bluuebunny/crossref_metadata_2025 huggingface dataset:
Bimolekulare Filme in Schichtkris tallen: Matrizenwirkung der Festkörperschichten bei Uranglimmern / Bimolekular Films in Layer Structures: Matrix Effect of the Inorganic Sheets of Uranium Micas
Authors: Fernández-González Martin , Weiss Armin , Beneke Klaus , Lagaly Gerhard
Published: March 2015

Besides the mica-type layer silicates, uranium micas (Me{UO2PO4}) are excellent examples of layer compounds which incorporate long chain alkyl compounds between the layers with formation of bimolecular films. They are recommended as models for the study of phase transformations of bimolecular films. Comparison between layer silicates and uranium micas reveals the matrix effect of the inorganic sheets. Bimolecular films between silicate sheets rearrange into well organized kink blocks by two-dimensional cooperative reactions. In uranium micas the different lateral symmetry but identical packing density makes kink block formation less regular and proceeding only by one-dimensional cooperative reactions.
Siliciumverbindungen mit starken intramolekularen sterischen Wechselwirkungen, V. Organosilylnitrite, -nitrate und verwandte Verbindungen / Silicon Compounds with Strong Intramolecular Steric Interactions, V. Organosilicon Nitrites, Nitrates and Related Compounds
Authors: Weidenbruch Manfred , Sabeti Fateh
Published: March 2015

The reaction of triisopropyl- or tricyclohexylhalosilanes with silver salts gives the corresponding silyl nitrites and silyl nitrates. The insertion reaction of sulfur trioxide or dichlorocarbene into the silicon hydrogen bond of triisopropylsilane and tricyclohexylsilane yields the sulfates and the dichloromethyl derivatives, respectively.
Der Substituenteneinfluß auf die Fluoreszenz des 1.3-Diphenyl-2-pyrazolins / Substituent Effects on the Fluorescence of 1,3-Diphenyl-2-pyrazoline
Authors: Strähle H. , Seitz W. , Güsten H.
Published: March 2015

The electronic absorption spectra, absolute fluorescence spectra and fluorescence quantum yields as well as the fluorescence decay times of nine 1,3-diphenyl-2-pyrazolines substituted in the para-position of the 1-phenyl ring and of 19 substituted in the paraposition of the 3-phenyl ring were measured in degassed benzene at room temperature. The fluorescence quantum yields are about 0.90 with the exception of the NO2- and J-substituted 1,3-diphenyl-2-pyrazolines. The fluorescence decay time ranges from 2 to 4 nsec. The natural fluorescence lifetimes determined experimentally agree well with those calculated from the absorption spectra according to STRICKLER and BERG. A plot of the Hammett σp-values versus the energies of the absolute fluorescence maxima of the psubstituted 1- and 3-phenyl ring of the 2-pyrazoline system shows a statistically significant linear correlation with moderate precision. The linearity between ground state substituent constants and fluorescence energies reveals that the relative importance of the inductive and the resonance effects of the substituents remains constant during the transition from the ground state to the relaxed excited singlet state. In the excited singlet state of 1,3-diphenyl-2-pyrazoline the p-substituents provide more room for a larger charge displacement in the intramolecular charge-transfer. The structural bands in the fluorescence spectra resulting from strong electron accepting substituents in the para-position of the 1-phenyl ring are considered as the result of the ring breathing vibration due to a local excitation of the 1-phenyl ring.
Synthese von Insektenlockstoffen an Metathesekatalysatoren / Synthesis of Insect Attractants by Metathesis Catalysts
Authors: Küpper Friedrich-Wilhelm , Streck Roland
Published: March 2015

Insect sex attractants are of considerable practical interest inasmuch as it is possible with their aid to control and to combat certain damaging species of insects selectively with minimum damage of the environment. Instead of the known multistage syntheses the metathesis reaction offers the possibility to produce some insect sex pheromones inexpensively on a large commercial scale starting with cheap petrochemicals. Thus, the sex attractants of the common housefly, of the face fly and of the gypsy moth could be prepared by using suitable starting alkenes and homogeneous or heterogeneous catalysts.
Spektroskopische Untersuchungen zur Struktur des 5.6-Didehydro-11.12-dihydro-dibenzo[a. e]cyclooctens / Spectroscopic Investigations about the Structure of 5,6-Didehydro-11,12-dihydro-dibenzo[a, e]cyclooctene
Authors: Meier Herbert , Gugel Hansjörg , Kolshorn Heinz
Published: March 2015

5,6-Didehydro-11,12-dihydro-dibenzo[a,e]cyclooctene is a highly strained cycloalkyne. At room temperature it exists in a chiral C2-conformation. A direct proof is the AA′ BB′ pattern of the 1H NMR spectrum, for which also a computer calculation was performed. The spectroscopic fingerprints of the ring strain and the ring inversion are discussed.
Notizen: The Isomerisation of Hydrocarbon Ions, V. Isomeric Pentylbenzenes and their [M-CH3]+ Fragments
Authors: Heimbrecht J. , Levsen K. , Schwarz H.
Published: March 2015

In contrast to the corresponding butyl ions the [M–CH3]+ ions from isomeric pentylbenzenes do not isomerise completely to a mixture of interconverting structures prior to decomposition.
Notizen: Synthetic Studies towards anti-Leukaemic Alkaloids, IX
Authors: Rahman Atta-Ur
Published: March 2015

The synthesis of 15-acetoxydihydrocatharanthine, of key intermediate in the synthesis of the anti-cancer alkaloid vinrosidine (3), is described by a novel modification of the PREVOST reaction.
Zur Darstellung und Kristallstruktur von Na2CuAs, K2CuAs und K2CuSb.
Authors: Eisenmann Brigitte , Savelsberg Gerhard , Schäfer Herbert
Published: March 2015

The three new compounds crystallize orthorhombic, space group Cmcm with

Na2CuAs: a = 8.86(2) Å, b = 7.22(2) Å, c = 5.34(2) Å;

K2CuAs: a = 10.02(2) Å, b = 7.56(2) Å, c = 5.89(2) Å;

K2CuSb: a = 10.50(2) Å, b = 7.93(2) Å, c = 6.23(2) Å.

