Published by De Gruyter

Volume 59 Issue 2

Issue of Zeitschrift für Naturforschung B

Contents
Journal Overview

June 2, 2014

Zur Reaktion von 2,3-Dihydro-1,3-diisopropy1-4,5-imidazol-2-yliden mit Bromderivaten der Meldrumsäure [1, 2] / On the Reaction of 2,3-Dihydro-1,3-diisopropy1-4,5-dimethylimidazol-2-ylidene with Bromine Derivatives of Meldrum’s Acid [1, 2]

Norbert Kuhn, Ahmed Al-Sheikh, Simon Schwarz, Manfred Steimann

Page range: 129-133

Abstract

The Imidazolium salts [ImH][MelBr] (7) and [ImBr][MelBr] (8) have been obtained from the carbene Im (5) and the Meldrum’s acid derivatives MelHBr (3) and MelBr 2 (4). The crystal structure analyses of 7 and 8 reveal the presence of ion pairs linked by short OH (7: 2.163 Å ) and OBr (8: 2.872 Å ) contacts.

June 2, 2014

Polyol Metal Complexes, 45 [1]. D-Glucopyranosides as Ligands in Nickel Complexes

Sven Herdin, Gerhard Kettenbach, Peter Klüfers

Page range: 134-139

Abstract

Crystalline nickel complexes with dianionic glucopyranoside ligands have been obtained by the reaction of methyl-D-glucopyranoside (Me-β -D-Glcp) or sucrose (Suc) with the cellulose solvent Ni-tren, an aqueous solution of [(tren)Ni(OH) 2 ], tren = tri(2-aminoethyl)amine. Crystals of a nickel complex of α,α-trehalose (α,α-Tre) form after the reaction of the disaccharide with Ni-Me 3 tren, the N,N′,N″-trimethyl analogue of Ni-tren. The metal-binding site is the O 3 ,O 4 diolate in [(tren)Ni(Me-β-D-Glcp3,4H −2 )] · 5.5H 2 O; in [(tren)Ni(Suc2’,3’H −2 )] · 6H 2 O, hydrogen-bond-supported O 2 ,O 3 chelation in the glucose part of the disaccharide is observed. The same metal-binding site as sucrose is exhibited by α,α-trehalose in [(tren)Ni(α,α-Tre2,3H −2 )] ・ 5H 2 O but without the support by an intramolecular hydrogen bond.

June 2, 2014

Crystal Structures of the Supramolecular Aggregates of the Methyl and Chloro Substituted Gallanes Me_xGaCl_3-x

Christian Lustig, Norbert W Mitzel

Page range: 140-147

Abstract

The crystal structures of the complete series of compounds of the general formula Me x GaCl 3−x have been determined. New polymorphs of GaCl 3 and MeGaCl 2 were found. All chloro compounds Me x GaCl 3−x (x = 0, 1, 2) are dimers with Ga 2 Cl 2 four-membered rings. (GaCl 3 ) 2 and (MeGaCl 2 ) 2 are aggregated into layers with the same aggregation motif (each molecule connected to four neighbouring molecules), (Me 2 GaCl) 2 is associated in a ladder-like structure (each molecule connected to two neighbouring molecules), GaMe 3 forms weakly Ga···C bound pseudo-tetramers aggregated into layers by further Ga···C contacts (each molecule has two shorter Ga···C’ and C···Ga’ and two weaker Ga···C’ and C···Ga’ contacts).

June 2, 2014

DFT and G2MP2 Calculations of the N-N Bond Dissociation Enthalpies and Enthalpies of Formation of Hydrazine, Monomethylhydrazine and Symmetrical and Unsymmetrical Dimethylhydrazine

Manfred A Bohn, Thomas M Klapötke

Page range: 148-152

Abstract

In a combined DFT (B3LYP) and G2MP2 theoretical study the following enthalpies of formation (ΔH° f ) and bond dissociation enthalpies (BDE) for hydrazine, methylhydrazine (MMH), 1,1- dimethylhydrazine (UDMH) and 1,2-dimethylhydrazine (SDMH) were determined: BDE/kJ mol −1 : N 2 H 4 , 278±4; MMH, 272±4; UDMH, 259±12; SDMH, 272±12. ΔH° f /kJ mol −1 : N 2 H 4 , 95±6; MMH, 94±4; UDMH, 80±4; SDMH, 91±4. The bond enthalpy for the N-N bond in hydrazine amounts to BE (N-N, H 2 N−NH 2 ) = 159±4 kJ mol −1 .

