Band 31, Heft 1

The results of a combined infrared and Raman-spectroscopic analysis of the compounds [N(C 2 H 5 ) 4 ] 3 [Ln(III)(NCO) 6 ] (Ln = Yb, Lu) confirms the assumption that the central ion Ln 3+ is octahedrally surrounded by six linear isocyanate ligands. The recently determined temperature dependence of the magnetic susceptibility of the Yb-complex in the range 1.0 < T < 300.2 K is compatible with the crystal field (= CF) splitting pattern: 0 = Ε(Γ 6 ) < Ε(Γ 8 ) < Ε(Γ 7 ) ≪ Ε(Γ' 8 ) < Ε(Γ' 7 ) and a spectroscopic splitting factor |g exp (Γ 6 )| = 2.576 [i.e. k(t lu ) = 0.955]. Using the cubic first-order CF-functions, the energy differences ΔE(Γ 8 -Γ 6 ) and ΔΕ(Γ 7 -Γ 6 ) are fixed at 277 ± 10 and 650 ±130 cm -1 respectively. On this basis, the estimated ratio B 4 °/B 6 ° of the two underlying cubic CF-parameters is discussed in terms of both “electrostatic” and “covalency” effects. This analysis has been used to interpret the paramagnetism of Cs 2 NaYbCl 6 in terms of much larger CF-parameters than previously suggested

Some significant features of the low-energy part of the crystal field (=CF) splitting pattern of the organometallic 5f 2 -system (η 5 -C 5 H 5 ) 4 U(IV) can be deduced from the temperature dependence of the magnetic susceptibility which has been measured on polycrystalline samples between 1.1 and 298 K. The results of model calculations performed independently on the basis of three different semi-empirical approaches are compatible with the deductions from the experiments and allow estimates of the sign and order of magnitude of quantities like the CF-splitting parameters B 4 0 and B 6 0 viz. the (averaged) angular overlap parameters e σ and e π „ and of the valence state ionisation potential of the 5f-electrons. Anticipating a rather weakly perturbed tetrahedral CF, the observed magnetic properties may be satisfactorily simulated if the six lowest-lying first-order CF-states and one common scaling factor are accounted for

Dioxouranium(VI) derivatives of the type UO 2 (NO 3 ) 2 (SBH 2 ) 2 have been synthesised by the reactions of dioxouranium(VI) nitrate hexahydrate with the nitrogen donor ligands (SBH 2 ) in 1: 2 molar ratio. The Schiff bases used in these reactions are of the general type, o-HOC 6 H 4 C(CH 3 ): NX 1 OH (where X 1 = -CH 2 CH 2 -, -CH 2 CH(CH 3 )- and -CH 2 CH 2 CH 2 -), CH 3 C(OH)CHC(CH 3 ): NX 2 OH and o-OHC 6 H 4 CH: NX 2 OH (where X 2 = -CH 2 CH 2 -, -CH 2 CH(CH 3 )-, -CH 2 CH 2 CH 2 - and o-C 6 H 4 ). The resulting new derivatives have been characterized on the basis of elemental analysis, magnetic susceptibility, conductance measurements and infrared spectra

The new intermetallic compounds Ca 11 Sb 10 and Ca 11 Bi 10 crystallize tetragonal in the Yb 11 Sb 10 -structure type. There are 4-membered Sb(Bi)-rings, Sb 2 (Bi 2 )-dumb-bells and isolated Sb(Bi)atoms in the structure

The charge distribution in the methoxy -substituted olefins of the series ethylene, methyl vinyl ether, 1,1-dimethoxyethylene, cis- and trans-dimethoxyethylene, tetramethoxyethylene, is discussed on the basis of the 1 H and 13 C NMR spectra

Noble metal electrodes do not stand the tests for anodic electro syntheses in technical applications. Mainly due to the high oxygen overvoltage lead dioxide can act as substitute. A novel process for the preparation of lead dioxide coated titanium anodes is described. The important procedure is a treatment of the clean titanium surface with a Ti(IV)-containing solution. By scanning electron microscopy it is established that three dimensional nucleation takes place. Lead dioxide anodes prepared following this process until now have livetimes of better than 3400 hours

A novel method enables the production of lead dioxide-coated electrodes with life times of several thousand hours in certain electrooxidations. The most important step of this technique is described as an adsorption of Ti(IV)-oxalate at the titanium surface. By potential-time plots and by potentiodynamic investigation it is shown, that by Ti(IV)-adsorption the titanium surface is lifted to a higher (more noble) potential and in this way is protected against further dissolution or oxidation