There are Cu–E(V)–Cu–E(V)-zigzag-chains in the structure, in which the Cu-atoms are linearly bonded to the E(V)-atoms.
Komplexchemie polyfunktioneller Liganden, XXXVIII. Präparative und schwingungsspektroskopische Untersuchungen zum Reaktionsverhalten von Mn2(CO)10 gegenüber dem tritertiären Phosphin 1.1.1-Tris(diphenylphosphinomethyl)äthan.
Authors: Ellermann Jochen , Lindner Helmut A.
Published: March 2015

Decacarbonyldimanganese reacts with the tritertiary phosphine 1,1,1-tris(diphenylphosphinomethyl)ethane (triphos) to give the ionic complex [Mn(CO)3triphos][Mn(CO)5]. Treatment of [Mn(CO)3triphos][Mn(CO)5] with Na[B(C6H5)4], HClO4 and NH4PF6 yields the manganese(I) salts [Mn(CO)3triphos]Y (Y = B(C6H5)4, ClO4, PF6). The IR (2100-300 cm-1) and FIR spectra (350-200 cm-1) of all compounds are reported. Based on Raman polarization data the assignment of the v(CO) (A1 + E), δ(MnCO) (A1 + 2 E), v(MnC) (A1 + E) and v(MnP) (A1) modes was possible for the coordination polyhedra cis-Mn(CO)3P3(point group C3v). The v(MnP) (E) mode was unobserved due to its very low frequency.
Preparation of 4-Hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl A Reinvestigation of Methods Using Hydrogen Peroxide in the Presence of Catalysts
Authors: Sosnovsky G. , Konieczny M.
Published: March 2015

The preparation of the key intermediate for spin labeling, 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (2), was reinvestigated using sodium tungstate or phosphotungstic acid with or without either Trilon or Triton B. A two-fold and a 3.5-fold molar excess of a 30% aqueous hydrogen peroxide solution was used. The oxidation of 4-hydroxy-2,2,6,6-tetramethylpiperidine (1) with a two-fold molar excess of a 30% aqueous hydrogen peroxide solution in the presence of sodium tungstate alone, under vigorous stirring for two hours, is the superior method (A) for the preparation of 2 in virtually quantitative yield.
Pyridazines, LXXXVI. Some Mesoionic Mercaptoazolopyridazines
Authors: Bregar Z. , Stanovnik B. , Tišler M.
Published: March 2015

6-Mercapto anhydro salts of imidazo(1,2-b)- (2) and s-triazolo(4,3-b)pyridazines (7) were prepared and investigated. They were transformed into the corresponding 6-methylthio derivatives (3 or 8). Compounds of the type 3 are thermally demethylated into 4, but in the case of the 2-unsubstituted compound (3, R = H) also ring opening occurred to give compound 5 as minor product.
Impulsphotolytische Untersuchungen zum Mechanismus der photochemischen WoLFF-Umlagerung.
Authors: Bölsing F. , Spanuth E.
Published: March 2015

9,10-Diazophenanthrone undergoes WOLFF rearrangement in alcoholic solvents and yields esters of 9-fluorene carboxylic acid. By flash light photolysis four intermediates could be detected. Kinetic measurements showed that the ketene formed by photolysis reacts with the solvent to give a cyclopentadienylic carbanion, which is protonated. A carbene or an oxirene intermediate could not be found.
Notizen: Die Kristallstruktur von Tetramethylarsonium-dibromodimethylindat [(CH3)4As][(CH3)2InBr2].
Authors: Schwarz W. , Guder H. J. , Prewo R. , Hausen H. D.
Published: March 2015

[(CH3)4As][(CH3)2InBr2] has been prepared by reaction of (CH3)3AsBr2 with ln(CH3)3. The compound crystallizes in the orthorhombic space-group P212121 and four formula units in the cell. The structure was refined by least square analysis to a R-value of 0.072. As in [(CH3)4As][CH3InCl3] or [(CH3)4Sb][CH3InCl3] isolated cationic and anionic tetrahedra are found in the new compound.
Notizen: Inhibitor-Effekt von BF3 auf die Umlagerung von / Inhibitory Effect of BF3 on the Rearrangement of
Authors: Michalski J. , ŁoPusinski A. , Stec W. J. , Fluck E.
Published: March 2015

The rapid conversion of phosphorus thiocyanates into isothiocyanates is caused by nucleophilic reagents. Thiocyanate structures can be stabilized by adding BF3. The mechanisms of conversion and stabilization are discussed.
Aluminium-Stickstoff-Verbindungen mit adamantanähnlichem Gerüst. / Aluminium Nitrogen Compounds Having a Skeleton Similar to Adamantane
Authors: Nöth H. , Wolfgardt P.
Published: March 2015

Aluminium nitrogen compounds having an adamantane cage structure 1 are produced from aminoalanes HXAlN(CH3)2 (X = H, Cl, Br, I) and primary amines. The hydridic Η-atoms of [(R2NAlH)2NR]2 (R = CH3) can be replaced by halogen using mercury halides. In contrast, methylation was not achieved by Hg(CH3)2 or Al(CH3)3 · O(C2H5)2 respectively. LiAlH4 and (CH3)2NH degrade the adamantane skeleton with aminoalane formation.

The spectroscopic data of the new compounds will be discussed
Photoelektronenspektren von Verbindungen der V. Hauptgruppe, VI Methyl- und Trifluormethyl-Cyanphosphine, MenP(CN)3-n und (CF3)nP(CN)3-n (n = 0, 1, 2, 3). / Photoelectron Spectra of Group V Compounds, VI Methyl- and Trifluoromethyl-Cyanophosphines, MenP(CN)3-n and (CF3)nΡ(CN)3-n (n = 0, 1, 2, 3)
Authors: Elbel Susanne , Dieck Heindirk Tom , Demuth Reinhard
Published: March 2015

The He I photoelectron spectra of the series RnP(CN)3-n (R = Me, CF3; n = 0, 1, 2, 3) and of Me2ECN (E = N, P, As) are interpreted. The PE assignments are based on the comparison with the PE data of analogous halogeno and hydrogen derivatives as well as related cyano compounds and on simple MO considerations (composite molecule-approach). Hyperconjugative and inductive effects of the substituents CN, Me, F, Cl, and especially CF3 are assessed. The various effects of changing substituents or central atoms within the series are used to confirm the interpretation. The differing electronic structures of halogeno and cyano (pseudohalogeno) compounds are discussed on the basis of their PE spectra
Additionsreaktionen mit fluorierten Diazoverbindungen: Über die Darstellung von N-Perfluorisopropyl-oxathiazolin- und S-Perfluorisopropyl-oxathiazol-Derivaten. / Addition Reactions with Fluorinated Diazo Compounds: The Preparation of N-Perfluoroisopropyl-oxathiazoline- and S-Perfluoroisopropyl-oxathiazole Derivatives
Authors: Steinbeisser Hartmut , Mews Rüdiger
Published: March 2015

