Structures of I{/i2-SeC(NH2)2} Ag{SeC(NH2)2}2]22+2 Cl~ * 4 DMF and [Ph3PAu{SC(NHMe)2}]+Cl" * SC(NHMe)2  
 Abstract    The title compounds were prepared from chloro(organophosphine)metal(I) complexes and the urea homologues SeC(NH2)2 and SC(NHMe)2 in good yields. Recrystallization of [Ph,PAg{SeC(NH2)2}]+C r from D M F/C H 2C12 leads in low yield to the dinuclear complex [{/r-SeC(NH2)2}Ag{SeC(NH2)2}2]22+2 C r-4 D M F . The crystal structure reveals short A g-A g contacts and unexpectedly acute angles at the bridging selenium atom. The crystal structure of [Ph3PAu{SC(NHMe)2}]+Cl_ • SC(NHMe)2 shows short N --C1 and N -S con­ tacts that probably correspond to hydrogen bonding. 
  Reference    (Z. Naturforsch. 49b, 21—26 [1994]; received August 12 1993) 
  Published    1994 
  Keywords    Coinage Metal Complexes, X-Ray, Urea Homologues 
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 TEI-XML for    default:Reihe_B/49/ZNB-1994-49b-0021.pdf 
 Identifier    ZNB-1994-49b-0021 
 Volume    49 
212Author    Z. NaturforschRequires cookie*
 Title    Gold-Alkalimetallsysteme, III. Hochdrucksynthese und Kristallstruktur von Rb3Au7 [1]  
 Abstract    G old-A lkali M etal-System s, III. H igh Pressure Synthesis and C rystal S tructure o f R b 3A u 7 [1] K laus-Jürgen Range*, G eorg H. G rosch, F ran z R au, U lrich K lem ent The intermetallic compound Rb3Au7 could be synthesized from the elements at 4 kbar, 700 °C in a modified Belt-type apparatus. The structure (Cmmm; a = 5.579(1), b = 13.267(5), c = 7.265(2) Ä; Z = 2; R = 0.035, Rw = 0,031) comprises three crystallographically independ­ ent Au atoms, arranged in layers along the c-axis. The shortest interatomic distances are A u -A u = 2.633Ä, A u -R b = 3.438Ä and R b -R b = 3.622Ä. Im System R ubidium -G old [2,3] sind bisher n u r die V erbindungen R b A u [4] und R b A u 5 [5,6] ein­ deutig nachgewiesen und strukturell c h a ra k te ri­ siert w orden. Die Existenz von R b A u 2 [2,3,7] ko n n te bisher nicht verifiziert werden. D ie h o m o ­ logen V erbindungen N aA u 2 [8] und K A u 2 [9] sind Lavesphasen und kristallisieren im kubischen M gC u2-Typ bzw. im hexagonalen M g Z n 2-Typ. Bei unseren V ersuchen zur H ochdrucksynthese einer L avesphase R b A u 2 fanden wir nun eine bisher im System R b -A u unbekannte Phase d er Z u sam ­ m ensetzung R b 3A u 7, über die im folgenden berich­ tet w ird. 