The polarographic maximum of nitrobenzene (first reduction step) is studied at pH 2.2, 5.3 and 7.8. The nature of the maximum is pH dependent and it changes from positive first kind (at pH = 2.2) to negative maximum of the first kind (at pH 5.3, 7.8). At higher flow-rates, compound maxima occur and clear reversal potentials are located where maximum of first kind is transformed into the second kind and vice versa. The morphology of current-time curves has been examined critically in the light of streaming patterns, electrode circuitry, flow-rates and exponents of t at varying intervals during the drop life

While the stable modification of CsNiF 3 is of green colour, a yellow phase is obtained by fluorination of CsNiCl 3 and decomposition of the product “CsNiF 4 ”, which contains Ni 4+ and Ni 3+ besides Ni 2+ . The two modifications have the 2L- and 9L-perovskite-structure, respectively, and are characterized by their X-ray patterns and low-temperature ligand field spectra. The differences in colours and spectral band positions are discussed with respect to the Ni-F-Ni bond angles

The aryl-sulfinato complexes π-C 7 H 7 Mo(CO) 2 SO 2 R have been synthesized by reaction of π-C 7 H 7 Mo(CO) 2 J with the Ag-SO 2 -R compounds. The sulfinate group is S-bonded. Mononuclear and dinuclear thioaryl complexes were isolated by reaction of π-C 7 H 7 Mo(CO) 2 Br with aryl mercaptanes R′-S-H in the presence of (C 2 H 5 ) 3 N which functioned as a proton acceptor. IR data indicate the dependence of the π-acceptor abilities of the sulfur atom from R′

Contrary to the published results it is shown the colour of the solid molecular complexes arene • 2 SbCl 3 is due to impurities in these systems. These impurities are mainly the radical ions of the aromatic compounds. If the formation of these radical ions is avoided the complexes in the solid state are colourless or slightly yellow-coloured

Reaction of (C 6 H 5 ) 2 PCl with CF 3 COOH yields diphenylphosphinic acid 1-diphenylphosphoryl-2,2,2-trifluoroethylester (1a) as a final product. 1a can be hydrolized leading to (1-hydroxy-2,2,2-trifluoroethyl)-diphenylphosphine oxide (3a). The analogous reaction of (C 6 H 5 ) 2 PCl with C 2 F 5 COOH gives diphenylphosphinic acid -1-diphenylphosphoryl-2,2,3,3,3-pentafluoropropylester (1b). Compounds 1a, 1b and 3a were identified by high resolution nuclear magnetic double resonance and 31 P-Fourier transform spectroscopy

By the reaction of tris(diethylphosphoryl)phosphine with amines compounds of type 1 are obtained, the structure of which is discussed by NMR and X-ray photoelectron spectra. Some chemical and physical properties are described

The crystal structure of the title compound has been determined from three-dimensional X-ray diffractometer data. Crystals are monoclinic, space group P2 1 /c with 8 Cu(C 4 H 10 NO)SCN units in a cell of dimensions α = 11.951(4), b = 8.954(3), c = 16.805(6) Å, and β = 107.5(1)°. The structure was refined by least squares techniques to a final discrepancy factor of 0.041 based on 2234 observed independent reflexions. The compound is polymeric with copper atoms alternately bridged by two oxygen atoms and two thiocyanato groups. The coordination geometry around each copper atom is distorted square pyramidal. The basal plane consists of the two bridging oxygen atoms (mean value Cu-O: 1.914(3) Å), the amino nitrogen atom (mean value Cu-N: 2.035(3) Å) and the nitrogen atom from the thiocyanato group (mean value Cu-N: 1.908(3) Å) while the axial coordination site is occupied by a sulfur atom from a thiocyanato group (mean value Cu-S: 2.979(2) Å) centrosymmetric to the first. The magnetic susceptibility of the compound shows a broad maximum at 200 K

Dimethylstannandiylbis(di-tert-butylphosphine) reacts with tetracarbonyl nickel under formation of tricarbonyl-dimethylstannandiylbis(di-tert-butylphosphine)nickel and polymeric dicarbonyl-dimethylstannanediylbis(di-tent-butylphosphine)nickel and with hexacarbonylchromium under UV-irradiation as well as with tetracarbonyl-norbornadienechromium yielding tetracarbonyl-dimethylstannandiylbis(di-tent-butylphosphine)-chromium. IR and NMR spectra of the new compounds are discussed

Condensation of triethylorthoformate with cyclic methylene-active compounds gives rise to ethoxymethylene-, bismethenyl- or triscompounds of type A, B or C resp. An explanation of this different behavior can be obtained by comparing the π-electron densities at the β-carbon atom of the exocyclic double blond of ethoxymethylen- and bismethenyl-compounds, which are calculated using HMO-theory. These calculationes show a limiting electron density, which can be used to explain the lack of further reaction to bis- and triscompounds, when certain heterocyclic active methylenes are used. Reactions of some heterocyclic diketones have been studied and, their behavior found in agreement with theoretical concepts

