Published by De Gruyter

Volume 52 Issue 11

Issue of Zeitschrift für Naturforschung B

Contents
Journal Overview

June 2, 2014

Oxotitan-Addukte mit Dimethylsulfoxid: [TiO(OSMe₂)₅]Cl₂ und [Ti₄O₆(OSMe₂)₁₂]Cl₄ · 5Me₂SO · 1/2 H₂O / Oxotitanium Compounds with Dimethylsulfoxide: [TiO(OSMe₂)₅]Cl₂ and [Ti₄O₆(OSMe₂)₁₂]Cl₄ · 5Me₂SO · 1/2 H₂O

Susanne Rabe, Ulrich Müller

Page range: 1291-1295

Abstract

While TiCl 4 and Na 2 S 4 react in in the presence of PPh 4 Cl in dichloromethane to yield (PPh 4 ) 2 [TiSCl 4 ]·2CH 2 Cl 2 , we obtained [Ti 4 O 6 (OSMe 2 ) 12 ]Cl 4· 5Me 2 SO · 1/2H 2 O (1) from the same reactants in dimethylsulfoxide. Compound 1 is only stable in the presence of dimethylsulfoxide. The crystal structure determination at 153 K shows the presence of cations having an adamantane-like Ti 4 O 6 4+ skeleton with three Me 2 SO molecules coordinated to each Ti atom via their O atoms. Crystal data: monoclinic, P 2 1 /n, Z = 4, a = 1096.9, b = 3097, c = 2342.7 pm, β = 93.90° (at -120 °C; R = 0.087 % for 4098 reflections). In an attempt to produce the same compound only from TiCl 4 and Me 2 SO, [TiO(OSMe 2 ) 5 ]Cl 2 was obtained. Its cation has a rather short Ti=O bond (164.8 pm) and a distorted octahedral coordination of the titanium atom. The crystals are triclinic, P1̄, Z = 2, R = 0.050 for 2063 reflections measured at 153 K.

June 2, 2014

Reaktionen von Cadmium-und Quecksilber(II)halogeniden und -pseudohalogeniden mit Kronenethern: Kristallstrukturen der Komplexe von Benzo-18-krone-6 mit CdX₂ und HgX₂ (X = CI, Br) und von Dibenzo-18-krone-6 mit Hg(CN)₂ / Reactions of Cadmium and Mercury(II) Halides and Pseudohalides with Crown Ethers: Crystal Structures of the Complexes of Benzo-18-crown-6 with CdX₂ and HgX₂ (X = Cl, Br) and of Dibenzo-18-crown-6 with Hg(CN)₂

Joachim Pickardt, Sven Wiese, Pirka Wischlinski

Page range: 1296-1300

Abstract

The reactions of benzo-18-crown-6 with MeX 2 (Me = Cd, Hg; X = Cl. Br), and of dibenzo-18-crown-6 with Hg(CN) 2 afford the compounds [Me(benzo-18-crown-6)X 2 ] (1-4) and [Hg(dibenzo-18-crown-6)(CN) 2 (5), resp., the crystal structures of which were determined. They consist of isolated neutral molecules, the crystalline Cd complexes and 5 contain one molecule of water of crystallization per formula unit, which however is not coordinated to the metal atom. The metal atoms are coordinated by the six O atoms of the ligands and the two halide atoms, or the two CN groups for 5, resp., the coordination being more unsymmetrical for the benzo than for the dibenzo ligand.

June 2, 2014

[H₂⊂(Mo^v₂O₄)₆O₄(μ₂-OH)₁₂(Mo^VIO₃)₄]^6- and [Na⊂{(Mo^V₂O₄)₃(μ₂-OH)₃H(PhP0₃)₄}₂]^7-: A Further Example for the Validity of the Concept of Unit Construction in Polyoxometalate Chemistry

Achim Müller, Stephan Dillinger, Erich Krickemeyer, Hartmut Bögge, Winfried Plass, Anja Stammler, Robert C. Haushalter

Page range: 1301-1306

Abstract

The compound Na 7 [Na⊂{(Mo V 2 O 4 ) 3 (μ 2 -OH) 3 H(PhPO 3 ) 4 } 2 ] · 2N 2 H 4 · 26 H 2 O (formulation with respect to the aggregate in the crystal) has been synthesized and characterized by single-crystal X-ray structure analysis (which alone does not allow the determination of the formula), UV/Vis/NIR/IR, 31 P{ 1 H}, 1 H and 23 Na NMR spectroscopy as well as magnetic susceptibility measurements. The compound is formed under similar conditions as (NH 2 Me 2 ) 6 [H 2 ⊂(Mo V 2 O 4 ) 6 O 4 (μ 2 -C)H) 12 (Mo VI O 3 ) 4 ].Correspondingly, both cluster frame works are built up by the same {(Mo V 2 O 4 ) 3 (μ 2 -OH) 3 } 3+ units.