June 2, 2014

Triethoxysilane, Tetraethoxysilane and Hexaethoxydisiloxane – Three Complementary Reagents for the Synthesis of Hydrogen-Rich Silylarenes

Oliver Minge, Stefan Nogai, Hubert Schmidbaur

Page range: 153-160

Abstract

Triethoxysilane HSi(OEt) 3 , tetraethoxysilane Si(OEt) 4 and hexaethoxydisiloxane Si 2 O(OEt) 6 have been probed as reagents for the synthesis of hydrogen-rich silyl-arenes Ar(SiH 3 ) n . A large set of new silyl-arenes, varying in their substitution patterns and grades, have been prepared. The results establish the two new silylating agents HSi(OEt) 3 and Si 2 O(OEt) 6 as particularly useful alternatives to Si(OEt) 4 . The products, which include trihydrosilyl-substituted methylbenzenes, naphthalenes and ferrocenes, have been characterized by NMR and IR spectroscopy, mass spectrometry and single crystal X-ray diffraction.

June 2, 2014

Dimeric Methylzinc Bis(2-pyridylmethyl)amide – Synthesis, Molecular Structure and Reaction with Dimethylzinc

Matthias Westerhausen, Alexander N Kneifel, Ivonne Lindner, Jelena Grčić, Heinrich Nöth

Page range: 161-166

Abstract

The zincation of bis(2-pyridylmethyl)amine with dimethylzinc yields dimeric methylzinc bis(2-pyridylmethyl)amide (1) with a central Zn 2 N 2 cycle with Zn-N distances of 204.8(5) and 209.8(4) pm. The Zn-C bond length of 197.0(5) pm lies in the characteristic region. The addition of dimethylzinc to 1 leads to an opening of the Zn 2 N 2 cycle and the formation of tetramethyltrizinc bis[bis(2-pyridylmethyl)amide] (2). The dimethylzinc molecule coordinates to a pyridyl and an amide group, the C-Zn-C bond angle of 135.3(3) being rather large. In solution, compound 2 loses methane at room temperature and the intramolecular metalation product tris(methylzinc) bis(2- pyridylmethyl)amide 1,3-di(2-pyridyl)-2-azapropane-1,2-diide (3) precipitates. The newly formed Zn-C bond is extremely long at 219.7(5) pm.

June 2, 2014

Synthese und Struktur der Nitridokomplexe (Ph₃Sb)₂Cl₃Os≡N-RhCl(COD), (Me₂PhP)₂(PhCN)Cl₂Re≡N-RhCl₂(C₅Me₅), [(Me₂PhP)₃(PhCN)ClRe≡N-OsCl₂(CO)₃][OsCl₃(CO)₃] und [(Me₂PhP)₃(PhCN)ClRe≡N-ReCl₄-N≡ReCl(NCPh)(PMe₂Ph)₃][OsCl₄(CO)₂] / Synthesis and Structure of the Nitrido Complexes (Ph₃Sb)₂Cl₃Os≡N-RhCl(COD), (Me₂PhP)₂(PhCN)Cl₂Re≡N-RhCl₂(C₅Me₅), [(Me₂PhP)₃(PhCN)ClRe≡N-OsCl₂(CO)₃][OsCl₃(CO)₃], and [(Me₂PhP)₃(PhCN)ClRe≡N-ReCl₄-N≡ReCl(NCPh)(PMe₂Ph)₃][OsCl₄(CO)₂]

Simon Schwarz, Montserrat Galceran Mestres, Elke Niquet, Carlos F Barboza da Silva, Joachim Strähle

