Zur Kenntnis der Verbindung H3P–BJ3

Phosphine or phosphonium iodide react with boron triiodide in CS₂ or benzene to form the adduct H₃P–BI₃. The water-sensitive white solid is thermally stable up to ～150°C. Its IR and NMR spectrum are recorded.     

Purification and analysis of partially alkylated cyclodextrins by liquid and gas chromatography

Complex mixtures of partially alkylated cyclodextrins can be analyzed by both HPLC and high temperature capillary GC. Because of the limited efficiency of LC, suitable analytical and preparative separations can be achieved only with systems of carefully optimized selectivity. Using LC it has been possible to isolate and purify single cyclodextrin species from very complex mixtures of components which contain unreacted hydroxyl groups in addition to the alkoxy groups. Analysis of the reaction mixtures and of fractions taken from LC separations can be performed with advantage by high resolution capillary GC at high temperatures between 300 and 400 °C. The thermal stability of partially alkylated cyclodextrins in high temperature GC is considerably increased by trimethylsilylation of the free hydroxyl groups. Fast atom bombardment mass spectrometry and proton NMR were used to identify species isolated from the preparative LC separations.     

Static dipole and quadrupole polarizabilities of alkaline earth atoms

Static dipole and quadrupole polarizability (α_d and α_q, respectively) values of coupled Hartree–Fock quality have been calculated for the alkaline earth atoms Be(2s), Mg(3s), Ca(4s), and Sr(5s) using a method based on the many-body perturbation theory. The present values of α_d and α_q for Be and α_d for Mg are in excellent agreement with the other available results of similar accuracy. The CHF calculations of α_d for Sr and α_q for Mg, Ca, and Sr are being reported for the first time.     

Beiträge zum chemischen Transport oxidischer Metallverbindungen. V. Der Transport ternärer und quaternärer Mischferrite über ihre Metallchloride

Contributions to the Chemical Transport of Metal Oxides. V. Transport of Ternary and Quaternary Mixed Ferrites by their Chlorides The transport by means of HCl as transporting gas in a closed system in the case of the ternary mixed ferrites (Ni_0,8Fe_2,2O₄, Mn_0,75Fe_2,25O₄, Mn_1,286Fe_1,714O₄) and the quaternary mixed ferrites (Mg_0,5Mn_0,5Fe₂O₄, Mg_0,75Mn_0,536Fe_1,714O₄, Mg_0,281Mn_0,469Fe_2,25O₄, Mn_0,5Zn_0,5Fe₂O₄, Mn_0,5Zn_0,45Fe_2,05O₄, Ni_0,5Zn_0,5Fe₂O₄) between T₂ = 1100?1000°C and T₁ = 1000?800°C was investigated. Transported crystals were characterized by chemical analysis and the saturation magnetization, the transport rate has been checked. In the case of Mn_0,5Zn_0,45Fe_2,05O₄ two phases were transported. By discussing the phase diagram an explanation is given.     

Zur Reaktion des Germaniums mit Germaniumtetrachlorid und zur Existenz der Oxidchloride GeOCl2 und GeOCl6 im Gleichgewicht

On the Reaction of Germanium with Germanium Tetrachloride and on the Existence of the Oxidechlorides GeOCl₂ and GeOCl₆ at the Equilibrium The above equilibrium was measured in a Gauge-manometer and the enthalpy of formation and the entropy for GeCl₂,g were derived from these results. From total pressure measurements and transport experiments of GeO₂ with GeCl₄ follows, that the oxidechlorides Ge₂OCl₆ and GeOCl₂ are not present in measurable concentrations, that means the enthalpy of formation of GeOCl₂ must be higher than ?327 kJ · mol^?1.     

Peroxofluorokomplexe der Übergangsmetalle. IX. Kristallstruktur von Ba3[Ti(O2)F5]2 · 2 H2O

Transition Metal Peroxofluoro Complexes. IX. Crystal Structure of Ba₃[Ti(O₂)F₅]₂ · 2 H₂O The pale yellow hydrat Ba₃[Ti(O₂)F₅]₂ · 2 H₂O crystallizes tetragonal (space group P4₂/mbc, a = 1 248.5(3), c = 812.2(2) pm; Z = 4; R = 0.026 for 404 independent reflections). It contains isolated [Ti(O₂)F₅]^3? anions. Thermal decomposition leads directly to α-Ba₃Ti₂O₂F₁₀, which is isotypic to α-Ba₃Al₂F₁₂.     