June 2, 2014

Kristallstruktur von Bromnitrat BrONO₂ / Crystal Structure of Bromine Nitrate BrONO₂

Rolf Minkwitz, Thomas Hertel

Page range: 1307-1310

Abstract

The crystal structure of bromine nitrate BrONO 2 has been determined on a single crystal with MoKα radiation at -83°C. The structure is orthorhombic, space group P2 1 2 1 2 1 , Z = 4, and the cell dimensions are a = 403.2(2), b = 684.9(4), c = 1201.4(5) pm. An intermolecular Br.....O contact leads to the formation of chains within the crystal. Attempts to synthesize a bromine(III)-nitrate by oxidizing CF 3 Br and CF 3 Br with ClONO 2 were not successful.

June 2, 2014

Crystal Structure of an Ammonium Dithiocyanatocuprate(I) Complex with 18-Crown-6, [NH₄(18-Crown-6){Cu(NCS)₂}] Obtained from Zero Valent Metal

Julia A. Manskaya, Volodimir N. Kokozay, Konstantin V. Domasevitch

Page range: 1311-1314

Abstract

The new macrocyclic dithiocyanatocuprate(I) complex [NH 4 (18-crown-6){Cu(NCS) 2 }] has been prepared using a direct method of interaction and characterized by X-ray crystallography (orthorhombic, space group Cmc2 1 , with a = 12.453(2), b = 21.650(4), c = 8.151(2) Å, V = 2197.6(8) Å 3 , Z = 4 , R1 (F) = 0.054; wR2(F 2 ) = 0.141 for 972 unique reflections with I > 2σ(I) and R1(F) = 0.082; w/?2(F 2 ) = 0.210 for all 1098 unique reflections). The lattice comprises complex cations [NH 4 (18-crown-6)] + and infinite polymeric anions [Cu(NCS) 2 ] - of a one-dimensional zig-zag structure. The copper atoms adopt three-fold coordination [CuN 2 S] (Cu-N 1,89( 1), 1,90( 1) Å; Cu-S 2.278(4) Å).

June 2, 2014

Donor-stabilisierte Trisalkinylborane. Kristallstruktur von H₅C₅N–B(C≡CH)₃ und Elektronenstruktur von B(C≡CH)₃ / Donor-Stabilized Trisalkinylboranes. Crystal Structure of H₅C₅N–B (C≡CH)₃ and Electronic Structure of B(C≡CH)₃

Andreas Madema, Hans Pritzkow, Walter Siebert, Thomas Sommerfeld, Lorenz S. Cederbaum

Page range: 1315-1320

Abstract

The synthesis and properties of donor-stabilized trisethinylborane compounds 1 - 3 (donor = pyridine, tetrahydrothiophene, tetrahydrofuran) and of the tris(trimethylsilylethinyl)boranediethylether adduct 4 are reported. Attempts to obtain donor-free trisorganylethinylboranes have failed. 11 B NMR data of 1 - 4 and the X-ray structure analysis of 1 and 3 reveal that the boron atoms are four-coordinated. The B-C bonds in 1 are somewhat longer and the C≡C bonds shorter than in diborylacetylenes.

June 2, 2014

Synthese und Kristallstruktur der Benzyltriphenylphosphonium-bromide: [C₆H₅-CH₂P(C₆H₅)₃]⁺Br^-CH₂Cl₂ und [C₆H₅-CH₂P(C₆H₅)₃]⁺Br₃^- / Synthesis and Crystal Structures of (Benzyl)triphenylphosphonium Bromides, [C₆H₅-CH₂P(C₆H₅)₃]⁺Br^-CH₂Cl₂ and [C₆H₅-CH₂P(C₆H₅)₃]⁺Br₃^-

