bluuebunny/crossref_metadata_2025 huggingface dataset:
Does Experience Matter for Patterns of Expansion by US Companies in Latin America and the Caribbean?
Authors: Charles Sawyer W. , B. Wooster Rossitza , R. Blanco Luisa
Published: March 2015

We describe expansion patterns by US companies in Latin America and the Caribbean (LAC) between 1980 and 2005 using a unique sample that utilizes country, industry and time-series information on firms’ investments. We build on previous research to explore the effect of experience on firms’ preference for equity commitment. Using the time-series properties of our data, we examine the extent to which previous investments in the region influence firms’ expansion patterns. Our analysis includes the traditional determinants of entry mode choices such as firm-specific factors, market-seeking factors, resource-seeking factors and country-specific factors. Bivariate probit results indicate that companies with previous experience in the region are more likely to commit equity going forward and this also holds for more recent companies with greater growth opportunities.
Conversion of sulfur-free black liquor into fuel gas by supercritical water gasification
Authors: Huet Marion , Roubaud Anne , Lachenal Dominique
Published: March 2015

Supercritical water gasification of weak sulfur-free black liquor (BL) was performed in a batch autoclave at temperatures between 430°C and 470°C, pressure between 24 and 27 MPa and residence time between 2 and 63 min. Results show that the gas produced was a mixture of mainly hydrogen, methane, and carbon dioxide. Maximum conversion was achieved at 470°C and 60 min. Energy recovery (ER, ratio between the energy in the gas and in the initial BL) was 46%. Thirty-four percent of the carbon and 53% of the hydrogen initially present in BL were converted into gases. Nearly 15% of initial organic carbon remains in the liquid phase and consists mainly of phenolic compounds, which are stable under those conditions. A higher temperature is needed to convert all the organic carbon. Thermodynamic equilibrium should be reached at 700°C leading to a complete conversion and a better efficiency. Sodium recovery is close to typical kraft recovery value and compatible with causticizing.
A new cis-p-coumaroyl flavonol glycoside from the inner barks of Sophora japonica L.
Authors: Si Chuan-Ling , Yu Guo-Jing , Du Zhen-Guo , Huang Xiao-Feng , Fan Su , Du Hai-Shun , Hu Wei-Cheng
Published: March 2015

Tree barks could be a rich source of novel bioactive compounds, which are not well explored. In this work, the chemical constituent investigation of extractives from the inner barks of Sophora japonica L. (Leguminosae) led to the isolation of a new cis-p-coumaroyl flavonol glycoside, which was elucidated as kaempferol 3-O-(4″-cis-p-coumaroyl)-α-rhamnopyranoside (IV). The structure of the new compound was established mainly based on extensive spectroscopic techniques. In addition, among the four known phenolics purified in this study, including three flavonol glycosides [rutin (I), kaempferol-3-O-(6″-galloyl)-β-glucopyranoside (II), and quercitrin (V)], as well as a phenolic acid [trans-ferulic acid (III)], compounds II and III have never been reported in S. japonica previously.
Experimental and Stochastic Modeling of the Globular Microstructure and the Microsegregation Evolution during the Solidification of Magnesium Alloys Cast at Low Superheat via Containerless Melting
Authors: Nastac Laurentiu , El-Kaddah Nagy
Published: March 2015

Casting at low superheat has a strong influence on the solidification morphology and macro- and microstructures of cast alloys. This paper shows the microstructure and microsegregation of cast Mg AZ31B alloy at superheat of 5°C, summarizes the multiscale model, and describes the simulation results obtained with a previously developed stochastic mesoscopic solidification model capable of predicting the microstructure of the cast alloy. The simulation results are compared with casting experiments carried out using the Magnetic Suspension Melting process. Casting at this low superheat was found to produce castings with a fine globular grain structure, with an average grain size of about 80 µm, which is about one-third the size of that obtained by conventional casting techniques. The stochastic model was validated against the experimental measured grain structure and Al microsegregation. A parametric study was performed to determine some key material and process parameters related to processing of cast Mg AZ31B alloy.
The Application of MHD Side Stirring Technology to Aluminium Melting Furnaces for Operational Efficiency Improvement – A Case Study
Authors: Peel Alan , Menet Pierre Yves
Published: March 2015

Electromagnetic stirring in aluminium melting and holding furnaces is widely introduced and accepted throughout the aluminium industry but this paper looks to discuss some of the differentiating factors that have allowed the air-cooled MHD technology to provide effective circulation of the molten metal in furnaces when applied to the side of the melting furnace (rather than the traditional bottom-mounted location). This technology has been installed by Constellium and we discuss some of the benefits that have been experienced from the various installations. As well as providing certain key operational benefits this new technology allows for low-energy use and has removed many of the inherent risks of the older water-cooled technology in proximity to aluminium.
Intra-channel Cross-Phase Modulation Effect in Dispersion Compensated Single Channel Lightwave System with Negative Residual Dispersion
Authors: Syed Nitu , Faisal Mohammad
Published: March 2015

Advanced modulation schemes, particularly the phase-modulated signals, have already drawn huge research interests for ultra-high speed long-haul lightwave transmission systems. We have considered 40 Gbit/s optical RZ pulse propagating in a periodically dispersion managed (DM) single channel system with negative residual dispersion. We investigate the effects of negative residual dispersion on intra-channel cross-phase modulation (IXPM)-induced phase shift. Analytical estimation for phase shift has been deduced using perturbed variational formulation. We therefore explore the impact of variation of various parameters such as transmission distance, duty cycle, bit rate, etc. on phase shift. The outcome of our work is to explore the performance of the dispersion compensated system with some negative residual dispersion so that the IXPM-induced phase shift remains low in optical fiber communication.
Novel Design for Surface Plasmon Resonance Lenses
Authors: Chang Kao-Der , Lu Ruei-Chang , Liao Yu-Ping , Lee Keh-Yi
Published: March 2015

New design for surface plasmon resonance (SPR) lens having a sub-wavelength size of spot in the far-field region is proposed in this work. An extra structure of concentrically annular grating fabricated on the top surface of SPR lens is utilized to improve the quality of focusing. Numerical simulation results of the novel type of SPR lenses with different grating structures are presented and compared.
Status of pinnipeds in Southeast Asia
Authors: Mahood Simon P. , Duckworth J.W.
Published: March 2015

There are no published records of pinnipeds in Southeast Asia. Photographs in the national media between January 2010 and December 2013 documented seven pinniped records. All were individuals caught by fishermen in the central part of Vietnam (17°56′N south to 15°23′N). All except one pinniped record can be assigned to Largha (=Spotted) Seal
Über die Darstellung und röntgenographische Untersuchung von Verbindungen des Formeltyps K2LnF5
Authors: Güde Klaus , Hebecker Christoph
Published: March 2015

