On the crystal chemistry of three copper(II)-arsenates: Cu3(AsO4)2-III,Na4Cu(AsO4)2, and KCu4(AsO4)3

The three copper(II)-arsenates were synthesized under hydrothermal conditions; their crystal structures were determined by single-crystal X-ray diffraction methods:Cu₃(AsO₄)₂-III:a=5.046(2) Å,b=5.417(2) Å,c=6.354(2) Å, =70.61(2)°, =86.52(2)°, =68.43(2)°,Z=1, space group ,R=0.035 for 1674 reflections with sin / 0.90 Å^–1.Na₄Cu(AsO₄)₂:a=4.882(2) Å,b=5.870(2) Å,c=6.958(3) Å, =98.51(2)°, =90.76(2)°, =105.97(2)°,Z=1, space group ,R=0.028 for 2157 reflections with sin / 0.90 Å^–1.KCu₄(AsO₄)₃:a=12.234(5) Å,b=12.438(5) Å,c=7.307(3) Å, =118.17(2)°,Z=4, space group C2/c,R=0.029 for 1896 reflections with sin / 0.80 Å^–1.Within these three compounds the Cu atoms are square planar [4], tetragonal pyramidal [4+1], and tetragonal bipyramidal [4+2] coordinated by O atoms; an exception is the Cu(2)^[4+1] atom in Cu₃(AsO₄)₂-III: the coordination polyhedron is a representative for the transition from a tetragonal pyramid towards a trigonal bipyramid. In KCu₄(AsO₄)₃ the Cu(1)^[4]O₄ square and the As(1)O₄ tetrahedron share a common O—O edge of 2.428(5) Å, resulting in distortions of both the CuO₄ square and the AsO₄ tetrahedron. The two Na atoms in Na₄Cu(AsO₄)₂ are [6] coordinated, the K atom in KCu₄(AsO₄)₃ is [8] coordinated by O atoms.Die drei Kupfer(II)-Arsenate wurden unter Hydrothermalbedingungen gezüchtet und ihre Kristallstrukturen mittels Einkristall-Röntgenbeugungsmethoden ermittelt:Cu₃(AsO₄)₂-III:a = 5.046(2) Å,b = 5.417(2) Å,c = 6.354(2) Å, = 70.61 (2)°, = 86.52(2)°, = 68.43(2)°,Z = 1, Raumgruppe ,R = 0.035 für 1674 Reflexe mit sin / 0.90 Å^–1.Na₄Cu(AsO₄)₂:a = 4.882(2) Å,b = 5.870(2) Å,c = 6.958(3) Å, = 98.51(2)°, = 90.76(2)°, = 105.97(2)°,Z = 1, Raumgruppe ,R = 0.028 für 2157 Reflexe mit sin / 0.90 Å^–1.KCu₄(AsO₄)₃:a = 12.234(5) Å,b = 12.438(5) Å,c = 7.307(3) Å, = 118.17(2)°,Z = 4, Raumgruppe C2/c,R = 0.029 für 1896 Reflexe mit sin / 0.80 Å^–1.Die Cu-Atome in diesen drei Verbindungen sind durch O-Atome quadratisch planar [4], tetragonal pyramidal [4 + 1] und tetragonal dipyramidal [4 + 2]-koordiniert; eine Ausnahme ist das Cu(2)^{[4 + 1]}-Atom in Cu₃(AsO₄)₂-III: Das Koordinationspolyeder stellt einen Vertreter des Übergangs von einer tetragonalen Pyramide zu einer trigonalen Dipyramide dar. In KCu₄(AsO₄)₃ haben das Cu(1)^[4]O₄-Quadrat und das As(1)O₄-Tetraeder eine gemeinsame O—O-Kante von 2.428(5) Å, was eine Verzerrung der beiden Koordinationsfiguren CuO₄-Quadrat und AsO₄-Tetraeder bedingt. Die zwei Na-Atome in Na₄Cu(AsO₄)₃ sind durch O-Atome [6]-koordiniert, das K-Atom in KCu₄(AsO₄)₃ ist [8]-koordiniert.