Page range: 167-173

Abstract

The reaction of (Ph 3 Sb) 2 Cl 3 OsN with [Rh(μ-Cl)(COD)] 2 in benzonitrile yields the heteronuclear nitrido complex (Ph 3 Sb) 2 Cl 3 Os≡N-RhCl(COD) (1). It crystallizes as dark brown blocks in the triclinic space group P1 with a = 1080.09(5), b = 1173.15(5), c = 1702.28(9) pm, α = 101.214(4), β = 92.923(8), γ = 92.836(5)֯, and Z = 2. The complex fragment RhCl(COD) is coordinated to the osmium nitrido complex via a linear nitrido bridge Os≡N-Rh, with a bond angle Os-N-Rh = 175.3(5)° and distances Os-N = 168.6(6) and Rh-N = 184.6(6) pm. The heteronuclear complexes (Me 2 PhP) 2 (PhCN)Cl 2 Re≡N-RhCl 2 (C 5 Me 5 ) (2) and [(Me 2 PhP) 3 (PhCN)ClRe≡NOsCl 2 ( CO) 3 ][OsCl 3 (CO) 3 ] (3) are obtained by the reaction of (Me 2 PhP) 3 Cl 2 ReN with [RhCl(μ- Cl)(C 5 Me 5 )] 2 and [OsCl(μ-Cl)(CO) 3 ] 2 , respectively, in benzonitrile. 2 forms orange red crystals with the composition 2・C 6 H 5 CN in the monoclinic space group P2 1 /c and a =910.23(7), b =1255.4(1), c = 3761.5(3) pm, β = 95.617(9)° and Z = 4. The nitrido bridge Re≡N-Rh to the complex fragment [RhCl 2 (C 5 Me 5 )] has a bond angle Re-N-Rh of 171.9(3)° and distances Re-N = 169.4(5) and Rh-N = 201.9(5) pm. 3 forms yellow orange plates with the monoclinic space group P2 1 /c and a = 1113.74(5), b = 2038.5(2), c = 2130.1(1) pm, β = 90.298(6)° and Z = 4. The nitrido bridge within the complex cation [(Me 2 PhP) 3 (PhCN)ClRe≡N-OsCl 2 (CO) 3 ] + is characterized by a bond angle Re-N-Os of 167.7(4)° and distances Re-N = 169.5(8) and Os-N = 206.1(8) pm. The ligands of the octahedral anion [OsCl 3 (CO) 3 ] − are in a facial arrangement. The synthesis of 3 yields [{(Me 2 PhP) 3 (PhCN)ClRe≡N} 2 ReCl 4 ][OsCl 4 (CO) 2 ] (4) as a byproduct. It crystallizes as red brown blocks with the composition 4·CH 2 Cl 2 in the space group P1 and a = 1444.2(1), b = 1536.3(1), c = 2150.5(2) pm, α =87.41(1), β =88.54(1), γ =62.453(8)° and Z =2. In the two symmetry independent, centrosymmetric cations [(Me 2 PhP) 3 (PhCN)ClRe≡N-ReCl 4 -N≡ReCl(NCPh)(PMe 2 Ph) 3 ] 2+ of 4 two nitrido complexes [(Me 2 PhP) 3 (PhCN)ClReN] + coordinate with their terminal nitrido ligands a central, square planar ReCl 4 unit. The resulting nitrido bridges with bond angles Re(1)-N(1)- Re(2) = 167.0(4)° and Re(3)-N(2)-Re(4) = 168.9(4)°, respectively, exhibit distances Re(1)-N(1) = 172.4(7) and Re(2)-N(1) = 197.1(7) or Re(3)-N(2) = 171.4(6) and Re(4)-N(2) = 197.1(6) pm. The two carbonyl ligands of the anion [OsCl 4 (CO) 2 ] 2− are in cis position.

June 2, 2014

Ternary Rare Earth Metal Silicides RE₂RE’₃Si₄ with Orthorhombic Sm₅Ge₄ or Tetragonal Zr₅Si₄ Type Structure

Ute Ch Rodewald, Birgit Heying, Dirk Johrendt, Rolf-Dieter Hoffmann, Rainer Pöttgen

