Go toArchive
Browse byFacets
Bookbag ( 0 )
Facet   Publication Year 2001  [X]
Facet   section ZfN Section B  [X]
Results  200 Items
Sorted by   
Publication Year
2001[X]
161Author    Y. Elerman3, E. Kavlakoglu3, A. Elmali3, E. KendibRequires cookie*
 Title    Crystal Structure and Magnetic Properties of an Oxygen-Bridged Trinuclear Copper(II) Complex  
 Abstract    Trinuclear Copper(II) Complex, Super-Exchange Interactions, Antiferromagnetic Coupling [Cu, (L)3].3(C1C>4) (LH = l,3-diaminopropan-2-ol) was synthesized and its crystal structure determined. It crystallizes in the triclinic space group P I with a = 10.504(2), b = 10.856(2), c = 12.519(2) A, a = 74.41(1), ß = 70.60(1), 7 = 63.60(1)°, V = 1193.6(3) A3, Z = 2. The structure consists of trimeric [Cu3(L)3]+3 units and three perchlorate anions in the asymmetric unit. In the compound three copper(II) ions are linked by l,3-diamino-2-propanol molecules in such a way that an almost equilateral triangle is formed. The coordination spheres of the three copper(II) ions are slightly different from each other. The coordination geometry of Cul is a distorted square pyramid, and that of Cu2 is almost square planar while that of Cu3 is tetrahedrally distorted square planar. The copper(II) centers are separated by average 3.481(2) A and antiferromagnetically coupled (-J = 100 cm-1), which follows from temperat-ure-dependent magnetic susceptibility measurements in the temperature range 4.4 to 299 K. The average Cu-O-Cu angle is 128.1(1)° in the super-exchange pathway. As the temperature is increased, the magnetic moment rises from 1.41 ^b at 4.4 K to 2.22 ^ b at 299 K. In the \(T) curve no characteristic maximum was observed. The magnetic super-exchange interaction for the title compound is due to the effective overlap of the magnetic orbitals (dx2 _y2) with orbitals of bridging alkoxide oxygen atoms 
  Reference    Z. Naturforsch. 56b, 1123—1128 (2001); received July 6 2001 
  Published    2001 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_B/56/ZNB-2001-56b-1123.pdf 
 Identifier    ZNB-2001-56b-1123 
 Volume    56 
162Author    Y. Elerman3, H. Karab, A. Elmali3Requires cookie*
 Title    Importance of Orbital Complementarity in Spin Coupling through Two Different Bridging Groups. Synthesis, Crystal Structure, Magnetic Properties and Magneto-Structural Correlations in a Dicopper(II) Complex of Endogenous Alkoxo Bridging Ligand with Exogenous Pyrazolate  
 Abstract    Binuclear Copper(II) Complex, Super-Exchange Interactions, Antiferromagnetic Coupling [Qi2(L3)(3,5-prz)] (L3 = 1,3-bis(2-hydroxy-4-methoxybenzylideneamino)-propan-2-ol) (3) was synthesized and its crystal structure determined. The compound consists of discrete binu­ clear units, in which copper atoms are linked by the alkoxide oxygen atom of the ligand and the pyrazolate nitrogen atoms. Variable-temperature magnetic susceptibility measurements for a powdered sample of the complex were carried out in the temperature range 4.4 -308 K and anal­ ysed to obtain values of the parameter J in the exchange Hamiltonian H = —2 JS i -S2. Recently, the dicopper(II) complexes [Cu2(L')(3,5-prz)] (L1 = l,3-bis(2-hydroxy-l-napthylideneamino)-propan-2-ol) (1) and [Cu2(L2)(3,5-prz)], (L2 = l,3-bis(2-hydroxy-5-chlorosalicylideneamino)-propan-2-ol) (2) were reported. These compounds show antiferromagnetic behaviour (—2 J: 444 cm-1 for 1, 164 cm-1 for 2, and 472 cm-1 for 3). The strength of the super-exchange interaction (—2 J) of 2 is much less than that of 1 and 3, a result which is difficult to explain in terms of structural factors on the basis of widely accepted criteria. The differences in the mag­ netic behaviour have been rationalized in terms of the bridging ligand orbital complementary / countercomplementary concept. 