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Zur Kristallchemie dreier Kupfer (II)-Arsenate: Cu₃(AsO₄)₂-III, Na₄Cu(AsO₄)₂ und KCu₄(AsO₄)₃

     

Thermodynamic properties of liquids,including solutions

Summary A new theoretical treatment of the dependence of surface pressure on the concentration of linear polymer molecules in a monolayer is presented. The development follows closely that in the author's new theory of the thermodynamic properties of three-dimensional solutions.

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Zusammenfassung Es wird eine neuartige theoretische Untersuchung vorgelegt über die Abhängigkeit des Oberflächendruckes von der Konzentration an linearen Makromolekülen in einer monomolekularen Schicht. Die Entwicklung schließt sich eng an des Autors neue Theorie der dynamischen Eigenschaften von dreidimensionalen Lösungen an.

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Glossary A Area of the monolayer surface - B ₁,B ₂ Functions in the expansion of in powers ofm/A. See [38] - E Intermolecular energy in the monolayer. See [2]. It is negative for attraction energy - G Gibbs energy. See [1] - H Enthalpy. See [1] - K Equilibrium constant, defined by [3]. Equal to 1 for perfect randomness of segment contacts - K A constant, related toK by [8] - M ₁,M ₂ Molar masses (molecular weights) of substrate and polymer - N _a Avogadros number=6.0225×10²³ mol^–1 - R Molar gas constant=8.3143 JK^–1 mol^–1 - S Entropy. See [1] - S _cc Correction to the combinatorial entropy to allow for imperfect randomness - S _or Contribution to the entropy of mixing to allow for concentration dependence of entropy of orientation, vibration and rotation of molecules and segments - S _rm Combinatorial entropy of mixing, assuming perfect randomness - T Temperature in kelvins - a ₀ ,a ₀ Areas in monolayer occupied by one mole (Avogadros number) of solvent and polymer segments, respectively. See [10] - g _K A function ofK and the concentration, defined by [7] - m Mass of polymer in the monolayer - m/A Mass/area ratio. Related to area fractions by [14] - n Average number of segments per polymer molecule - r _a =a ₀ /a ₀ Segment area ratio. See [16] - r = ₀ / ₀ Contacting segment outline ratio. See [16] - r _a/ =r _a /r See [16] - r _/a =r /r _a See [16] - x ₁,x ₂ Mole fractions of solvent and polymer in the monolayer - z ,z Contacting segment outline fractions, defined by [9] - Surface pressure required to keep monolayer in areaA - , Designating solvent and polymer segments, respectively - , , Energy per unit length of contact between pairs of segments of the type indicated. See [6] - Energy change when two unit lengths of contacts between like segments are replaced by two unit lengths of contacts between unlike segments. Defined by [6] - Energy parameter, defined by [5] - ₁, ₂ Densities of the pure components (mass/volume) - _m Surface density of polymer in a completely filled monolayer (mass/area) - , Sum of the contacting outlines, for segments of the type indicated, in the monolayer - ⁰ , ⁰ Average contacting outline per segment, of the type indicated - , , Sum of the contact lengths, for contacts of the type indicated, in the monolayer - ₁, ₂ Area fractions, measuring the fractions of the monolayer area occupied by solvent and polymer molecules, respectively.     

Influence of MgO loading on the structure and catalytic performance of Pd/γ-Al2O3, I. Effect of interaction between MgO and γ-Al2O3

The influence of MgO dispersed on -Al₂O₃ in different amounts on the structure and performances of Pd/-Al₂O₃ catalysts has been studied by means of XRD, H₂–O₂ titration, BET and catalytic activity test for CO oxidation. It was found that introduction of MgO enhanced greatly the CO oxidation activity of catalyst. It seems that the enhanced activity stems from the stronger interaction between MgO and -Al₂O₃ at a given temperature (e.g. 450 °C).     