J. Hübner, D. Wulff-Molder, H. Vogt, M. Meisel

Page range: 1321-1324

Abstract

(Benzyl)triphenylphosphonium bromide, [C 6 H 5 -CH 2 P(C 6 H 5 ) 3 ] + Br - (CH 2 Cl 2 ) (1) has been prepared by the reaction of triphenylphosphine with benzylbromide and its structure determined. The colorless crystals are triclinic, space group P1̄, Z = 2, a = 976.0(3), b = 1069.0(3), c = 1226.1(4) pm, α = 94.13(3), β = 104.70(3), γ = 100.14(3)°. The lattice contains Br - anions and [C 6 H 5 -CH 2 P(C 6 H 5 ) 3 ] + cations. [C 6 H 5 -CH 2 P(C 6 H 5 ) 3 ]Br 3 (2) has been obtained by treating compound 1 with equimolar quantities of elemental bromine in methylene chloride solution. The red crystals of 2 are monoclinic, space group P2 1 /c, Z = 4, a = 917.9(2), b = 1022.6(2), c = 2573.6(5) pm, β = 99.11(2)°, and comprise[C 6 H 5 -CH 2 P(C 6 H 5 ) 3 ] + cations and linear, slightly asymmetrical Br 3 - anions with bromine-bromine distances of 246.19(11) and 263.69(11) pm.

June 2, 2014

Nickel(II)-Tyrosine-and -Tryptophan-Nucleobase Ternary Complexes

M. C. Apella, A. Terron, J. J. Fiol, V. Moreno, E. Molins

Page range: 1325-1330

Abstract

The interaction between Ni(II) and amino acids with an aromatic residue (such as tyrosine and tryptophan) and either 9 substituted bases or nucleosides has been studied. Ternary derivatives obtained in solid state were characterised by, among other techniques, elemental analysis, thermogravimetry, electronic and infrared spectroscopy. The following complexes have been obtained: 1: [Ni (tyr) 2 (9EtAde) 2 ] × 4H 2 O; 2: [Ni (tyr) 2 (9EtGua) 2 ] × 5H 2 O; 3: [Ni (tyr)(guo) × 5H 2 O];4: [Ni (tyr)(ino) × 5H 2 O];5: [Ni (trp) 2 (9EtGua)(H 2 O)] × 2H 2 O, where tyr is tyrosinate, trp tryptophanate, ino inosinate and guo guanosinate. Thermogrammes are in agreement with the number of water molecules and nickel content (calculated as NiO), together with the ternary nature of these complexes. The binary compounds Ni(tyr) 2 × 3H 2 O and Ni(trp)2 × 3.5H 2 O were also obtained and the corresponding thermogrammes were registered for comparison purposes. Compounds 1, 2 and5 are water soluble; besides, 1 is fairly soluble in methanol. Compounds 3 and 4 seem to be polymeric. Infrared spectra clearly show the presence of bands either from the amino acid or the base suggesting nickel octahedral coordination through the carboxylic and amino acids groups and a nitrogen from the purine base. These compounds were obtained in water at pH close to 7.0. With other bases such as cytosine and uracil, or their corresponding nucleosides, the same synthesis failed to yield ternary compounds [1,2].

June 2, 2014

Crystal and Molecular Structures of N,N'-Diphenyl-N"-trichloroacetyl- phosphorictriamide and N,N,-Tetraethyl-N"-benzoylphosphorictriamide. The Effect of Various Substituents on the Structural Parameters of the [C(O)N(H)P(O)] Moiety

Vladimir M. Amirkhanov, Vladimir A. Ovchynnikov, Tadeusz Glowiak, Henryk Kozlowski

Page range: 1331-1336

Abstract

X-ray structures of two phosphazo analogues of β-diketones: N,N′-diphenyl-N″-trichloracetyl- phosphorictriamide and N,N′-tetraethyl-N″-benzoyl-phosphorictriamide have been determined. The results obtained in this study and the data reported earlier allow to discuss the impact of various substitutents on the phosphoricamido C(O)N(H)P(O) moiety.

June 2, 2014

Die Struktur von GaAsO₄ ·2H₂O : Ein neues Mitglied der Variscit-Familie / The Structure of GaAsO₄·2H₂O : A New Member of the Variscite Family

Stefan Dick

Page range: 1337-1340

Abstract

GaAsO 4 · 2H 2 O was synthesized hydrothermally from Ga 2 O 3 and a K + -AsO 4 3- solution at pH=2. A single crystal structure determination showed that GaAsO 4 · 2H 2 O is isotypic with variscite and therefore the first gallium arsenate with octahedrally coordinated Ga(III). Crystal data: space group Pbca, a = 1016,0(1), b = 886,2(1), c = 994. 1(1) pm, R g = 0,0266. GaAsO 4 · 2H 2 O dehydrates at 439 K with formation of an amorphous material and poor crystalline GaAsO 4 . The crystal data of all known compounds with variscite structure have been compiled.