  Reference    Z. Naturforsch. 56b, 1129—1137 (2001); received July 18 2001 
  Published    2001 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_B/56/ZNB-2001-56b-1129.pdf 
 Identifier    ZNB-2001-56b-1129 
 Volume    56 
163Author    Ceyhan Kayran, Pazilaiti RouziRequires cookie*
 Title    Thermal Catalytic Hydrosilylation of Conjugated Dienes with Triethylsilane in the Presence of Tricarbonyl(o-xylene)Metal (Metal = Cr, Mo, W) Complexes  
 Abstract    The thermal catalytic hydrosilylation of 1,3-butadiene (1), rra«5-2-methyl-l,3-pentadiene 
  Reference    Z. Naturforsch. 56b, 1138—1142 (2001); received July 2 2001 
  Published    2001 
  Keywords    Hydrosilylation, Tungsten, Carbonyl 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_B/56/ZNB-2001-56b-1138.pdf 
 Identifier    ZNB-2001-56b-1138 
 Volume    56 
164Author    MarcW. Pohlkamp, Wolfgang JeitschkoRequires cookie*
 Title    Preparation, Properties, and Crystal Structure of Quaternary Silicide Carbides /?Cr2Si2C (R = Y, La -Nd, Sm, Gd -Ho)  
 Abstract    Quaternary Silicide Carbides The title compounds were prepared by arc-melting cold-pressed pellets of the elemental components. They crystallize with a tetragonal structure already reported for CeCr:Si2C. It was refined from single-crystal X-ray data of PrCriSiiC: PMmmm, a -402.2(1) pm, c = 535.2(1) pm, Z = 1, R = 0.012 for 252 structure factors and 10 variable parameters. Magnetic susceptibility measurements with a SQUID magnetometer indicate Pauli paramagnetism for YCr^Si^C, while CeCnSi^C shows mixed valent behavior. The carbon atoms in the structure of these compounds are isolated from each other. The silicon atoms form pairs with a Si-Si distance of 245.3 pm, somewhat greater than the single-bond distance of 235.2 pm in elemental silicon. Together with the chromium atoms, the silicon pairs and carbon atoms form a three-dimensionally infinite polyanion, which has some similarity with the polyanions found in several related tetragonal structures, e. g., the structures of ThCriSii and LuNi^I^C. 
  Reference    Z. Naturforsch. 56b, 1143—1148 (2001); received June 13 2001 
  Published    2001 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_B/56/ZNB-2001-56b-1143.pdf 
 Identifier    ZNB-2001-56b-1143 
 Volume    56 
165Author    Petra Lauxmann, Thomas SchleidRequires cookie*
 Title    CsCu3Dy2S5 und CsCu3Er2S5 : Zwei isotype quaternäre Sulfide der Lanthanoide mit Kanalstrukturen CsCu3Dy2S5 and CsCu3Er2S5: Two Isotypic Quaternary Sulfides of the Lanthanides with Channel Structures  
 Abstract    Orthorhombic single crystals of CsCu3 Dy2 S5 (a = 397.54(4), b = 1414.8(1), c = 1685.7(2) pm) and CsCu3 Er2 S5 (a = 394.82(4), b= 1410.9(1), c = 1667.2(2) pm; both Cmcm, Z = 4) are obtained as by-products (pale yellow or pink transparent needles) in attempts to synthesize CuMS2 (M = Dy and Er) through the oxidation of elemental copper, dysprosium and erbium, respectively, with sulfur (molar ratios: 1 :1 :2) in the presence of equimolar amounts of cesium chloride (CsCl) as fluxing agent at 900 °C within fourteen days from torch-sealed evacuated silica tubes. Their crystal structure contains octahedral [MS6]9~ units (d(M-S) = 269 -282 pm) which share edges and vertices to form layers ^ {(M 2 S5)4_} parallel (010). These are three-dimensional-ly interconnected along [010] by two crystallographically different Cu+ cations in tetrahedral coordination of S2_ anions (d(Cu-S) = 227 -269 pm) according to ^{(Cu^MtSs)-}. Thereby a likewise layered substructure 2,{(Cu3 S5)7 -} is formed parallel (010) by edge-and vertex-linking of all [CuS4]7~ tetrahedra. Large channels within the <£>{(Cu3 M2 S5)~ } network spread along [100] and suit well to take up the highly coordinated Cs+ cations, which are surrounded by eight plus one S2~ anions at distances between 340 and 358 pm (8 x) with the ninth ligand 420 -421 pm apart in the shape of (2+7)-fold capped trigonal prisms. 