Results of X-ray studies on single crystals of K2GdF5 and on other K2LnF5-type compounds are reported. Single crystals of K2GdF5 have been prepared from 2 :1-mixtures of the binary fluorides. These samples were investigated by X-ray methods. K2GdF5 crystallizes orthorhombically with unit cell dimensions: a = 10.814(4), b = 6.623(1), c = 7.389(3) Å, space group No. 62, Pnam -D16
2h , Z = 4. In addition we have corrected earlier results about cell constants of the series of K2LnF5-type compounds.
Zwei neue Bis(trimethylsilyl)aminoderivate des Antimons: MeSb(N{SiMe3}2)2 und MeCl2Sb(N{SiMe3}2)2
Authors: Kolondra W. , Schwarz W. , Weidlein J.
Published: March 2015

Unexpectedly the reaction of SbCl3 with Na(N{SiMe3}2) in a 1:3 molar ratio forms MeSb(N{SiMe3}2)2, I, (Me = CH3) and other trimethylsilyl compounds. The colourless and liquid methylstibane derivative I is monomeric in solution and forms MeSbCl2(N{SiMe3}2)2 (II) on reaction with SO2Cl2. Both new compounds have been characterized by analyses, NMR, IR and Raman spectra. The X-ray structure determination for II shows the monoclinic space group P21/C with 4 monomeric units per cell. The structure was refined to an R-value of 0,052.
Synthese von PR3 (R = Ph, OMe) substituierten Cubanclustern vom M2M'2S4-Typ und Molekülstruktur von (C5Me5)2Cr2Co2{P(OMe)3}2(μ3 -S)4
Authors: Brunner Henri , Meier Walter , Wächter Joachim , Pfisterer Heike , Ziegler Manfred L.
Published: March 2015

The reaction of the cubane cluster (C5Me5)2Cr2Co2(CO)2S4 with PR3 (R = Ph, OMe) resulted in a stepwise substitution of CO ligands by PR3. One of the reaction products, (C5Me5)2Cr2Co2{P(OMe)3}2S4, was characterized by an X-ray diffraction study, confirming that the 60-e core of composition Cr2Co2S4 was retained.
Lineare Oligophosphaalkane, XI [1] Stabilisierung von Phosphiniden, PH, im Clusteryerband — Röntgenstrukturanalyse von Fe4(CO)10[(μ2-PPri)2CH2](μ2-PPriMe)(μ2-H)(μ4-PH)
Authors: Brauer David J. , Hasselkuß Gerd , Hietkamp Sibbele , Sommer Herbert , Stelzer Othmar
Published: March 2015

Reaction of HPriP-CH2-PPriH with Fe2(CO)9 in a molar ratio of 1:2 produces a mixture of cluster compounds from which Fe4(CO)10[(μ2-PPri)2CH2](μ2-PPriMe)(μ2-H)(μ4-PH) could be isolated by liquid chromatography. X-ray structural analysis shows a planar trapezoid arrangement for the four iron atoms (Fe1 -Fe2 2,648(1), Fe2 -Fe3 2,790(1), Fe3 -Fe4 2,643(1), Fe1 --Fe4 4,109(1) Å ) capped by the novel bidentate phosphido bridge (μ2-PPri)2CH2 and the unsubstituted phosphinidene, PH( Fe1 - P4 2,284(1), Fe2 - P4 2,410(1), Fe3 - P4 2,405(1), Fe4 - P4 2,288(1), P4 - H1 1,39(4) Å).
Übergangsmetallkomplexe instabiler Ylide, IX [1] Zur Reaktivität von Pentacarbonyl(dimethyloxosulfoniomethanid)chrom(0) gegenüber Organoelementmethyldiphenylphosphanen RnECH2PPh2 (ERn = Ph2Sb, MeS, PhS, PhSe) und (RnE)2CH2 (RnE = Ph2Sb, MeS)
Authors: Weber Lothar , Wewers Dietmar , Lücke Ewald
Published: March 2015

Treatment of the sulfur ylide complex (CO)5Cr[CH2S(O)Me2] (1) with the bifunctional phosphines Ph2PCH2ERn (ERn = SMe, SPh, SePh) lead to pentacarbonylchromium phosphorus ylide complexes (CO)5CrCH2PPh2CH2ERn. Only the S-methyl derivate could be converted to the metallocycle (CO)4[xxx] (ERn = SMe) by UV-irridiation. The ylide chelate complex (CO)4[xxx]Ph2 is formed directly by the thermal reaction of Ph2PCH2SbPh2 with 1. N o ylide complexes result from the reaction of 1 with (Ph2Sb)2CH2 and (MeS)2CH2. The only products identified were (CO)5Cr[Ph2SbCH2SbPh2] and [(CO)5CrS(Me) - ]2CH2, respectively.
Reaktion der Alkoxo-oxovanadium(V)-dichloride mit Bis(tert-butylamino)-dimethylsilan/ Reaction of Alkoxo Oxovanadium(V) Dichlorides with Bis(tert-butylamino) Dimethylsilane
Authors: Preuss Fritz , Fuchslocher Edith , Sheldrick William S.
Published: March 2015

The iminovanadium (V) com pounds tC4H9N = V(NtC4H9-SiMe2-NHtC4H9)Cl2 (3) and [VCl(μ-Cl)(NtC4H9)(NHtC4H9)(NH2
tC4H9)]2 have been prepared by reaction of Me2Si(NHtC4H9)2 with VO(OC2H5)Cl2 and VO(O tC3H7)Cl2, respectively. 3 was investigated by 1H , 51V NMR spectroscopy and X-ray diffraction analysis; the structure has been found to be a mononuclear vanadium complex with a distorted trigonal bipyramidal arrangement of the ligands.
Nitrido-zido-Komplexe des Molybdän(VI): Synthese und Kristallstruktur von MoN(N3)2Cl(terpy)/ Nitrido Azido Complexes of Molybdenum(VI): Synthesis and Crystal Structure of MoN(N3)2Cl(terpy)
Authors: Beck Johannes , Schweda Eberhard , Strähle Joachim
Published: March 2015

MoN(N3)2Cl(terpy) is formed by the reaction of MoCl4(C2H5CN)2 with (CH3)3SiN3 and subsequent addition of terpy. This complex appears also as the main product o f the heterogeneous reaction between MoCl3(terpy) and (CH3)3SiN3. It crystallizes in the monoclinic space group P 21/c with the lattice parameters a = 875.5, b = 1041.4, c = 1891.3 pm, β = 97.00°, Z = 4. The central Mo atom is seven-coordinated in the form of a slightly distorted pentagonal bipyramid, the nitrido and chloro ligands being in axial positions. The triply bonded nitrido ligand ( Mo - N 1 = 166.2 pm) causes a strong trans effect, resulting in a long Mo-Cl distance of 271.9 pm.
Elektrisch leitfähiges μ-Cyano(tetrabenzoporphyrinato)cobalt(III)/ Electric Conductive Electric Conductive //-Cyano(tetrabenzoporphyrinato)cobalt(III)-Cyano(tetrabenzoporphyrinato)cobalt(III)
Authors: Hanack Michael , Hedtmann-Rein Carola
Published: March 2015

The preparation of tetrabenzoporphyrinatocobalt(II) and tetrabenzoporphyrinatocobalt(III)- cyanide derivatives either with terminal or bridging cyanide is described. The IR and the 1H NMR spectra as well as magnetic measurements are in accordance with the proposed structures and the oxidation states of the complexes. μ-Cyano(tetrabenzoporphyrinato)cobalt(III) (4) exhibits a powder conductivity of σRT = 4 ·10-2 S/cm, without additional external doping.
Neue Zintlphasen: Ba3GaSb3, Ca3GaAs3 und Ca3InP3 / On New Zintlphases: Ba3GaSb3, Ca3GaAs3 und Ca3InP3
Authors: Cordier Gerhard , Schäfer Herbert , Steher Michael
Published: March 2015

The new compounds Ca3GaAs3 and Ca3InP3 crystallize in the orthorhombic system, space group Pnma (No. 62) with the lattice constants

Ca3GaAs3: a = 1217.1(5) pm, b = 419.7(2) pm, c = 1341.4(5) pm;

Ca3InP3: a = 1201.9(5) pm, b = 413.8(2) pm, c = 1346.0(5) pm.

