Zur Kenntnis des RbNiCrF6-Typs. V. Neue Fluoride CsBMF6 mit B = MnII bzw. NiII und M = Ga,Fe, Rh bzw. Sc,In, Tl,Rh

On the RbNiCrF₆ Type. V. New Fluorides of the Type CsBMF₆ with B = Mn^II or Ni^II and M = Ga, Fe, Rh or Sc, In, Tl, Rh New prepared are the cubic compounds CsNiScF₆ (light yellow, a = 10.60 Å); CsNiInF₆ (lightyellow, a = 10.64 Å); CsNiTlF₆ (light yellow, a = 10.60 Å); CsNiRhF₆ (light redbrown, a = 10.37 Å); CsMnGaF₆ (pink, a = 10.42 Å); CsMnFeF₆ (light green, a = 10.55 Å) and CsMnRhF₆ (redbrown, a = 10.58 Å), all RbNiCrF₆ type of structure. The Madelung part of lattice energy, MAPLE, is calculated and discussed.     

Transition metal iodates. II. Crystallographic,magnetic, and nonlinear optic survey of the 3d iodates

The anhydrous iodates of Cr, Mn, Fe, Co and β-Ni form a single isomorphous family, crystallizing in space group P6₃ or P6₃22 with lattice constants typified by Mn(IO₃)₂ of a = 11.178 ± 0.002, c = 5.035 ± 0.001 Å and four formulas per unit cell; in addition, α-Ni(IO₃)₂ forms as a second phase. Mn(IO₃)₂, Fe(IO₃)₃, α-Ni(IO₃)₂ and β-Ni(IO₃)₂ order antiferromagnetically at 6.5, 17.0, 3.5 and 5.0 K, respectively; Cr(IO₃)₃ and Co(IO₃)₂ remain paramagnetic to 1.5 K. Below Θ_N, a weak ferromagnetic moment develops in the Mn, α-Ni and β-Ni iodates. All the anhydrous iodates generate second harmonics. Co(IO₃)₂ · 4H₂O and β-Ni(IO₃)₂ · 4H₂O crystallize isomorphously in space group $\text{P2}{}_1\text{c}$, with lattice constants a = 8.370 ± 0.005, b = 6.572 ± 0.007, c = 8.514 ± 0.008 Å, β = 99.8 ± 0.1° for the Co compound. Co(IO₃)₂ · 2H₂O is triclinic, with a = 6.666 ± 0.015, b = 10.991 ± 0.025, c = 4.913 ± 0.011 Å, α = 93.1 ± 0.1, β = 92.1 ± 0.1, γ = 98.9 ± 0.1°, space group $\text{P}\text{1}$, and Ni(IO₃)₂ · 2H₂O is orthorhombic, a = 9.14986 ± 0.00008, b = 12.20896 ± 0.00022, c = 6.58353 ± 0.00013Å at 298 K, space group Pbca. The Co iodate hydrates are paramagnetic to 1.5 K; both Ni hydrates are antiferromagnetic, the dihydrate also developing a weak ferromagnetic moment. The lattice spacings of all 11 compounds are presented, 9 with indexing.     

Elaboration,structure cristalline et proprietes physiques (transport,susceptibilité magnétique et R.M.N.) du spinelle CuV2S4

Single crystals of CuV₂S₄ have been made by chemical vapor transport with chlorine as the transport agent. Characterization by an X-ray study, density measurements by the hydrostatic technique and electron microprobe analysis were performed. They showed no deviation from stoichiometry of the compound. Refinement of the structure (space group Fd3m) has been done. Transport properties, magnetic susceptibility and N.M.R. data from 1.5°K to 300°K present discontinuities below 100°K. Observed properties are discussed in view of the previously proposed band model. The relationships between magnetic susceptibility and Knight shifts are included in this paper.     