  Reference    Z. Naturforsch. 56b, 1149—1154 (2001); eingegangen am 27. August 2001 
  Published    2001 
  Keywords    Copper, Lanthanides, Sulfides 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_B/56/ZNB-2001-56b-1149.pdf 
 Identifier    ZNB-2001-56b-1149 
 Volume    56 
166Author    Gerhard Müller, Hans-Joachim Matheus3, Martin WinklerbRequires cookie*
 Title    Donor-Acceptor Complexes between Simple Phosphines. First Structural Data for an Almost Forgotten Class of Compounds  
 Abstract    Lewis acid-base adducts between simple phosphines have been structurally characterized for the first time in the form of (Me3 P)PBr3 (1) and (MeiPjPB^Bz' (2; Bz' = 3,5-dimethyl-benzyl). On the basis of its solid-state structure the bonding situation in 1 may be described as intermediate between a neutral donor-acceptor complex containing hypervalent phosphorus(III) and an ion pair, according to the resonance formulae Me3 P —► PBn — [Me3 P-PBr2 ]+Br_ . The weak (incomplete) bond formation to the third bromine atom clearly reflects the reluctance of trivalent phosphorus to accommodate more than four electron pairs in its valence shell. (Crystal data for 1: monoclinic P2\ln, a = 7.142(3), b = 16.844(2), c = 8.139(4) A, ß = 106.24(2)°, Z = 4). As a result of the inferior acceptor properties of PB^Bz' as compared to PBr3 , 2 has more ion pair character [MeiP-PBrBz] Br"othan 1. (Crystal data for 2: orthorhombic P 2j 2i2 i, a = 7.063(2), b = 8.578(2)rf c = 25.158(4) A, Z = 4). Both compounds have short P-P bonds (1: 2.264(2); 2: 2.236(2) A). The results are compared with previous IR/Raman and NMR investigations on 1 : 1 and 2 : 1 adducts between organophosphines (as donors) and phosphorus trihalides (as acceptors). 
  Reference    Z. Naturforsch. 56b, 1155—1162 (2001); received July 17 2001 
  Published    2001 
  Keywords    Hypervalence, Phosphines, Lewis Acid-Base Adducts 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_B/56/ZNB-2001-56b-1155.pdf 
 Identifier    ZNB-2001-56b-1155 
 Volume    56 
167Author    Gerhard Müller, Jörg Brand, SimoneElisabeth JetterRequires cookie*
 Title    Donor-Acceptor Complexes between Organoamines and Phosphorus Tribromide  
 Abstract    Lewis acid-base adducts between NMe3, tmeda (A^A^Af'-tetramethylethylenediamine), and 1.4-dimethylpiperazine as donors and PBr3 as acceptor have been prepared and structurally characterized. NMe3 and tmeda form 1:1 adducts (Me3 N)PBr3 (1) and (tmeda)PBr3 (2), re­ spectively, while 1,4-dimethylpiperazine adds 2 molecules of PBr3 leading to [(1,4-dimethyl-piperazine)(PBr3):] (3). Adduct 2 is found in two modifications 2a and 2b with different crystal and molecular structures. (Crystal data of 1: monoclinic P2\/n, a = 5.983(3), b = 10.821(2), c = 13.877(5) Ä, ß = 99.70(2)°, Z = 4. 2a: monoclinic P2i/c, a = 7.891(1), b = 12.826(1), c = 12.218(2) A ,ß = 102.162(6)°, Z = 4. 2b: monoclinic P2]/n, a = 11.687(2), b = 8.375(1), c = 12.668(1) A, ß = 102.74(1)°, Z = 4. 3: monoclinic P2Jc, a = 6.383(3), b = 16.36(3), c = 8.407(3) A,ß= 101.49(2)°, Z= 2). The molecular structures of 1 and 2 indicate a partially ionic character with a strongly bonded amine and one (1) or two (2) weakly bonded bromine atoms. In 2 the donor tmeda is bonded through both nitrogen atoms to one phosphorus atom. In 3 the 1.4-dimethylpiperazine ring is in chair conformation, the methyl and PBr3 substituents being in equatorial and axial positions, respectively. Due to axial-axial repulsion the N-P donor-acceptor bonds are long while the P-Br bonds are rather uniform in length. 
