Structure of Galactomannans from <Emphasis Type="Italic">Gleditsia delavayi</Emphasis> and <Emphasis Type="Italic">G. aquatica</Emphasis> by <Superscript>1</Superscript>H and <Superscript>13</Superscript>C NMR Spectroscopy

The structure of galactomannans isolated from seeds of G. delavayi and G. aquatica was studied by ¹H and ¹³C NMR spectroscopy. It was found that the galactomannans consisted mainly of β-1-4-bound mannopyranoses, a part of which was substituted on the C-6 hydroxyl by terminal units of α-galactopyranose.__________Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 12–13, January–February, 2005.     

Folipidine,a New Type Quinoline Alkaloid from Plants of the <Emphasis Type="Italic">Haplophyllum</Emphasis> Genus

The new quinoline alkaloid folipidine, the structure of which was established by chemical transformations and spectral data (UV, IR, mass, NMR) using APT, 2D ¹H-¹H COSY, NOESY, and ¹H-¹³C HSQC, HMBC, was isolated from two plants of the Haplophyllum genus. Folipidine is the first representative of a new type of quinoline alkaloids that contain a heteroaromatic skeleton of [3,4-b] conjugated pyrrole and quinoline fragments. The total alkaloids of these plants exhibit antitumor activity. Folipidine does not possess such activity.__________Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 49–52, January–February, 2005.     

Fabrication of a novel Li<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>MoO<Subscript><Emphasis Type="Italic">y</Emphasis></Subscript> film modified electrode and its application as an electrochemical sensor of iodate

A novel organic gel film modified electrode was simply and conveniently fabricated by casting Li_xMoO_y and polypropylene carbonate (PPC) onto the surface of a gold electrode. The cyclic voltammetry and amperometry studies demonstrated that the Li_xMoO_y film modified electrode has a high stability and a good electrocatalytic activity for the reduction of iodate. In amperometry, a good linear relationship between the steady current and the concentration of iodate was obtained in the range from 3×10^–7 to 1×10^–4 mol L^–1 with a correlation coefficient of 0.9997 and a detection limit of 1×10^–7 mol L^–1.     

Extraction and spectrophotometric determination of titanium(IV) withN 1-hydroxy-N 1,N 2-diphenylbenzamidine and thiocyanate

A precise, reliable, sensitive, and selective method for the determination of titanium(IV) is described. Titanium(IV) reacts withN ¹-hydroxy-N ¹,N ²-diphenylbenzamidine (HDPBA) and thiocyanate to form an orange-coloured mixed-ligand complex of stoichiometry 112 (Ti SCN^– HDPBA). The complex is quantitatively extractable into toluene from 0.05–0.15M hydrochloric acid. The spectrum of the complex exhibits an absorption maximum at 400 nm with a molar absorptivity of 20000M ^–1 cm^–1 and the coloured system obeys Beer's law in the concentration range 0.20–3.0 gml^–1 titanium. The effects of foreign ions and of various experimental parameters have been studied to establish the optimum conditions for the extraction and determination of titanium. The precision of the method has been evaluated and the relative standard deviation has been found to be 0.53%. The method has been successfully applied to the determination of titanium in synthetic matrices corresponding to titanium-containing ores, minerals, and alloys.     

Development of a PVC-membrane ion-selective bulk optode,for UO<Stack><Subscript>2</Subscript><Superscript>2+</Superscript></Stack> ion,based on tri-<Emphasis Type="Italic">n</Emphasis>-octylphosphine oxide and dibenzoylmethane

A novel uranyl ion-selective bulk optode membrane, incorporating tri-n-octylphosphine oxide for cation recognition and a lipophilic chromoionophore dibenzoylmethane, has been prepared. The PVC membrane composition was optimized to result in the widest working concentration range. The response range of the proposed optode is 4.1×10^–6 to 2.0×10^–4 mol L^–1 UO₂²⁺. The probe works at pH 4.0. Ion interference is low and selectivity, reproducibility, and stability are good.     