In the structures distorted GaAs4- and InP4-tetrahedra resp. are connected by common corners to chains.

The new compound Ba3GaSb3 crystallizes in the orthorhom bic system, space group Pnma (No. 62) with the lattice constants

a = 1411.7(5) pm, b - 2116.7(7) pm, c = 712.8(3) pm.

Two distorted GaSb4-tetrahedra are connected by a common edge to isolated Ga2Sb6-groups. The three compounds belong to the Zintl phases.
Synthesen und Eigenschaften von Piperidin-N-oxyboranen / Synthesis and Properties of Piperidine-N-oxyboranes
Authors: Armbrecht Michael , Maringgele Walter , Meller Anton , Noltemeyer Mathias , Sheldrick George M.
Published: March 2015

Piperidine-N-oxyboranes and 2,2,6,6-Tetramethylpiperidine-N-oxyboranes have been prepared starting from halogenoboranes by three methods:

a) By reaction with N-hydroxypiperidine and triethylamine;

b) by cleavage of the Si -O-bond in piperidine-N-oxy-trimethylsilanes and

c) by reaction with metallated piperidine-N-oxy compounds.

Diboryloxides and diborylamides, resp., are obtained upon reaction of piperidine-N-oxybrom oboranes with hexamethyldisiloxane and hexamethyldisilazane. Steric influences upon reactivity and spectroscopic properties are discussed. The compounds are characterized by elemental analysis, mass and NMR spectroscopy (1H , 11B , 13C, 14N, 29Si). An X-ray analysis has been carried out for tris(2,2,6,6-tetram ethylpiperidine-1-oxy)borane 13.
Darstellung und spektroskopische Charakterisierung der Acetylenkomplexe CpV(CO)2R1C2R2 und CpV(CO)(L)R1C2R2 (Cp=η5-C5H5; R1, R2 = H, Me, Ph, SiMe3; L = PMe3
tBuNC) / Preparation and Spectroscopic Characterization of the Acetylene Complexes CpV(CO)2R1C2R2 and CpV(CO)(L)R1C2R2 (Cp=η5-C5H5; R1, R2 = H, Me, Ph, SiMe3; L = PMe3
tBuNC)
Authors: Alt H. G. , Engelhardt H. E.
Published: March 2015

The photo-induced reaction of CpV(CO)4 (1) (Cp =η5-C5H5) with alkynes R1C2R2 (R1, R2 = H, Me, Ph, SiMe3) in pentane solution yields the substitution products CpV(CO)2R1C2R2 (2). One CO ligand of complexes 2 is readily displaced by PMe3 or tBuNC affording the derivatives CpV(CO)(L)R1C2R2 {3(PMe3), 4 (tBuNC)}. Compounds 2-4 are characterized by their IR, 1H, 13C, 51V NMR and mass spectra. The alkyne in compounds 2-4 shows typical features of a four electron ligand. The barrier for the rotation of the alkyne ligand around the vanadium alkyne bond axis in the complexes 3-4 is comparatively low (⊿ G≠ = 44.4-68.3 kJ/mol) depending mainly on the steric requirements of the acetylene ligand.
Bonding in the P(PH3)2 and N(PH3)2 Cations. An ab initio Study
Authors: Schoeller Wolfgang W.
Published: March 2015

Ab initio SCF calculations at a double-ζ level were perform ed on the cations N(PH3)2
+ and P(PH3)2
+. Although both structures are isoelectronic, their bonding situation is different. The latter corresponds to a dipolar structure (phosphide) with considerable negative charge at the central phosphorus atom. The d-orbitals contribute to bonding as polarization functions rather than participate in hybridization.
Die Bildung eines Zirconium-substituierten Phosphor-Ylids durch sigmatrope Wasserstoffverschiebung / Formation o f a Zirconium Substituted Phosphorus Ylide by Sigmatropic Hydrogen Migration
Authors: Erker Gerhard , Czisch Peter , Mynott Richard
Published: March 2015

σ-Crotylmetallocenyl substituted ylides (1) Cp2M(-CH2CH=CHCH3)(CHPPh3), M=Zr,Hf, are formed upon treatment of a mixture of (s-cis-) and (s-trans-η4-butadiene)metallocene complexes with the phosphorus ylide methylenetriphenylphosphorane (4). From the ( s-cis-/s-trans-butadiene) zirconocene equilibrium mixture (7/5) only the (s-cis-conjugated diene)metallocene isomer reacts with the ylide at -50 °C. Under kinetic control the fram-σ-crotylzirconocenyl-ylide (lb) is formed selectively; subsequent crotyl cis-trans-isomerization (1b⇆1b′) takes place at higher temperature (> -20 °C ). A mechanism including a concerted intramolecular homo-1,5- hydrogen migration step is proposed.
Die Chloro-rhodate(III) [RhCl6]3- und [RhCl5(H2O)]2- · Kristallstruktur von (NH4)3RhCl6 · H2O / The Chloro Rhodates(III) [RhCl6]3- and [RhCl5(H2O)]2- · Crystal Sructure of (NH4)3RhCl6 · H2O
Authors: Treiber Ulrich , Zwilling Michael , Schweda Eberhard , Strähle Joachim
Published: March 2015

(NH4)3RhCl6 · H2O is obtained in form of deep red needles by slow evaporation of an aqueous solution of RhCI3 and excess NH4Cl. It crystallizes in the orthorhombic space group Pnma with lattice constants a = 1219.3. b = 700.7, c = 1416.7 and Z = 4. The structure is built up by octahedral RhCl6
3- anions and NH4
+ cations. The water molecules form hydrogen bridges with NH4
+ cations. The reaction of (NH4)3RhCl6 with Ag+ yields Ag2[RhCl5(H2O)] and AgCl.
Neuartige basische Liganden für die homogenkatalytische Homologisierung von Methanol zu Ethanol, IV [1] Synthese, Eigenschaften und NMR-spektroskopische Untersuchungen von mehrzähnigen Furfurylphosphanen / Novel Basic Ligands for the Homogeneous Catalytic Homologation of Methanol to Ethanol, IV [1] Synthesis, Properties and NMR Spectroscopic Investigations on Polydentate Furfurylphosphanes
Authors: Lindner Ekkehard , Scheytt Christoph
Published: March 2015