  Reference    Z. Naturforsch. 56b, 1163—1171 (2001); received July 17 2001 
  Published    2001 
  Keywords    Hypervalence, Phosphines, Lewis Acid-Base Adducts 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_B/56/ZNB-2001-56b-1163.pdf 
 Identifier    ZNB-2001-56b-1163 
 Volume    56 
168Author    Georg Ziegler, Willi KantlehnerRequires cookie*
 Title    Orthoamides, LVI [1]. A New Method of Wide Scope for the Preparation of Aryl Formates  
 Abstract    26 are prepared by formylation of hydroxyarenes 3a-u, 25 with /V,Af-diformylacetamide (1) or triformamide (2), respectively, in fairly good yields. The reactions can be catalyzed by sodium diformamide or praseodymium(III) triflate. The thiolformate 28 was obtained analogously from 1-thionaphthol (27). 
  Reference    Z. Naturforsch. 56b, 1172—1177 (2001); received July 13 2001 
  Published    2001 
  Keywords    Aryl Formates, Formylation, Hydroxyarenes Aryl formates 4a-u, 6 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_B/56/ZNB-2001-56b-1172.pdf 
 Identifier    ZNB-2001-56b-1172 
 Volume    56 
169Author    Georg Ziegler3, Erwin Haug3, Wolfgang Freyb, Willi Kantlehner3Requires cookie*
 Title    Orthoamide, LVII [1]. Lassen sich aromatische Aldehyde nach Fries aus Arylformiaten hersteilen? Orthoamides, LVII [1]. Can Aromatic Aldehydes be Prepared from Aryl Formates via the Fries Rearrangement?  
 Abstract    The aromatic hydroxyaldehydes 3a-3g, 5a-5f, 8 , 10 can be prepared by the action of BC13, BBr3 or trifluoromethanesulfonic acid, on the aryl formates la-lf, 4a-e, 7, 9 via Fries rear­ rangement. BBr3 is more effective than BC13. The activating ability of BBr3 can be improved by addition of FeCl3. Rearrangements which are induced by trifluoromethanesulfonic acid can give rise to the formations of regioisomers, which might be different from the products formed when the reaction is performed with Lewis acids. The yields of the aldehydes are lowered by subsequent condensation reactions. This view was confirmed by the isolation of a con­ densation product, which was characterized as a dibenzo[a,y']xanthene derivative 6 by crystal structure analysis. For the Fries rearrangement of formyl groups a new mechanism is proposed. 2-Hydroxy-1-naphthaldehyde 5c can be obtained in good yield from formic acid, BBr3, and 2 -naphthol. 
  Reference    Z. Naturforsch. 56b, 1178—1187 (2001); eingegangen am 13. Juli 2001 
  Published    2001 
  Keywords    Aromatic Hydroxyaldehydes, Fries Rearrangement, Formylation 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_B/56/ZNB-2001-56b-1178.pdf 
 Identifier    ZNB-2001-56b-1178 
 Volume    56 
170Author    Jörg Dalluhn, Hans-Heinrich Pröhl, Oliver Moers, Armand Blaschette, PeterG. JonesRequires cookie*
 Title    Polysulfonylamine, CXLVII [1]. Die ersten N,N-disulfonylierten Thioharnstoffe: Synthese von (R S02)2N -C(S)-NMe2 (R = Me, 4-M e-C6H4) und Kristallstruktur der Ditosylverbindung Polysulfonylamines, CXLVII [1]. The First N,N-Disulfonylated Thioureas: Synthesis of (R S 0 2 )2 N -C ( S ) -N M e 2 (R = Me, 4 -M e -C 6 H 4) and Crystal Structure of the Ditosyl Compound  
 Abstract    The moisture-sensitive title compounds were obtained in good yields by treating the corre­ sponding silver salts AgN(S0 2 R) 2 with the thiocarbamoyl chloride Me2 NC(S)Cl in aceto-nitrile. In the NMR solution spectra of the novel thioureas, as recorded at room temperature for 13C and up to 120 °C for 'H, the Me2N group invariably gives rise to two distinct resonan­ ces, reflecting unusually high barriers to rotation about the_C(S)-NMe2 bond. The crystal structure of the ditosyl compound (triclinic, space group P I, X-ray diffraction at -130 °C) contains two independent molecules A and B, in which the bond lengths and angles are nearly identical, whereas the conformations exhibit pronounced discrepancies. The amide N and thiocarbonyl C atoms have trigonal-planar environments, but the S -N -S planes are strikingly rotated into approximately perpendicular orientations relative to the planar C2N -C (S)-N moieties. Other remarkable features of the molecular structures are the exceedingly long C(S)-NS2 bonds [mean: 145.4(3) pm] and the concomitantly short C -S and C(S)-NC2 bonds [mean values: 164.8(2), 132.6(3) pm]. The packing is governed by a three-dimensional system of weak hydrogen bonds and may be viewed as a self-clathrate, in which (B) 2 dimers constructed from C -H —S=C interactions are inserted as guest species into parallel tunnels between (A)oo tapes based upon short C -H — 0=S contacts. 