  Reference    (Z. Naturforsch. 49b, 27—30 [1994]; eingegangen am 6. Juli 1993) 
  Published    1994 
  Keywords    Trirubidium Heptagold, High Pressure Synthesis, Crystal Structure 
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 Identifier    ZNB-1994-49b-0027 
 Volume    49 
213Author    Z. NaturforschRequires cookie*
 Title    Reactions of Bis(hexamethyldisilazanyl)manganese(II) with Nitrogen Containing Ligands: Syntheses and X-Ray Structures of [Mn( 1,10-phen){N(SiMe3)2}2] and |Mn(4,4 -bipy){N(SiMe3)2}2] THF  
 Abstract    , 1993 Manganese Amides, X-Ray The reaction of [Mn{N(SiMe3)2}2 (THF)] 1 with 2,2'-bipyridine (2,2'-bipy), 1,10-phenan-throline (1,10-phen) and 4,4'-bipyridine (4,4'-bipy) yields three new complexes: [Mn(2,2'-bipy){N(SiMe3)2}2] 2, [Mn(l,10-phen){N(SiMe3)2}2] 3, and [Mn(4,4'-bipy){N(SiMe3)2}2] ■ THF 4. The crystal structure of 3 reveals mononuclear species with pseudo-tetrahedral coordinated manganese(II) ions. Crystal data for 3: orthorhombic, a = 1741.0(2), b = 1879.3(3), c = 1967.0(3) pm, V = 6.436(2) nm3, Z = 8, space group Pbca. Compound 4 crystallizes in the monoclinic system, space group P 2{/c; the lattice parameters are: a = 2139.5(3), b = 925.30(10), c = 1786.4(2) pm, ß = 101.34(1)°, V= 3.4675(7) nm3, Z = 4. The molecular structure of 4 consists of zig-zag infinite chains, with bridging 4,4'-bipyridine groups. 
  Reference    (Z. Naturforsch. 49b, 31—3 [1994]; received August 9) 
  Published    1994 
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 Identifier    ZNB-1994-49b-0031 
 Volume    49 
214Author    JonesRequires cookie*
 Title    Polysulfonylamine  
 Abstract    , LIV [1] (12-Krone-4)lithiumdimesylamid-Acetonitril (3/2): Ein Kristall mit zwei prinzipiell unterschiedlichen Konformationen des gleichen Coronanden Polysulfonylam ines, L IV [1] (12-Crow n-4)lithium D im esylam ide-A cetonitrile (3/2): A Crystal w ith Two F undam entally D ifferent C onform ations of the Sam e C oronand A rm an d Blaschette*, K arl-H einz N agel, P e te r G. [Li(12-crown-4){N(S02CH3)2}] is obtained from equimolar amounts of lithium dimesyl­ amide and 12-crown-4 in methanol and crystallizes from acetonitrile as a 3/2 solvate. The crystallographic data of the latter at -130 °C are: monoclinic, space group P 2In, a = 1053.4(3), b = 904.3(3), c = 2791.2(8) pm, ß = 95.66(3)°, V = 2.646 nm3, Z = 6, Dx = 1.441 Mgm~3. Apart from CH3CN molecules residing in lattice cavities, the structure consists of two crystallogra-phically independent [Li(12-crown-4){N(S02CH3)2}] ion pairs A and B in the ratio 2:1. In B, the Li and N atoms lie on a crystallographic twofold axis. In both ion pairs, Li is hexa-coordinated by the four crown oxygen atoms O(C) and by one oxygen O(S) from each sul-fonyl group of the anionic ligand. The coordination geometry of Li in A closely resembles that of Cu11 in the known structure of [Cu(12-crown-4)Cl2] and can be pictured as a distorted octahedron, where two cis sites are occupied by the O(S) atoms and the remaining vertices by the four oxygens of the macrocycle, which displays a [4 8] conformation. The lithium atom, the two O(S) and two O(C) atoms are arranged in an approximately square-planar pattern with L i-O (S) 203.6 and 205.1, L i-O (C) 206.9 and 219.1 pm, trans angles of 173.7 and 174.8°, and cis angles in the range 87.1 -93.6°. The angle between the remaining two Li -O(C) bonds with distances 214.7 and 221.5 pm is only 146.5° compared with 180° in an ideal octahedron. In ion pair B, the coronand assumes a [3 3 3 3] conformation close to C4 symmetry, as observ­ ed e. g. in the known structures of [Li(12-crown-4)NCS] with a square-pyramidal 0 4N-co-ordination and [Ca(12-crown-4)(H20) 4]Cl2-4 H zO with a square-antiprismatic 0 8-geometry. The coordination polyhedron in B can be viewed as an incomplete cube in which two verti­ ces related by a face diagonal are unoccupied. Important bond lengths and angles in B are: L i-O (S) 216.8, L i-O (C) 214.0 and 228.7pm; 0 (S) -L i-0 (S) 82.0, 0 (C) -L i-0 (C) 75.7/76.3 for adjacent and 120.4/121.9° for opposite ring oxygens. 