Friedel-crafts copolymerization of thiophene and p-di(chloromethyl)benzene. I. Products,kinetics, and mechanism of the early stages of the reaction

The rate of polymerization of thiophene, at concentrations of catalyst (SnCl₄), and thiophene of the same order as was subsequently used in studying the reaction between thiophene and di(chloromethyl)benzene, is of the order of 10^-2%/hr at 30°C. There is no significant self-condensation of DCMB under the same conditions. Since the reaction between thiophene and DCMB is complete at 30°C in minutes rather than hours, it is assumed that self-condensation of thiophene or DCMB during the reaction between them will be negligible and should not influence the course of the reaction or the structure of the resulting polymer. Reaction at 30°C is much too fast for convenient study. A temperature of 0°C is more appropriate and was used in subsequent kinetic work. The first two products of the condensation of p-di(chloromethyl)benzene (DCMB) with thiophene have been identified by a combination of mass, infrared, and nuclear magnetic resonance spectroscopy as thenylchloromethylbenzene (TCMB) and dithenylbenzene (DTB). DCMB, TCMB, and DTB have been estimated quantitatively during the course of the reaction by gas-liquid chromatography (GLC), and it has been established that the rates of each of the two reaction steps is first-order with respect to the chloro compound (DCMB and TCMB respectively), thiophene, and SnCl₄. Rate constants for these two consecutive reactions were calculated to be k₁ = 2.79 × 10^-4l.²/mole²-sec, k₂ = 6.37 × 10^-3l.²/mole²-sec; the corresponding energies of activation are E₁ = 7.93 kcal/mole, E₂ = 7°67 kcal/mole. These rate constants are appreciably higher than values previously obtained for the corresponding DCMB–benzene reactions.     

Mechanism of Elimination Reactions : by W.H. Saunders Jr., and A.F. Cockerill,Wiley, New York,London, 1973,x + 641 pages. ß11.15.

The structure of H₃Os₃(CO)₉CCH₃ has been determined by a combination of nematic-phase PMR and X-ray powder photography; the compound is iso-structural with the analogous H₃Ru₃(CO)₉CCH₃, with an osmium to (bridging) hydride proton distance of 1.82 Å and an OsHOs angle of 103°.     

Electrophilic aromatic substitution. 14. [1] A kinetic,NMR, and Raman study of the aluminum chloride-catalyzed reaction of p-toluene-sulfonyl chloride with benzene and toluene in dichloromethane

Vacuum line kinetic studies of the reaction of p-toluenesulfonyl chloride and benzene or toluene, using aluminum chloride as the catalyst and dichloromethane as the solvent were determined at 25°C by means of gas chromatography. The reaction is first-order in arene, tosyl chloride, and in AlCl₃ as catalyst. Noncompetitive results are k_T/k_B=22±7 with a product sulfone isomer distribution: ortho, 14±1%; meta, 4.3±0.2%; and para 82±1%. With hexadeuteriobenzene k_H/k_D was determined to be 1.8±0.1. Rate constant ratios and product isomer distributions were also determined competitively: with AlCl₃, k_T/k_B=30±2; % ortho, 13±1; % meta, 4.0±0.5; % para, 84±3; with SbCl₅, k_T/k_B=40±4; % ortho 10.3±0.4; % meta, 4.7±0.2; and % para, 85.0±0.5. The k_T/k_B ratio for AlCl₃ and the meta sulfone product percentages for both AlCl₃ and SbCl₅ are considerably higher than those reported in the literature. NMR and Raman studies suggest a molecular complex between p-tosyl chloride and AlCl₃, with coordination through oxygen as the dominant species and the probable electrophile in CH₂Cl₂. A reaction mechanism consistent with the kinetic and spectroscopic results is proposed. © 1998 John Wiley & Sons, Inc. Int J Chem Kinet 30: 367–372,1998     

Aromatic polyamides. III. Copoly(4,4′-oxanilideterephthalamide—4,4′-phenyleneterephthalamide): Synthesis,wet-spinning,fiber thermal characterization,and stability in sulfuric acid