June 2, 2014

Planare CuO₄-Polygone und eine einseitig offene Te⁴⁺O₃-Koordination in SrCuTe₂O₆ / Planar CuO₄ Polygons and a One-Sided Open Te⁴⁺O₃ Coordination in SrCuTe₂O₆

L. Wulff, Hk. Müller-Buschbaum

Page range: 1341-1344

Abstract

The new compound SrCuTe 2 O 6 has been prepared by quenching single crystals grown from a flux of SrCO 3 , TeO 2 and CuCO 3· Cu(OH) 2 . X-ray investigations show cubic symmetry, space group O 7 -P4 1 32, lattice constant a = 12.473(1), Z = 12. The crystal structure is characterized by square planar CuO 4 polygons and a one-sided open triangular oxygen coordination of Te 4+ , both incorporated in a Sr/O network. The one sided oxygen coordination of tellurium is completed by the lone pair of Te 4+ . Calculations of the Coulomb parts of lattice energy led to the position of the lone pair centre.

June 2, 2014

Contribution to the Chemistry of Boron, 241. Improved Synthesis of 2,4,6-Trichloroborazine

Heinrich Nöth, Hermann Sachdev

Page range: 1345-1348

Abstract

2,4,6-Trichloroborazine 2,4,6-Trichloroborazine is an important starting material for the preparation of many borazine derivatives, particularly for the parent borazine (HB=NH) 3 . Both are precursors for the CVD of boron nitride. Improved conditions for the synthesis of (CIB=NH) 3 to give high yields are reported.

June 2, 2014

Die Kristallstrukturen der isotypen Erdalkalimetall-Nitridowolfra- mat(VI)-Nitrid-Oxide Ca₅₁[WN₄]₁₂N₈O₃ und Sr₅₁[WN₄]₁₂N₈O₃ / The Crystal Structures of the Isotypic Alkaline Earth-Nitridotungstate(VI)- Nitride-OxidesCa₅₁[WN₄]₁₂N₈O₃ and Sr₅₁[WN₄]₁₂N₈O₃

Peter Höhn, Matthias Ludwig, Rüdiger Kniep

Page range: 1349-1358

Abstract

Yellow single crystals of the isotypic phases Ca 51 [WN 4 ] 12 N 8 O 3 and Sr 51 [WN 4 ] 12 N 8 O 3 (triclinic, P1̄ (#2 ); a= 1056.4(3) / 1113.1(5) pm, b = 1239.7(3) / 1304.4(5) pm, c= 1598.2(3) / 1679.4(9) pm, α = 102.78(1)/102.47(2)°, β= 95.15( 1)/95.43(3)°, γ = 109.89(1)/109.77(2)°; Z = 1) were grown in a Tl-flux (Ca:Tl, molar ratio 5:1, W-crucible; T max = 1273K; reaction with N 2 , 1 atm, 36 h) or from pellets (Sr 2 N + W, molar ratio 6:1; T max = 1023K; reaction with N 2 , 1 atm, 36 h). The crystal structures contain tetrahedral anions [WN 4 ] 6- in addition to isolated nitride and isolated oxide ions, which are octahedrally coordinated by Ca and Sr, respectively.

June 2, 2014

Oxyfunctionalization of Allyl Thioether Ruthenium Complexes with Dimethyldioxirane

Wolfdieter A. Schenk, Bernhard Steinmetz, Michael Hagel, Waldemar Adam, Chantu R. Saha-Möller

Page range: 1359-1371

Abstract

Allyl thioether complexes [CpRu(P-P)(SRR′)]PF 6 (P-P = Ph 2 PCH 2 PPh 2 (dppm), Ph 2 PC 2 H 4 PP 2 (dppe), R = Me, Et, Ph, R′ = 3-propenyl, 3-cyclohexenyl, 2-methyl-2-buten-4-yl) and [CpRu(chir)(SRR′)]PF 6 (chir = (S,S)-Ph 2 PCHMeCHMePPh 2 , R = Me, CH 2 Ph, R′ = 2-methyl-2-buten-4-yl) are obtained from the corresponding thiolate complexes by reaction with the appropriate allyl bromide. Careful oxidation with dimethyldioxirane (DMD) gave the allyl sulfoxide complexes [CpRu(P-P)(MeS(O)CH 2 CH=CH 2 )]PF 6 (P-P = dppm, dppe). Double oxidation to the corresponding sulfinylmethyl epoxide complexes can be readily achieved with an excess of DMD. Oxidation of the chir complexes proceeds with only moderate diastereoselectivity. The structure of the (R, R/S, S) diastereomer of [CpRu(dppm)(MeS(O)CH 2 CHCH 2 O)]PF 6 was determined: monoclinic space group P2 1 /c (No. 14), a = 11.21(2), b = 16.762(9), c = 18.45(4) Å, β = 94.4(1)°, Z = 4. For a representative example, the decomplexation of the sulfoxide-epoxide ligand by sodium iodide in acetone was demonstrated.