Theoretical calculations of95Mo-NMR chemical shifts for compounds [MoO4−n S n ]2−

Summary Theoretical calculation of⁹⁵Mo-NMR chemical shifts for [MoO_4–n S _n ]^2– (n=0–4) compounds is reported here for the first time on the basis of Fenske-Hall method and Sum-Over-State (SOS) perturbation theory. A systematic decrease in shielding of⁹⁵Mo nuclei with increase of number of sulfur in [MoO_4–n S _n ]^2–, which is observed experimentally, can be reasonably explained by our calculation. A good linear relationship between chemical shifts of calculation and experiment is obtained. The electronic structure and bonding in these compounds are also discussed.Supported by Nature Science Foundation of China     

Electrodeposition of Lu on W and Al electrodes: Electrochemical formation of Lu–Al alloys and oxoacidity reactions of Lu(III) in the eutectic LiCl–KCl

The electrodeposition of lutetium on inert electrodes and the formation of lutetium–aluminium alloys were investigated in the eutectic LiCl–KCl in the temperature range 673–823 K. On a tungsten electrode, the electroreduction of Lu(III) proceeds in a single step and electrocrystalization plays an important role. Experimental current–time transients are in good agreement with theoretical models based on either instantaneous or progressive nucleation with three dimensional growth of the nuclei, depending on the working temperature. The diffusion coefficient of Lu(III) was determined by chronopotentiometry by applying the Sand equation. The activation energy for diffusion was found to be 31.5 ± 1.3 kJ mol⁻¹. Al₃Lu and mixtures of Al₃Lu and Al₂Lu, characterized by XRD analysis and SEM, were obtained from the LiCl–KCl melt containing Lu(III) by potentiostatic electrolysis using an Al electrode. The activity of Lu and the standard Gibbs energies of formation for Al₃Lu were estimated from open-circuit chronopotentiometric measurements. The E–pO²⁻(potential–oxoacidity) diagram for Lu–O stable compounds in LiCl–KCl at 723 K has been constructed by combining theoretical and experimental data. In this way, the apparent standard potential for the Lu(III)/Lu system has been determined by potentiometry. Potentiometric titrations of Lu(III) solutions with oxide donors, using a yttria stabilized zirconia membrane electrode “YSZME” as a pO²⁻ indicator electrode, have shown the stability of LuOCl and Lu₂O₃ in the melt and their solubility products have been determined at 723 K.     

Chromium(III) Hydroxide Solubility in The Aqueous Na+-OH?-H2PO?4-HPO2?4-PO3?4-H2O System: A Thermodynamic Model

Chromium(III)-phosphate reactions are expected to be important in managing high-level radioactive wastes stored in tanks at many DOE sites. Extensive studies on the solubility of amorphous Cr(III) solids in a wide range of pH (2.8–14) and phosphate concentrations (10^–4 to 1.0 m) at room temperature (22±2)°C were carried out to obtain reliable thermodynamic data for important Cr(III)-phosphate reactions. A combination of techniques (XRD, XANES, EXAFS, Raman spectroscopy, total chemical composition, and thermodynamic analyses of solubility data) was used to characterize solid and aqueous species. Contrary to the data recently reported in the literature,⁽¹⁾ only a limited number of aqueous species [Cr(OH)₃H₂PO^–₄, Cr(OH)₃(H₂PO₄)^2–₂), and Cr(OH)₃HPO^2–₄] with up to about four orders of magnitude lower values for the formation constants of these species are required to explain Cr(III)-phosphate reactions in a wide range of pH and phosphate concentrations. The log K^o values of reactions involving these species [Cr(OH)₃(aq)+H₂PO^–₄&#x21CC;Cr(OH)₃H₂PO^–₄; Cr(OH)₃(aq)+2H₂PO^–₄&#x21CC;Cr(OH)₃(H₂PO₄)^2–₂; Cr(OH)₃(aq)+HPO^2–₄&#x21CC;Cr(OH)₃HPO^2–₄] were found to be 2.78±0.3, 3.48±0.3, and 1.97±0.3, respectively.     