The furfurylphosphonium salts [RP(CH2C4H2O3]Br (2a-c, e, f) [R = Ph (a). Mes (b). Me (c), t-Bu (e), CH7C4H3O (f)] and [Ph2P(CH2C4H3O)2]Br (6) are obtained by reaction of the silvlphosphanes RP(SiMe3)2 (1a-c, e). P(SiMe3), (3) and Ph2PSiMe3 (5) with BrCH2C4H3O (eq. (1). (2) and (5)). In THF 2a-c, e, f and 6 are degraded by LiAlH4 to give the tri- and bidentate alkyl and aryl furfurylphosphanes RP(CH2C4H3O)2 (4a-c, e, f) and Ph2PCH2C4H3O (7). respectively (eq. (3) and (5)). The formation of EtP(CH2C4H3O)2 (4d) succeeds via degradation of the phosphonium salt [EtP(CH2C4H3O)3]I (2d) which results from the reaction of 4f and EtI (eq. (4)). From Ph2PCI (8) and the Grignard compound ClMg(CH2)2C4(CH3)H2O the bidentate P,O-ligand Ph2P(CH2)2C4(CH3)H2O (9) can also be isolated (eq.'(6)), 1H, 31P{1H}, and 13C{1H} NMR spectroscopic investigations afford an insight into the structures of the novel compounds.
Darstellung, spektroskopische und elektrochemische Charakterisierung von Pentachloromonocarbonylosmat(IV), [OsCl5(CO)]- / Preparation, Spectroscopical and Electrochemical Characterization of Pentachlorom onocarbonylosm ate(IV), [OsCl5(CO)]-
Authors: Bruns M. , Preetz W.
Published: March 2015

The first carbonyl compound of quadrivalent osmium [OsCl5(CO)]- is prepared by chlorination of trans-[OsX4(CO)2]- (X = Br, I) dissolved in CH2Cl2. It is reduced immediately by Br- and I- to give [OsCl5(CO)]2-. The standard potential [OsCl5(CO)]-/ [OsCl5(CO)]2- in acetonitrile referred to the saturated mercury-mercurous sulphate electrode is 0.623 V. The IR and Ra bands of [OsCl5(CO)]- are assigned according to point group C4v. Compared with the corresponding Os(III) complex there is a shift to higher frequencies of ν(CO) and ν(OsCI) of about 170 and 25 cm-1, whereas ν(OsC) and δ(OsCO) are lowered by 158 and 110cm-1, respectively. The electronic absorption spectrum shows six d - d bands coupled with vibrations in the near infrared region. The O - O transitions are calculated from the vibrational fine structure, taking into consideration shifts by 13C isotopic substitution. The lowest levels are confirmed by peaks in the electronic Raman spectrum. From the estimated Racah parameter B = 280 cm-1 the low nephelauxetic ratio β55 = 0.41 is deduced indicating the high covalency in [OsCl5(CO)]-. Owing to the strong oxidizing character of Os(IV) the intensive charge transfer transitions in the visible region are shifted bathochromicly by about 4000 cm1 in relation to corresponding bands of [OsCl5(CO)]2-.
Beiträge zur Chemie des Bors, 168 [1] Synthese und Struktur von Azadiboriridinen / Contributions to the Chemistry of Boron, 168 [1] Synthesis and Structure of Azadiboriridines
Authors: Dirschl Franz , Hanecker Elisabeth , Nöth Heinrich , Rattay Wilfried , Wagner Walter
Published: March 2015

Two representatives of the three membered B2N-ring system have been obtained by dehalogenation of diborylamines Me3CN[BHalNR2]2. In solution there is no restricted rotation at the exocyclic BN bond, even at low temperature. In contrast, the X-ray structure analysis of the bis-tetramethylpiperidino derivative 10a reveals alternation of short and long BN bonds; one of the tetramethylpiperidino groups stands nearly coplanar with the B2N-ring system, the other, however, is almost perpendicular to the ring plane. The ring contains a short BB bond (1.612 Å).
Darstellung und NMR-Spektroskopie der Argentat-Komplexe [Ag{(μ-PR2)M(CO)5}2]-, M = Cr, Mo, W / Preparation and NMR Spectroscopy of the Argentate Complexes [Ag{(μ-PR2)M(CO)5
2]-, M = Cr, Mo, W
Authors: Obendorf Dagmar , Peringer Paul
Published: March 2015

The products of the reaction between [AgCl(dppe)], [M(CO)5PR2H] and TlOEt are the ionic complexes [Ag(η2-dppe)2]+(Ag{(μ-PR2)M(CO)5}2]-, R = Ph. M = Cr, Mo, W; R = Cy, M = Cr (dppe = (CH2PPh2)2, Cy = Cyclohexyl). The silver(I)-phosphido-ate title complexes are also accessible from AgO3SCF3, [M(CO)5PR2H] and Et2NH or MeO-. Asymmetric phosphido argen- tates of the type [Ag{(μ-PR2)M(CO)5}{(μ-PR′2)M′(CO)5}]-, R = R′ = Ph; M, M′ = Cr, Mo, W; M ≠ M′. R = Ph, R′ = Cy, M = Cr, Mo, W, M′ = Cr are formed via synproportionation of the respective symmetric compounds. The new complexes were characterized by 31P NMR spectroscopy.
Doppelte Kupplungsreaktion eines Diazoniumsalzes mit 2,10-Dimethoxy-1,6-methano[10]annulen sowie Röntgenstrukturanalyse / Double Coupling Reaction of a Diazonium Salt with 2,10-Dimethoxy-1,6-methano[10]annulene and X-Ray Structure Analysis
Authors: Neidlein Richard , Günther Gernot , Kramer Walter , Gieren Alfred , Lamm Viktor , Betz Helmut
Published: March 2015

The synthesis of 8a by coupling reaction of 2.10-dim ethoxy-1,6-m ethano[10]annulene (6) with 2-nitro-4-chlorophenyl-diazonium-tetrafluoroborate (7) as well as its spectroscopic properties are described; an X-ray structure analysis of 8 a × CHC13 is reported.
Studies on Diamagnetic Susceptibility of Biologically Active Heterocycles, Part 2 Diamagnetic Susceptibilities of 4H-1,4-Benzothiazines and their Sulfones
Authors: Gupta R. R. , Kumar M. , Kumar Rakesh
Published: March 2015

Diamagnetic susceptibilities for a number of 4H-1,4-benzothiazines and their sulfones are reported. A theoretical method to estimate diamagnetic susceptibilities of 4H-1,4-benzothiazines is also reported. Benzothiazine has been considered to be composed of two units, one consisting of a benzene ring containing amino and thio groups at ortho positions with other substituents and other consisting of β-diketones/β-ketoesters. Diamagnetic contributions of these two units have been calculated from diamagnetic susceptibilities of substituted o-aminobenzenethiols and β-diketones/β-ketoesters and have been used in estimating diamagnetic susceptibilities of 1,4- benzothiazines. It has provided excellent results of theoretical diamagnetic susceptibility. Such an excellent agreement between experimental and theoretical results has been attributed to the fact that the interactions between substituents, which do affect diamagnetism, have been duly accounted for in such calculations. Diamagnetic susceptibility contribution of oxygen atoms attached to sulphur forming sulfone group is also reported.
A Practical Synthesis o f 2-Azidophenylisocyanide
Authors: El-Shihi Taha , Herrmann Rudolf
Published: March 2015