Copoly(4,4′-oxanilideterephthalamide—4,4′-phenyleneterephthalamide) (A-202/PPD) was synthesized by reaction of 4,4′-diaminooxanilide, p-phenylenediamine, and terephthaloyl chloride in organic solvents. Copolymer inherent viscosities in H₂SO₄ as high as 10.3 were obtained. Isotropic copolymer solutions (4%—5% concentration) of A-202/40%–80% PPD were spun to fibers with tenacity/elongation/modulus at 1% extension in the 13–14 gpd/1.5%–2%/700–1000 gpd range. Oxamide and amide stabilities in 98–100% H₂SO₄ and 20% oleum were compared. Poly(4,4′-oxanilideterephthalamide) (A-202), A-202/PPD copolymers, and poly(4,4′-phenyleneterephthalamide) (PPT) were unstable in 20% oleum, but all proved relatively stable in 100% H₂SO₄. However, the oxamide linkage proved less stable than the amide linkage in 98% H₂SO₄. A-202 and A-202/PPD copolymers formed stable anisotropic spinning solutions in 1% oleum at 10–20% concentrations. Dynamic mechanical analyses (Vibron) showed no glass transition temperature (T_g) below 200°C. Dilatometric measurement of A-202/50% PPD revealed a T_g at 257°C. Differential thermal analyses of A-202/40–80% PPD exhibited endotherms at 470–480°C. Thermogravimetric analyses showed no significant weight loss below 400°C.     

Molecular Cobalt Clusters as Precursors of Distinct Active Species in Electrochemical,Photochemical, and Photoelectrochemical Water Oxidation Reactions in Phosphate Electrolytes

Three cobalt model molecular compounds, Co‐cubane ([Co₄(µ₃‐O)₄(µ‐OAc)₄py₄]), Co‐trimer ([Co₃(μ₃‐O)(µ‐OAc)₆py₃]PF₆), and Co‐dimer ([Co₂(μ‐OH)₂(µ‐OAc)(OAc)₂py₄]PF₆), are investigated as water oxidation reaction (WOR) catalysts, using electrochemical, photochemical, and photoelectrochemical methodologies in phosphate electrolyte. The actual species contributing to the catalytic activity observed in the WOR are derived from the transformation of these cobalt compounds. The catalytic activity observed is highly dependent on the initial compound structure and on the particular WOR methodology used. Co‐cubane shows no activity in the electrochemical WOR and negligible activity in the photochemical WOR, but is active in the photoelectrochemical WOR, in which it behaves as a precursor to catalytically active species. Co‐dimer also shows no activity in the electrochemical WOR, but behaves as a precursor to catalytically active species in both the photochemical and photoelectrochemical WOR experiments. Co‐trimer behaves as a precursor to catalytically active species in all three of the WOR methodologies.     

Thermodynamic properties of alkali halides. IV. Apparent molal volumes,expansibilities, compressibilities,and heat capacities in urea-water mixtures

The apparent molal volume φ_v, expansibility φ_E, compressibility φ_K, and heat capacity φ_c of NaCl were measured in urea-water mixtures, as a function of salt (<1.5m) and urea (<13m) concentrations at 25°C. At a fixed urea concentration, the transfer functions from H₂O to 3m urea are linear functions of the NaCl aquamolality. At a fixed salt aquamolality, (0.1m), the sign of the transfer functions is in the direction of a decrease in the structure-breaking effect, and the absolute values of the transfer functions tend to level off at high urea concentrations (13m). The functions φ_v, φ_E, φ_K, φ_c, and (?φ_v/?T)_p were measured for the sodium halides and alkali, bromides (chlorides in the case of φ_K) at a fixed salt aquamolality of 0.1m and fixed urea molality of 3m. The corresponding transfer functions from H₂O to 3m urea are opposite those from H₂O to D₂O and similarly are relatively independent of ionic size. This suggests that urea, shows no specific interaction affinity for ions and that the overall number of water molecules influenced by the ions is relatively constant for all alkali halides. The lithium halides are an exception in that Li⁺ seems to have hardly any structure-breaking effect.     