Page range: 174-181

Abstract

Ternary silicides RE 2 RE′ 3 Si 4 (RE = La, Ce; RE′= Y, Lu) were synthesized by arc-melting of the elements. Single crystals were grown by annealing the arc-molten buttons slightly below the melting points in water-cooled silica tubes in an induction furnace. Five silicides RE 2 RE 3 ′Si 4 were investigated by X-ray powder and single crystal diffraction: Zr 5 Si 4 type, P4 1 2 1 2, a = 779.4(3), c = 1441.3(9) pm, wR2 = 0.072, 1806 F 2 values, 45 variables for La 1.72(4) Y 3.28(4) Si 4 , P4 3 2 1 2, a = 769.92(7), c = 1412.3(1) pm, wR2 = 0.079, 1846 F 2 values, 45 variables, BASF = 0.36(4) for La 1.72(2) Lu 3.28(2) Si 4 , P4 1 2 1 2, a = 778.6(1), c = 1433.9(3) pm, wR2 = 0.054, 1910 F 2 values, 46 variables, BASF = 0.34(4) for Ce 1.82(6) Lu 3.18(6) Si 4 , P4 3 2 1 2, a = 778.8(3), c = 1436.0(10) pm, wR2 = 0.166, 1916 F 2 values, 45 variables for Ce 1.71(7) Y 3.29(7) Si 4 , and Sm 5 Ge 4 type, Pnma, a = 749.2(2), b = 1484.2(7), c = 780.3(2) pm, wR2 = 0.070, 1956 F 2 values and 49 variables for Ce 1.47(3) Y 3.53(3) Si 4 . The local coordinations of both structure types are very similar, i. e. CN 18, 16, and 14 coordination polyhedra for the RE1, RE2, and RE3 atoms. The main structural motif is the eightfold coordination of the RE3 positions by rare earth metal atoms. These slightly distorted RERE’ 8 cubes are condensed via common corners (Zr 5 Si 4 type) or via common edges (Sm 5 Ge 4 type). All silicon atoms in these silicides form Si 2 pairs at Si-Si distances ranging from 254 to 258 pm. DFT band structure calculations confirm the metallic character of both silicides and the trivalent state of cerium in Ce 5 Si 4 . The COHP analysis (Crystal Orbital Hamilton Population) of the Si-Si bonds shows a significant occupation of Si-Si antibonding orbitals, which is partially compensated by a Si-Si π*,σ*Y-4d (Ce-5d) back donation.

June 2, 2014

Synthesis and Structural Relationship of the Ternary Indides Sc₃Ni_2.10(5)In_3.60(5), Sc₃Ni_2.14(2)In_3.76(2), ScPd_0.981(2)In and Sc₃Rh_1.594(9)In₄

Mar’yana Lukachuk, Vasyl’ I Zaremba, Rolf-Dieter Hoffmann, Rainer Pöttgen

Page range: 182-189

Abstract

The ternary scandium transition metal indides Sc 3 Ni 2.10(5) In 3.60(5) , Sc 3 Ni 2.14(2) In 3.76(2) , ScPd 0.981(2) In, and Sc 3 Rh 1.594(9) In 4 have been synthesized from the elements in glassy carbon crucibles in a high frequency furnace or by arc-melting. They have been investigated by X-ray powder diffraction and the structures refined on the basis of single crystal diffractometer data: Lu 3 Co 1.87 In 4 type, P6̄, a = 745.7(1), c = 342.85(7) pm, wR2 = 0.0689, 545 F 2 , 24 parameters for Sc 3 Ni 2.10(5) In 3.60(5) , a = 753.63(7), c = 344.3(1) pm, wR2 = 0.0362, 792 F 2 , 22 parameters for Sc 3 Ni 2.14(2) In 3.76(2) , P6̄2m, ZrNiAl type, a = 764.1(2), c = 345.90(8) pm, wR2 = 0.0333, 326 F 2 , 15 parameters for ScPd 0.981(2) In, and P6̄, a = 769.4(1), c = 684.1(1) pm, wR2 = 0.0526, 1097 F 2 , 35 parameters for the new structure type Sc 3 Rh 1.594(9) In 4 . In the three structure types the scandium atoms build trigonal prisms. The latter are filled exclusively by palladium atoms in ScPd 0.981(2) In, while transition metal and indium atoms fill these sites in the other three structures. The different coloring of the trigonal prismatic sites leads to a symmetry reduction for the structures of Sc 3 Ni 2.10(5) In 3.76(5) , Sc 3 Ni 2.14(2) In 3.76(2) and Sc 3 Rh 1.594(9) In 4 . The structural relationship is described on the basis of a group-subgroup scheme. Chemical bonding in these intermetallics is briefly discussed.