  Reference    Z. Naturforsch. 56b, 1188—1195 (2001); eingegangen am 4. September 2001 
  Published    2001 
  Keywords    Sulfonylthioureas, Thioamide Single Bond, Weak Hydrogen Bonding 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_B/56/ZNB-2001-56b-1188.pdf 
 Identifier    ZNB-2001-56b-1188 
 Volume    56 
171Author    Gerhard Himbert, Oliver GerulatRequires cookie*
 Title    Einige Umsetzungen von Inhydrazinen mit Isocyanaten: [2+2]-und [4+2]Cycloadditionen, (Hydrazinoethinyl)metallierung Some Reactions of Ynehydrazines with Isocyanates: [2+2]-and [4+2]Cycloadditions, (Hydrazinoethynyl)metallation  
 Abstract    The (silylethynyl)-and the (tolylethinyl)-hydrazines la and lb react with aryl isocyanates 2 a -e and arylsulfonyl isocyanates 2f,g to form the corresponding substituted 3-arylimino-(or arylsulfonylimino-) l,l,2-trimethyl-5-oxopyrazolidinium-4-ides 3a-h. The silyl group in the 4-position can be replaced by a hydrogen atom (formation of 6a-e). Heating of 6d in toluene induced the unequivocal transformation of the betaine to an isomer, the spectrocopic data of which are in concordance with those of the 4-quinolone derivative 7. Aroyl isocyanates 8 react in a [4+2]cycloaddition with la to furnish the l,3-oxazin-4-ones 9a and b. The stannyla-ted ynehydrazine lc adds the cumulenic system of an aryl isocyanate (2d) across the Csp-Sn single bond, and trimethylstannyl ./V-(p-chlorophenyl)-3-(trimethylhydrazino)propiolimidate 10 is isolated. With two molecules of 2d the hydantoin derivative 11 is formed. 
  Reference    Z. Naturforsch. 56b, 1196—1204 (2001); eingegangen am 2. August 2001 
  Published    2001 
  Keywords    Cycloadditions, Cyclic Betaines, l, 3-Oxazin-4-ones 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_B/56/ZNB-2001-56b-1196.pdf 
 Identifier    ZNB-2001-56b-1196 
 Volume    56 
172Author    Cungen Zhang, Christoph Janiak, Horst BrombacherRequires cookie*
 Title    Structural Influence of Hydrogen Bonding and ^r-Stacking in fra/is-Diazido-tetra- kis(pyrazole)nickel(II) and rra/is-Diazido-tetrakis(3-methylpyrazoIe)nickel(II)  
 Abstract    The molecular nickel complexes fra«s-diazido-tetrakis(pyrazole)nickel(II) and trans-dia-zido-tetrakis(3-methylpyrazole)nickel(II) feature terminal monohapto-bound azide ligands. The pyrazole (pyr) ring planes are aligned along the Nazide-Ni-Nazide axis by intramolecular N-H—Nazide bonds. The crystal packing is controlled by jr-stacking between both pyrazole rings and azide ligands, N -H —Nazide hydrogen bonds, and intermolecular N-H—jrpyr and C-H —N/jrazide interactions. 