Some compounds of iron(III) with tertiary and secondary nitrogen bases

Summary The iron(III) compound, FeCl(OH)(MeCO₂) · MeCO₂ H · 0.5 H₂O, combines with tertiary nitrogen bases, pyridine, quinoline and-picoline, to form FeCl(OH)(MeCO₂) · (Base) 0.5 H₂O and with-picoline to give FeCl(OH)(MeCO₂) (-picoline). The secondary nitrogen bases (BH), such as, piperidine, pyrrolidine and diethylamine, on the other hand, react with the elimination of base hydrochloride to form Fe(B)(OH)(MeCO₂) · 0.5 H₂O compounds, containing covalently bonded bases. Pyrrole and indole (BH) combine with the partial elimination of chlorine to give Fe₃Cl₂(B)(OH)₃(MeCO₂)₃ · 3(BH). Phthalimide (BH), however, forms a simple addition compound Fe₂Cl₂(OH)₂(MeCO₂)₂ · (BH). The i.r. spectra, room temperature magnetic susceptibilities, thermal decompositions wherever possible and molar conductance have been studied.     

Error of Atomic Charges Derived from Electrostatic Potential

The purpose of this article is to show that CHELP, CHELPG, and Merz and Kollman undergo error for the charge on atoms of HCOO^– (H₂O) _n for n = 1 6. We also demonstrate that the CHELP, CHELPG, and Merz and Kollman show error for the tendency toward change in the charges on carbons for CH₃NH⁺ ₃ (CH₃)₂NH⁺ ₂ (CH₃)₃NH⁺ (CH₃)₄N⁺.     

Some theoretical aspects on morphology development in seeded composite latexes. I. Batch conditions below monomer saturation

In seeded emulsion polymerization, during the second stage, new interfaces appear and the surface area changes. A thermodynamic equilibrium approach is presented which predicts particle morphology of a whole range of non-spherical particles upon polymer conversion. Simulation takes into account swelling ratio, molar volumes and interfacial tension. As the particle geometry is complex, a new mathematical procedure is detailed.The computed data are useful to discuss either the stability or the instability of the particles morphology. These results must be compared with actual experimental structures.Abreviations and symbols G Gibbs' free energy - reduced Gibbs' free energy - _i interfacial tension - ₁₂ interfacial tension between polymer 1 and polymer 2 - _1w interfacial tension between polymer 1 and water - _2w interfacial tension between polymer 2 and water - r ₁ polymer 1 swollen by monomer 2 sphere radius - r ₂ polymer 2 swollen by monomer 2 sphere radius - r _i interfacial radius - h ₁ sphere 1 distance to minimal section - h ₂ sphere 2 distance to minimal section - h _i interfacial sphere distance to minimal section - sign ofh _i, positive when the interface sphere is on the side of the sphere 2, negative when the interface sphere is on the side of the sphere 1 - A ₁₂ surface between polymer 1 and polymer 2 - A _1w surface between polymer 1 and water - A _1w ⁰ surface between polymer 1 and water before polymerization - A _2w surface between polymer 2 and water - v ₁ volume of the polymer 1 swollen by monomer 2 - v _i volume of the polymer 1 swollen by monomer 2 before polymerization - v ₂ volume of the polymer 2 swollen by monomer 2 - V _p1 polymer 1 molar volume - V _p2 polymer 2 molar volume - V _m2 monomer 2 molar volume - n _p2 polymer 2 number of mole - n _p1 polymer 1 number of moles - n _m21 monomer 2 number of mole in the swollen polymer 1 - n _m22 monomer 2 number of mole in the swollen polymer 2 - n _m2 monomer 2 total number of mole - n _m2 monomer 2 number of mole before polymerization - TGn ₁ polymer 1 swelling rate - TGn ₂ polymer 2 swelling rate - TGn _i maximum number of mole of monomer 2 in polymeri by mole of polymeri - x polymer 2 conversion rate - K, p, q mathematical variables - D, r, a mathematical variables     

Thiocyanate bond mode determination on solid manganese(II) mixed ligand coordination compounds

