Volume 34, Issue 5

The crystal structures of Li 3 In 2 , Li 5 Tl 2 and Li 3 Tl have been determined by single crystal methods. Li 3 In 2 crystallizes trigonalrhombohedrally, space group R3̅m-D 5 3d , a = 475.3(1) pm and c = 1478(1) pm. It is isotypic with Li 3 Al 2 and Li 3 Ga 2 . Li 5 Tl 2 is isotypic with Li 5 Sn 2 , space group R3̅m-D 5 3d with a = 471.6(1) pm and c = 2039(5) pm. Li 3 Tl crystallizes cubicly, Fm3m-O 5 h , a = 667.1(3) pm in a structure formerly described as „BiF 3 -type’’ structure.

The new compounds CaAleTeio and CaGaeTeio crystallize with the following lattice constants There are dense packings of the Te atoms which are very similar to each other. Different in both structures are the distributions of the element(III) atoms at the distorted tetrahedral sites and of the Ca atoms at the distorted octahedral sites.

The vinyldifluorophosphoranes Ph n PF 2 (CH = CH 2 ) 3-n (2a: n = 1, 2b: n = 2) or Ph 2 PF 2 (C 6 H 4 -CH = CH 2 ) 4 were obtained in good yield by direct fluorination of the corresponding phosphines. Catalytic addition of Ph 2 PH or PhPH 2 to 2b gives phosphino-ethyl-substituted fluorophosphoranes which have not yet been obtained by partial fluorination. The structures have been established by NMR ( 19 F, 31 P) and in addition by sulfurisation. Whereas 2b does not polymerize, homopolymerisation of the styrene derivative 4 gives polymer fixed difluorophosphorane.

A new family of modifications of silica is obtained by thermal dehydration of crystalline silicic acids with layer structures. Examples are SiO2 · 0.11 H 2 O, SiO 2 · 0.04 H 2 O, SiO 2 prepared by dehydration of H 2 Si 14 O 29 · 5.4 H 2 O, H 2 Si 8 O 17 · xH 2 O and H 2 Si 4 O 9 . The “water content” can amount up to 3 weight percent and results from uncondensed inter-layer silanol groups or from water molecules which are trapped between the layers. In some cases dehydration in the presence of organic interlayer molecules leads to different forms of silica.

The title compounds can be synthesized by fusion reaction of the alkali carbonates with copper and sulfur at 790 °C. The structure was solved from X-ray diffractometer data of single crystals and refined to an R-value of 0.06. The compounds crystallize with the same layer-type structure which is closely related to that of KCU 3 S 2 . Crystal data for K 3 Cu 8 S 6 (Rb 3 Cu 8 S 6 ): space group C2/m,z = 2, ϱ calc = 4.27(4.76) g/cm 3 , a = 17.332(4) (17.840(6)) Å, b = 3.830(2) (3.865(1)) Å, c = 9.889(4) (10.011(3)) Å, β = 104.12(2)° (104.91(2)°).

Symmetrically 1,5 bridged cyclotetra(λ 3 -phosphazanes) 2a, b are formed from cyclotri-(λ 3 -phosphazanes) 1a, b and heptamethyldisilazane. Substitution of halogens at P 3 and P 7 in 2a, b by alkoxy or phenoxy substituents is achieved with alcohols in the presence of triethylamin to give 2c, d. NMR spectroscopy shows 2a, b to exist as isomers A or B, whereas for 2c, d additional asymmetric isomers like C or D are assumed.

Compounds with the composition SbCl 4 + [Sb 2 F 11-s Cl s ] - with 0 ≤ s ≤ 2 can be obtained from SbF 5 /SbCl 5 mixtures. The title compound is one of them. Its crystal structure was determined with X-ray diffraction data and was refined to a residual index of R = 0.052. It is isotypic to the compounds with s = 0 and s = 2, crystallizing in the space group P2 1 /n with a = 1103, b = 1055, c = 1290 and β = 95,9°. In the anion [F 4 (F 1-u Cl u )Sb-F-Sb(F 1-v Cl v )F 4 ] - two ligand positions that are cis to the bridging F atom are statistically occupied by fluorine and chlorine, with u = 0,1 and v = 0,4. The tetrahedral SbCl 4 + ion is coordinated to the anion so that on top of each of the tetrahedron faces there is one F atom at a distance of 298 to 335 pm.

Tl 6 Au 2 I 10 forms black crystals with a golden luster. In a closed system the temperature of decomposition is 276 °C. In vacuum or under inert gas Tl 6 Au 2 I 10 decomposes above 65 °C forming 1 mol I 2 . Above 180 °C a second mol I 2 is formed giving TlI and gold. The space group is P6̅2c with the lattice constants a = 10.569 and c = 13.431 Å and Z = 2. Tl 6 Au 2 I 10 is built up by a framework of Tl 6 I 6 with channels parallel to the c-axis. These channels contain Au + mainly with a trigonal planar coordination or linear I - 3 -polyiodide ions and I - ions, resp.