  Reference    Z. Naturforsch. 56b, 1205—1208 (2001); received July 20 2001 
  Published    2001 
  Keywords    Nickel Complexes, ^-Stacking, Hydrogen Bonding 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_B/56/ZNB-2001-56b-1205.pdf 
 Identifier    ZNB-2001-56b-1205 
 Volume    56 
173Author    R. Obert Weiss, Frank Pühlhofer, Frank HampelRequires cookie*
 Title    7-Azoniafluorenonderivate durch elektrostatisch aktivierte SNAr-Reaktionen 7-Azoniafluorenone Derivatives by Electrostatically Activated SNAr-Reactions  
 Abstract    7-Azoniafluorenone, SNAr-Reactions, Electrostatic Effects Various fluorosubstituted benzoylchlorides la -c are transformed into the corresponding acylpyridinium triflates 2a-c by one equivalent of the reagent pair 4-dimethyl-aminopyri-dine/trimethylsilyltriflate (DMAP/TMSOTf). Due to the combined electrostatic and mesom-eric effect of the acylpyridinium function, fluorine substituents in o-and p-positions can be subsequently substituted with a pyridinio group by additional equivalents of DMAP/ TMSOTf via an SNAr mechanism. Whereas the p-substitution product can be isolated as the highly electrophilic dication salt 3b, the corresponding mono-and bis-orthosubstituted polycation salts 3a and 3c are transformed under the reaction conditions to the 7-azonia-fluorenone derivatives 4a,c by a novel cyclo-acylation. Structural and electrochemical data of these compounds are presented. 
  Reference    Z. Naturforsch. 56b, 1209—1216 (2001); eingegangen am 9. Juli 2001 
  Published    2001 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_B/56/ZNB-2001-56b-1209.pdf 
 Identifier    ZNB-2001-56b-1209 
 Volume    56 
174Author    NicolayI. DodoffRequires cookie*
 Title    Palladium(II) and Platinum(II) Complexes o f iV-3-Pyridinylmethanesulfonamide  
 Abstract    , 2001 IR Spectra, Palladium(II) and Platinum(II) Complexes, /V-3-Pyridinylmethanesulfonamide The complexes ds-[Pd(PMSA)2Cl2] a's-[Pt(PMSA)2X2], rrans-[Pt(PMSA)2I2] and [Pt(PMSA)4]Cl2 (PMSA = N-3-pyridinylmethanesulfonamide; X = Cl, Br, I) have been syn­ thesized and characterized by elemental analysis, molar electric conductivity, IR and 'H NMR spectra. A detailed assignment of the IR spectra (4000-150 cm !) of the complexes, supported by an approximate normal coordinate analysis, has been performed. The com­ plexes are of square-planar type and the PMSA ligand is coordinated via the pyridine nitro­ gen atom. 
  Reference    Z. Naturforsch. 56b, 1217—1226 (2001); received August 28 
  Published    2001 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_B/56/ZNB-2001-56b-1217.pdf 
 Identifier    ZNB-2001-56b-1217 
 Volume    56 
175Author    Fazila Zulfiqar, Abdul MalikRequires cookie*
 Title    Facile Approach to Versatile Chiral Intermediates for Fused Cyclopentanoid Natural Products  
 Abstract    Intermediates, Fused cyclopentanoids A facile approach to cis-and rrans-2-(l-hydroxymethyl)vinyl-l-vinylcyclohexan-l-ols and to the corresponding cyclopentane, cycloheptane, and cyclooctane derivatives has been devel­ oped, starting from cycloalkanones involving the key steps of Rupe and Claisen orthoester rearrangements. The formation of intervening products could be explained by allylic strain and jr-stacking, respectively. 
  Reference    Z. Naturforsch. 56b, 1227—1234 (2001); received December 4 2000 Chiral 
  Published    2001 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_B/56/ZNB-2001-56b-1227.pdf 
 Identifier    ZNB-2001-56b-1227 
 Volume    56 
176Author    N. Orbert Kuhna, G. Erd Weyersa, D. Ieter Bläserb, Roland BoesebRequires cookie*
 Title    Nucleophilic A rom atic Substitution at 2-Fluoroimidazolium Ions: Synthesis and Crystal Structure of a Dicationic 2,2'-Biimidazolyl Derivative [1]  
 Abstract    Imidazoles, Enetetramine The dicationic 2,2-biimidazolyl derivative 5 has been obtained from the imidazolium salt 3 and the carbene 4 in good yield. The presence of the carbene 4 and its unstable dimer 7 were detected by NMR in the reduction product of 5 with potas­ sium. The crystal structure of 5 • H 20 is reported. 