  Reference    (Z. Naturforsch. 49b, 36—42 [1994]; eingegangen am 2. September 1993) 
  Published    1994 
  Keywords    Polysulfonylamines, (12-Crown-4)lithium Dimesylamide, Synthesis, Crystal Structure, Coronand Conformation 
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 TEI-XML for    default:Reihe_B/49/ZNB-1994-49b-0036.pdf 
 Identifier    ZNB-1994-49b-0036 
 Volume    49 
215Author    G. Stalke, M. Eorge, SheldrickRequires cookie*
 Title    Neue Cyclophosphazene mit Metallen der III. Hauptgruppe als Ringbausteine  
 Abstract    Acylic silylated phosphazenes of the type HN(PR2NSiMe3)2 (1) react quantitatively with molecules MMe3 (M = Al, Ga, In) under ring formation and CH4 evolution. The ring com­ pounds N(PPh2NSiMe3)2AlMe2 (2 a) and N(PPh2NSiMe3)2InMe2 (4 a) have been investiga­ ted by X-ray structure determination. 2a and 4a crystallize in the space groups P 1 and P 3 15 respectively; they show different conformations regarding the cyclohexane framework. NMR spectroscopy of the nuclei in the chelating phosphazene ligand indicates decreasing Lewis acidity of the metal containing fragments in the series AlMe2 > GaMe2 > InMe2. 
  Reference    (Z. Naturforsch. 49b, 43—49 [1994]; eingegangen am 22. September 1993) 
  Published    1994 
  Keywords    Cyclophosphazenes, Chelating Ligands, Conformational Isomers, Lewis Acidity, 27Al NMR Spectra 
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 TEI-XML for    default:Reihe_B/49/ZNB-1994-49b-0043.pdf 
 Identifier    ZNB-1994-49b-0043 
 Volume    49 
216Author    Z. NaturforschRequires cookie*
 Title    Darstellung, Eigenschaften und elektronische Raman-Spektren von Di(bromo)phthalocyaninatometallaten(III) der Eisengruppe  
 Abstract    Synthesis, P ro p erties an d E lectronic R am an Spectra of D i(b ro m o)p h th alo cy an in ato m etalates(III) of the Iron G roup E lem ents Svend Sievertsen, H en d rik Schlehahn, H ein er H om borg Low spin di(bromo)phthalocyaninatometalates of tervalent iron, ruthenium and osmium ([MBr2Pc2-]') are formed by the reaction of [FeBrPc2~] or H[MBr2Pc2 ] (M = Ru, Os) with ex­ cess bromide in DMF or THF and isolated as ("Bu4N)+ salts. The electronic spectra show the typical J i-jr*-transitions (B, Q, N region) of the Pc2~ ligand together with a number of extra bands due to trip-multiplett and (Pc, Br — » M)CT transitions. vs(MBr) is observed in the resonance Raman (RR) spectrum (RR enhanced for M = Fe, Ru) at 161 cm-1 (Fe), 183 cm4 (Ru) and 192 cm-1 (Os), vas(MBr) at 251 cm4 (Fe), 234 cm-1 (Ru) and 218 cm-1 (Os) in the FIR spectra. The RR spectra obtained by excitation at low absorbance between the B and Q region are dominated by the intraconfigurational 'T 7 — > r 8" transition due to spin orbit split­ ting of the 2T2g ground state for Fe at 583 cm-1, Ru at 1026/1050 cm-1 and Os at 3131 cm4 . In the MIR resp. NIR spectra vibronically induced transitions are observed for the Ru or Os complex. 