The mercuric EDTA dehydrogenation of the isomeric 1,2- and 2,1-(phenyl-pyrrolidino)-ethanols yields with two electron removal the corresponding oxazolidines. The analogous 1,2- and 2,1-(amino-phenyl)pyrrolidines by double dehydrogenation produce the amidines resp. by subsequent hydrolysis the lactams. An explanation for the different course of the reaction is given

N-(3-chloro-1,4-dihydro-1,4-dioxo-2-naphthyl)acetamide (1) reacts with aromatic amines to give the 2-acylamino-3-arylamino-1,4-naphthoquinones. Whereas with the substituted o-phenylenediamines, o-aminophenols, o-aminobenzenethiols and 2-amino-3-hydroxy pyridine it gives angular heterocyclic compounds. A common reaction path is suggested

Treatment of 5-arylidene-2-thiohydantoin (1a-d) with alkyl bromoacetate and chloroacetic acid gave the esters 2a-f and the acids 2g-j, respectively. 2a was refluxed with concentrated hydrochloric acid to give 5-benzylidene hydantoin. 2 was cyclized with acetic anhydride to give the bicyclic product 3. 5-Arylidene-2-thiohydantoin derivatives (1a, b) and (8a) condense with formaldehyde and primary or secondary amines to give the corresponding Mannich bases 6a-f and 8c-e, respectively. The assigned structure 6 and 8 finds support from the chemical evidences

The synthesis of 3-substituted-6,7-dihydrodipyrido-[1,2-α:2′,1′-c]-pyrazinediium dibromides is described. The 3-alkoxy and 3-carbomethoxy derivatives can be regarded as reversible one electron transfer systems. The most active compound is the 3-methoxy derivative which is a very effective post-emergent herbicide at 1-2 kg/hectare

A diquaternary salt of 2,2′-oxydipyridine has been prepared using methyl fluorosulphonate as quaternising agent. It is unstable at physiological pH values and is reduced at a much lower potential than the bipyridylium herbicides, diquat and paraquat

Flaviolin was found in the blackish potato culture solution of Phoma wasabiae

The reaction of aromatic and aliphatic sulfonic azides with benzene under the influence of aluminiumchloride has been examined. The intermolecular substitution reactions - sulfonylation, amination and alkylation - are dependent from the structural effect of the corresponding substituent

1-Phenyl-3-alkoxycarbonyl-triazenes react with aluminiumchloride in benzene by elimination of nitrogen, especially to alkylbenzenes and diphenyl; anilin is formed with practical constant yield, independently of the alkyl group. On the basis of these experimental results during the reaction of alkoxycarbonyl azides with benzene under the influence of Lewis acids triazenes are not formed as intermediates

Amorphous Au 2 O 3 , aq can be transformed in perchloric acid solution (1,6-1,9 n: quartz tube, filling grade 30%: 275→235°C) to single crystals of ruby orthorhombic Au 2 O 3 . Space group Fdd 2

The lithium salts of thioalkyl- and cyclothioalkylsubstituted Carboxylic acids, sulfinic acids and dithiocarboxylic acids are prepared by treatment of the monometallated s-trithiane, tetrathiocane, pentathiecane, 2,4- dithiapentane and trithioacetaldehyde with carbon dioxide, sulfur dioxide and carbon disulfide

A linear combination of the effect of substituents on pre-equilibrium and subsequent rate limiting step, K and k respectively, describes the structure reactivity, relationship of the form log k/k 0 = -2.17σ + + 3.3 σ, where former corresponds to V(V)-ketone complex and the latter its rate limiting disproportionation

Kleine, ausschließlich Heteroatome enthaltende Element-Stickstoff-Ringe werden vielfach bevorzugt dann gebildet, wenn an das N-Atom eine tert-Butyl- oder Trimethylsilyl-Gruppe gebunden ist 1 . Ausgehend vom zweifach tert-Butyl-substituierten Phosphatriazen (1) 2 erhält man durch 1.2-Addition von AsCl 3 die offenkettige Zwischenverbindung 3 2, die ihrerseits durch cyclisierende Si-N-Spaltung 1.3-Di(tert-butyl)-2.4-dichlor-diazaphosphaarsetidin (3) bildet 6

By investigations in the system Mg-Ni-P we found the phase Mg 2,5 Ni 11.5 P 7 , which crystallizes in a hexagonal lattice