2-Azidophenylisocyanide is useful for the synthesis of β-lactams by four-component-condensation. Its preparation by various methods is compared. The synthesis starting with 2-aminobenzoic acid via Hofmann degradation of 2-aminobenzamide is the method of choice.
Reaktionen von 1,2,4-Thiadiazol-3,5-dicarbonitril mit Schwefelchloriden: Röntgenstrukturanalyse von S3(CN)4Cl2·AsF5 und S3(CN)8Cl2/Reactions of 1,2,4-Thiadiazol-3,5-dicarbonitrile with Sulfur Chlorides: X-Ray Crystal Structure Analysis of S3(CN)4Cl2·A sF5 and S3(CN)8Cl2
Authors: Roesky Herbert W. , Sundermeyer Jörg , Schimkowiak Jürgen , Gries Thomas , Noltemeyer Mathias , Sheldrick George M.
Published: March 2015

The reactions between 1,2,4-thiadiazol-3,5-dicarbonitrile, S(CN)4, and sulfur chlorides (SCl2 and S2Cl2) in the presence of Adogen® 464 (Aldrich) proceeds with formation of S3(CN)4Cl2 (1) and S3(CN)8Cl2 (2). These main products were characterized by X-ray structure determination of an adduct 1a and of 2. This adduct 1a was obtained by addition of the Lewis acid AsF5 in liquid SO2. 1a crystallizes with one SO2 molecule in the space group P21/n with a = 1177.3(2), b = 1082.8(1), c = 1255.3(5) pm, β = 109.73(3)°, Z = 4, V = 1.5061 nm3. It contains two five-membered rings connected by a nitrogen atom. AsF5 is coordinated to one of the ring nitrogen atoms [N(1)] adjacent to the sulfur atom S(1) and C(1)Cl-group. The other ring contains an S(2)-S(3) bond of length 207.7(4) pm. The rings are planar within experimental error. 2 crystallizes in the space group P21/n with a = 782.12(6), b = 1498.1(5), c = 1217.8(2) pm, β = 102.43(1)°, Z = 4, V = 1.3934 nm3. 2 is formed by addition of one molecule of SCl2 to two molecules of S(CN)4.
Phthalocyanines on Mineral Carriers, 2 Synthesis of Cobalt(II) and Copper(II)-phthalocyanines on γ-Al2O3 and SiO2
Authors: Wöhrle Dieter , Hündorf Uwe , Schulz-Ekloff Günter , Ignatzek Erwin
Published: March 2015

The reaction of metal loaded γ-Al2O3 and SiO2 with benzene-1,2-dicarbonitrile (2) resp. 1H-isoindole- 1,3(H )diimine (3) results in the β-modification of metallized phthalocyanines (1; metals: Cu(II), Co(II)). 1 is formed with an average yield of 48-64% in uniform distribution on the carriers from the reaction with 2. The sizes of the surface areas of the supports are not changed significantly by loading with 1. Non-uniform distribution or even unsupported crystals of 1 are found if the synthesis is carried out with 3.
tert-Butylimino-δ-Organovanadium(V)-Verbindungen Darstellung und NMR-spektroskopische Untersuchungen/tert-Butylimino-δ-Organovanadium (V) Compounds Synthesis and NMR Spectroscopic Studies
Authors: Preuss Fritz , Becker Flarald
Published: March 2015

The compounds tC4H9N=VR(OtC4H9)2 (R = CH3, nC4H9, CH2SiMe3, Mes) and tC4H9N = VMes2(OtC4H9) have been prepared by reaction of tert-butyliminovanadium (V) chlorides with LiR; tC4H9N=V(CH2SiMe3)2(OtC4H9) and tC4H9N=VR3 (R = CH2SiMe3, Mes) could only be characterized by NMR spectroscopy. The 1H, 13C and 51V NMR spectra are discussed; the constants of 51V , 14N coupling have been determined.
Die Kristallstruktur des wasserfreien CsTlI4 / The Crystal Structure of Dehydrated CsTlI4
Authors: Thiele Gerhard , Rotter Heinz W. , Zimmermann Klaus
Published: March 2015

CsTlI4, which has been synthesized either by heating of a 1:1 mixture of CsI/TlI with iodine in a closed system or by dehydration of CsTlI4 · 2H2O, crystallizes in the monoclinic space group P21/c with a = 731.10(24) pm. b = 1870.42(126) pm. c = 847.70(43) pm. β = 105.14(4)°. Z = 4.

In the crystal structure the Cs cations are coordinated by 11 iodine atoms which belong to seven TlI4 anions.
Darstellung und Reaktionen des Tetrahedran-Moleküls Fe2(CO)6(P-tert-C4H9)2 / Preparation and Reactions of the Tetrahedrane Molecule Fe2(CO)6(P-tert-C4H9)2
Authors: De Rajib Lai , Wolters Doris , Vahrenkamp Heinrich
Published: March 2015

The Fe2P2 tetrahedrane compound Fe2(CO)6(P -tBu)2 has been obtained by oxidation of Fe2(CO)6(μ-PFtBu)2. Due to its short (206 pm) P-P bond it can be called a diphosphene com­plex. In contrast to this the P-P bond is its principal centre of reactivity: CO, C2H4, and C2H2 (with concomitant hydrogenation) are inserted. H2 and HCl are added with P-P cleavage, and reductive cleavage occurs with LiBHEt3. The crystal structures of the title compound and of its CO and C2H4 insertion products have been determined.
[Bis(oxamidoxim)nickeI(II)]-[Bis(oxalato)platinat(II)]-Dihydrat x [Bis(oxamidoximato)nickel(II)]: Getrennte parallele Stapel im Verhältnis 2:1 / [Bis(oxamide oxime)nickel(II)] [Bis(oxalato)platinate(II)] Dihydrate x [Bis(oxamide oximato)nickel(II)]: Segregated Parallel Stacks in the Ratio 2:1
Authors: Endres Helmut , Liebich-Brudy Gisela
Published: March 2015