Rhenium(VII) nitride chloride, ReNCl 4 , is prepared by the reaction of ReCl 5 with nitrogen trichloride. It forms metallic glazing, hygroscopic needles with an effective magnetic moment of 0.23 B.M. In the mass spectrum only the molecular ion ReNCl 4 ⊕ is present, followed by ReNCl 3 ⊕ . The crystal structure was determined by X-ray diffraction methods (space group Il, 265 independent reflexions, R = 0.071). The structure consists of ReNCl 4 units, which are linked by strongly alternated Re ≡ N-Re chains with different bond lengths of r Re ≡ N = 158 pm and r Re-N = 248 pm. The structure is very similar to that of WOCl 4 .

Cathodic reduction of Nb 3 S 4 and Nb 3 Se 4 electrodes in electrolytes containing cations of appropriate size results in the formation of ternary phases A n+ x/n [Nb 3 X 4 ] x- . The cations A n+ are taken up into empty channels of the rigid lattice framework and exhibit high ionic mobility at room temperature.

The reaction between (h 5 -cyclopentadienyl)carbonyl(triphenylphosphine)iridium and bis(pentafluorophenyl)acetylene has been investigated in detail. As in earlier studies involving the analogous cobalt and rhodium complexes, the metallocyclic product 1-(h 5 -cyclopentadienyl)-1-triphenylphosphine-2,3,4,5-tetrakis-pentafluorophenyl)iridole (3) has been obtained, although in very low yield. A variety of highly fluorinated organic products have also been isolated and identified, including hexakis(pentafluorophenyl)-benzene (5), Zraws-1,2-bis(pentafluorophenyl)ethene (6) and 1,2,3,4-tetrakis(pentafluoro-phenyl)naphthalene (4). The latter product has been synthesized by an independent method. Reaction mechanisms to account for the formation of 4 under these conditions are discussed.

The essential fatty acids linoleic, α-linolenic and arachidonic acid have been crystallized for the first time. The crystal and molecular structures have been elucidated by X-ray analysis. Linoleic acid crystallizes monoclinic P2 1 /c with a = 4298(3), b = 463.2(3), c = 937.7(6) pm, β = 109.38(8)°, Z = 4. The closely packed molecules are stretched with a tttttts̄CssCs̄tt conformation a . By comparison of the unit-cell constants and calculated densities of the unsaturated fatty acids it may be shown that both α-linolenic acid and arachidonic acid also possess stretched structures in the crystal lattice, α-linolenic acid must display a tttttts̄CssCs̄s̄Cs and arachidonic acid a tts̄CssCs̄s̄CssCs̄ttt conformation.

Tris o-benzosemiquinone complexes of iron and chromium are reported. These complexes contain three 3,5-di-t-butyl-o-semiquinato ligands and a trivalent metal ion. The iron complex can be obtained from either the more highly oxidized o-quinone or reduced catechol dianion precursor. The coordinated o-semiquinone ligand is surprisingly stable. A simple infrared criterion is suggested for detecting the presence of a coordinated o-semiquinone.

The reaction of 2-(2′-pyridyl)-indan-1,3-dione (pyrophthalone, 1) with reactive malonic acid derivatives (2) yields the indanoquinolizinone derivative (5) by rearrangement of the instable zwitter-ionic compound 3 and decarboxylation of the seven-membered intermediate 4. In order to support this mechanism the lactone 15 was thermolyzed to give fluorenone (16) by decarboxylation.

The rate of the aminolysis of 2-(2-hydroxybenzyl)phenylacetates with n-butylamine in dioxane is diminished by the addition of triethylamine. This can be quantitatively described by the competitive formation of complexes between monoacetate and n-butylamine or triethylamine, if the assumption is made, that the complex with triethylamine is aminolysed slowly or not at all. The neighboring group effect in aminolysis cannot be explained therefore by a base catalysed decomposition of the tetrahedral intermediate.

The reaction of several 1,2-disubstituted benzenes with crotonic acid in polyphosphoric acid has provided a number of previously undescribed 5,6-disubstituted indan-1-ones. Guaiacol, o-cresol, 1,3-benzodioxole, 1,4-benzodioxan and dihydrobenzofuran yielded indanones (4-8) in which acylation of the benzene ring occurred exclusively para to the free hydroxyl groups of the first two substrates and para to the ether oxygen in the last. Catechol, salicylaldehyde, o-hydroxy acetophenone and o-chloro phenol yielded no indanones and formed crotonate esters. A further four indanones (9-12) were derived from demethylation and acetylation procedures. Annelation of the methyl cyclopentanone ring occurred acrose the furan ring in benzofuran to provide the new heterocycle 1-methyl benzofurocyclopentan-3-one in moderate yield. The assigned carbon- 13 NMR spectral shifts for all indanones are set out in Table II.