June 2, 2014

Tris(2-isocyanocarbonsäureester)-Halbsandwich-Komplexe [(Aren)M(CNCHR¹CO₂R²)₃]²⁺ (M = Ru, Rh, Ir) / Tris(2-isocyanocarboxylic Acid Ester) – Halfsandwich Complexes [(arene)M(CNCHR¹CO₂R²)₃]²⁺ (M = Ru, Rh, Ir)

Markus A Lang, Peter Mayer, Wolfgang Beck

Page range: 190-195

Abstract

By reaction of chloro bridged halfsandwich complexes with silver salts and subsequent addition of isocyanocarboxylic acid esters the isocyanide complexes [(arene)M(CNCHR 1 CO 2 R 2 ) 3 ] 2+ (X − ) 2 (arene = C 6 Me 6 , p-cymene, M = Ru; arene = C 5 Me 5 , M = Rh, Ir), (R 1 = H, Me, CHMe 2 , CH 2 Ph, X = BF 4 , CF 3 SO 3 ) were prepared and characterized. The structure of [(C 5 Me 5 ) Ir(CNCH 2 CO 2 Et) 3 ] 2+ (CF 3 SO 3 − ) 2 was determined by X-ray structure analysis.

June 2, 2014

Palladium(II) Complexes with Benzoxazol-2-ylidene Ligands: Crystal Structures of trans-Chloro(benzoxazol-2-ylidene)- bis(triphenylphosphine)palladium(II) Chloride and cis-Diiodo(benzoxazol-2-ylidene)(triphenylphosphine)palladium(II)

F. Ekkehardt Hahn, Thomas Lügger, Matthias Beinhoff

Page range: 196-201

Abstract

The palladium(II) complexes trans-[PdCl(L)(PPh 3 ) 2 ]Cl, 5, and cis-[PdI 2 (L)PPh 3 ], 7, (L = benzoxazol- 2-ylidene) have been synthesized by treatment of the complexes trans-[PdX 2 (PPh 3 ) 2 ] (4: X = Cl, 6: X = 1) with 2-(trimethylsiloxy)pheny1 isocyanide 1, and subsequent hydrolysis of the Si-O bond. The crystal structures of 5 and 7*CH 2 Cl 2 were established by X-ray diffraction. NMR and IR studies indicate, that the unexpected cis-configuration of 7 obtained from trans-[PdI 2 (PPh 3 ) 2 ] is not the result of a solution equilibrium between the cis- and the trans-isomers.

June 2, 2014

High-Pressure Synthesis, Crystal Structure, and Properties of the New Orthorhombic Rare-Earth meta-Oxoborates RE(BO₂)₃ (RE = Dy – Lu)

Holger Emme, Tanja Nikelski, Thomas Schleid, Rainer Pöttgen, Manfred Heinrich Möller, Hubert Huppertz

Page range: 202-215

Abstract

The new orthorhombic meta-oxoborates RE(BO 2 ) 3 (≡REB 3 O 6 ) (RE = Dy-Lu) have been synthesized under high-pressure and high-temperature conditions in a Walker-type multianvil apparatus at 7.5 GPa and 1100 °C. They are isotypic to the known ambient pressure phase Tb(BO 2 ) 3 , space group Pnma. In contrast to Dy(BO 2 ) 3 , which was also obtained in small amounts under high-temperature conditions, the preparation of the higher orthorhombic homologues RE(BO 2 ) 3 (RE = Ho-Lu) was only possible using high-pressure. The meta-oxoborates RE(BO 2 ) 3 (RE = Dy-Er) were synthesized as pure products, whereas the orthorhombic phases with RE = Tm-Lu were only obtained as byproducts. With the exception of Yb(BO 2 ) 3 it was possible to establish single crystal data for all compounds. The results of temperature-resolved in-situ powder-diffraction measurements, DTA, IR-spectroscopic investigations, and magnetic properties are also presented.