Reaction of fluorosulphonyl isocyanate with excess (CF3)2CN2 (1) gives the oxathiazoline (3); the isomeric oxathiazole (5) is obtained from perfluoro isopropyl sulphonyl isocyanate and 1. 3 is hydrolized much more readily than 4, from these reactions 2,2,5,5-tetrakis-(trifluoromethyl)oxazolidone or (CF3)2CF-SO2NH2 are isolated
Optisch aktive Übergangsmetall-Komplexe, XLIII. (—)578-C5H5Mn(NO)(COC6H5)PN. Darstellung, Epimerisierung und Stereochemie des Ligandenaustauschs.
Authors: Brunner Henri , Steger Wolfgang
Published: March 2015

In the reaction of [C5H5Mn(NO)(CO)PN*]PF6 (1) with LiC6H5 5-exo-C6H5C5H5Mn(NO)-(CO)PN* (2) and C5H5Mn(NO)(COC6H5)PN* (3) are formed. If the reaction is carried out with optically active starting material 1 the optically active ring addition and benzoyl compounds 2 and 8 resp., are obtained. Whereas the ring addition product 2 is configurationally stable, the benzoyl complex 3 in solution epimerizes according to 1st order kinetics. The change of configuration at the Mn atom occurs by PN* dissociation with formation of a chiral intermediate. This is demonstrated by the fact that exchange of PN* in (-)578-C5H5Mn(NO)(COC6H5)PN* (1a) with P(OC2H5)3 gives (+)578-C5H5Mn(NO)-(COC6H5)P(OC2H5)3 (4a), a reaction proceeding with retention of configuration at the metal atom
Notizen: Darstellung und Kristalldaten des Wismut-Sulfid-Chlorids Bi4S5Cl2. / Preparation and Crystal Data of the Bismuth Sulphide Chloride Bi4S5Cl2
Authors: Krämer Volker
Published: March 2015

The title compound was prepared for the first time by thermal dissociation of BiSCl as well as by sintering of 2 BiSCl + Bi2S3 at 340°C. Bi4S5Cl2 crystallizes rhombohedrally, its hexagonal lattice parameters are α = 19.804(5) and c = 12.359(3) Å; X-ray powder diffraction data are listed
Beiträge zur Untersuchung anorganischer nichtstöchiometrischer Verbindungen, VI: Präparative und strukturelle Untersuchung von WNb15O40F und nahe benachbarten Defektstrukturen im System Nb2O5—WO3—NbO2F / Contributions to the Study of Inorganic Non-Stoichiometric Compounds, VI: Preparative and Structural Investigations of WNb15O40F and Closely Related Defect Structures in the System Nb2O5—WO3—NbO2F
Authors: Krämer Eberhard , Gruehn Reginald
Published: March 2015

In the quaternary system H–Nb2O5–WO3–NbO2F the phase WNb15O40F was prepared in form of light-yellow needles. The compound crystallizes in the monoclinic system with the unit cell dimensions a = 22.254 A, b = 3.829 A, c = 20.298 A and β = 114.29°, space group C 2. Electron optical investigations showed the crystal structure containing 5 x 3 x co-blocks of Nb—(O, F)-octahedra, with metal atoms in tetrahedral positions located at the junctions of every four blocks. X-ray investigations showed a range of homogeneity between (O, F)/ (W, Nb) = 2.556 < 2.563 (WNb15O40F) < 2.571.

The hypothetical phase WNb18O47F2 with 6 x 3-blocks was found as a microdomain by electron microscopy.
Cu2+-Ionen in tetragonal gestauchten Koordinationsoktaedern — Spektroskopische Untersuchungen zum Jahn-Teller-Effekt von Cu2+ in Mischkristallen Ba2CuxZn1-xF6.
Authors: Friebel C. , Propach V. , Reinen D.
Published: March 2015

Usually the Jahn-Teller effect of Cu2+ in a regular octahedral host lattice site leads to a tetragonal elongation with a small o-rhombic component. If the relevant crystallographic site is slightly tetragonally compressed however in the host lattice structure already – as in Ba2ZnF6 – the Jahn-Teller effect may stabilize this distortion symmetry as well. This can be deduced from the EPR-spectroscopic gn -values of 1.99 for the mixed crystals Ba2Zn1-xCuxF6 up to x = 0.3. The angular overlap parameters obtained from the ligand field spectra suggest in addition, that the tetragonal compression of the CuF6 polyhedra is considerable, with CuF distances of about 1.90 Å (2 x) and 2.14 Å (4 x), respectively.

Increasing cooperative elastic interactions between the CuF6 polyhedra in the (001) planes at larger Cu2+-concentrations induce tetragonally elongated octahedra (with a small o-rhombic component) in antiferrodistortive order at x ≥ 0.6. This cooperative Jahn-Teller order, which is characteristic for Ba2CuF6, can be verified simply by acentric displacements of the F-.ligands connecting two Cu2+-ions in the (001) planes.
Molecular Compounds of HgCl2 with Organic Donors. A 35Cl NQR Study
Authors: Fichtner W. , Weiss Alarich
Published: March 2015

Molecular compounds of HgCl2 with organic donor molecules (dioxane, 1,3,5-trioxane, 1,3,5-trithiane, tetrahydrothiophene, 1,4-cyclohexandione, collidine, benzaldehyde, orthochlorobenzaldehyde, metachlorobenzaldehyde, parachlorobenzaldehyde) and the double salts K2HgCl4 • H2O and Rb2HgCl4 • H2O were studied by 35Cl NQR spectroscopy in the temperature range 77 K ≦ T ⪅ 300 K. The results are discussed with respect to the coordination around the Hg atom within the complex. The molecular compound, except those with sulfur-containing donors, seem to adapt an approximately octahedral coordination at the Hg atom. According to the 35Cl NQR results, HgCl2 may form dimers and trimers with orthochlorobenzaldehyde and parachlorobenzaldehyde, respectively. Isotypy of K2HgCl4 • H2O and Rb2HgCl4 • H2O is in accordance with the NQR experiments.
Carbocyclisch substituierte N-Methansulfonyl-isoindoline Synthesevorstufen für unsymmetrisch substituierte 2H-Isoindole / Carbocyclic Substituted N-Methane-sulfonyl-isoindolines Synthetic Precursors for Unsymmetric Substituted 2H-Isoindoles
Authors: Kreher Richard , Use Götz
Published: March 2015

N-methane-sulfonyl-isoindolines substituted in the carbocyclic moiety can be prepared from the corresponding 1,2-bis-[brommethyl]benzenes and methane sulfonamid by cyclisation under basic conditions. The title compounds are interesting precursors for the generation of carbocyclic substituted 2H-isoindoles via base catalysed 1,2-elimination of methane sulfinic acid. By this reaction sequence the sulfonyl residue is simultaneously involved as a protecting group and as a leaving group.
Substituenteneinflüsse auf die 13C–NMR-chemischen Verschiebungen cis- und trans-konfigurierter Trimethincyanine / Substituent Effects on the 13C NMR Chemical Shifts of Trimethincyanines with cis and trans Configuration
Authors: Grahn Walter
Published: March 2015

