Field-desorption mass spectra of flavonoid acylglycosides. II. Natural cinnamoyl and benzoyl derivatives

The field-desorption mass spectra of 14 flavonoid glycosides esterified with p-coumaric, ferulic, caffeic, p-hydroxybenzoic, and gallic acids have been studied. For all the compounds the molecular ions and the ions of the aglycone (A) were obtained as the main peaks. The spectra also contained a number of other fragmentary ions, including the ion of the acylated anhydrosugar. For flavonol glycosides in which the carbohydrate is esterified by cinnamic acids, the (A + Ac), and for the diacylglycosides the (A + 2 Ac), ions are diagnostic. The formation of these strong ions corresponding in mass to the molecules of the mono- and diacylated aglycone permits the assumption of the existence of acyl migration in the breakdown of the initial molecular ion.All-Union Scientific-Research Institute of Medicinal Plants, Moscow. L. Ya. Karpov Scientific-Research Institute of Physical Chemistry. Irkutsk Institute of Organic Chemistry, Siberian Branch, Academy of Sciences of the USSR. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 582–589, September–October, 1984.     

Ion-beam irradiation effects on polyimide-UV–vis and infrared spectroscopic study

Ion-beam irradiation effects on polyimide, Kapton™, were studied with respect to optical and electronic properties. Stack films of Kapton™ (12.5 μm thick) were irradiated to various ion beams in air or vacuo at room temperature and subjected to ultraviolet–visible (UV–vis) spectroscopy, and change in absorbance and energy gap is discussed. The UV–vis absorption spectrum, which is assigned to the transition of electrons in benzene rings from π to π* orbital, upon He²⁺ (6 MeV/u) irradiation in air, shifted towards longer wavelength direction for all cases, and the shift was more obvious for higher linear energy transfer (LET) ion beams. The energy gap of the transition was estimated, and the H⁺ and He²⁺ ion beams caused little change in the transition energy gap Eg, while the heavier ions such as C⁶⁺ and Si¹⁴⁺ caused more significant decrease. This decrease is assumed to the structural changes around benzene rings, and the infrared spectroscopy revealed breakage in imide groups next to benzene ring in the repeating unit of polyimide.     

Influence of sorption on the catalytic activity of iron(III) and copper(II) ions

An analysis is made of earlier work by the authors in investigating the catalytic activity of Fe(III) and Cu(II) ions in solution and on different surfaces in certain redox reactions: the decomposition of H₂O₂, oxidation of ascorbic acid, etc. General principles have been established which provide a means of predicting one or another action of sorption on the catalytic activity: if the reaction proceeds within the ion exchanger phase as in a homogeneous (concentrated) solution, it is most probable to have a decrease (or cessation) of the catalytic activities of the ions. If the ion catalysts are included in a surface complex in whose coordination sphere there are places which the substrate may occupy the reaction is facilitated. The analysis carried out of the influence of sorption on the catalytic activity of the iron and copper ions shows a favorable change in the catalytic activity for these ions during their sorption on different types of surfaces.Translated from Teoreticheskie i Éksperimental'naya Khimiya, Vol. 22, No. 6, pp. 706–711, November–December, 1986.     

Influence of metal ions on the activity and stability of the glucose isomerase from Streptomyces atratus

The influence of a number of bivalent metals on the activity ofStreptomyces atratus glucose isomerase has been studied. Mg²⁺ ions are activators and Co²⁺ ions are stabilizers of the glucose isomerase activity. The effective kinetic parameters for the action of the enzyme have been determined.Institute of Microbiology, Uzbek Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 838–842, November–December, 1991.     

MD studies of electrolyte solution|liquid mercury interfaces

We report molecular dynamics (MD) computer simulations of a single lithium or iodide ion near a water|liquid mercury interface. The ion–mercury and the water–mercury potentials are derived from ab initio calculations of an ion or a water molecule and a mercury cluster consisting of seven, nine or 10 atoms. The flexible BJH water model and a mercury–mercury potential derived from pseudopotential theory are employed. The ion–water potentials are also based on ab initio calculations. The structural properties at the interfaces are described in terms of various density profiles and the ion–mercury radial distribution functions (RDF). An analysis of the induced rearrangements of the mercury atoms at and below the surface is also performed. Finally, the spectral densities of the hindered translational motions of the ions parallel and perpendicular to the mercury surface are reported. We conclude that, while the I⁻-ion is contact adsorbed on the mercury surface, the Li⁺-ion is not.     

Structural and dynamic investigations of aqueous clusters of Na+ and K+

Using computer modeling, we have studied Na⁺–24H₂O and K⁺–24H₂O clusters. We propose ion-water interaction potentials. We obtain structural, energy, and dynamic characteristics of the studied clusters. We show different mechanisms for exchange of water molecules surrounding the Na⁺ and K⁺ ions: single-particle in the case of Na⁺, and close to K⁺, along with single-particle exchange, a large percentage of multiparticle cooperative exchange of water molecules. This difference is explained by the different degrees of orientation of the water molecules surrounding these ions, by the presence of a unified deformed network of H bonds in the K⁺ cluster and its absence in the Na⁺ cluster. We propose a negative hydration mechanism for the K⁺ ion.Institute of General and Inorganic Chemistry, Russian Academy of Sciences. Institute of Physical Chemistry, Russian Academy of Sciences. Translated from Zhurnal Strukturnoi Khimii, Vol. 34, No. 2, pp. 96–104, March–April, 1993.     