Synthesized and in solid state characterized compounds correspond to the following types [Mn(NCS)₂L_mL'_n] · x D, [Mn(NCS)₂L_y]_z, and [MnX₂(CH₃SCN)(CH₃OH)] · x D (L=CH₃OH or O-donors; L=CH₃SCN or N-donors; D=solvent molecules; x=0, 1 or 2; m=0, 1 or 2; n=1, 2 or 3; y=0, 1, 2, 3 or 4; z2; X=Cl or Br). Derivatographic investigations confirm the formation of intermediates, especially for L=H₂O the existence of thermic stable partially dehydrated (hydrate poor) species (y=1/2 or 1/3) and -NCS-bonding with different ligating atoms. Solid state FT-IR analysis were carried out for band shapes, measurements of the integrated intensity, and correlations between located absorption maxima for v(CN), v(CS), (NCS), v(MnN), and v(MnS) and the thiocyanate bond mode.     

Fatty acids and prostaglandins of thermal cyanobacteria

The compositions of the fatty acids and prostaglandins of extracts from thermophilic cyanobacteria of the taxaOscillatoria andMicrocystidaceae have been investigated. The fatty acids include not only saturated but also polyunsaturated species, including 20:3, 20:4, and 22:4 acids with a known pharmaceutical effect. It has been shown for the first time that the lipid fraction of thermophilic cyanobacteria includes a set of prostaglandins of groups A, E, and F, both in the free form and in the form of esters — MeA₁, AcA₁, AcMeA₁, MeA₂, AcA₂, AcMeA₂, MeA₃, AcA₃, AcMeA₃, 6-ketoE₁, MeE₁, AcE₁, AcMeE₁, MeE₂, AcE₂, AcMeE₂, MeE₃, AcE₃, AcMeE₃, 6-ketoF₁, MeF₁, AcF₁, AcMeF₁, 6-ketoF₂, MeF₂, AcF₂, and AcMeF₂, The latter, together with other previously known compounds, undoubtedly make a contribution to the healing properties of thermal springs.Pacific Ocean Institute of Organic Chemistry, Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 869–874, November-December, 1996. Original article submitted August 14, 1995; revision submitted August 12, 1996.     

Crystal structure of ether solvate of octanuclear lutetium aluminohydride complex {[(Bu 2 t C5H3)LuH]4[Et2O·AlH4]2[AlH4]2}·Et2O

Overall X-ray structural analysis (XSA) of ether solvate crystals of the unusual octanuclear lutetium aluminohydride complex [(CpLuH)₄(Et₂O·AlH₄)₂(AlH₄)₂]·Et₂O (I) (Cp = 1.3–Bu₂ ¹C₅H₃) is reported. In complex I, four Lu atoms are located in vertices of an elongated tetrahedron; over each face of the tetrahedron there is one Al atom. Th'e octanuclear metal core of I is a very distorted cube with an approximate point symmeby D_2d formed by the bridging hydrogen bonds (covalent metal-metal bonds are absent in I). Each Lu atom in I (neglecting individual H and C atoms) has the same distorted square-pyramidal coordination with the -Cp ring in the apical position and three Al atoms and the nearest Lu atom in the base of the pyramid.Institute of Physiologically Active Substances, Russian Academy of Sciences. Translated fromZhurnal Strukturnoi Khimii, Vol. 34, No. 5, pp. 167–174, September–October, 1993.Translated by T. Yudanova     

Untersuchungen der Hydroxylammonium-Fluorozirconate(IV)

Summary Hydroxylammonium fluorozirconates have been investigated. Two new microcristalline phases have been isolated from aqueous solutions: (NH₃OH)₂ZrF₆ (1) and (NH₃OH)₃ZrF₇ (2). The crystals were prepared by slow evaporation of the solution of NH₂OH, Zr, and HF. Different compositions of the crystals were achieved by varying the molar ratios of the components. They were characterized by thermal analysis, vibrational spectroscopy, and structure (single crystal x-ray methods). (NH₃OH)₂ZrF₆ (1) crystallizes triclinic, P (No.: 2),a=7.400(2),b=7.609(2),c=7.887(2) Å, =57.29(3)°, =62.16(3)°, =67.83(2)°. (NH₃OH)₃ZrF₇ (2) crystallizes triclinic, P (No.: 2),a=7.128(1),b=7.989(1),c=8.888(1) Å, =109.72(1)°, =91.01(1)°, =104.27(1)°.