The 13C NMR chemical shifts of fifteen 6 substituted 2,3-dihydro-1,4-diazepinium salts (cis trimethincyanines) (1) and twelve 2 substituted bis(dimethylamino)trimethinium salts (trans trimethincyanines) (2) have been determined. A comparison of the substituentinduced shifts (13C SCS) of 1 and 2 allows no distinction between steric and electronic effects. In the three 6 п-electron systems 1, 2 and monosubstituted benzenes the 13C SCS are similar for the substituent bearing carbon atoms. A surprisingly large 4JFCCNC coupling constant has been observed.
Organic Reaction Schemes and General Reaction — Matrix Types, I Rearrangement Reactions
Authors: Bart Jan C. J. , Garagnani Enea
Published: March 2015

A sample consisting of about 120 organic rearrangement reactions has been quantified in terms general reaction matrices R̃ expressing electron-flow processes. About two thirds of the reactions considered conform to only two distinct R̃-matrices, 80% to five such schemes. The frequency distribution is qualitatively similar to that found for larger, more randomly chosen, sets of organic reactions. Examples of the various electron-flow processes are given. The bearings of the results on synthesis-planning are discussed.
Thienoquinolines, IV1 Synthesis of Thieno(2,3-b)quinolines
Authors: Shanmugam P. , Kanakarajan K. , Soundararajan N.
Published: March 2015

Synthesis of several thieno(2,3-b)quinolines is described starting from appropriately substituted 2-oxo-3-vinylquinolines.
Elektrochemische Synthesen, ΧII Glimmlichtelektrolyse von wäßrigen Braunkohle-, Aktivkohle- und Graphitsuspensionen sowie von wäßrigen Phenollösungen / Electrochemical Syntheses, XII Glow Discharge Electrolysis of Aqueous Brown Coal, Charcoal and Graphite Suspensions, as well as of Aqueous Phenole Solutions
Authors: Fritz Heinz P. , Huber Reinhard
Published: March 2015

The gaseous reaction products of the glow discharge electrolysis of aqueous suspensions of carbon-rich substances like brown coal, charcoal and graphite were investigated qualitatively and quantitatively. Furthermore, the chemical reactions of phenole in sulfuric acid solution in the presence of Fe3+ during glow discharge electrolysis were studied.
Die Molekül- und Kristallstruktur von Tetrachlorophosphoniumpentachlorovanadat(IV), [PCl4] [VCl5] / The Molecular and Crystal Structure of Tetrachlorophosphoniumpentachlorovanadate(IV), [PCl4][VCl5]
Authors: Ziegler Manfred L. , Nuber Bernd , Weidenhammer Klaus , Hoch Gerhard
Published: March 2015

The structure of [PCl4][VCl5] was determined from threedimensional X-ray data. The VCl5
- ion is bipyramidal with almost C2v symmetry.
Darstellung und spektroskopische Untersuchung von Bis(alkylmetall)-diacetylhydrazinderivaten des Aluminiums, Galliums, Indiums und Antimons / Preparation and Spectroscopic Investigations on Bis(alkylmetal)diacetylhydrazin Derivatives of Aluminium, Gallium, Indium and Antimony
Authors: Eberwein Bernd , Lieb Waldemar , Weidlein Johann
Published: March 2015

The interaction of N,N′-diacetylhydrazine with the trialkys of aluminium, gallium and indium and with Sb(CH3)5 yields bis(alkylmetal) compounds of the formula (RxM)2[O2N2(CCH3)2]

(x = 2, M = Al, Ga, In; R = CH3, C2H5 and x = 4, M = Sb; R = CH3). The M2O2N2C2 skeleton of these compounds forms a centrosymmetric system of two fused five-membered rings, with C2h or S2 symmetry.
Einzelvorgänge der thermischen Umwandlung von Magnesiumhydroxid ins Oxid / Details of the Thermal Conversion of Magnesium Hydroxide into Oxide
Authors: Koubowetz Franz , Noller Heinrich
Published: March 2015

The decomposition of Mg(OH)2 was studied by means of thermogravimetry, IR-spectroscopy, DTA, thermodesorption with GC and MS, and X-ray analysis.

Water was evolved in two steps, at 230 °C (a small amount only) and 380 °C. The band at 3700 cm-1, that is assigned to OH groups of Mg(OH)2, was not present above 270 °C. Assuming that only surface OH groups appear in the IR spectrum, but no bulk OH groups, the steps at 230 °C and 380 °C can be attributed to the decomposition of the surface and the bulk, resp.
Ni(II) Complexes with bis(β-Acylvinyl)amines and (8-Quinolyl-β-acylvinyl)amines
Authors: Dabrowski Janusz , Krówczyński Adam
Published: March 2015

The title complexes have been obtained and shown by elemental analysis, IR and PMR spectra to be octahedral. The trans structure has been assigned to bis(β-acylvinyl)amine complexes based on magnetic equivalence of geminal methyl groups in appropriately substituted representatives of this group of compounds. The (8-quinolyl-β-acylvinyl)-amine complexes may have either trans or s-cis (meso) configuration.
Improvements in the Preparation of Spin-Labeled Phosphorus Compounds of Potential Cytotoxicity
Authors: Sosnovsky G. , Konieczny M.
Published: March 2015

The syntheses of spin-labeled phosphorus compounds containing the ethyleneimine, —N, and nitrogen mustard, —N(CH2CH2Cl)2, moieties were reinvestigated. By a judicious choice of solvents, stoichiometry, and reaction conditions yields of these compounds have been optimised. Thus, monoradical diamidates (5) and (9) wore prepared in 95 and 82% yields, respectively, and diradical monoamidates (7) and (12) were prepared in 95 and 45% yields, respectively. The nitrogen mustard derivative (16) was obtained in 92% yield.