June 2, 2014

Four Isotypic Highly Coordinated Lanthanide Complexes of the Tripodal Ligand Bis[(2-pyridyl)methyl][(1-methylimidazol-2-yl)methyl]amine

Michael Merkel, Matthias Pascaly, Christian Köster, Bernt Krebs

Page range: 216-220

Abstract

The Ln(III) complexes (Ln = Pr, Nd, Sm and Tb) of the tripodal ligand bis[(2-pyridyl)methyl][(1- methylimidazol-2-yl)methyl]amine (bpia) have been synthesized and characterized by single crystal X-ray structure determination as well as vibrational spectroscopy. The coordination spheres of the lanthanide cations are completed by three chelating nitrate anions yielding neutral complexes with a tenfold coordination of the metal ions. All four compounds are found to be isotypic, crystallizing in space group P1̄ (No. 2) with Z = 2. On comparing the IR-spectra of the new complexes to the spectra of the free ligands a shift to higher wave numbers is observed for corresponding bands in both, bpia and nitrate ligands.

June 2, 2014

Carbamoyl and Thiocarbamoyl Derivatives of 3-Aminopropyl-dimethyl-phosphine Oxide

Victoria Lachkova, Helmut Keck, Rosario Scopelliti, Wolfgang Kläui, Sabi Varbanov, Gerhard Hägele

Page range: 221-227

Abstract

A series of fourteen new 3-[N-substituted carbamoyl (or thiocarbamoyl)]-aminopropyl-dimethyl-phosphine oxides have been synthesized and characterized. The compounds were prepared via reaction of the 3-aminopropyl-dimethyl-phosphine oxide with the corresponding isocyanates or isothiocyanates. The composition of the compounds was proved by elemental analysis and the structures were confirmed by IR, 1 H, 31 P, 31 P{ 1 H} NMR spectroscopy and by mass spectrometry. The structures of 3[(N-phenyl-thiocarbamoyl)amino]propyl-dimethyl-phosphine oxide (5), 3[(N-4- chlorophenyl-thiocarbamoyl)amino]propyl-dimethyl-phosphine oxide (6), and 3[(N-benzyl-thiocarbamoyl) amino]propyl-dimethyl-phosphine oxide (9) have been confirmed by X-ray diffraction.

June 2, 2014

The Crystal Structures of [N,N’-Bis(3-methoxysalicylidene)-1,3- diaminopropane]nickel(II) and -copper(II)

Ayhan Elmali, Celal T Zeyrek, Yalcin Elerman

Page range: 228-232

Abstract

[N,N′’-Bis(3-methoxysalicylidene)-1,3-diaminopropane]nickel(II) dihydrate [Ni(C 19 H 20 N 2 O 4 )· 2(H 2 O)] 1 and [N,N′-bis(3-methoxysalicylidene)-1,4-diaminobutane]copper(II) [Cu(C 20 H 22 N 2 O 4 )] 2 have been synthesized and their crystal structures determined. Crystals of compound 1 are orthorhombic, space group Pnma, a = 7.509(3), b = 22.070(7), c = 11.532(4) Å, V = 1611.1(12) Å 3 , Z = 4 and D c = 1.498 g·cm −3 . The molecule 1 has mirror symmetry, but the ligand is not planar. The two parts of the Schiff base moieties are folded so as to form an angle of 21.6(1)°. The Ni atom is in a distorted octahedral geometry and coordinated by the donor atoms of the ligand in the horizontal plane and of two water molecules. Crystals of compound 2 are monoclinic, space group P2 1 /c, a = 9.488(1), b = 21.918(3), c = 8.413(1) Å, β = 91.45(1)°, V = 1749.0(4) Å 3 , Z = 4 and D c = 1.587 g·cm −3 . The Cu atom is coordinated by an N 2 O 2 donor set from the imine-phenol ligand in a distorted planar geometry, with the two phenolate O atoms deprotonated. The Cu-O bond lengths are 1.854(3) and 1.868(3)Å . The Cu-N bond lengths are 1.931(3) and 1.950(3) Å, the dihedral angle between the two 3-methoxysalicylidene groups is 43.4(1)°.