  Reference    Z. Naturforsch. 56b, 1235—1237 (2001); eingegangen am 7. August 2001 
  Published    2001 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_B/56/ZNB-2001-56b-1235_n.pdf 
 Identifier    ZNB-2001-56b-1235_n 
 Volume    56 
177Author    Andreas Nägele3, Cynthia Dayb, Abdessadek Lachgarb, H.-Jürgen Meyer3, Sonderdruckanforderungen An, ProfH. Dr, -J MeyerRequires cookie*
 Title    Interpenetrierende Clusterstränge in der Kristallstruktur von Ko,77Nb6Cl15 Interpenetrating Cluster Chains in the Structure of Ko.77Nb6Cl15  
 Abstract    The solid state reaction of KCl, NbCl5 and Nb powder at 760 °C yielded black crystals of KNb6Cl15. The structure of the compound has been determ ined using single-crystal X-ray m e­ thods. KNb6Cli5 crystallizes in the orthorhombic space group Pmma (no. 51) with lattice constants a = 1780.1(2), b = 1341.4(1), and c = 925.5(1) pm, Z = 4, and R1 = 0.039 for all 2727 observed reflec­ tions. [ (N ^ C l ^ C l ^ 3'3]-anions in the structure are linked via two Cla a bridges to form one set of li­ near and one set of kinked chains along the cry­ stallographic c and a directions. Four remaining Cla a bridges interconnect both sets of chains to a three-dim ensional network. The potassium occu­ pancy on a 4k site was refined to a value of 0.384(3) consistent with the formula K0 77Nb6C li5. Ternäre Niobchloride des Formeltyps A Nb6Cl15 wurden bereits verschiedentlich beschrieben. Ver­ bindungen mit A = Li [1] und Na [2] kristallisieren kubisch (Ia3d) mit identischen Schweratomstruk-turen. Die Alkalim etall-Ionen Li (KZ = 4) und Na (KZ = 6) besetzen in den Strukturen A N b6Cl15 aber unterschiedliche Splitlagen und sind dyna­ misch fehlgeordnet. Die V ertreter mit A = In und TI [3] kristallisieren orthorhombisch (Pmma). Ihre Kationen befinden sich in zweifach überdachten, würfelförmigen Cl-Umgebungen (KZ = 10). Die Kenntnis des Formeltyps A N b6Cl15 mit schweren Alkalim etallen ist noch unvollständig. Einkristall­ 
  Reference    Z. Naturforsch. 56b, 1238—1240 (2001); eingegangen am 26. Juli 2001 
  Published    2001 
  Keywords    Niobium, Chloride, Cluster 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_B/56/ZNB-2001-56b-1238_n.pdf 
 Identifier    ZNB-2001-56b-1238_n 
 Volume    56 
178Author    Florian Stadler, Thomas Fickenscher, Rainer PöttgenRequires cookie*
 Title    Synthesis and Structure of RE2Rh2Cd (RE = La, Ce, Pr, Nd, Sm)  
 Abstract    New intermetallic cadmium compounds /?£2Rh2Cd (r e = La, Ce, Pr, Nd, Sm) were syn­ thesized from the elements in sealed tantalum tubes in a high-frequency furnace. They were characterized through X-ray powder data: Mo2FeB2 type, space group P4/mbm, Z = 2. Single crystal data of the cerium compound (a = 762.8(1), c = 377.8(1) pm, wR2 = 0.0662, 199 F2 values, and 13 variable parameters) revealed small defects on the rhodium position leading to the composition Ce2R h186(3)Cd for the investi­ gated crystal. According to the course of the cell volumes Ce2Rh2Cd may be classified as a mixed-valent compound. The Ce2Rh2Cd structure is an intergrowth of slightly distorted A1B2 and CsCl related slabs of compositions CeRh2 and CeCd. Within the CeRh2 slab short Ce-Rh contacts (284-300 pm) are indicative of strong Ce-Rh bonding. The Rh-Rh distance within the A1B2 re­ lated slab is 289 pm. 