June 2, 2014

Prediction of Dissociation Constants of Ammonium Ion in 20 Mass % Ethanol + Water Mixed Solvent Solutions Containing Sodium Chloride

Masunobu Maeda, Chisako Iwata

Page range: 1372-1375

Abstract

Dissociation constants of amonium ion (K a = [H + ][NH 3 ]/[NH 4+ ], where [ ] denotes the concentration) in 20 mass % ethanol + water mixtures with different concentrations of sodium chloride were determined by means of a glass electrode. The dissociation constants in pK a units (on molarity and molality bases) increase linearly with increasing ionic strength. Activity coefficients of ammonia in the ethanol + water mixtures were determined by a transpiration method. The observed dissociation constants on the molality scale were compared with those calculated from the Pitzer equations modified on the basis of the principles of corresponding states. The observed values agreed with the calculated ones almost within experimental uncertainties.

June 2, 2014

Synthesis of N-(2-Phenyl-cyclopropyI)-Substituted Nucleoside Analogues

René Csuk, Yvonne von Scholz

Page range: 1376-1382

Abstract

A novel class of nucleoside analogues containing adenine, hypoxanthine, thymine, uracil, thiouracil and cytosine as the heterocyclic moieties have been prepared starting from 2-phenylcyclopropylamine. These compounds showed weak antitumor activity. The resolution of the racemates on an analytical scale was performed by HPLC using chiral phases.

June 2, 2014

Syntheses of Anomeric Pairs of New C-Nucleosides via 1,3-Dipolar Cycloaddition Reaction, Part I

Zahida Maqbool, Mashooda Hasan, Kevin T. Pott, Abdul Malik, Tanveer Ahmad Nizami, Wolfgang Voelter

Page range: 1383-1392

Abstract

A convenient pathway to a variety of β-and α-C-nucleosides has been developed by utilizing 1,3-dipolar cycloaddition reactions of various exocyclic and endocyclic heterocyclic ylides with β (5a) and α (5b) anomers of ethyl 3-(2′,3′-O-isopropylidene-5′-O-trityl-D-ribofurano-syl) propiolate, respectively. Assignment of configuration at exposition of the C-nucleosides could be made by a comparative study of the properties of corresponding α and β anomers with a reasonable degree of certainity.

June 2, 2014

Syntheses of Anomeric Pairs of New C-Nucleosides via 1,3-Dipolar Cycloaddition Reaction, Part II

Zahida Maqboor, Mashooda Hasan, Kevin T. Potts, Abdul Malik, Tanveer Ahmad Nizami, Wolfgang Voelter

Page range: 1393-1400

Abstract

1,3-Dipolar cycloaddition of dipolarophiles (1) and (2) with endocyclic heterocyclic azomethine ylides (4), (14) and (24), prepared in situ, leads to the protected β-and α-C-nucleo-sides (7), (8), (17), (18), (27) and (28), respectively. These, on subsequent hydrolysis, provide the corresponding C-nucleosides. The structures of all the synthesized com pounds are con firmed through analytical and spectral data. The assignment of configuration at C -1′ position of the C-nucleosides could be done by a comparative study of the properties of the corresponding α and β anomers with a reasonable degree of certainity.

June 2, 2014

A Convenient One-Pot Synthesis of Pyrazolo[3,4-d]pyrimidines and s-Triazolo[3,4-b][1,3,5]thiadiazines

Zeinab A. Hozien, Abd El-Wareth A. O. Sarhan, Hassan A. H. El-Sherief, Abdalla M. Mahmoud

Page range: 1401-1412

Abstract

The reaction of 5-amino-3-aryl-1-phenylpyrazoles (1a-d) with formaldehyde and secondary amines in boiling ethanol gave the corresponding 4-alkylaminomethyl derivatives (2a-f) and bis-(4-pyrazolyl)methane (4a,b) as byproduct. Such reaction with primary aliphatic and aro matic amines at room temperature afforded 1,3,5-trisubstituted (5a-h) and 1,3.5,7-tetrasubstituted tetrahydropyrazolo[3,4-d]pyrimidines (8a-k) respectively in good yield. Similarily, the Mannich reaction of 5-mercapto-3-phenyl-1,2,4-triazole (9) with secondary amines, in boiling ethanol, and primary aromatic amines, at room temperature, gave 2 -substituted aminomethyl derivatives (10a-c) and (14a-g) respectively,while with primary aliphatic amines, p-toluidine and p-anisidine,at room temperature,and with other primary aromatic amines, in boiling ethanol, afforded the cyclized products 12,4-triazolo[3,4-b]thiadiazines (13a-e); (15f,g) and (15a-e), respectively.