A study of early colour change due to simulated accelerated sunlight exposure in Scots pine (Pinus sylvestris)

A detailed study of early colour change in Scots pine (Pinus sylvestris) due to accelerated simulated sunlight exposure was undertaken focusing on the first 24 h of change. Colour changes were monitored with a Datacolor check spectrophotometer and compared with a set of controls. Measurements on both samples and controls were performed hourly for the first 24 h and there after daily until 168 h’ exposure with extra measurements at 200, 350 and 500 h. A subset of samples was extracted prior to exposure to check the effects of any colour change due to the presence of extractives. Data was analysed using the reflectance spectra (400–700 nm) as well as the CIE-L^*a^*b^* system and ΔE. The majority of colour changes were found to occur within the first 24 h. This was unaffected by the removal of extractives from the wood and was independent of temperature. Mechanical properties and weight changes were also monitored to allow a comparison of sensitivity between the differing methods.     

Synthesis of Schiff bases and benzylamino derivatives containing [1-B<Subscript>10</Subscript>H<Subscript>9</Subscript>NH<Subscript>3</Subscript>]<Superscript>−</Superscript> anion

Reactions of an amino derivative of the closo-decaborate anion [1-B₁₀H₉NH₃]^– with aromatic aldehydes afforded Schiff bases [1-B₁₀H₉NH=CHAr]^– (Ar=Ph, C₆H₄-2-OMe, or C₆H₄-4-NHCOMe). The reduction of the latter with sodium borohydride gave the corresponding benzylamino derivatives [1-B₁₀H₉NH₂CH₂Ar]^–.Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 2004–2007, September, 2004.     

NMR studies of 4(3H)-quinazolinones and 4(3H)-quinazolinethiones

Summary Unambiguous¹H and¹³C NMR assignments for 4(3H)-quinazolinones1–6 and their corresponding 4-thiones7–12 have been made. This resulted in the revision of the previous assignments for the two benzenoid carbons (C-5 and C-8) of quinazolinones1,2,4, and5. Thionation of the nucleophilic amides1–6 has been found to cause a distinct change in the¹³C chemical shift of particularly C-4, but also of those of C-4a, C-5, and C-8a. One-bond and several long range heteronuclear coupling constants for the compounds have also been measured.

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Kernresonanzspektroskopie von 4(3H)-Chinazolinonen und 4(3H)-Chinazolinthionen

Zusammenfassung Die¹H- und¹³C-NMR-Spektren der 4(3H)-Chinazolinone1–6 und ihrer entsprechenden 4-Thione7–12 wurden zugeordnet. Dabei zeigte sich, daß eine frühere Zuordnung der beiden benzoiden Kohlenstoffe (C-5 und C-8) der Chinazolinone1,2,4 und5 falsch war. Ersatz des Sauerstoffs durch Schwefel in den nukleophilen Amiden1–6 führt insbesondere für C-4, aber auch für C-4a, C-5 und C-8a zu einer deutlichen Änderung der chemischen Verschiebung. Heteronukleare Kopplungskonstanten über eine und über mehrere Bindungen wurden bestimmt.

     

Raman and infrared spectra of6Li2C2O4 and7Li2C2O4

Raman and infrared spectra of polycrystalline⁶Li₂C₂O₄ and⁷Li₂C₂O₄ have been investigated in the wavenumber region from 1,800 to 40 cm^–1. The internal C₂O₄ ^–2 vibrations have been studied on the basis of a D_2h molecular structure and the correlation field splittings have been found to be about 40 cm^–1 for the stretching modes and about 15 cm^–1 for the bending modes. The external vibrations of the Li⁺ and C₂O₄ ^–2 sites have been discussed by considering the results of the factor group analysis and the⁶Li/⁷Li isotope effect on the normal vibrations.