The complex salt [Ni(C2H6N4O2)2][Pt(C2O4)2] × [Νi(C2Η5Ν4O2)2] × 2 H2O has been crystal­lized by interdiffusion of [Ni(C2H6N4O2)3]Cl2 and K2[Pt(C2O4)2]. It is triclinic. Ρ1̄. a = 3.673(1), b = 13.622(4), c = 14.371(4) Å, α = 94.01(2), β = 95.11(2), γ = 92.14(2)°. V = 713.7(4) Å3, Z = 1, Mr = 994.96, Dx = 2.31 g cm-3, MoKα, γ = 0.710 Å. μ = 61.3 cm-1, F(000) = 488, room temperature, wR = 0.034 for 3109 observed independent reflections. Segregated parallel stacksof [Pt(C2O4)2]2- anions, [Ni(C2H6N4O2)2]2+ cations, and neutral [Ni(C2HsN4O2)2] complex molecules run along a, and there is a 2:1 ratio of Ni and Pt complex stacks, interlinked by a network of strong intermolecular H bridges. The difference between the double positive and the neutral Ni complexes is marginal, as the assignment of the charges is based upon a slightly asymmetric intermolecular Ο-H--O bridge. 1.06(7) and 1.44(8) Å.
Ring Expansion of Carbocyclic β-Keto-ester with Acetylenic Esters
Authors: Abou-Elzahab Μ. Μ. , Ayyad S. Ν. , Zimaity Μ. T.
Published: March 2015

The β-keto-ester 1b and 7 reacted with dimethyl acetylenedicarboxylate (DMAD) to give the cyclooctadienone derivatives (2a and 3b). the acid hydrolysis of which afforded the anhydride 4. Also 1a, b reacted with ethyl propiolate and gave substituted cyclooctadienone (6a, b). Michael reaction of 11 with DMAD gave adduct 12 which underwent cyclization via photo-cycloaddition (2+2) to give the photo-product (14).
Reaktionen mit Kaliumsuperoxid 2 [1]. Spaltung von N-Acyl-glycinderivaten / Reactions with Potassium Superoxide 2 [1]. Cleavage of N-Acyl-glycine Derivatives
Authors: Lissel Manfred , Gau Achim
Published: March 2015

N-Acyl-glycine derivatives are cleaved by the action of potassium superoxide in ether or pyridine solution to give the corresponding carboxamides.
Dimere Naphthochinone, 17. Synthesen von Stypandron und Dianellinon / Dimeric Naphthoquinones, 17. Synthesis of Stypandrone and Dianellinone
Authors: Laatsch Hartmut
Published: March 2015

The naphthoquinone stypandrone (2b) ist synthesized via the intermediates 5a, 6a and 6b. Selective monoalkylation of its hydroquinone yields the monoether 12b, which, on phenol oxida­tion and oxidative dealkylation, leads to 13 and dianellinone (2a). The synthesis confirms the 3.3′-dimerisation of the natural product.
Darstellung und Kristallstruktur des Bis(tetramethylammonium)hexasulfids / Preparation and Crystal Structure of Bis(tetramethylammonium)hexasulfide [1]
Authors: Böttcher P. , Flamm W.
Published: March 2015

Bis(tetramethylammonium)hexasulfide has been synthesized from tetramethylammoniumchlorid and Na2S5 in aqueous solution. Single crystal X-ray investigations revealed its structure. It crystallizes in the monoclinic system, space group P2/c, with two formula units in the cell. The cell constants are as follows: a = 7.353(1) Å , b - 5.712(2) Å, c = 20.318(4) Å, β = 99.3(1)°
Zur Koordination von Thiocyanat in ternären Metallkomplexen Die Kristallstruktur von Ba2Cd(SCN)6 • 7 H2O / On the Coordination of Thiocyanate in Ternary Metal Complexes The Crystal Structure of Ba2Cd(SCN)6 • 7 H2O
Authors: Brodersen Klaus , Böhm Karl
Published: March 2015

The title compound was prepared by reaction of aqueous solutions of Ba(SCN)2 • 3 H2O and CdSO4 • 8/3 H2O in the molar ratio of 3:1. The crystal structure was solved by X-ray methods (Mr = 861.61, space group P 21/c, Z = 4, a = 943.6(3) pm, b = 1469.7(6) pm, c = 1827.1(6) pm, β = 109.02(7), V = 2395.4 106 pm3, λ (AgKa) = 55.83 pm, dc = 2.38 gcm-3, μ(AgKa) = 22.4 cm-1, F(000) = 1591.9, T = 298 K, final R = 0.035 for 1350 independent reflexions). The structure consists of two crystallographically independent, distorted Cd(SCN)6 octahedra. Both crystallographically different Ba2+ cations are surrounded by 4 oxygen atoms of water and 5 nitrogen atoms of SCN, forming chains in the direction o f the b-axis
Halogen-Metall-Austausch an Dihalogenphosphan-Komplexen; Synthese von Diphosphan-, Diphosphen- und Phosphiniden-Derivaten / Halogen Metal Exchange; Diphosphane-, D iphosphene-, Phosphinidene-Complexes
Authors: Lang Heinrich , Hüttner Gottfried , Jibril Ibrahim
Published: March 2015

Complexes of dihalophosphanes LnM-P(R)(Hal)2 (LnM = 16-electron fragment e.g. Cp(CO)2Mn) undergo transformations into phosphinidene-, diphosphene- or diphosphanederivatives upon treatment with metallating agents (e.g. tBuLi/TMEDA).

On the basis of many experimental observations a unified reaction scheme is proposed for these syntheses. The preparation and reactivity of diphosphane complexes LnM-(R)P(H) -(R)P(H)-MLn is discussed in some detail. Analytic, spectroscopic and X-ray techniques are used to establish the results. A prominent finding is the observation of an extremely long P-P distance (235.1(3) pm) for the sterically strained meso-[Cp(CO)2Mn]2(tC4H9)P(CH3) -(tC4H9)P(CH3)
Nitriles in Heterocyclic Synthesis: A Novel Synthesis of Polyfunctionally Substituted Pyrrole Derivatives
Authors: Abdelrazek Fathy Mohamed , Fadda Ahmed Ali
Published: March 2015

β-Thiocyanatomethyl cinnam onitrile derivatives coupled with aromatic diazonium salts to afford the corresponding azo com pounds, which undergo reductive cyclization into pyrrole derivatives
The Oxidation of Trimethylamine by OH Radicals in Aqueous Solution, as Studied by Pulse Radiolysis, ESR, and Product Analysis. The Reactions of the Alkylamine Radical Cation, the Aminoalkyl Radical, and the Protonated Aminoalkyl Radical
Authors: Das Suresh , von Sonntag Clemens
Published: March 2015

Hydroxyl radical reactions with trimethylamine in aqueous solution lead to the formation of the aminoalkyl radical (CH3)2NCH2 (A) and its conjugated acid (CH3)2HN+CH2 (AH+) as well as to the alkylamine radical cation (CH3)3N+(N+). These radicals are transform ed into each other by hydrolytic reactions, e.g.