[xxx]
Synthesis of 5 H-Thiazolo[2,3-b]quinazoline-3,5(2 H)-dione. Its Condensation with Aldehydes, Coupling with Diazonium Salts and Cleavage by Amines
Authors: Ali Mohamed I. , Hammouda Hamdy A. , Abd-Elfattah Abd-Elsamei M.
Published: March 2015

Cyclodehydration of (4-oxo-3,4-dihydro-2-quinazolinylthio)acetic acid (1) afforded 5 H-thiazolo[2,3-b]quinazoline-3,5(2 H)-dione (2). Condensation of 2 with aldehydes gave the 2-arylmethylene derivatives (6 a-d) and coupling with diazonium salts gave the hydrazones (9a, b). The thiazolone ring in 2 has been cleaved by amines to give a-(4-oxo-3,4-dihydro-2-quinazolinylthio)acetanilides (11 a-d). The arylmethylene derivatives of the angular isomer of 2, 5 H-thiazolo[3,2-a]quinazoline-1,5(2 H)-dione (4), were also prepared.
Utility of the Cleavage of Nitrosamides for the Preparation of Chiral Acids after Chromatographic Separation of their Diastereomeric Amides
Authors: Schmidtchen Franz P. , Rauschenbach Peter , Simon Helmut
Published: March 2015

A method for optical resolution of chiral acids is described. It consists of the conversion of racemic acids to diastereomeric amides, their chromatographic separation and subsequent deamidation via the nitrosamide route. Reaction conditions for cleavage of amide derivatives of phenylalanine and methylbenzylamine are given. No or only negligible racemization of carboxylic acids, chiral in α-position takes place under those conditions. The extent of Ε,Ζ-isomerization of double bonds is very small, as is the extent of double bond migration from the Δ3-position into conjugation with the carboxyl function. Enantiomerically pure R- or S[2-3H]2-methylbutanoic acid and (-)methyl-3(p-chlorophenyl)-2-chloropropionate (Bidisin®) were prepared by this procedure.
Notizen: Homogene katalytische Hydrierung mit dem System NiCl2 und CoCl2 plus NaBH4 in Dimethylformamid und Dimethylacetamid unter milden Bedingungen / Homogeneous Catalytical Hydrogenation with the System NiCl2 and CoCl2 plus NaBH4 in Dimethylformamide and Dimethylacetamide under Mild Conditions
Authors: Strohmeier Walter , Steigerwald Hannelore
Published: March 2015

A homogeneous catalytic hydrogenation system can be prepared by reaction of NiCl2 · 6 H2O or CoCl · 6 H2O with NaBH4 in dimethylformamide or dimethylacetamide. This system is a quite efficient catalyst for hydrogenation of unsaturated compounds under mild conditions but it is very sensitive to traces of air. Reaction rates r up to 15 (mmol ­· 1-1 · min-1) were observed. 1,3-Cyclohexadiene is very selectively hydrogenated to cyclohexene in dimethylacetamide.
The Tetrakis(trimethylphosphine)cobalt Anion
Authors: Hammer Reinhard , Klein Hans-Friedrich
Published: March 2015

Reduction of paramagnetic L4Co (L = (CH3)3P) (d9) by alkali metals affords salts of L4Co- (d10). These are strong reducing agents, powerful bases and very able nucleophiles. They rapidly exchange three of their phosphine ligands for CO. Their reactions with a variety of inorganic and organic halides are shown to be effectively oxidative additions. From the distinct thermochromic behaviour of these salts both in the solid state and in solution a reversible formation involving different states of solvation is deduced.
Die intramolekulare Beweglichkeit von Alkinen in Wolframkomplexen des Typs C5H5W(CO)(L)R (L = Alkin; R = CH3, C6H5) / The Intramolecular Mobility of Alkynes in Tungsten Compounds of the Type C5H5W(CO)(L)R (L = Alkyne; R = CH3, C6H5)
Authors: Alt H. G. , Stadler W.
Published: March 2015

Complexes of the type C5H5W(CO)(L)R (L = alkyne; R = CH3, C6H5) are obtained by irradiation of a solution containing both C5H5W(CO)3R and L. The intramolecular mobility of the π-bonded acetylene in the 16-electron complexes C5H5W(CO)(L)R can be demonstrated by temperature-dependent 1H NMR spectroscopy.
Phosphororganische Derivate von Übergangsmetallcyanokomplexen, IV Intermediärverbindungen aus sauren Phosphonium-cyano-kobaltaten(III) / Organophosphorus Derivatives of Cyanometalates, IV Intermediate Compounds from Phosphonium-hydrogen-cyano-cobaltates(III)
Authors: Papp S. , Czeglédi S.
Published: March 2015

The coordinatively unsaturated intermediates prepared by thermal decomposition of the phosphonium hydrogen cyanocobaltates were investigated by magnetic methods, IR and visible spectroscopy. Their reactions with amines and phosphines yield novel preparable species.
The Preparation of Some Unsymmetrically 2,2′ -Disubstituted Stilbenes
Authors: Mintas M. , Jakopčić K. , Klasinc L.
Published: March 2015

The new unsymmetrically 2,2′-disubstituted stilbenes with NO2, F, Cl, Br, OCH3, CH3 and NH2 groups as substituents have been prepared by WITTIG or PERKIN reactions. The compounds 1-8 were prepared due to the studies of fragmentation on electron impact, photochemistry and photoelectron spectroscopy. Their geometrical configuration has been established by 1H NMR and IR spectra.
Infrared Spectral Studies of Metal Chelates of 2-Furan Carboxaldoxime
Authors: Gupta V. K. , Bhat A. N.
Published: March 2015

2-Furan carboxaldoxime (anti-form) or anti-furan 2-aldoxime (FDH) forms octahedral complexes of the type M(FDH)2Cl2 (M = Mn, Co, Ni, Cu and Zn) and M(FDH)3Cl3 (M = Cr and Fe). The infra red spectral studies have revealed that the coordination of the metal involved the oxime oxygen and the furan ring oxygen. However, the ligand acts as bidentate in case of M(FDH)2Cl2 while it is monodentate in M(FDH)3Cl3. The M-O bands in the infrared spectra may be taken as a criterion for the denticity of the ligand in its various metal complexes. Bands at 670-630 cm-1 and around 450 cm-1 indicate the bidentate ligand, while the absence of the band at 670-630 cm-1 reveals monodenticity. The : C=N-stretching frequency has been found to increase with decreasing stability of the bivalent metal complexes, while it is insensitive in case of the trivalent metal complexes.
Notizen: Gezielte Synthese von Sulfinato-O–und -S-Komplexen einiger Übergangsmetalle, XVIII1 Synthese eines Sulfinato-O-Komplexes und Ionisationsisomerie bei Palladium(II)2 / Directed Synthesis of Sulfinato-O and -S Complexes of Some Transition Metals, XVIII1. Synthesis of a Sulfinato-O Complex and Ionization Isomerism with Palladium(II)2
Authors: Lorenz Ingo-Peter , Lindner Ekkehard , Reuther Wolfgang
Published: March 2015

The sulfinato-O complex (p-CH3C6H4S(O)O)2Pd(en) (2a) and its ionization isomer, the ionic compound [Pd(en)2][p-CH3C6H4SO2]2 (2b), are obtained from 1 by ligand addition in dependence of the nature of the solvent. 2 a, b can be transformed into each other reversibly. For 2 a two structural models are discussed. The pseudooctahedral configuration with two bidentate ethylene diamine and two sulfinato-O ligands in trans position seems to be more likely.
Notizen: Übergangsmetall-Carben-Komplexe, CIII Zur Reaktion von Pentacarbonyl(methoxyphenylcarben)chrom(0) mit ß-Diketonen / Transition Metal Carbene Complexes, CIII On the Reaction of Pentacarbonyl(methoxyphenylcarbene)chromium(0) with ß-Diketones
Authors: Fischer Ernst Otto , Selmayr Tassilo
Published: March 2015