     

Platinum-dihalide complexes with N-alkyl O-ethylthiocarbamates

Summary The thiocarbamic esters (L)ETC(EtOSCNHEt) and PTC (EtOSCNHPr) act as sulphur donors towards platinum halides, yielding the cis-[Pt(L)₂Cl₂], trans-[Pt(L)₂Br₂], [Pt(L)₃X]X (X = Cl or Br) and [Pt(L)₄]X₂ (X = Cl, Br or I) complexes. By addition of n-hexane to platinum chloride solutions in pure ligands the 16 adducts [Pt(L)₄]-Cl₂·2L have been isolated. The non-bonded ligand molecules are easily released to give the corresponding 14 complexes. The compounds have been characterized by elemental analysis and spectroscopy. The 14 and 16 complexes decompose in benzene to form the 13 species, except for [Pt(ETC)₄]I₂, which releases two ligand molecules to give trans-[Pt(ETC)₂I₂]. The 12 and 13 complexes have been tested for in vitro cytostatic activity against KB cells.     

Arrangement and Diffusive Mobility of Extraframework Species in the Hydrated Ammonium Forms of Zeolites Clinoptilolite and Chabazite

The location and diffusive mobility of ammonium ions and water molecules in the channels of the NH₄substituted forms of the natural zeolites clinoptilolite (NH₄)_6.5[Al_6.5Si_29.5O₇₂] · 12.6H₂O and chabazite (NH₄)_9.6Ca_0.6Na_0.3[Al_11.1Si_24.9O₇₂] · 25.8H₂O were studied by Xray diffraction analysis and ¹H NMR spectroscopy. The arrangement of the extraframework subsystem was shown to be largely determined by hydrogen bonds N—H...O(H₂O) of length 2.7–2.9 . The diffusive mobility of the ions was found to correspond to abnormally low energy barriers, similar to those for H₂O diffusion. The activation parameters for the diffusion jumps of the ions and molecules are E(NH₄) = E(H₂O) = 31(2) kJ/mole, ₀(NH₄) = 2 · 10¹¹ sec^-1, ₀(H₂O) = 4 · 10¹² sec^-1 in NH₄chabazite and E(NH₄) = E(H₂O) = 25(1) kJ/mole, ₀(NH₄) = 2 · 10¹⁰ sec^-1, ₀(H₂O) = 3 · 10¹¹ sec^-1 in NH₄clinoptilolite. It is suggested that the development of ion and molecular diffusion is caused by the same defects, whose formation with temperature rise is controlled by Hbond rearrangement.     

Formation of a Dimer with a Double Hydroxo Bridge in Nitric Acid Solutions of the Nitrosotetranitrohydroxo Complex of Ruthenium(II). Crystal Structure of K2[RuNO(NO2)3(μ-OH)]2

Fine yellowish orange crystals of the binuclear complex K₂[RuNO(NO₂)₃(-OH)]₂ were obtained by the reaction of K₂[RuNO(NO₂)₄OH] with a stoichiometric amount of 0.8 M nitric acid at room temperature. The compound was investigated by IR spectroscopy, X-ray phase analysis (DRON-3M, CuK radiation), and X-ray diffraction analysis (Nonius CAD-4, MoK radiation, graphite monochromator, scan mode, 1406 reflections). The crystals are poorly soluble in water and practically insoluble in ethanol and acetone; the compound is stable when stored in air. Crystal data for H₂K₂N₈O₁₆Ru₂ are: a = 8.596(2), b = 10.111(1), c = 9.537(1) , = 104.42(1)°, V = 802.8(2) ³, space group , Z = 2, _calc = 2.691 g/cm³. The structure is built of [RuNO(NO₂)₃(- complex anions and K⁺ cations.     