Zur Kenntnis der RbNiCrF6Typs. III. Neue Fluoride des Typs CsZnMF6 mit M = Al,Ga, In,Tl, Sc,Ti, V,Mn, Cu,Rh

On the RbNiCrF₆ Type. III. New Fluorides of the Type CsZnMF₆ (M = Al, Ga, In, Tl, Sc, Ti, V, Mn, Cu, Rh) Cubic compounds are CsZnGaF₆ [3] (colourless, a = 10.29 Å); CsZnInF₆ (colourless, a = 10.58 Å); CsZnTlF₆ (colourless, a = 10.62 Å); CsZnScF₆ (colourless, a = 10.58 Å); CsZnTiF₆ (lightblue, a = 10.50 Å); CsZnVF₆ (lightgreen, a = 10.43 Å); CsZnMnF₆ (redbrown, a = 10.40 Å); CsZnCuF₆ (light brown, a = 10.24 Å); CsZnRhF₆ (redbrown, a = 10.41 Å), all RbNiCrF₆ type of structure, in addition non cubic: CsZnAlF₆ (colourless). The Madelung part of lattice energy, MAPLE, is calculated and discussed.     

Metals in Biochemistry : P.M. Harrision and R.J. Hoare. Publ. Chapman & Hall,London and New York 1980, 78 pp + index. Price £2.45

The complex H₂Os₃(μ₃-NCH₃)(CO)₁₂ in decalin at 198°C in 35% yield. Crystal data for the former obtained at ?158°C are: orthorhombic, space group Pmcn, a 14.113(2), b 6.605(1), c 17.683(4) », Z = 4, D_c 3.44 g cm^?3. The hydrogen atoms are related by symmetry. The position of the unique hydrogen atom has been refined. It is observed asymmetrically bridging (closer to the unique Os atom) the longer edge of the isosceles triosmium triangle. The hydrogen atoms are out of the trimetal plane away from the triply-bridging nitrogen atom.Crystal data for the tetraosmium complex at 25°C are: monoclinic, space group C2/c a 30.818(9), b 8.463(2), c 16.621(2), », β 108.90(2)°, Z = 8, D_c 3.75 g cm^?3. The four osmium atoms form a distorted tetrahedral framework capped by the nitrogen atom of the methylnitrene group on the face containing the three longer OsOs separations.     

Trigonal-planare CuX3-Gruppen in Cu2Mo6X14, X = Cl,Br, I

Trigonal Planar CuX₃-Groups in Cu₂Mo₆X₁₄, X = Cl, Br, I Cu₂Mo₆Cl₁₄ (I), Cu₂Mo₆Br₁₄ (II) and Cu₂Mo₆I₁₄ (III) were synthesized by thermal treatment of corresponding mixtures of copper(I) and molybdenum(II) halides. The crystal structures were determined by single crystal X-ray analyses. I and II show isotypism, cubic, Pn3 (no. 201, sec. setting), Z = 4, I: a = 12.772(3) Å, II: a = 13.350(2) Å. III shows a new structural type, orthorhombic, Pbca (No. 61), Z = 4, a = 16.058(3) Å, b = 10.643(2) Å, c = 16.963(3) Å. Trigonal planar CuX₃ units were found in I? III. Structural behaviour relations are discussed, especially with regard to ionic conductivity.     

High-pressure photoionization mass spectrometry. Effect of internal energy and density on the ion–molecule reactions occurring in methyl,dimethyl, and trimethylamine