Pentacarbonyl(methoxyphenylcarbene)-chromium(0) and ß-diketonesR1COCH2COR2 (R1, R2 = CH3, CF3, NHCONH) react on heating to give the meso-, RR- and SS-configurational isomers of 1,2-dimethoxy-1,2-diphenylethane.
Reaktionen des 2.2.4.4.6-Pentachlor-2.4-diphospha-1.3.5-s-triazins / Reactions of 2,2,4,4,6-Pentachloro-2,4-diphospha-1,3,5-s-triazine
Authors: Fluck E. , Schmid E.
Published: March 2015

2,2,4,4,6-Pentakisdimethylamino-2,4-diphospha-1,3,5-s-triazine (2), 2,2,4,4-tetrachloro-6-diethylamino-2,4-diphospha-1,3,5-s-triazine (4), and 2,2,4,4,6-pentakisethyleneimino-2,4-diphospha-1,3,5-s-triazine (5) were synthesized by reacting 2,2,4,4,6-pentachloro-2,4-diphospha-1,3,5-s-triazine (1) with the corresponding amines. The products are characterized by their NMR spectra. Attempts to react 1 with alkylation and arylation reagents are described.
Röntgenographische Strukturuntersuchung von Cäsiumhexaoxo-tetrahydroxo-pentaborat-2-dimethylsulfoxid / X-ray Study of the Structure of Cesiumhexaoxo-tetrahydroxo-pentaborate-2-dimethyl Sulfoxide
Authors: Frohnecke J. , Hartl H. , Heller G.
Published: March 2015

The compound Cs[B5O6(OH)4] · 2 DMSO was prepared by hydrolysis of tris(methoxy)-borane in organic solvents with small amounts of water in presence of cesium tert-butylate and recrystallized in DMSO (dimethyl sulfoxide). Cs[B5O6(OH)4] · 2 DMSO crystallizes in the monoclinic space group Ρ21/a with a= 9.593(2), b=19.179(4), c= 11.585(2) A, β= 119.99(2)° and Ζ = 4. The crystal structure was determined by single-crystal diffractometer data and refined to a conventional R value of 9.9%. The crystal structure consists of chains of pentaborate anions [B5O6(OH)4]- linked by hydrogen bonds. The cesium cation and the DMSO molecules join the chains to sheets by coordination and hydrogen bonds respectively.
Kristall- und Molekülstruktur des Bis-tetraäthylammoniumtetracyanonitrosylferrat(I) / Crystal and Molecular Structure of Bis-tetraethylammoniumtetracyanonitrosylferrate(I)
Authors: Kopf Jürgen , Schmidt Jörn
Published: March 2015

Crystals of [(C2H5)4N]2[Fe(CN)4NO] are rhombic with α = 3392.0(21) [pm], b = 760.4(8) [pm], and c = 983.2(9) [pm]; the space group is Pna21. The structure was determined by three-dimensional Patterson and Fourier methods on the basis of 1363 independent reflections. The unit cell consists of 4 molecular units. The anion forms a tetragonal pyramid which is only slightly distorted by narrowing one of the NC–Fe–NO angles. As expected from the electronic structure the apical NO group is almost linearly bonded to the central atom. The cations occur in two different conformations.
Strahlenchemische Cycloadditionen mit Äthylen und Acetylen (Produktbildung und Lösungsmittelwahl) / Radiation Chemical Cycloaddition Reactions with Ethylene and Acetylene
Authors: Mirbach Manfred J. , Mirbach Marlis F. , Saus Alfons
Published: March 2015

The (2+2) cycloadditions of maleic acid anhydride (MSA) and 1,3-cyclohexadiene (CHD) to ethylene and acetylene were initiated with gamma-rays in different solvents. The four-membered ring products were formed with high selectivity and surprisingly high energy yields in solvents with triplett energies smaller than ethylene and acetylene but higher than MSA and CHD resp. In benzonitrile as a solvent MSA reacts with ethylene to give cyclobutane-1,2-dicarboxylic acid anhydride (1) (G = 0.04) and with acetylene to give cyclobut-3-ene-1,2-dicarboxylic acid anhydride (2) (G = 3.7). The cyclobutene derivative (2) is formed in ≥ 80% yield and the bicyclopropyl derivative (8), which is the main product in the photochemical reaction, with a yield of ≤ 20%. 1,3-Cyclohexadiene was also added to ethylene to give bicyclo(4,2,0)oct-2-ene (G = 0.4) and bicyclo(2,2,2)oct-2-ene (G = 0.1) under gamma irradiation in methylnaphthalene as a solvent. Under similar conditions addition to acetylene gave bicyclo(4,2,0)octa-2,7-diene (G = 0.04) and bicyclo(2,2,2)octa-2,5-diene (G = 0.3), respectively.
Einfluß der Lebensdauer auf die Äthylen-Eliminierung aus Nichtterminalen Kohlenstoffpositionen bei Isomeren C11H15
+-Ionen in der Gasphase1 / On the Influence of Life Time on the Ethylene Elimination from Nonterminal Carbon Positions of Isomeric Gaseous C11H15
+ Ions
Authors: Bohlmann Ferdinand , Brehm Manfred , Schwarz Helmut
Published: March 2015

Using 13C-labelled compounds it is demonstrated that the extent of carbon randomization preceding or accompanying the ethylene elimination from C11H15+ is strongly influenced by the life time of the ions. Furtheron it is shown that the amount of these isomerisation reactions depends upon the structure of the precursor ions.
Beiträge zur Chemie der Pyrrolpigmente, XVII / On the Chemistry of Pyrrole Pigments, XVII
Authors: Falk Heinz , Gergely Stefan , Grubmayr Karl , Hofer Otmar
Published: March 2015

The (Z,Z)-configuration of the bilivioline chromophoric system was established investigating an appropriate model compound by means of pK measurement, 1H NMR spectroscopy Lanthanide ion induced shift technique, electron absorption spectroscopy and PPP calculations. Moreover a syn-syn conformation which is twisted at the a-methine single bond and planar within the pyrromethene unit (based on the concept of partial structures of bile pigments) of the molecule was deduced.
Yields of 2-Deoxy-D-gluconic, D-Gluconic and Other Sugar Acids in Gamma-Irradiated Aqueous Solutions of D-Glucose
Authors: Esterbauer Hermann , Schubert Jack , Sanders Edward B. , Sweeley Charles C.
Published: March 2015

The yields of 2-deoxy-D-gluconic, D-gluconic and other sugar acids from 60Co-gamma irradiated (dose rate = 4 Krads/min) D-glucose solutions are reported. The acids produced upon radiolyses were separated from glucose and neutral products by anion exchange, assayed by gas chromatography of the trimethylsilyl derivatives, and definitive identification made by mass spectrometry. In He degassed, irradiated 0.055 M glucose G(2-deoxy-D-gluconic acid) = 0.62 and G(D-gluconic acid) = 0.20. The approximate G values for the other identified acids are: glyceric acid 0.03, 2-deoxy-tetronic acid 0.04, tetronic acid 0.03, 4-deoxypentonic acid 0.02, deoxyketogluconic acid 0.17.