Morpholine complexes of copper(II) alkanoates and chloroacetates

Summary Morpholine complexes of copper(II) alkanoates and chloroacetates of formula Cu(O₂CR)₂(Morph)_n (where R = H, Me, Et, n-Pr, i-Pr, n-Bu, i-Bu, CH₂Cl, CHCl₂ and CCl₃; Morph = Morpholine and n=1 and/or 2) have been isolated by the direct interaction of morpholine with the respective copper(II) carboxylates in a suitable organic medium and characterized by elemental analyses and various physicochemical techniques. Molecular weight determinations show that 11 complexes are dimeric whereas 21 complexes are monomeric in solution. Electronic spectra and magnetic moments suggest that 11 complexes are dinuclear carboxylate bridged species while 21 addition complexes have atrans-octahedral configuration. The i.r. spectra indicate that morpholine behaves as a monodentate ligand and coordinates through its nitrogen atom.     

Characterization of airborne particulates by laser microprobe mass analysis

Summary Laser microprobe mass analysis (LAMMA) was applied to characterize aerosol particles collected and separated from 16m to 0.06m by a low pressure cascade impactor. Positive ion LAMMA spectra showed characteristic molecular peaks such as PbCl⁺, a series of Si₂O⁺–Si₂O₄ ⁺ and NaAl₂Si₂O₂ ⁺–NaAl₂Si₂O₅ ⁺, and TiO⁺ in 0.06–0.12m, 0.5–1m and 4–8m fraction, respectively. In the negative ion LAMMA spectra, it was observed that the fragment peaks of sulfate ions were deficient above 2m and those of nitrate ions were deficient under 2m. LAMMA allows remarkable insights into the chemical nature of aerosol particles.

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Charakterisierung luftgetragener Teilchen durch Laser-Microprobe-Massenspektrometrie

Zusammenfassung Laser-Microprobe-Spektrometrie (LAMMS) wurde zur Analyse atmosphärischen Aerosols herangezogen, welches im Korngrößenbereich zwischen 16m und 0.06m mit einem Niederdruckkaskadenimpaktor fraktioniert gesammelt wurde. Positive LAMMS-Spektren zeigten charakteristische molekulare Peaks, wie etwa PbCl⁺, eine Serie von Si₂O⁺–Si₂O₄ ⁺ und NaAl₂Si₂O₂ ⁺–NaAl₂Si₂O₅ ⁺, sowie TiO⁺ in der 0,06–0,12-m,- 0,5–1–m- bzw. 4–8-m-Fraktion. In den negativen LAMMS-Spektren konnten über 2m keine Fragmentpeaks für Sulfationen, unter 2m. keine für Nitrationen beobachtet werden. LAMMS ermöglicht eine bemerkenswerte Einsicht in die chemische Natur von Aerosolteilchen.

     

A new one-dimensional coordination polymer containing a μ-[N(CN)2]− bridging ligand. Synthesis,crystal structure and magnetic properties of Mn[N(CN)2]2-(2,4′-bpy)2 (2,4′-bpy = 2,4′-bipyridine)

The new one-dimensional (1D) coordination complex Mn[N(CN)₂]₂(2,4-bpy)₂ (1) (2,4-bpy = 2,4-bipyridine) has been synthesized. X-ray crystallography analysis reveals that the structure of (1) consists of linear chains of manganese atoms bridged by end-to-end dicyanamide ligands and coordinated by 2,4-bipyridine ligands. Weak – interactions between pyridine planes of adjacent chains force 1D Mn[N(CN)₂]₂(2,4-bpy)₂ chains into interesting 2D supramolecular arrays. Variable temperature magnetic susceptibility measurement for complex (1) shows that antiferromagnetic exchange interactions exist between manganese(II) centres of the linear chain.     