The ion–molecule reactions of CH₃NH₂⁺, (CH₃)₂NH⁺, and (CH₃)₃N⁺ with the respective amines have been investigated at thermal kinetic energies in a high-pressure photoionization mass spectrometer at several wavelengths (energies) in the vacuum ultraviolet. The absolute rate coefficient for proton transfer from (CH₃)₃N⁺ to (CH₃)₃N decreases from 8.2 × 10^?10 cm³/molecule · sec at 147.0 nm (8.4 eV) to 4.9 × 10^?10 cm³/molecule. sec at 106.7-104.8 nm (11.7 eV). In dimethylamine, the rate coefficient decreases from 11.6 × 10^?10 cm³/molecular. sec at 8 4 eV to 10.2 × 10^?10 cm³/molecule osec at 11.7 eV, while no significant effect of energy was detected in methylamine. The reactions of several fragment ions are also reported. Experiments were also carried out at pressures up to 0.5 torr in order to investigate the further solvation of CH₃NH₂⁺, (CH₃)₂NH₂⁺, and (CH₃)₃NH⁺. It was found that the maximum proton solvation numbers in methyl-, dimethyl-, and trimethyl-amine are 4, 3, and 2, respectively, under these conditions.     

Beiträge zu den Eigenschaften von Titanaten mit Ilmenitstruktur. I. Aspekte eines Hochtemperaturphasenübergangs in NiTiO3

Contributions to the Properties of Titanates with Ilmenite Structure. I. Aspects of a High Temperature Phase Transition in NiTiO₃ NiTiO₃ (Ilmenite structure) shows an anomalous increase of the electrical conductivity in the temperature range between 1 250°C and 1 290°C. The temperature dependence of the Seebeck coefficient is also found to be anomalous in this region. DTA experiments are consistent with a phase transition; the transition enthalpy was estimated to Δ_uH_m = 17 ± 3 kJmol^?1. NiTiO₃ powders and single crystals were quenched from 1 350°C and 1 200°C to room temperature; in principle no differences of the lattice parameters or atomic positions could be detected. The determination of the distribution of cations using x-ray powder methods failt because of strong texture effects. Structure refinements with single crystal methods suggest an ordered Ilmenite structure independent of the quenching temperature. The results are in agreement with a reversible order-disorder transition of higher order. It seems to be impossible to quench the high temperature phase by conventional methods.     

Progress in Inorganic Chemistry,Vol. 21 : edited by S.J. Lippard,Wiley—Interscience,New York/London/Sydney/Toronto, 1976, viii + 294 pages, $27.70, £15.00.

The same secondary ferrocenylisopropylcarbenium ion was formed from treatment with concentrated H₂SO₄ at 10°C of either ferrocenylisopropylcarbinol or ferrocenylmethyldimethylcarbinol and the same secondary ferrocenyldiphenylmethylcarbenium ion was obtained when either ferrocenyldiphenylmethylcarbinol or ferrocenylmethyldiphenylcarbinol was treated with CF₃COOH at 5°C. The results indicate the occurrence of 1,2-hydride shifts converting tertiary to secondary carbocations, thus providing a novel demonstration of the extraordinary stability of α-ferrocenyl substituted carbocations.     

Strahlungschemie von Kohlenwasserstoffen. 19. Mitteilung. Die Deuteriumabspaltung in isotop-isomeren Cyclohexanen

The G-value for D₂ production has been measured for C₆D₁₂ and for gem-, cis-, and trans-C₆H₁₀D₂. The G-values for the unimolecular process are 0.24, 0.023, 0.010 and 0.004, resp. In C₆D₁₂ two bimolecular processes can be distinguished: one includes ‘hot’ D-atoms, e. g. a species that shows no isotope effect for the hydrogen abstraction yielding D₂ and HD, resp.; its G-value is 1.22. The other process goes via thermal D-atoms, it has a G-value of 1.97 and gives an isotope effect for abstraction: k_D/k_H = 0.075 (10°C). In the partially deuteriated cyclohexanes, only the former process can be observed. Its G-value depends on the irradiation temperature and phase, is independent of the position of the D-atoms in the molecule and amounts to 0.035 (10°C), 0.028 (?40°C solid), 0.040 (?40°C liquid with 25% hexane). The following conclusions can be drawn: the unimolecular detachment shows no intramolecular isotope effect in partially deuteriated molecules and comes only from the gem-, cis- and trans-positions. Most of the G-values for the D₂ and HD production by different reaction paths can be cross-checked by G-values from different mixtures. The agreement between these values is excellent.     