Transport Properties of Selective Membranes Reversible to Nitrogen-Containing Organic Base Cations: Permeability and Ion Flow

Main transport properties were studied for selective membranes with low dielectric constants based on liquid ion exchangers involving nitrogen-containing organic base cations. Permeabilities and ion flows through a membrane were calculated for major and interfering ions. Dependences of the transport properties of membranes on the concentrations of the ion exchanger and near-membrane solution and their potentiometric characteristics are presented. It was demonstrated that the transport properties of liquid membranes are determined by two main factors: the transfer of counterions through the phase boundary by the extraction–exchange mechanism and the leaching of the ion exchanger from the membrane.     

Protein kinase from cotton seeds

A Ca²⁺-dependent protein kinase C, active at pH 6.5–8.0 has been found in cotton seeds for the first time. The localization of the enzyme in the seeds has been established and some of its properties are described (stability in various media, capacity for performing the phosphorylation of various substrates, activation by calcium ions). Highly active preparations of cottonseed protein kinase C have been isolated by biospecific chromatography.Institute of Bioorganic Chemistry, Uzbek SSR Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 255–259, March–April, 1989.     

Electrical Conductivity and Complexation of Sodium Borate in Trehalose and Sucrose Aqueous Solutions

The formation equilibrium constants for the esterification reaction between sucrose or trehalose and borate ion have been determined by measuring the pH changes produced when the corresponding sugar is added to sodium borate solutions. The speciation of the ternary sugar–borate–water system was calculated from this equilibrium information and used to separate the contribution of each ionic species to the electrical conductivity of the system. From the analysis of the results it is concluded that, in the viscosity region studied, the complex borate–trehalose and borate–sucrose ions obey Walden's rule, while the behavior of the smaller borate ion is not clear. The dramatic difference of the infinite dilution molar conductivity, and consequently of the hydrodynamic radius, of the trehalose– and sucrose–borate ester ions is ascribed to the formation of an intramolecular diester in aqueous trehalose.     

Indicator Tubes and Indicator Powders for Determining Fluoride and Chloride Ions

Noncovalent immobilization of Arsenazo I, Alizarin Red, Xylenol Orange, and diphenylcarbazone by incorporation into silicic acid xerogels and modification of silica gels was studied, and procedures for determining fluoride and chloride ions by solid-phase spectrophotometry and test methods were developed. Reactions of immobilized reagents with aluminum(III), zirconium(IV), and mercury(II) were studied. The possibility of using immobilized reagent–metal ion–halide ion systems for the determination of halide ions was assessed. Indicator powders were proposed for determining 0.5–10 mg/L fluoride ions and 1–30 mg/L chloride ions, and indicator tubes were developed for determining 20–200 mg/L chloride ions. The determination of fluoride and chloride ions is based on exchange complexation reactions proceeding in the systems immobilized Xylenol Orange–zirconium(IV) and immobilized diphenylcarbazone–mercury(II), respectively. Performance characteristics of the developed procedures were estimated. The procedures were verified by determining halide ions in Narzan mineral water.     

Quantification of SIMS depth profiles of ODS-superalloys by using cluster ion formation from reactive primary ions

Cluster ion formation, with both oxygen and caesium as reactive elements, (MO^– and MCs⁺ ions) has been studied using secondary ion mass spectrometry. A comparison of various primary ion beam conditions is given. The investigations were carried out on aluminium oxide films and required a special charge compensation method. An improvement in the quantification concentration by use of cluster ions can only be expected from MCs⁺ measurements; however the total ionization probabilities still depend on matrix composition.     

The stability of the molecular and some fragmentary ions in the mass spectra of cardenolides

Summary The stability of the molecular ions of the cardenolides depends to the greatest extent on the nature of the substituent at C₁₀. A tendency is observed to a decrease in the intensities of the peaks of the main ions of the series formed by the cleavage of the bonds of the steroid skeleton with a decrease in the stability of the M⁺ ion. The anomalous increase in the intensity of some fragmentary ions in the spectra of the 19^–COOR compounds is due to the lactonization of the latter under the conditions of mass spectrometry.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 158–166, March–April, 1975.     

Complexes with metal-nitroxyl group coordination

This review covers research on coordination compounds of transition metals with stable nitroxyl radicals, in which the nitroxyl fragment is coordinated by the metal ion. Greatest attention is given to generalized aspects of the synthesis of compounds containing a metal-nitroxyl group bond and their magnetic properties in the solid state. Recent developments in the theoretical understanding of the magnetic properties of polycrystalline compounds of this class are discussed. The structure of these complexes and the nature of exchange interactions in them between unpaired electrons of various paramagnetic sites are examined. The review covers studies published in the period from 1980 to 1987. Earlier investigations were reviewed by Larionov [6].Institute of Inorganic Chemistry, Siberian Branch, Academy of Sciences of the USSR. Translated from Zhurnal Strukturnoi Khimii, Vol. 30, No. 5, pp. 142–165, September–October, 1989.     