June 2, 2014

Isolation and Characterization of 1-Tigloyl-3-acetylazadirachtol from the Seed Kernels of the Thai Neem Azadirachta siamensis Valeton

H.-O. Kalinowski, C. Krack, K. Ermel, C. Chriathamjaree

Page range: 1413-1417

Abstract

The Thai neem A. siamensis (Valeton) is the main source for botanical insecticides in Thailand. Although azadirachtin A (aza A) is present in Thai neem, there are some other related compounds which may contribute to its bioefficiency. Analytical HPLC of Thai neem samples showed a peak closely eluted with azadirachtin. A large-scale cleanup involving two liquid/liquid extraction steps, silica filtration, and finally two successive preparative HPLC separations, resulted in the pure compound, which was identified as 1-tigloyl-3-acetylazadirachtol by 1D -and 2D - 1 H and 13 C NMR spectroscopy.

June 2, 2014

ab initio MO Optimization of Molecular Structures of Fluoro- and Chloro-Substituted Dibenzo-p-dioxines and the Effect of Halogen Substitution at the 2,3,7,8-Positions on Metabolic Attack

Roland Weber, Till Kühn, Hanspaul Hagenmaier, Günter Häfelinger

Page range: 1418-1431

Abstract

Full ab initio optimizations were performed on the molecular structures of 24 fluorinated and chlorinated dibenzodioxines (PFDD/PCDD ) and dibenzofurans (PFDF/PCDF). Reasonable agreement was found by comparing the geometries of four calculated structures with known X-ray data from the literature. For the fluorine substituent, calculated electron densities (Mulliken total charges and π-electron charges) clearly demonstrate the opposite influence of the inductive (I) and mesomeric (M) effect. The changes in π-densities at carbons in ortho-, meta- and para-position are constant for each fluorine substituent (independent of degree, pattern, and position of substitution). It is thus possible to calculate the π-densities of the substituted dioxines by increments starting from dibenzodioxine. π-Charges from quantum mechanical calculations and the increment system show good agreement even for OctaFDD (O 8 FDD ), where eight substituent effects are acting additively. Compared with fluorine, the chlorine substituent exercises a smaller -I-effect and a clearly weaker +M-effect. The HOMO coefficients of the unsubstituted dibenzodioxine and dibenzofuran, extracted from ab initio calculations, yield a good explanation for the observed regioselective metabolic attack at the 2,3,7,8-positions. The squares of the HOMO-coefficients of the 2,3,7,8-positions in dibenzodioxine (DD ) are about ten times greater than those of the 1,4,6,9-positions. These HOMO coefficients are practically unaffected by halide substitution. But halogen substitution reduces strongly the electron density at the halogen-bound carbon, which, however, is a necessary prerequisite for the electrophilic oxygen transfer during metabolism. One would therefore expect halogen substitution of dibenzodioxine and dibenzofuran (DF) at the 2,3,7,8-position to hinder metabolism, as is indeed found. This provides a plausible explanation for the highly selective tissue retention of 2,3,7,8-substituted PCDDs and PCDFs. Our ab initio calculations of five tetra CDDs (T 4 CDDs) confirm the postulate of Kobayashi et al. [1 ] who, using semiempirical calculations, found a correlation between the toxicity of a dioxine congener and its absolute molecular hardness. The 2,3,7,8-T 4 CDD also exhibits the smallest absolute hardness (derived from the HOMO-LUMO energy gap) in our calculations.