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Raman- und Infrarot-Spektren von⁶Li₂C₂O₄ und⁷Li₂C₂O₄

Zusammenfassung Es wurdenRaman- und IR-Spektren von polykristallinem⁶Li₂C₂O₄ und⁷Li₂C₂O₄ im Bereich der Wellenzahlen von 1800 bis 40 cm^–1 untersucht. Die internen Schwingungen wurden auf der Basis einer D_2h Molekülstruktur analysiert. Für die Streckschwingungen wurde eine Korrelationsaufspaltung von etwa 40 cm^–1 gefunden, für die Deformationsschwingungen etwa 15 cm^–1. Die Diskussion der externen Schwingungen von Li⁺ und C₂O₄ ^–2 erfolgte unter Berücksichtigung der Resultate der Faktorgruppenanalyse und des⁶Li/⁷Li Isotopeneffekts auf die Normalschwingungen.

     

Terpenes,Coumarins, and Flavones from <Emphasis Type="Italic">Acacia pennatula</Emphasis>

The chemical analysis of the acetone extract of the dried leaves from Acacia pennatula yielded triacontanol, β-sitosterol palmitate, β-sitosterol, squalene, nonaprenol, norphytane, lupenone, lupeol, daphnetin and catechin, while from the methanol extract were isolated catechin, epigallocatechin, eriodictyol, β-sitosteryl-β-D-glucopyranoside, and stigmasteryl-β-D-glucopyranoside. The structures of all these natural products were established based on their IR, ¹H, and ¹³C NMR and MS data.__________Published in Khimiya Prirodnykh Soedinenii, No. 3, pp. 240–241, May–June, 2005.     

Triterpene glycosides from <Emphasis Type="Italic">Astragalus</Emphasis> and their genins. LXXVII. Cyclomacrogenin B,a new cycloartane triterpenoid

Ten pure compounds, three of which were identified as β-sitosterol, β-sitosterol β-D-glucopyranoside, and D-3-O-methyl-chiro-inositol, were isolated from roots of Astragalus macropus Bunge (Leguminosae). The structure of the new cycloartane triterpenoid cyclomacrogenin B was established as 24R-cycloartan-1α,3β,7β,24,25-pentaol. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 502–504, September-October, 2008. Original article submitted May 26, 2008.     

<Emphasis Type="Italic">O</Emphasis>- and <Emphasis Type="Italic">N</Emphasis>-Alkylation of <Emphasis Type="Italic">N</Emphasis>-halosuccinimides in ionic reactions with 1-phenyltricyclo [4.1.0.0<Superscript>2,7</Superscript>]heptane

N-Bromo and N-chlorosuccinimides add to 1-phenyltricyclo[4.1.0.0^2,7]heptane in CH₂Cl₂ with cleavage of the C(1)-C(7) bond to give isomeric 1 : 1 Markownikoff-type endo, anti-adducts of the norpinane structure in a ∼3 :7 ratio corresponding to N and O alkylation of succinimide.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No.2, pp. 457–460, February, 2005     

New results in the ammonolysis of hexafluoro-cyclo-triphosphazene: Crystal structure of P3N3F5–NH–P3N3F4NH2