[xxx]

Radicals AH+ are more acidic (pKa ≈ 3.6) than the radicals N+(pKa ≈ 8.0). Consequently, N+ predom inate over AH+ under quasi equilibrium conditions (e.g. in the presence of phosphate buffer) and are the only species observed by ESR in acid solutions. Reacting with the protonated amine. OH radicals abstract hydrogen at nitrogen and at carbon with comparable ease. Reaction of OH radicals with the free amine may initially also generate N+, beside H-abstraction at carbon. Radicals A’ absorb more strongly at 260 nm (ε = 3390 dm3mol-1cm-1) than the radical cation N+(ε = 950 dm3mol-1cm-1). Radical A' has reducing properties whereas radicals AH+ and N+ have oxidizing properties and hence can be monitored with p-nitroacetophenone (the reducing radicals), and Fe(CN)6
4- , N ,N'-tetramethyl-p-phenylenediamine and 2,2'-azinobis-(3-ethyl-benzthiazoline- 6-sulphonate) (the oxidizing radicals). These radicals mainly (≥ 85 % ) disproportionate. one of the products being formaldehyde
Synthese und Struktur von Monoazadienkomplexen des Nickels: Cinnamylidenanilin- bis(triphenylphosphin)nickel / Synthesis and Structure of Monoazadiene Complexes of Nickel: Cinnamylideneanilinebis( triphenylphosphine)nickel
Authors: Müller Christiane , Stamp Lutz , Dieck Heindirk torn
Published: March 2015

The ethylene ligand in (C2H4)Ni[P(C6H5)3]2 is substituted at -20 °C by cinnamylideneaniline C6H5N=CH-CH=CHC6H5 to yield a polymer-like intermediate. Extraction at room temperature with n-hexane gives solutions, from which the very sparingly soluble title com pound crystallizes after several days. Since numerous coordination m odes are possible for 1-m̱onoazadienes (MAD)RN=CH-CH=CHR', an X-ray structure analysis was performed, which showed an η2 (C=C )-coordinated MAD ligand. Although the ligand conform ation is almost s-trans, the significant deviation from planarity (24°) in the solid state is in agreem ent with the rather small proton coupling 3J(H2-H3)= 4.5 Hz in solution
Die Kristallstruktur von PPh4[MoOCl4(OCHNMe2)] / The Crystal Structure of PPh4[MoOCl4(OCHNMe2)]
Authors: Fenske Dieter , Jansen Kay , Dehnicke Kurt
Published: March 2015

Green crystals of the title compound are formed in the reaction of (PPh4)2 [Mo2(O2C -Ph)4Cl2] ·2 CH2Cl2 with dimethyl formamide/carbon tetrachloride in the presence of water. According to the structural investigations by X-ray methods PPh4[MoCl4(O CHNMe2)] crystallizes orthorhombically in the space group C2221 with four formula units per unit cell (3132 observed, independent reflexions, R - 0.068). The cell dimensions are a = 792.1 pm, b = 1656.8 pm, c = 2211.3 pm. The structure consists of PPh4
⊕ cations and anions [MoOCl4(OCHNMe2)]⊖, in which the coordination sphere of the molybdenum atom is of distorted octahedral geometry. The ligands are four equatorial chlorine atoms, one terminal O atom (Mo = O 165 pm) and the O atom of the dimethyl formamide molecule (MoO 232 pm). The IR spectrum is reported
Formylwolfram-Komplexe / Formyl Tungsten Complexes
Authors: Berke Heinz , Kundel Peter
Published: March 2015

Bis(phosphite)-substituted formyl complexes (OC)2(ON)L2WCHO L = P(OMe)3 (4a), P(OEt)3 (4b), P(OiPr)3 (4c) were generated from the corresponding cationic (OC)3(ON)WL2
+ system s using borohydride reagents. The decomposition of 4a-4c leads to hydride com pounds (OC)2(ON)L2WH or (OC)3(ON)LWH , L=P(OMe)3 (5a, 6a), L=P(OEt)3 (5b, 6b), L=P(OiPr)3 (5c, 6c).
Zur Reaktion von (CO)4FeP(R)Cl2 mit Na2Cr2(CO)10 / Reactions of (CO)4FeP(R)Cl2 with Na2Cr2(CO)10
Authors: Borm Jutta , Knoll Konrad , Zsolnai Laszlo , Huttner Gottfried
Published: March 2015

(CO)4FeP(R)Cl2 reacts with Na2Cr2(CO)10 to give the μ3 RP capped trigonal heterom etallic closed cluster Fe(CO)3Cr(CO)4Cr(CO)5(μ3-PR)(1) as a major product. ACr(CO)5-derivative of a metal substituted phosphane [(μ2(tBuPCl)Fe2(CO)7)(tBuPH)]Cr(CO)5 (2) is obtained as a minor component.

The analogous reaction with (CO)4FeP(Ph)Cl2 only gives the known cluster Fe3(CO)9(μ3-PR)2 (3), while (CO)4FeP(c-hexyl)Cl2 results in 4, a pentacarbonylchromiumderivative of the diiron species Fe2(CO)6μ-(PR)3. Species o f this type, containing an Fe2(CO)6 entity doubly bridged by μ2-PR entities, which are them selves linked by another PR-group, are obtained in a systematic high yield process by reacting Fe2(CO)6(μ2-RPH)2 with n-BuLi/TMEDA , RPCl2. For com pound identification, analytical and spectroscopic data as well as four X-ray analyses are presented.
14N- und 15N-NMR-Spektroskopie von Diazaphospholen und die lineare Korrelation der chemischen Verschiebung von zweifach koordiniertem N und P / 14N and 15N NMR Spectroscopy of Diazaphospholes and the Linear Correlation of the Chemical Shift of Two-Coordinate N and P
Authors: Schmidpeter Alfred , Wrackmeyer Bernd
Published: March 2015

A systematic natural abundance 15N NMR study of diazaphospholes is presented for the first time, giving accurate values for chemical shifts, δN , and coupling constants J(31P15N), J(15N1H ). 14N NMR spectra can be used to predict the magnitude of 1J( 31P14N) if the broadening of the 31P resonance by scalar relaxation is known. The relaxation behaviour of the 14N nuclei corresponds to that found in azoles indicating a comparable electronic ground state structure. The comparison of the chemical shifts, δN, in the diazaphospholes with δN of corresponding triazoles reveals differences which can be traced to the N-P σ-bonds and to the influence o f the phosphorus atom on the π-system. A linear correlation δN/δP exists coordinate nitrogen and phosphorus, respectively.
Zur Reaktion von Pt(PPh3)4 mit [2,3-Bis(diphenylphosphino)-N-methyl-maleinimid]platin(II)-chlorid / Reaction of Pt(PPh3)4 with [2,3-Bis(diphenylphosphino)-N-methylmaleimide]platinum(II)-chloride
Authors: Bensmann Walter , Fenske Dieter , Matern Eberhard
Published: March 2015

[2,3-Bis(diphenylphosphino)-N-methylmaleimide]PtCl2 reacts with Pt(PPh3)4 to form a new diamagnetic Pt-complex 4. Its formation is a result of P-C-cleavage by insertion of Pt. The structure was determined by single crystal X-ray analysis. 4 crystallizes in the triclinic space group P1̄ (4 A), and in the monoclinic space group P 21/c (4B). The lattice constants (at 180 K) are: 4A: a = 1069.9(8), b = 1494.9(11), c = 2013.7(18) pm, α = 84.27(3), β = 86.24(2), γ = 71.91(2)°;4B: a = 1480.8(5), b = 1488.6(5), c = 3302.8(13) pm, β = 102.61(3)°.
Suillin, ein charakteristischer Inhaltsstoff von Röhrlingen der Gattung Suillus (Boletales) / Suillin, a Characteristic M etabolite from Boletes of the Genus Suillus (Boletales)
Authors: Jägers Erhard , Pasupathy Vinayagar , Hovenbitzer Anke , Steglich Wolfgang
Published: March 2015