June 2, 2014

Rb[B₂P₂O₈(OH)] und Cs[B₂P₂O₈(OH )]: Die ersten Borophosphate mit dreidimensional vernetzter Anionenteilstruktur /Rb[B₂P₂O₈(OH)] and Cs[B₂P₂O₈(OH )]: The First Borophosphates with a Threedimensional Anionic Tetrahedral Structure

Cornelia Häuf, Rüdiger Kniep

Page range: 1432-1435

Abstract

The isotypic borophosphates Rb[B 2 P 2 O 8 (OH)] and Cs[B 2 P 2 O 8 (OH)] were grown under hydrothermal conditions. The crystal structures were solved by single crystal methods (Rb[B 2 P 2 O 8 (OH)]/ Cs[B 2 P 2 O 8 (OH)]: monoclinic, P2 1 /c, a = 676.2(3)/682.7(3), b = 1217.3(5)/ 1236.8(5), c = 885.0(4)/900.6(5) pm, β = 97.3(1)/ 98.1(1)°. Z = 4). The structures contain a complex framework of three-, four-, six-, nine- and twelvemembered rings of tetrahedra. Along [100] the twelve-membered rings are stacked to give wide channels which contain the Rb + /Cs + -ions in an icosahedral coordination.

June 2, 2014

Asymmetrische Katalysen, 116. Triaza-und Tetraaza-Makrocyclen mit chiralen "pendant arms" in der enantio- selektiven Cyclopropanierung / Asymmetrie Catalyses, 116. Triaza and Tetraaza Macrocycles with Chiral Pendant Arms in the Enantioselective Cyclopropanation

Henri Brunner, Andreas Winter, Bernhard Nuber

Page range: 1436-1438

Abstract

The chiral ligands 1 - 5 were tested in the Cu 1 - catalyzed enantioselective cyclopropanation of styrene with ethyl diazoacetate. The new ligand 5 was synthesized by reaction of 1,4,8,11-tetraazacyclotetradecane (cyclam ) with (S)-propylene oxide and characterized by X-ray analysis.

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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.

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

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Volume 52 Issue 11

Issue of Zeitschrift für Naturforschung B

Oxotitan-Addukte mit Dimethylsulfoxid: [TiO(OSMe2)5]Cl2 und [Ti4O6(OSMe2)12]Cl4 · 5Me2SO · 1/2 H2O / Oxotitanium Compounds with Dimethylsulfoxide: [TiO(OSMe2)5]Cl2 and [Ti4O6(OSMe2)12]Cl4 · 5Me2SO · 1/2 H2O

Abstract

Abstract

[H2⊂(Mov2O4)6O4(μ2-OH)12(MoVIO3)4]6- and [Na⊂{(MoV2O4)3(μ2-OH)3H(PhP03)4}2]7-: A Further Example for the Validity of the Concept of Unit Construction in Polyoxometalate Chemistry

Abstract

Kristallstruktur von Bromnitrat BrONO2 / Crystal Structure of Bromine Nitrate BrONO2

Abstract

Crystal Structure of an Ammonium Dithiocyanatocuprate(I) Complex with 18-Crown-6, [NH4(18-Crown-6){Cu(NCS)2}] Obtained from Zero Valent Metal

Abstract

Donor-stabilisierte Trisalkinylborane. Kristallstruktur von H5C5N–B(C≡CH)3 und Elektronenstruktur von B(C≡CH)3 / Donor-Stabilized Trisalkinylboranes. Crystal Structure of H5C5N–B (C≡CH)3 and Electronic Structure of B(C≡CH)3

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Synthese und Kristallstruktur der Benzyltriphenylphosphonium-bromide: [C6H5-CH2P(C6H5)3]+Br-CH2Cl2 und [C6H5-CH2P(C6H5)3]+Br3- / Synthesis and Crystal Structures of (Benzyl)triphenylphosphonium Bromides, [C6H5-CH2P(C6H5)3]+Br-CH2Cl2 and [C6H5-CH2P(C6H5)3]+Br3-

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Nickel(II)-Tyrosine-and -Tryptophan-Nucleobase Ternary Complexes

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Crystal and Molecular Structures of N,N'-Diphenyl-N"-trichloroacetyl- phosphorictriamide and N,N,-Tetraethyl-N"-benzoylphosphorictriamide. The Effect of Various Substituents on the Structural Parameters of the [C(O)N(H)P(O)] Moiety

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Die Struktur von GaAsO4 ·2H2O : Ein neues Mitglied der Variscit-Familie / The Structure of GaAsO4·2H2O : A New Member of the Variscite Family

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Planare CuO4-Polygone und eine einseitig offene Te4+O3-Koordination in SrCuTe2O6 / Planar CuO4 Polygons and a One-Sided Open Te4+O3 Coordination in SrCuTe2O6

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Contribution to the Chemistry of Boron, 241. Improved Synthesis of 2,4,6-Trichloroborazine