The reaction of hexafluoro-cyclo-triphosphazene P₃N₃F₆ with ammonia in acetonitrile has been studied. New compounds, (2-imino-2,4,4,6,6-pentafluoro-2λ⁵,4λ⁵,6λ⁵-cyclo-triphosphaza-1,3,5-trienyl)-2-amino-4,4,6,6-tetrafluoro-2λ⁵,4λ⁵,6λ⁵-cyclo-triphosphaza-1,3,5-triene, P₃N₃F₅–NH–P₃N₃F₄NH₂ (2) and cis and trans isomers of non-gem-2,4-diamino-2,4,6,6-tetrafluoro-2λ⁵,4λ⁵,6λ⁵-cyclo-triphosphaza-1,3,5-triene, P₃N₃F₄(NH₂)₂ (4, 5)_, were detected by GC/MS, and ³¹P NMR spectroscopy in reaction mixtures. X-ray diffraction analysis of P₃N₃F₅–NH–P₃N₃F₄NH₂ (2) revealed two conformational polymorphs, 2A and 2B, the latter being built up of two different conformers that were further denoted as 2B_a (the same as the single conformer in 2A) and 2B_b. The compound 2 was characterized by spectroscopic methods and its 2D potential energy surface (PES) was described by density functional theory computations depending on two dihedral angles. The calculated PES spans over 30 kJ/mol in energy including 8 local minima and all first and second order saddle points. The occurrence of the two experimentally observed conformers 2B_a and 2B_b seems to be governed by crystal packing effects.     

Kinetic energy analysis of atomic multiplets

Summary A kinetic energy analysis of total energy differences in atomic multiplets arising fromf ^m (m=2–12) electronic configurations is performed within the nonrelativistic restricted Hartree-Fock framework. For these 1290 multiplets of 22 lanthanoid (Ce to Er) and actinoid (Th to Fm) atoms, a very good linear correlation between the total energy difference and the kinetic energy difference of the outermostf-electrons is found. The present results, together with our previous ones for the multiplets arising froms ^mpⁿ (m=1,2;n=2–4) ands ^mdⁿ (m=0–2;n=2–8) electronic configurations, demonstrate that the kinetic energy difference of electrons in open subshells is an excellent predictor of total energy differences among atomic multiplet states.     

Der Einfluß großer Salzkonzentrationen auf die Oxydationsreaktion von Fe(phen) 3 2+ mit Ce(IV) in Schwefelsäure

The influence of NaClO₄, NaCl and Na₂SO₄ on the oxidation of Fe(phen) ₃ ²⁺ by Ce(IV) was investigated by means of the stopped-flow method. At the concentrations range of NaClO₄ and NaCl 0.1–1.0M the rate constant values decrease from 1.03·10⁵ to 0.56·10⁵M^–1s^–1 and from 1.08·10⁵ to 0.81·10⁵M^–1s^–1 respectively.In varying concentrations of Na₂SO₄ solutions (0.05–0.35M) the rate constant values decrease from 1.05·10⁵M^–1s^–1 to 0.45·10⁵M^–1s^–1.Taking into account the negative salt effect the mechanism of the reaction progress is proposed.

     

Analysis of effect of specific C-H ...X interaction on the direct13C-1H spin-spin coupling constants based onab initio quantum-chemical calculations

Anab initio quantum-chemical calculation of the direct^13C–¹H spin-spin coupling constants in the CH₄–H₂O system was carried out and experimental data obtained for a series ofN-vinyl compounds were analyzed. The specific C-H ....X (X = O, N) intramolecular interactions result in increasing the direct¹³C–¹H spin-spin coupling constant of the hydrogen involved in bonding and decreasing the direct¹³C-¹H spin-spin coupling constant for the hydrogen atom that takes no part in the interaction.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1362–1365, Tune, 1996.     

Triterpene Glycosides from <Emphasis Type="Italic">Astragalus</Emphasis> and Their Genins. LXXI. Cycloorbicoside D,a New Glycoside from <Emphasis Type="Italic">Astragalus orbiculatus</Emphasis>

The new cycloartane glycoside cycloorbicoside D, which has the structure 23ξ,24ξ-cycloartan-3β6α,16β,23,24,25-hexaol 3-O-β-D-xylopyranoside, was isolated from the aerial part of Astragalus orbiculatus Ledeb. (Leguminosae). __________ Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 345–346, July–August, 2005.