June 2, 2014

Dialkoxy-Substituted, C₁-Symmetric Metallocenes: Synthesis and Catalytic Behavior in the Propylene Polymerization Reaction

Martin Schlögl, Bernhard Rieger

Page range: 233-240

Abstract

The synthesis of a series of C 1 -symmetric metallocene complexes rac-[1-(5,6-dialkoxy-2-methyl- 1-η 5 -indenyl)-2-(9-η 5 -fluorenyl)ethane]zirconium dichlorides (alkyl: n-butyl, n-hexyl, n-octyl, n-decyl) is described. These complexes are versatile catalysts in the polymerization of propylene after in situ activation with triisobutylaluminum (TIBA) and Ph 3 C[B(C 6 F 5 ) 4 ] in toluene and heptane solution. All catalysts show higher solubility and improved polymerization properties in industrially used hydrocarbon solvents (e.g. heptane). However, the molecular weights and isotacticity values of the resulting polypropylene materials are decreased compared to the ethoxy-bridged analogue rac- [1-(5,6-ethylenedioxy-2-methyl-η 5 -indenyl)-2-(9-η 5 -fluorenyl)ethane]zirconium dichloride. A possible explanation is based on enhanced interaction of the active catalyst centers with Al(III) scavenger molecules even at low Al : Zr ratios, leading to reversible chain transfer.

June 2, 2014

Isolation and Structure of a New Ceramide from the Basidiomycete Hygrophorus eburnesus

Yan Qu, Hong-Bin Zhang, Ji-Kai Liu

Page range: 241-244

Abstract

A new ceramide, named hygrophamide (1), was isolated from the fruiting bodies of the basidiomycetes Hygrophorus eburnesus Fr.. The structure of the compound was elucidated as (2S, 3S, 4R, 2’R)-2-(2’-hydroxy-9’Z-ene-tetracosanoylamino)-octadecane- 1,3,4-triol (1) by spectral and chemical methods.

June 2, 2014

Pubesamides A, B, and C, Three New N-Benzoyltyramide Derivatives Isolated from Casimiroa pubescens

Aída N García-Argáez, Nadia M. González-Lugo, Hortensia Parra-Delgado, Mariano Martínez-Vázquez

Page range: 245-248

Abstract

Three new N-benzoyltyramides derivatives named pubesamides A, B and C together with the known skimmianine, β -sitosterol and daucosterol were isolated from seeds of C. pubescens. Their structures were determined by spectroscopic data.

June 2, 2014

RETRACTION NOTICE: Synthesis with Enaminones: Novel and Facile Synthesis of Indenopyrimidine, Indenopyridine, Fluorenone, and Indenopyran Derivatives

Tarek M. Abu Elmaati, Ibrahim Elghamry, Fathy M. A El-Taweel

Page range: 249-249

About this journal

Objective
Zeitschrift fuer Naturforschung B (ZNB) publishes novel research in all areas of inorganic chemistry, organic chemistry, and analytical chemistry. In particular, the journal focuses on solid state chemistry, coordination chemistry, main group element chemistry, synthetic organic chemistry, natural product chemistry and, to a lesser extent, on analytical chemistry. For more than 65 years Zeitschrift fuer Naturforschung B has been open to contributions from all fields of experimental and theoretical chemistry. Zeitschrift fuer Naturforschung B publishes 12 issues per volume/year. Sometimes double issues occur.

Topics

Solid state chemistry
Coordination chemistry
Main group element chemistry
Organic chemistry
Natural product chemistry

Article formats
Original (full) papers, research notes and preliminary communications, reports on specific research topics of current interest (reviews)

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Volume 59 Issue 2

Issue of Zeitschrift für Naturforschung B

Zur Reaktion von 2,3-Dihydro-1,3-diisopropy1-4,5-imidazol-2-yliden mit Bromderivaten der Meldrumsäure [1, 2] / On the Reaction of 2,3-Dihydro-1,3-diisopropy1-4,5-dimethylimidazol-2-ylidene with Bromine Derivatives of Meldrum’s Acid [1, 2]

Abstract

Polyol Metal Complexes, 45 [1]. D-Glucopyranosides as Ligands in Nickel Complexes

Abstract

Crystal Structures of the Supramolecular Aggregates of the Methyl and Chloro Substituted Gallanes MexGaCl3-x