In N2O saturated glucose solutions D-gluconic acid yields increased by a factor of ∼1.9 while that of 2-deoxy-D-gluconic acid increased by a factor of only ∼ 1.1.
Zur Kenntnis des Argyrodit-Strukturtyps: Die Kristallstruktur von Ag8SiS6 / The Argyrodite Structure Type : The Crystal Structure of Ag8SiS6
Authors: Krebs Bernt , Mandt Jürgen
Published: March 2015

The room temperature modification of Ag8SiS6 is orthorhombic, space group Pna21, with α = 15.024, b = 7.428, c = 10.533 Å, Z = 4. A complete single crystal X-ray structure analysis shows the structure to contain tetrahedral SiS4
(4-) units (Si-S 2.094(12) ... 2.130(12) Å) besides isolated sulfide groups coordinated by Ag; the compound may thus be formulated as Ag8(SiS4)(S)2. The coordination of the Ag atoms by sulfur is distorted tetrahedral (Ag-S 2.557...2.757 A), approximately trigonal planar (Ag-S 2.386...2.775 A, with one additional weakly bonded axial S at 2.991 ... 3.330 Å), or linear (Ag-S 2.414... 2.443 Å). Within the (ordered) Ag sublattice the temperature factors are significantly higher than for Si and S, indicating a certain mobility of the Ag atoms. The arrangement of the thiosilicate -sulfide part of the structure is pseudocubic face-centered, showing the close structural relationship to the disordered cubic high temperature modification of Ag8GeTe6.
Über Oxocuprate, XXII Zur Kristallchemie von Kupferoxichlorid: Cu2OCl2 / On Oxocuprates, XXII The Crystal Structure of Cu2OCl2
Authors: Arpe R. , Müller-Buschbaum Ηk
Published: March 2015

Single crystals of Cu2OCl2 were prepared and investigated by X-ray methods. Cu2OCl2 crystallizes orthorhombic, space group D2h
24-Fddd (α = 969.9, b = 960.3, c = 746.2 pm). Cu2+ has a distorted octahedral coordination. The JAHN-TELLER-Effect and effective coordination number are discussed.
Photochemistry of (Iso)Alloxazines, V Mechanism of the Photoreaction of Flavin with 1,4-Cyclohexadiene and Analogous Compounds
Authors: Knappe Wolfgang-R.
Published: March 2015

On illumination flavin reacts from its triplet state with dihydroaromatic systems at room temperature yielding 1,5-dihydroflavin. Substrates which are substituted with methyl groups to hinder aromatisation (3,3-dimethyl-1-phenyl-1,4-cyclohexadiene, ergosterol, N-methylacridan, 1,3,10-trimethyl-1,5-dihydro-5-deazaisoalloxazine) yield at -40 °C 4a-substituted 4a,5-dihydroflavins (adducts), which on warming split homolytically, yielding a 1:1:1-mixture of 1,5-dihydroflavin/starting flavin/dimerized substrate after disproportionation and dimerisation, resp.

In the case of unblocked substrates these adducts are not UV-detectable even at -80 °C but split heterolytically, yielding 1,5-dihydroflavin and oxidized substrate in a 1:1-ratio.
Notizen: Eine Verfeinerung der Ba2CuF6-Struktur – Neutronenbeugungsuntersuchung am Kristallpulver / A Refinement of the Ba2CuF6 Structure by Powder Neutron Diffraction
Authors: Reinen D. , Weitzel H.
Published: March 2015

A refinement of the Ba2CuF6-structure by neutron diffraction leads to improved site parameters of the F--ligands. The CuF64--polyhedra are distinctly ortho-rhombic, in complete correspondence with EPR-spectro-scopic results.
Notizen: Preparation and Crystal Structure of NiHg
Authors: Pušelj M. , Ban Z.
Published: March 2015

A single phase binary amalgam of the composition NiHg was found to form at room temperature after an extended period of time (approx. 2 years).

X-ray powder diffraction analysis enabled us to determine the crystal structure. The compound crystallizes tetragonally with a = 4.22 Å and c = 3.14 Å. It belongs to L 10 crystal structure type.
Zur cis-trans-Isomerisierung von Diaza-λ3,λ3-diphosphetidinen / Cis/trans Isomerisation of Diaza-λ3,λ3-diphosphetidines
Authors: Zeiss Werner , Weis Josef
Published: March 2015

2,4-Dialkoxy-diazadiphosphetidines and 2-chloro-4-alkoxydiazadiphosphetidines are formed as pure cis isomers (2) and trans isomers (4) from 2,4-dichloro-diazadiphosphetidine (1). In contrast to 4, compounds 2 show isomerisation into a mixture of cis and trans isomers 2 and 3 on standing in solution. No isomerisation was observed for 3, R = tert-BuO, whereas only a mixture of isomeres 5 and 6 could be isolated with this mixed alkoxy compound.
1.3.5-Triaza-7-phosphaadamantan (Monophospha-urotropin) / 1,3,5-Triaza-7-phosphaadamantane (Monophospha-urotropine)
Authors: Fluck Ekkehard , Förster Juan-Enrique , Weidlein Johann , Hädicke Erich
Published: March 2015

Formation, structure, vibrational spectrum and some chemical properties of the title compound are described.
Aminofluorsilane : Bildung von Heterocyclen und Lithio-aminofluorsilanen / Aminofluorosilanes : Formation of Heterocyclic Compounds and Lithio-aminofluorosilanes
Authors: Klingebiel Uwe , Meller Anton
Published: March 2015

Fluorosilanes react with lithium amides and organolithium compounds to give aminofluorosilanes and organofluorosilanes. The reactivity of the monoaminofluorosilanes with butyllithium is decreasing with increasing size of the substituents and with their stabilisation in the molecule. Reactions observed include: a) (2 + 2) cycloaddition, b) ring closure under either C–H-cleavage or under migration of a methanideion and c) formation of stable lithio-aminofluorosilanes.
Darstellung, Racemattrennung und Reaktionen der tButyl-phenyl-thiophosphinsäure, tert-C4H9(C6H5)P(S)OH / Preparation, Separation into Enantiomers and Reactions of tButyl-phenyl-thiophosphinic acid, tC4Η9(C6Η5)Ρ(S)ΟΗ
Authors: Luckenbach Reiner , Bechtolsheimer Hans-H.
Published: March 2015