  Reference    (Z. Naturforsch. 49b, 50—56 [1994]; eingegangen am 31. August 1993) 
  Published    1994 
  Keywords    Phthalocyanines, Electronic Spectra, Vibrational Spectra, Electronic Resonance Raman Spectra 
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 Identifier    ZNB-1994-49b-0050 
 Volume    49 
217Author    W. S. Sheldrick, B. SchaafRequires cookie*
 Title    Cs2SnTe4, ein Polytelluridostannat(rV) mit Kettenstruktur ^[SnTeJ-] Cs2SnTe4, a Polytelluridostannate(IV ) w ith Chain S tructure ^[SnTef-]  
 Abstract    Polytelluridostannate(IV), Methanolothermal Synthesis, Crystal Structure The cesium polytelluridostannate(IV) Cs2SnTe4 has been prepared by methanolothermal reaction of Cs2CÖ3 with Sn and Te at 190 °C. The crystal structure contains chain anions i[SnTe|~]oin which individual SnTe4 tetrahedra are linked via T e -T e bonds of length 2.814(3) Ä. Weak Te —Te secondary bonds of length 3.631(3)-3.663(3) Ä connect neigh­ bouring chains into a framework structure. Nine Te atoms from three chain anions partici­ pate in the coordination sphere of the cesium cation. 
  Reference    (Z. Naturforsch. 49b, 57—59 [1994]; eingegangen am 13. September 1993) 
  Published    1994 
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 Identifier    ZNB-1994-49b-0057 
 Volume    49 
218Author    Hans-Ulrich Hummel, Petra Joerg, Gerhard Pezzei, Alexander WolskiRequires cookie*
 Title    Die Kristallstruktur von Gadolinium (III)-sulfit Trihydrat Gd2(S 0 3)3*3H20 Crystal Structure of Gadolinium(III)-sulfite Trihydrate Gd2(S 0 3)3-3 HzO  
 Abstract    Gadolinium(III)-sulfite, Preparation, Crystal Structure Gd2(S03)3 • 3 H20 is obtained by passing gaseous S 0 2 through a suspension of Gd20 3 in H20 at room temperature until a clear solution is formed. Single crystals are obtained by heating to 70(2) °C for 6 days. The compound crystallizes in the triclinic space group P 1 with a = 6.499(6), b = 6.621(3), c = 6.954(3) Ä, a = 110.71(5), ß = 90.54(3), y = 106.05(1)° and Z = 1. The two crystallographically different gadolinium atoms are both coordinated by eight oxygen atoms forming distorted square antiprisms. Gd(l) is coordinated by six O atoms of sulfite ligands and two O atoms of water, while Gd(2) is surrounded by seven O atoms of S 0 3 and one of HzO. Gd-O-bond lengths vary between 2.31(3) and 2.50(3) Ä. 
  Reference    (Z. Naturforsch. 49b, 60—62 [1994]; eingegangen am 9. Juli/23. September 1993) 
  Published    1994 
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 Identifier    ZNB-1994-49b-0060 
 Volume    49 
219Author    Gerhard Himbert, Dieter Fink, Martina Stürm, Herrn Prof, O J Dr, SchererRequires cookie*
 Title    Cycloadditionen, XXI [1]. 2-Methyl-2,3-butadiensäure-arylester; Synthese und thermische Reaktivität Cycloadditions, XXI [1] Aryl 2-methyl-2,3-butadienoates; Synthesis and Thermal Reactivity  
 Abstract    Aryl 2-Methyl-2,3-butadienoates, Intramolecular Diels-Alder Reaction The substituted phenyl, 1-naphthyl or the 9-anthrylmethyl esters of the 2-methyl-(or 2-phenyl)-2,3-alkadienoic acids (see 4 a -g , 9 a -d and 12a,b) are synthesized by condensation of the allenic acids 2 a -d with the substituted phenols 3 a -g , with 1-naphthol (8) or with 9-anthrylmethanol (11) in the presence of dicyclohexyl carbodiimide (DCC) and a catalytic amount of 4-dimethylaminopyridine (DMAP). An alternative route is the reaction of the acid chloride la with the phenols 3 a -c (see formation of 4 a -c) in the presence of triethylamine. All these compounds (except 12a) undergo the intramolecular Diels-Alder (IMDA)-reaction to form the tricycles 6 a -g , lO a-d and 13. The enol ether 6a is hydrolized during chromato­ graphy to give the tricyclic ketone 7. The influence of the geminal methyl group on the rate of the IMDA-reaction is investigated. 9-Anthryl-and (2,4,6-cycloheptatrien-l-on-2-yl)-2-methyl-2,3-butadienoate (15, 17), formed by reaction of 2-methyl-2,3-butadienoyl chloride (la) with 9-anthrone (14) and 2-tropolone (16) isomerise spontaneously to the IMDA-products 19 and 18. 