  Reference    Z. Naturforsch. 56b, 1241—1244 (2001); received September 10 2001 
  Published    2001 
  Keywords    Cadmium, Solid State Synthesis, Mixed Valence 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_B/56/ZNB-2001-56b-1241_n.pdf 
 Identifier    ZNB-2001-56b-1241_n 
 Volume    56 
179Author    Constantin Hoch, Caroline RöhrRequires cookie*
 Title    Neue Oxogermanate(IV) der schweren Alkalimetalle. Synthesen und Kristallstrukturen New Oxogermanates(IV) of the Heavy Alkaline Metals. Preparation and Crystal Structure  
 Abstract    The new germanates(IV) were synthesized via reaction of GeC>2 with AO2 (A=K, Rb, Cs) and the elemental alkaline metals and their crystal structures have been determined from single crystal X-ray data. ß-K^GeOi / Rh+GeC^ (monoclinic, P 2 \/c , a = 1047.6(3)/1103.2(2), b = 646.5(1)/673.3(1), c = 1048.1(3)/1084.5(2) pm, ß = 112.291(5) / 112.676(4)°, Z = 4) and CsioGe209 (monoclinic, P 2 \/c , a = 1293.7(2), b = 1148.6(2), c = 1926.4(2) pm, ß = 128.05(8)°, Z = 4) contain isolated, AöGe309 (A = Rb / Cs: monoclinic, P 2 \/c , a = 663.0(1) / 696.3(2), b = 1346.8(2) / 1403.1(3), c = 1666.6(2) / 1742.8(6) pm, ß = 107.47(2) / 107.88(2)°, Z = 2) cyclotrigermanate ions. In Cs3AlGe207 (monoclinic, C 2/c, a = 961.5(2), b = 1719.7(2), c = 761.7(1) pm, ß =126.5(1)°, Z = 4) digermanate ions are connected via [AIO4 ] tetrahedra to form ribbons. 
  Reference    Z. Naturforsch. 56b, 1245—1256 (2001); eingegangen am 30. August 2001 
  Published    2001 
  Keywords    Germanates, Oxogermanates, Alumogermanates 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_B/56/ZNB-2001-56b-1245.pdf 
 Identifier    ZNB-2001-56b-1245 
 Volume    56 
180Author    JamesD E T Wilton-Ely, Stefan Hofreiter, NorbertW. Mitzel, Hubert SchmidbaurRequires cookie*
 Title    Thiolate Complexes of Gold(I) Based on a Tris(phosphine) Support  
 Abstract    Gold(I) Complexes, Tri(tertiary phosphine) Complexes, Thiolate Complexes Treatment of the ligand l,3,5-tris[(diphenylphosphanyl)methyl]trimethylbenzene (P3) with (tetrahydrothiophene)gold(I) chloride results in the symmetrical trigold complex [(P3)(AuC1)3]. In the presence of sodium methoxide, [(P3)(AuC1)3] reacts with thiocresol (HSCöH4Me-4) and 2-mercaptoquinoline (2-HSQn) to provide the complexes [(P3)(AuSC6H4Me-4)3] and [(P3)(AuSQn)3], respectively. Reaction of [(P3)(AuCl)3] with KSCN also yields the expected product [(P3)(AuSCN)3], however, treatment with 2-10 molar equivalents of NaSMe re­ sults only in the unsymmetrical cationic complex [(P3)Au3(SMe)2]Cl. Reaction between [(P3)(AuOTf)3] (prepared in situ from [(P3)(AuC1)3] and AgOTf) and sodium sulfide yields the complex [(P3)Au3S]+0 S02CF3_ , the first example of a trigoldsulfonium unit coordinated to a tridentate phosphine. The tetrafluoroborate salt is obtained from [(P3)(AuCl)3] and Na2S • 9 H2O in the presence of NaBF4. The structure of [(P3)(AuSMe)2]Cl has been determined and reveals that in the solid the two methylthiolate units bridge the three gold atoms, but the structure of the cation is fiuxional in solution according to NMR data. 
  Reference    Z. Naturforsch. 56b, 1257—1263 (2001); received September 11 2001 
  Published    2001 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_B/56/ZNB-2001-56b-1257.pdf 
 Identifier    ZNB-2001-56b-1257 
 Volume    56 
Prev
...
6
7
8
9
10
Next