The preparation and enantiomer separation of an unsymmetrically substituted thiophosphinic acid, tbutyl-phenylthiophosphinic acid (1), is reported. Reaction of 1 with PCl5 and SOCl2 yield the corresponding thiophosphinyl chloride and phosphinyl chloride, respectively.
1H—NMR-spektroskopische Bestimmung der diastereomeren Reinheit und der absoluten Konfiguration am Phosphoratom von tButyl-phenyl-phosphinsäure-(—)-menthylester / Determination of the Diastereomeric Purity and the Absolute Configuration at Phosphorus of tButyl-phenyl-phosphinic Acid (—)-Menthyl Ester by Means of 1H NMR Spectroscopy
Authors: Luckenbach Reiner , Bechtolsheimer Hans-H.
Published: March 2015

The preparation and separation into diastereomers of tbutyl-phenyl-phosphinic acid (—)-menthyl ester (1a) is reported. The diastereomeric purity as well as the absolute configuration at phosphorus of 1 a can be deduced from the detailed analysis of the 1H NMR spectra of samples of 1a differing in their diastereomer ratios.
Darstellung und Kristallstruktur von Ba10Al3Ge7 / Preparation and Crystal Structure of Ba10Al3Ge7
Authors: Widera Axel , Schäfer Herbert
Published: March 2015

The new intermetallic compound Ba10Al3Ge7 crystallizes hexagonal in a new structure type (a = 974.9(5) pm, c =1647(1) pm, c/a = 1.69, P63/mcm). The Al-atoms, together with the Ge-atoms, form propeller-like Al3Ge7-units.
Complexes of Oxamic Acid with Cu(II), Ni(II), Co(II) and Cr(III)
Authors: Galinos A. G. , Tsangaris J. M. , Kouinis J. K.
Published: March 2015

The preparation of the complexes of oxamic acid with Cu(II), Ni(II), Co(II) and Cr(III) is reported. From the study of IR, diffuse reflectance spectra and the magnetic moments it is concluded that in all complexes the metal is coordinated with the amidic nitrogen, after ionization of one amidic hydrogen, and with the carboxyl oxygen.

Octahedral structures are proposed for the complexes K2[Ni(oxamic)2] · 2 H2O and K3[Cr(oxamic)3] and planar configurations for K2[Cu(oxamic)2] and K2[Co(oxamic)2].
Malondialdehyde aus Propinai / Malonaldehydes from Propynal
Authors: Wille Franz , Schwab Walter
Published: March 2015

Malonaldehyde (2 a) is possibly an intermediate in the reaction of propynal (1) with itself, which ends up in 3-ethinyl-2,4-diformyl-pentanedial (6 a), a compound containing two malonaldehyde groups bridged by a substituted methylene group. The alkali salts of the unstable 1-thiomalonaldehyde (7 a) are obtained from 3,3′-thiodiacroleine (8 a) or S-acroleinyl-diphenylthiourea (8 b) and alkalisulfide or ammonia. 2-Chloro, 2-bromo- and 2-iodo-malonaldehyde (14 a-c) are prepared from 1 via 2,3-dihalogenpropenals (12).
Darstellung und Kristallstruktur von Na2CuP, K2AgAs, K2AgSb und K2AgBi / Preparation and Crystal Structure of Na2CuP, K2AgAs, K2AgSb, and K2AgBi
Authors: Savelsberg Gerhard , Schäfer Herbert
Published: March 2015

The title compounds have been prepared and structurally characterized. Na2CuP crystallizes in the Na2CuAs-structure type/(Cmcm) forming infinite Cu—P-zigzag-chains. In the silver compounds we found analogous Ag—E(V)-chains in a cell with atomic positions, which slightly violate the above symmetry.
LiFe6Ge5 und LiFe6Ge4 Zwei Phasen mit enger Strukturbeziehung zu der Verbindung LiFe6Ge6 / LiFe6Ge5 and LiFe6Ge4 Two Phases with Close Structure Relations to the Compound LiFe6Ge6
Authors: Welk Erwin , Schuster Hans-Uwe
Published: March 2015

The phases LiFe6Ge5 and LiFe6Ge4 have been prepared and structurally characterized. They crystallize monoclinic (LiFe6Ge5: a = 8.744 Å, b = 5.045 Å, c = 14.841 Å, β = 101.42°; LiFe6Ge4: a = 8.739 Å, b = 5.045 Å, c = 7.170 Å, β = 113.94°; space group C 2/m), their structures show close relations to the structure of LiFe6Ge6 and binary iron-germanium-phases.
AB2X2-Verbindungen im CaAl2Si2-Typ, III Zur Struktur der Verbindungen CaZn2P2, CaCd2P2, CaZn2As2 und CaCd2As2 / AB2X2 Compounds with the CaAl2Si2 Structure, III The Crystal Structure of CaZn2P2, CaCd2P2, CaZn2As2, and CaCd2As2
Authors: Klüfers Peter , Mewis Albrecht
Published: March 2015

As confirmed by X-ray data, the four ternary compounds CaZn2P 2, CaCd2P2, CaZn2As2, and CaCd2As2 crystallize trigonally in a CaAl2Si2-type structure. Some conditions for the existence of this structure type are given.
Tri(tert-butyl)methylenphosphoran : Konsequenzen sterischer Hinderung für innermolekulare Beweglichkeit und thermischen Zerfallsmechanismus / Tri(tert-butyl)methylenephosphorane : Consequences of Sterical Hindrance for Intramolecular Motions and Thermal Decomposition Mechanism
Authors: Schmidbaur Hubert , Blaschke Günter , Köhler Frank H.
Published: March 2015

Dimethyl(tert-butyl)-, di(tert-butyl)methyl- and tri(tert-butyl)methylenephosphorane (CH3)n[(CH3)3C]3-nP=CH2, 3a-c, (n = 2,1, 0) have been synthesized from the corresponding phosphonium bromides, using standard methods, but under mild conditions. 3 c was found to be thermally unstable, undergoing reductive elimination of isobutene already at room temperature, with di(tert-butyl)methylphosphine as a by-product. 3 b is decomposed similarly above 80 °C. A mechanism for this unusual mode of ylide decomposition is proposed, based on the extreme steric crowding of the molecules. Restricted P–C bond rotation has been detected by 1H and 13C NMR spectroscopy for 3 c in toluene solution. Traces of protic species cause a rapid intermolecular H2C(P) hydrogen exchange.