Reactivity of the Unsaturated Triosmium Cluster [Os3(CO)8{Ph2PCH2P(Ph)C6H4}(μ-H)] with Thiols

The reaction of the unsaturated cluster [(-H)Os₃(CO)₈{Ph₂PCH₂P(Ph)C₆H₄}] 2 with C₂H₅SH, CH₃CH(CH₃)SH and C₆H₅SH are reported. The reaction of 2 with C₂H₅SH yields the new complexes [Os₃(CO)₈(-SC₂H₅)(¹-SC₂H₅){Ph₂PCH₂P(Ph)C₆H₄}(-H)] 9 and [Os₃(CO)₈)(SC₂H₅)(Ph₂PCH₂P)(Ph)C₆H₄}] 8 in 24 and 57% yields respectively and the known compound [(Os₃(CO)₈)(-SC₂H₅)(-dppm)(-H)] 7 in 5% yield. Compound 9, which exists as two isomers in solution, converts into 8 almost quantitatively in solution at 25°C and more rapidly in refluxing hexane. Compound8 reacts with H₂ at 110°C to give 7 in high yield (86%). Treatment of 2 with propane-2-thiol yields [Os₃(CO)₈{-SCH(CH₃)CH₃}{Ph₂PCH₂P(Ph)C₆H₄}] 10 and [(Os₃(CO)₈{-SCH(CH₃)CH₃}{¹-SCH(CH₃)CH₃}{Ph₂PCH₂P(Ph)C₆H₄}(-H)] 11 in 75 and 3% yields respectively while with C₆H₅SH, [(Os₃(CO)₈(-SC₆H₅)(-dppm)(-H)] 6 is obtained as the only product in 75% yield. In both 8 and 10, the thiolato ligand bridges the Os–Os edge which is also bridged by the metallated phenyl group. The new compounds have been characterized by elemental analyses and spectroscopic methods (IR, ¹H and ³¹P NMR). The molecular structures of 7, 8, 9 and 10 are reported as determined by X-ray diffraction studies.     

The influence of ionic surfactants on the acid-base properties and tautomeric equilibrium of 2-dimethylaminomethylphenol

Shifts in the acid-base and tautomeric equilibria have been observed in aqueous solutions of 2-dimethylaminomethylphenol (DAMP) containing surfactants. Cationic micelles of cetyltrimethylammonium bromide increase the dissociation constants of DAMP (pK₁ 0.3, pK₂ 0.5), and anionic micelles of sodium dodecyl sulfate reduce them (pK₁ 1.5, pK₂ 0.3). The constant of tautomeric equilibrium decreases when ionic surfactants are added. This is connected with the better solubilization of the neutral form by micelles.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1215–1218, July, 1994.     

Die Kristallstruktur des Natriumorthogermanats,Na4GeO4

The crystal structure of the title compound has been determined from single crystal X-ray diffraction data and refined toR=0.125. The unit cell is triclinic, space group P, (No. 2),a=5.688(1),b=5.701(1),c=8.583(1) Å, =81.32(1), =71.50(1), =67.95(1)° andZ=2. The structure consists of isolated [GeO₄] tetrahedra linked together by four- and five-coordinate sodium atoms. Na₄GeO₄ is isostructural with Na₄CoO₄ (which has been described to be non-centrosymmetric and for which a centrosymmetric model is presented), K₄GeO₄, K₄SnO₄ and K₄PbO₄.

     

Metal complexes in catalytic olefin transformations. 2. Structure of phosphine ligands attached to silica; Ni-catalysts for ethylene dimerization

-Bis(diphenylphosphine)aminopropyltriethoxysilane is synthesized and studied by IR and¹H,¹³C, and³¹P^1H NMR spectroscopies for the first time. Chemical modification of silica with (EtO)₃Si(CH₂)₃N(PPh₂)₂ gives the support (-DPAMPS) containing identical N(PPh₂)₂ ligands on its surface. Subsequent treatment of the support with (EtO)₃Si(CH₂)₃NH₂ and ClPPh₂ gives a silica surface containing two types of attached ligands, NH₂ and N(PPh₂)₂, in the ratio 11. The heterogenized complexes Ni-HMC, prepared by ligand exchange between Ni(PPh₃)_n (n=3, 4) and -DPAMPS, in combination with Et₂AlCl exhibit activity and selectivity for ethylene dimerization.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2674–2678, December, 1989.