Zur Kenntnis der Hydrate des Bariumchlorids. Röntgenographische,thermoanalytische, Raman- und IR-spektroskopische Untersuchungen

Hydrates of Barium Chloride. X-ray, Thermoanalytical, Raman, and I.R. Data In the system BaCl₂? H₂O the hydrates BaCl₂ · 2 H₂O, BaCl₂ · 1 H₂O, BaCl₂ · 1/2 H₂O, and BaCl₂ · uH₂O were obtained. X-ray powder data, i.r. and Raman spectra, as well as thermoanalytical measurements (TG, DTA) are reported. BaCl₂ · 1 H₂O and BaCl₂ · 1/2 H₂O, which are both isotype with the corresponding hydrates of SrCl₂, were prepared by dehydration of BaCl₂ · 2 H₂O or by back hydration of anhydrous BaCl₂ with the calculated amounts of water. BaCl₂ · uH₂O (u ≈? 1) is formed as the primary product by the reaction of anhydrous BaCl₂ with water vapour at room temperature. Preparation methods of salt hydrates by controlled back hydration of the anhydrous salts are reported.     

An electron-diffraction determination of the molecular structure of bis(difluorophosphino)ether,F2POPF2, in the gas phase

Gas-phase electron-diffraction methods have been used to determine the molecular structure of bis(difluorophosphino)ether, F₂POPF₂. Most of the geometrical parameters are strongly correlated due to overlapping peaks in the radial distribution curve. In the structure that fits the experimental data most closely, the P-F and P-O bond lengths are 159.7 ± 0.4 and 153.3 ± 0.6 pm respectively, and the POP angle is 2.53 ± 0.02 rad (145°). The conformation is such that the molecule has no symmetry elements other than I (point group C₁). In other refinements somewhat longer P-O and shorter P-F distances were obtained.     

Thermooxidative degradation of polyethylene. I and II. Structural changes occurring in low-density polyethylene,high-density polyethylene,and tetratetracontane heated in air

Samples of low-density polyethylene (LDPE), high-density polyethylene (HDPE), and tetratetracontane (n-C₄₄H₉₀) free from additives were heated in air at temperatures between 120 and 180°C. As a comparison, “as received” HDPE containing unspecified additives has also been included. The structural changes have been studied with gel chromatography, viscometry, infrared spectroscopy, differential scanning calorimetry, and gravimetric measurements. LDPE, HDPE, and n-C₄₄H₉₀ follow the same course of thermooxidative degradation when they are free from additives and present in the molten state. Both molecular-diminishing and enlargement reactions occur. At temperatures below 150°C molecular enlargement is not observed until after rather long exposure times, whereas at higher temperatures enlargement occurs immediately. The difference is because “peroxide curing” becomes increasingly important above 150°C, whereas ester formation is operating at all temperature levels. Degradation below T_m is restricted to the amorphous phase that results in a different degradation pattern. In accelerated testing work extrapolations of the Arrhenius type in the prediction of structural change are thus not justified, even within the actual narrow temperature range. Neither are changes in commonly used standards like carbonyl content justified as a measure of the changes; for example, in mechanical properties. The stabilizer in the unpurified HDPE not only influences the induction period but also the course of the thermooxidative degradation.     

Inorganic coordination polymers. VII. Zinc(II) dimethyl-, methylphenyl-, and diphenylphosphinates

Zinc dimethyl-, methylphenyl-, and diphenylphosphinate have been prepared by the reaction of Zn(C₂H₃O₂)₂·2H₂O with the appropriate acid or salt and found to exist in amorphous and crystalline forms. Zinc methylphenylphosphinate, the most tractable, exhibits many of the physical attributes of polymeric materials, both in solution and bulk form, supporting our earlier suggestion that these compounds are double-bridged coordination polymers. Thermogravimetric analysis indicates initial decomposition temperatures of 440, 425, and 490°C., respectively, for the three polymers, but long-term studies show initiation of decomposition at somewhat lower temperatures.