Abstract

DFT and G2MP2 Calculations of the N-N Bond Dissociation Enthalpies and Enthalpies of Formation of Hydrazine, Monomethylhydrazine and Symmetrical and Unsymmetrical Dimethylhydrazine

Abstract

Triethoxysilane, Tetraethoxysilane and Hexaethoxydisiloxane – Three Complementary Reagents for the Synthesis of Hydrogen-Rich Silylarenes

Abstract

Dimeric Methylzinc Bis(2-pyridylmethyl)amide – Synthesis, Molecular Structure and Reaction with Dimethylzinc

Abstract

Abstract

Ternary Rare Earth Metal Silicides RE2RE’3Si4 with Orthorhombic Sm5Ge4 or Tetragonal Zr5Si4 Type Structure

Abstract

Synthesis and Structural Relationship of the Ternary Indides Sc3Ni2.10(5)In3.60(5), Sc3Ni2.14(2)In3.76(2), ScPd0.981(2)In and Sc3Rh1.594(9)In4

Abstract

Tris(2-isocyanocarbonsäureester)-Halbsandwich-Komplexe [(Aren)M(CNCHR1CO2R2)3]2+ (M = Ru, Rh, Ir) / Tris(2-isocyanocarboxylic Acid Ester) – Halfsandwich Complexes [(arene)M(CNCHR1CO2R2)3]2+ (M = Ru, Rh, Ir)

Abstract

Palladium(II) Complexes with Benzoxazol-2-ylidene Ligands: Crystal Structures of trans-Chloro(benzoxazol-2-ylidene)- bis(triphenylphosphine)palladium(II) Chloride and cis-Diiodo(benzoxazol-2-ylidene)(triphenylphosphine)palladium(II)

Abstract

High-Pressure Synthesis, Crystal Structure, and Properties of the New Orthorhombic Rare-Earth meta-Oxoborates RE(BO2)3 (RE = Dy – Lu)

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Four Isotypic Highly Coordinated Lanthanide Complexes of the Tripodal Ligand Bis[(2-pyridyl)methyl][(1-methylimidazol-2-yl)methyl]amine

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Carbamoyl and Thiocarbamoyl Derivatives of 3-Aminopropyl-dimethyl-phosphine Oxide

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The Crystal Structures of [N,N’-Bis(3-methoxysalicylidene)-1,3- diaminopropane]nickel(II) and -copper(II)

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Dialkoxy-Substituted, C1-Symmetric Metallocenes: Synthesis and Catalytic Behavior in the Propylene Polymerization Reaction

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Isolation and Structure of a New Ceramide from the Basidiomycete Hygrophorus eburnesus

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Pubesamides A, B, and C, Three New N-Benzoyltyramide Derivatives Isolated from Casimiroa pubescens

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RETRACTION NOTICE: Synthesis with Enaminones: Novel and Facile Synthesis of Indenopyrimidine, Indenopyridine, Fluorenone, and Indenopyran Derivatives

Crystal Structures of the Supramolecular Aggregates of the Methyl and Chloro Substituted Gallanes Me_xGaCl_3-x

Ternary Rare Earth Metal Silicides RE₂RE’₃Si₄ with Orthorhombic Sm₅Ge₄ or Tetragonal Zr₅Si₄ Type Structure

Synthesis and Structural Relationship of the Ternary Indides Sc₃Ni_2.10(5)In_3.60(5), Sc₃Ni_2.14(2)In_3.76(2), ScPd_0.981(2)In and Sc₃Rh_1.594(9)In₄

Tris(2-isocyanocarbonsäureester)-Halbsandwich-Komplexe [(Aren)M(CNCHR¹CO₂R²)₃]²⁺ (M = Ru, Rh, Ir) / Tris(2-isocyanocarboxylic Acid Ester) – Halfsandwich Complexes [(arene)M(CNCHR¹CO₂R²)₃]²⁺ (M = Ru, Rh, Ir)

High-Pressure Synthesis, Crystal Structure, and Properties of the New Orthorhombic Rare-Earth meta-Oxoborates RE(BO₂)₃ (RE = Dy – Lu)

Dialkoxy-Substituted, C₁-Symmetric Metallocenes: Synthesis and Catalytic Behavior in the Propylene Polymerization Reaction