The synthesis of the triflates of several pentoses are described. These triflates are reacted with NaN 3 to the corresponding azido sugars. The S N 2 reaction is investigated by high pressure liquid chromatography.

Oligopeptides comprising the sequence of the C-terminal tetrapeptide of gastrine, Trp-Met-Asp-Phe-NH 2 , and several derivatives of glutathione, γ-Glu-Cys(SR)-Gly, were characterized by field desorption mass spectrometry. The field desorption mass spectra obtained at various field ion emitter temperatures reveal abundant molecular ions and fragmentation reactions that yield partial sequence information. In the series of glutathione derivatives investigated, characteristic ions formed by cleavage of the γ-Glu-Cys peptide bond determine the substituent at the Cys residue and can therefore be used to identify corresponding conjugation products of drug metabolites with glutathione.

The calculation of the radius of the transition state in the alkaline decarboxylation of trichloroacetate ion in water-ethanol solutions has been discussed. In applying a simple electro- static theory to solvent mixtures with water mole fractions less than about 0.7, it is shown that the radius of the transition state complex is about 5.5 Å and that the volume of the activated molecule is about four times that of the reactant ion. This result is in agreement with the postulated reaction mechanism and the experimentally calculated activation parameters. In the water rich solutions, the simple electrostatic theory is not applicable.

ReO 3 (O 2 PCl 2 ) · POCl 3 is prepared by the reaction of ReCl 5 with Cl 2 O in the presence of POCl 3 . According to the vibrational spectrum the structure consists of dimeric units with bridging O 2 PCl 2 groups.

Lithium (di-t-butyl)phosphide reacts with the trichlorides of yttrium, holmium, erbium, thulium, ytterbium and lutetium under elimination of lithium chloride and formation of the corresponding tris(di-t-butylphosphine) derivatives.

The crystal structure of the phase Al 2 O 3 · 2 P 2 O 5 · 9 H 2 O contains two different structural units: isolated PO 4 tetrahedra and larger aggregates consisting of two AlO 6 octahedra connected with three PO 4 tetrahedra by common vertices. Location of hydrogen positions failed. Interpretation of bond distances and molecular symmetry leads to a structural formula [Al 2 (H 1+x PO 4 ) 3 (H 2 O) 6 ](H 3-3x PO 4 ); 0 ≦ x ≦ 1 indicating proton disorder. Proton conductivity seems to be possible.

The kinetically stable triazatriphosphorinyl and tetraazatetra-phosphorocinyl azides 3 and 4 are prepared from the corresponding chlorides 1, 2 with sodium azide. 3 and 4 react with phosphanes to yield the λ 5 -diphosphazenes 5a-d. By the reaction of 1 or 2 with KCN the nitriles 6 and 7 are formed. -The new compounds are characterized on the basis of IR and mass spectra.

Under irradiation with monochromatic light of λ ≤ 407 nm homogeneous hydrogenation of acrylic ethylester with the catalyst IrCl(CO)[P(i-C 3 H 7 ) 3 ] 2 is much faster than in the dark reaction. Not the catalyst but the hydridocomplex is photochemically activated. With the sensitizer pentacene, photoactivation occurrs with visible light of λ ≤ 578 nm already.

Olefinic and aromatic sandwich-complexes of chromium have been oxidized and reduced electrochemically. Oxidation in dichloromethane at a Pt electrode was found to be in most cases chemically reversible. The oxidation of complexes with an 18-electron configuration was observed in a potential range of E 1/2 = -0.65 to -0.8 V whereas oxidation of complexes with a 17-electron configuration occurs between E 1/2 = -0.2 and -0.4 V. Only one of the 18- electron complexes but all 17-electron complexes were reduced in THF, most of these electron transitions being chemically reversible.

The 3,5-dimethylpyrazolyl-bis(o-phenylenedioxy)- spirophospborane reversibly forms a diastereomeric dimer, gives a labile adduct with more pyrazole and with the sodium salt of pyrazole the stable bis(pyrazolyl)phosphate anion, potentially a chelating ligand.

Three sulfurapatites have been prepared. They crystallize in the hexagonal system (P6 3 /m) with the following lattice constants:

Hydrate formation was observed after mechanical treatment of a type I kaolinite and sub-sequent leaching of the hydrazine-intercalation complex with water. Of the different methods investigated (high-pressure treatment, grinding in a ball mill, ultrasonics), a wet grinding of a hydrazine-kaolinite suspension proved to be most effective.