  Reference    (Z. Naturforsch. 49b, 63—75 [1994]; eingegangen am 2. August 1993) 
  Published    1994 
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 Identifier    ZNB-1994-49b-0063 
 Volume    49 
220Author    Dieter Sellmann+, Helge Friedrich, Falk Knoch, Matthias MollRequires cookie*
 Title    Übergangsmetallkomplexe mit Schwefelliganden, C*. Unerwartet einfache Bildung von Diazen-Komplexen und ein neuer Typ von Diastereomerie: [/#-N2H2{Fe(PPr3)('S4')}2] und analoge Komplexe mit [FeS]-Zentren. ( 'S /2-= l,2-Bis(2-mercaptophenylthio)ethan(2-)) Transition Metal Complexes with Sulfur Ligands, C*. Unexpectedly Facile Formation of Diazene Complexes and a New Type of Diastereomerism: [a-N2H2{Fe(PPr3)('S4')}2] and Analogous Complexes with [FeS]-Centers. ('S4'2~ = l,2-Bis(2-mercaptophenylthio)ethane(2-))  
 Abstract    Single pot reactions of FeCl2-4H20 with the tetradentate thioether-thiol 'S4-H 2' = 1,2-bis(2-mercaptophenylthio)ethane, phosphines such as PEt3, PPr3 or PBu3, and a ca. 40-fold excess of N2H4-H20 yield, in the presence of air, diazene complexes of the general formula [M-N2H2{Fe(PR3)('S4')}2]. In contrast to previous syntheses of diazene complexes, the yields can excel 80%, and the syntheses can be carried out on a 10 g scale. [M-N2H2{Fe(PPr3)('S4')}2], 1 and [M-N2H2{Fe(PEt3)('buS4')}2], 2 were characterized by X-ray structure analysis. 2 contains 'buS4'2-= l,2-bis(3,5-ditertiarybutyl-2-mercaptophenylthio)-ethane(2-), which is the tertiary-butyl derivative of 'S4'2-. 1 and 2 contain fram-HN=NH which bridges enantiomeric [Fe(PPr3)('S4')] or [Fe(PEt3)('buS4')] fragments. HN=NH is stabilized by 4c -6 e~-jr bonds, strong tricentric N -H — (S)2 bridges, and steric shielding. NMR studies show that centrosymmetric 1 isomerizes in solution at temperatures around 0 °C in order to give a diastereomerie diazene complex which is also centrosymmetric. The diastereomerism is traced back to bridging the chiral [Fe(PPr3)('S4')] fragments by frara-HN=NH in a differ­ ent way. The two different bridging modes are verified by X-ray structure analyses of analo­ gous ruthenium complexes. Because this new type of diastereomerism is basically caused by a different position only of the N -H — (S)2 bridges, it is termed hydrogen bridge diastereo­ merism. A mechanism for the isomerization is suggested. 1 exhibits three anodic waves in the cyclovoltammogram. The second wave indicates formation of the dication [1]2+, which is a redox isomer of the diprotonated (and as yet hypothetical) dinitrogen complex [a-N2{Fe(PPr3)('S4')}2]. The significance of [1]2+ and of its Lewis basic thiolate donors with respect to electrochemical reduction of molecular dinitrogen under mild conditions is dis­ cussed. 
  Reference    (Z. Naturforsch. 49b, 76—88 [1994]; eingegangen am 9. Juli 1993) 
  Published    1994 
  Keywords    Diazene, Iron Sulfur Complexes, Synthesis, X-Ray 
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 Identifier    ZNB-1994-49b-0076 
 Volume    49 
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