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Die Kristallstrukturen der isotypen Erdalkalimetall-Nitridowolfra- mat(VI)-Nitrid-Oxide Ca51[WN4]12N8O3 und Sr51[WN4]12N8O3 / The Crystal Structures of the Isotypic Alkaline Earth-Nitridotungstate(VI)- Nitride-OxidesCa51[WN4]12N8O3 and Sr51[WN4]12N8O3

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Oxyfunctionalization of Allyl Thioether Ruthenium Complexes with Dimethyldioxirane

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Prediction of Dissociation Constants of Ammonium Ion in 20 Mass % Ethanol + Water Mixed Solvent Solutions Containing Sodium Chloride

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Synthesis of N-(2-Phenyl-cyclopropyI)-Substituted Nucleoside Analogues

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Syntheses of Anomeric Pairs of New C-Nucleosides via 1,3-Dipolar Cycloaddition Reaction, Part I

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Syntheses of Anomeric Pairs of New C-Nucleosides via 1,3-Dipolar Cycloaddition Reaction, Part II

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A Convenient One-Pot Synthesis of Pyrazolo[3,4-d]pyrimidines and s-Triazolo[3,4-b][1,3,5]thiadiazines

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Isolation and Characterization of 1-Tigloyl-3-acetylazadirachtol from the Seed Kernels of the Thai Neem Azadirachta siamensis Valeton

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ab initio MO Optimization of Molecular Structures of Fluoro- and Chloro-Substituted Dibenzo-p-dioxines and the Effect of Halogen Substitution at the 2,3,7,8-Positions on Metabolic Attack

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Rb[B2P2O8(OH)] und Cs[B2P2O8(OH )]: Die ersten Borophosphate mit dreidimensional vernetzter Anionenteilstruktur /Rb[B2P2O8(OH)] and Cs[B2P2O8(OH )]: The First Borophosphates with a Threedimensional Anionic Tetrahedral Structure

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Asymmetrische Katalysen, 116. Triaza-und Tetraaza-Makrocyclen mit chiralen "pendant arms" in der enantio- selektiven Cyclopropanierung / Asymmetrie Catalyses, 116. Triaza and Tetraaza Macrocycles with Chiral Pendant Arms in the Enantioselective Cyclopropanation

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Oxotitan-Addukte mit Dimethylsulfoxid: [TiO(OSMe₂)₅]Cl₂ und [Ti₄O₆(OSMe₂)₁₂]Cl₄ · 5Me₂SO · 1/2 H₂O / Oxotitanium Compounds with Dimethylsulfoxide: [TiO(OSMe₂)₅]Cl₂ and [Ti₄O₆(OSMe₂)₁₂]Cl₄ · 5Me₂SO · 1/2 H₂O

[H₂⊂(Mo^v₂O₄)₆O₄(μ₂-OH)₁₂(Mo^VIO₃)₄]^6- and [Na⊂{(Mo^V₂O₄)₃(μ₂-OH)₃H(PhP0₃)₄}₂]^7-: A Further Example for the Validity of the Concept of Unit Construction in Polyoxometalate Chemistry

Kristallstruktur von Bromnitrat BrONO₂ / Crystal Structure of Bromine Nitrate BrONO₂

Crystal Structure of an Ammonium Dithiocyanatocuprate(I) Complex with 18-Crown-6, [NH₄(18-Crown-6){Cu(NCS)₂}] Obtained from Zero Valent Metal

Donor-stabilisierte Trisalkinylborane. Kristallstruktur von H₅C₅N–B(C≡CH)₃ und Elektronenstruktur von B(C≡CH)₃ / Donor-Stabilized Trisalkinylboranes. Crystal Structure of H₅C₅N–B (C≡CH)₃ and Electronic Structure of B(C≡CH)₃

Die Struktur von GaAsO₄ ·2H₂O : Ein neues Mitglied der Variscit-Familie / The Structure of GaAsO₄·2H₂O : A New Member of the Variscite Family

Planare CuO₄-Polygone und eine einseitig offene Te⁴⁺O₃-Koordination in SrCuTe₂O₆ / Planar CuO₄ Polygons and a One-Sided Open Te⁴⁺O₃ Coordination in SrCuTe₂O₆

Rb[B₂P₂O₈(OH)] und Cs[B₂P₂O₈(OH )]: Die ersten Borophosphate mit dreidimensional vernetzter Anionenteilstruktur /Rb[B₂P₂O₈(OH)] and Cs[B₂P₂O₈(OH )]: The First Borophosphates with a Threedimensional Anionic Tetrahedral Structure