Contact angle hysteresis, adhesion, and marine biofouling

Adhesive and marine biofouling release properties of coatings containing surface-oriented perfluoroalkyl groups were investigated. These coatings were prepared by cross-linking a copolymer of 1H,1H,2H,2H-heptadecafluorodecyl acrylate and acrylic acid with a copolymer of poly(2-isopropenyl-2-oxazoline) and methyl methacrylate at different molar ratios. The relationships between contact angle, contact angle hysteresis, adhesion, and marine biofouling were studied. Adhesion was determined by peel tests using pressure-sensitive adhesives. The chemical nature of the surfaces was studied by using X-ray photoelectron spectroscopy. Resistance to marine biofouling of an optimized coating was studied by immersion in seawater and compared to previous, less optimized coatings. The adhesive release properties of the coatings did not correlate well with the surface energies of the coatings estimated from the static and advancing contact angles nor with the amount of fluorine present on the surface. The adhesive properties of the surfaces, however, show a correlation with water receding contact angles and contact angle hysteresis (or wetting hysteresis) resulting from surface penetration and surface reconstruction. Coatings having the best release properties had both the highest cross-link density and the lowest contact angle hysteresis. An optimized coating exhibited unprecedented resistance to marine biofouling. Water contact angle hysteresis appears to correlate with marine biofouling resistance.     

Synthesis of Cannabinoid Model Compounds. Part 3. (6aR, 10aR)-N-ethyl-Δ8-tetrahydrocannabinol-18-amide, (6aR, 10aR, 17 RS)-N-ethyl-17-methyl-Δ8- tetrahydrocannabinol-18-amide and (6aR, 10aR)-17,18-didehydro-Δ8-tetrahydrocannabinol

The novel cannabinoids (6aR, 10aR)-N-ethyl-Δ⁸-tetrahydrocannabinol-18-amide (15) and (6aR, 10aR, 17 RS)-N-ethyl-17-methyl-Δ⁸- tetrahydrocannabinol-18-amide (16) , designed as cannabinoid affinity ligands, were synthesized from the corresponding acids 11 and 12 via the N-hydroxysuccinimide esters. Amide 16 was tested in the rat and was generalized to Δ⁹-tetrahydrocannabinol, being 5 times less potent than the training drug. An improved synthesis of (6aR, 10aR)-17,18-didehydro-Δ⁸-tetrahydrocannabinol (23) is reported. As model reaction for the preparation of a tritiated Δ⁸-tetrahydrocannabinol, compound 23 was selectively deuterated at C(17) and C(18) in benzene/Et₃N using [(C₆H₅)₃P]₃RuCl₂ as catalyst.     

d,h-m̈-Alkoxoalkylphosphonato-e-m̈-alkoxo-f-m̈-oxo-bis[trichloroantimon(V)]-Verbindungen

d,h-m?-Alkoxoalkylphosphonato-e-m?-alkoxo-f-m?-oxo-bis[trichloroantimony(V)] Compounds The binuclear antimony(V) complexes Cl₃Sb(O)[R³(R¹O)PO₂](OR²)SbCl₃ 1 to 7 with R¹, R² and R³ = Me or Et in solution slowly exchanges the R² groups between the equatorial oxygen atoms of the Sb₂O₂ ring. The SbO(3)PO(3)Sb ringsystem makes rapid pseudorotation. The resulting isomeres are detected by nmr spectroscopy.     

Acyl- und Alkylidenphosphane. XXVII [I.]. Molekül- und Kristallstruktur des Methyl[(N-phenyl,N-tri-methylsilyl)thiocarbamoyl]trimethylsilylphosphans

Acyl- and Alkylidenephosphines. XXVII. Molecular and Crystal Structure of Methyl-[(N-phenyl, N-trimethylsilyl)thiocarbamoyl]trimethylsilylphosphine . Methyl[(N-phenyl, N-trimethylsilyl)thiocarbamoyl]trimethylsilylphosphine 1a formed via an addition of methylbis(trimethylsilyl)phosphine to phenyl isothiocyanate [1], crystallizes in the monoclinic centrosymmetric space group P2₁/n with following dimensions of the unit cell determined at a temperature of measurement of ?80±3°C: a=1041.2(4);b=1706.9(12);c=1001.1(6)pm; β=106.41(4)°; Z = 4. An X-ray structure determination (R_w = 0.039) confirms the constitution of the compound as already derived from its nmr spectra. One trimethylsilyl group is bound to the phosphorus atom, whereas the other is connected with the sp²-hybridized nitrogen atom. Characteristic rounded bond lenghts and angles are: P? Si 231, P? CH₃ 184, P? C(S) 187, C?S 167, N? C(S) 137, and N? Si 181 pm as well as P? C? S 122°, P? C? N 117°, and S? C? N 121°.