Fruiting bodies of several Suillus species contain a colourless compound, suillin, which is concentrated in the cuticle of the pileus. Its structure has been established as 4-acetoxy-3-geranyl-geranyl-1,2 -dihydroxybenzene (1) by spectroscopic evidence, conversion into a cyclic carbonate 2 and synthesis of its deacetyl derivative 3.
Bis(methvldiphenvlsilvl)-sulfane: Ausgangsverbindungen zur Darstellung von Sulfanen H2Sn und D2Sn mit definierter Kettenlänge / Bis(methyldiphenylsilyl)-sulfanes: Starting Compounds for the Preparation of Sulfanes H2Sn and D2Sn of Definite Chain Length
Authors: Hahn Josef , Altenbach Klaus
Published: March 2015

The silylsulfanes (MePh2Si)2Sn, n = 2-5 (1a-d). have been prepared by reacting MePh2SiSNa (2) with iodine or chlorosulfanes SmCl2, m = 1−3. in toluene solution. Compounds 1a-d, which can unambiguously be characterized by their 1H and 29Si chemical shifts, are obtained pure when crystallized from solutions in pentane or pentane/CS2. They proved a convenient source for the generation of sulfanes H2Sn and deuterosulfanes D2Sn of definite chain length n = 2-5. Mixtures of the silylated sulfanes (MePh2Si)2Sn, n = 1−10. are formed on heating 2 with an excess of cyclooctasulfur.
Tris(silyl)silyl-chlorsilane und P-halogenierte Silylphosphane / Tris(silyl)silyl-chlorosilanes and P-Halogenated Silylphosphanes
Authors: Haase Martin , Klingebiel Uwe
Published: March 2015

Lithium-tris(trimethylsilyl)silan reacts with chlorosilanes to give thermally stable compounds (1−3). The chlorination of 3 leads to the formation of the silane (Me3Si)3SiSi(Cl)(CMe3)2 4. The reaction of tetramethylpiperidinodihalogenophosphanes with (Me3Si)3SiSi(Cl)(Cme3)2 results in ther­mally stable compounds (Me3Si)3Si−P(Hal)N(CMe2)2(CH2)3, Hal = F (5). Cl (6), (Me3Si)3Si−P(Cl)N(CHMe2)2 (7) undergoes thermaly rearrangement via a silicon-chlorine ex­change reaction to give (Me3Si)2Si(Cl)−P(SiMe3)N(CHMe2)2 (8). A byproduct − besides cyclic phosphanes - is the silylamine (Me3Si)2Si(Cl)N(CHMe2) (9). The formation of (9) can be ex­plained via the elimination of the phosphinidene Me3SiP.
Biologisch aktive 1,2,4-triazol-und imidazolhaltige phosphorylierte Alkohole / Biologically Active 1,2,4-Triazole and Imidazole Containing Phosphorylated Alcohols
Authors: Ekkehard Lindner , Varughese Kandenkulathu Abraham , Hübner Dieter
Published: March 2015

The addition of the secondary phosphane chalkogenides HP(E)R3
2 (E = O , S) to the 1,2,4-triazole or imidazole containing ketones R1C6H4−C(O)−CHR2−X (2, 3) [X = C2H2N3 (2), C3H3N2 (3)] results in the formation of the phosphorylated alcohols R3
2P(E)−C(OH)C6H4R1−CHR2−X (4, 5). 4, 5 are fungicides with partially high activity. Their structures are discussed on the basis of the IR and NM R spectra.
Rubidium-diarsasilicat(IV) Rb2SiAs2, ein Derivat der SiS2-Struktur / Rubidium Diarsasilicate(IV) Rb2SiAs2, a Derivative of the SiS2 Structure Type
Authors: Wolf Juliane , Weber Dieter , Schnering Hans-Georg von
Published: March 2015

Rb2SiAs2 was found as a byproduct in the course of the RbAs synthesis in a quartz container. The direct synthesis from the elements yields pure samples w-ithin 5 h at 925 K. Rb2SiAs2 forms transparent red needle-shaped crystals which split to bunches of golden, reflecting fibres. The compound is sensitive against moisture. Rb2SiAs2 is isotypic to K2SiP2 with a polyanionic chain [SiAs2]2- of edge-connected tetrahedra (isostructural and isoelectronic to SiS2) formed in a dis­torted cubic closed packed As arrangement, and with Rb in the octahedral holes (Ibam. No. 72; a = 726.6(5), b = 1377.1(6), c = 638.9(3) pm; Z = 4: Si−As = 238.1 pm; As−Si−As = 95.7° and Si−As−Si = 84.3° in the four membered Si2As2 rings).
Calamitische Flüssigkristalle: Beziehung zwischen Molekülstruktur und Mesogenität, trans-und cis-1,3,5,7-Tetraoxadecalin-Derivate [1,2] / Calamitic Liquid Crystals: Relationship Between Molecular Structure and Mesogenity, trans- and cis-1,3,5,7 -Tetraoxadecalin Derivatives [1, 2]
Authors: Kohne Bernd , Praefcke Klaus , Omar Rashad Shabana , Frolow Felix
Published: March 2015

1,3,5,7-Tetraoxadecalin has been introduced as a novel central unit into the chemistry of calamitic liquid crystals. 2e,6e-Disubstituted derivatives 3a−h and 4b, g, i of the trans or cis fused heterobicyclus, respectively, have been synthesized. Whereas most of these tram-products (3c−h) are nematic or smectic A (new “rod-like mesogens”), the cis-products (4b, g, i) are not liquid crystalline. The configurations and conformations of all compounds have been elucidated by spectroscopic methods in particular by 1H and 13C NMR. In addition the structures of 3d, 3g and 4i as representatives of both series have been confirmed by X-ray analysis. The 1,3,5,7- tetraoxadecalin unit in the non-mesomorphic ds-products exists, as expected, in the “O-inside" conformation which has been established both by 1H NMR and X-ray studies. The relationship between the chemical structure and mesomorphic behaviour of these 1,3,5,7-tetraoxadecalin derivatives is discussed, as well as the most likely structural requirements for turning the non- mesomorphic cis-products into mesomorphic ones. The name “roof-like mesogens" is proposed for this predicted new type of liquid crystals with three-dimensional geometry.
Dreifache Mannich-Cyclisierung Aufbau von drei benachbarten quartären sp3-Kohlenstoffzentren in einem Reaktionsschritt / Threefold Mannich Reaction Formation of Three Neighboring Quarternary sp3-Carbon Centers in a Single Reaction Step
Authors: Risch Nikolaus
Published: March 2015

Under the relatively mild conditions of a threefold Mannich reaction, starting from the 1,3-cyclohexanedione derivatives 2, the formation of three neighboring quarternary sp3-carbon centers succeeds in a single reaction step.