Preparation and properties of enzymes immobilized on supports activated by metal ions

Summary 1. Preparations of trypsin, -chymotrypsin, and glucose oxidase immobilized on synthetic and polysaccharide supports charged with transition-metal ions contain 3–64 mg of protein per 1 g of support.2. The activity of immobilized enzymes amounts to 100–10,000 U/g. The activity yield is 2.2–90X%.3. The pH dependence of the enzymes is shifted in the alkaline direction by 0.26–1.19 units. The Michaelis constants and inhibitor constants have decreased by factors of 1.5–21.4. The mechanism of the fixation of enzymes is determined by the formation of coordination bonds and by inclusion in inorganic gels. The properties of the enzymes are due to the surface charge of the activated supports.Institute of Biochemistry, Academy of Sciences of the Lithuanian SSR, Vilnius. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 629–637, September–October, 1978.     

Polymeric coumarin derivatives

Summary Copolymers of vinylpyrrolidone with coumarin, umbelliferone, esculetin, osthole, ostholic acid, meranzin hydrate, isoimperatorin, oxypeucedanin hydrate, isooxypeucedanin, gosferol, pranchimgin, and marmesin have been synthesized and their structures have been studied.On the basis of a study of UV, IR, and NMR spectra, and also of chemical properties, it has been established that copolymerization takes place at the 3,4 double bond of the lactone ring and side chains do not participate in polymerization.In a pharmacological study of monomeric coumarins and their copolymers it was found that they all possess well-defined spasmolytic and hypotensive properties.Leningrad Sanitary-Hygienic Medical Institute. Institute of Macromolecular Compounds, Academy of Sciences of the USSR. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 714–720, November–December, 1974.     

Studies on the equilibrium uptake of some metal ions on titanium arsenate and titanium tungstoarsenate gels using radiotracers

Sorption of some univalent, divalent and trivalent metal ions has been studied on the hydrogen form of titanium arsenate and titanium tungstoarsenate gels as a function of initial solution concentration at pH 5–6. The effect of pH on maximum uptake (Q_max) has also been seen for some representative ions. Sorption of metal ion becomes almost negligible below pH 1.8, with the exception of monovalent cations. Rubidium ions exhibit interesting adsorption behaviour. The data have been compared with the exchange properties of these two inorganic ion exchangers, as reported earlier^6,8.     

Modication of the properties of allapinin and deoxypeganine by their mechanical treatment

The change in the physicochemical properties of plant drugs — allapinin and deoxypeganine — on their grinding in an AGO-2U activator with a regulable energy loading have been studied.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent, fax (3712) 89 14 75. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 272–276, March–April, 1995. Original article submitted November 1, 1994.     

Field desorption mass spectra of flavonoid acylglycosides. I. Natural acetyl derivatives

The field desorption mass spectra (FD spectra) of 17 natural flavonoid acetylglycosides have been studied. In the spectra of each of the 0-monoglycosides the molecular ion (M or M + H) appears as the main peak and it is accompanied by the ions of the aglycone (A or A + H) and of the acylated anhydrosugar (S). The intensity of the latter peak is largely connected with the structure of the substance. In the FD spectra of flavone 0-biosides, fragment S is absent but its mass can be calculated from the difference (M – A). Useful information for establishing the position of the acetyl group is given by the fragments S₁ and (M – S₁) corresponding to the detachment of the terminal sugar residue. The FD spectra of flavone C-glycosides differ greatly from the spectra of the 0-glycosides: In them the main peak is that of the ion (M), but peaks (A) and (S) are absent and the ions present resemble the fragmentation of the C-glycosides under the action of electron impact.All-Union Scientific-Institute of Medicinal Plants, Moscow. L. Ya. Karpov Scientific-Research Institute of Physical Chemistry, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 573–582, September–October, 1984.     

Reactions of carbon cluster ions stored in an RF trap

Reactions of carbon clusterions with O₂ were studied by using an RF ion trap in which cluster ions of specific size produced by laser ablation could be stored selectively. Reaction rate constants for positive and negative carbon cluster ions were estimated. In the case of the positive cluster ions, these were consistent with the previous experimental results using FTMS. Negative carbon cluster ions C _n ^– (n=4–8) were much less reactive than positive cluster ions. The C_nO^– products were seen only in n=4 and 6.     

Isolation of proteins from cottonseed meal II. The salt method

Summary On the basis of the results of a study of the amino acid compositions of various protein fractions from cottonseed flour and meal it has been established that the fraction of salt-soluble proteins (globulins) does not change its composition and properties in the processing of cotton seeds. The yield of protein from the industrial meal using the salt-extraction method is 16%.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 626–628, September–October, 1974.