Synthesis,Structure and Properties of Inverse-Keggin Potassium Tetraniobooctatungstosilicate

Ｓｙｎｔｈｅｓｉｓ，ＳｔｒｕｃｔｕｒｅａｎｄＰｒｏｐｅｒｔｉｅｓｏｆＩｎｖｅｒｓｅ－ＫｅｇｇｉｎＰｏｔａｓｓｉｕｍＴｅｔｒａｎｉｏｂｏｏｃｔａｔｕｎｇｓｔｏｓｉｌｉｃａｔｅＹＵＥＢｉｎ，ＴＡＮＧＬｉ－ｈａｏ，ＲＵＩＣｈｅｎｇ－ｇｕｏ，ＬＩＵＨｕｉ－ｚ...     

Synthesis of Novel Hydrophobic Media and Purification of Recombinant HBsAg

ＩｎｔｒｏｄｕｃｔｉｏｎＳｉｎｃｅｔｈｅｌａｓｔｔｗｅｎｔｙｙｅａｒｓ,ｈｙｄｒｏｐｈｏｂｉｃｉｎｔｅｒａｃｔｉｏｎｃｈｒｏｍａｔｏｇｒａｐｈｙ（ＨＩＣ）ｔｅｃｈｎｉｑｕｅｈａｓｂｅｅｎｓｕｃｃｅｓｓｆｕｌｙａｐｐｌｉｅｄｔｏｐｕｒｉｆｙｉｎｇｍａｎ...     

Laser flash photolysis of fullerols of C_(60) and of C_(70) in aqueous solutions

Ｓｉｎｃｅｇｒａｍｑｕａｎｔｉｔｉｅｓｏｆｆｕｌｌｅｒｅｎｅｓｗｅｒｅｓｅｐａｒａｔｅｄｆｒｏｍｃａｒｂｏｎｓｏｏｔｓ,ｍａｎｙｓｔｕｄｉｅｓｈａｖｅｂｅｅｎｔｒｉｇｇｅｒｅｄｏｎｔｈｅｉｒｓｔｒｕｃｔｕｒｅｓ,ｐｒｏｐｅｒｔｉｅｓａｎｄｒｅａｃｔｉｏｎｓ.Ａｓｆｕｌｌｅｒｅｎｅｓｃａｎｐｒｏｄｕｃｅｖｅｒｙｈｉｇｈｑｕａｎｔｕｍｙｉｅｌｄｓｏｆｓｉｎｇｌｅｔｏｘｙｇｅｎｗｈｉｌｅｅｘｃｉｔｅｄｂｙｌｉｇｈｔ,ｍｏｒｅｉｎｔｅｒｅｓｔｈａｓｂｅｅｎｆｏｃｕｓｅｄｏｎｔｈｅｅｘａｍｉｎａｔｉｏｎｏｆｔ…     

Characterization and Dehydrogenation Activity of SBA-15 and HMS Supported Chromia Catalysts

ＩｎｔｒｏｄｕｃｔｉｏｎＥｎｏｒｍｏｕｓｓｔｕｄｙｈａｓｂｅｅｎｄｅｖｏｔｅｄｔｏＭ4 1Ｓ ,ｔｈｅｆｉｒｓｔｆａｍｉｌｙｏｆｍｅｓｏｐｏｒｏｕｓｍｏｌｅｃｕｌａｒｓｉｅｖｅｓｒｅｐｏｒｔｅｄｉｎ1992 ,1,2 ｉｎｃｌｕｄｉｎｇｔｈｅｉｒｍｏｄｉｆｉｃａｔｉｏｎｓａｎｄａｐｐｌｉｃａｔｉｏｎｓｉｎｃａｔａｌｙｓｉｓ .Ｔｈｅａｔｔｒａｃｔｉｖｅｐｒｏｐｅｒｔｉｅｓｏｆｔｈｅｓｅｍａｔｅｒｉａｌｓａｒｅｔｈｅｉｒｈｉｇｈｓｐｅｃｉｆｉｃｓｕｒｆａｃｅａｒｅａ (>10 0 0ｍ2 /ｇ) ,ｗｅｌｌ ｄｅ ｆｉｎｅｄｓｔｒ…     

Synthesis, Mechanism of Formation and Insecticidal Activity of Novel Fluorinated Organophosphorus Compounds

ＩｎｔｒｏｄｕｃｔｉｏｎＯｒｇａｎｏｐｈｏｓｐｈｏｒｕｓｃｏｍｐｏｕｎｄｓａｒｅｗｉｄｅｌｙｕｓｅｄａｓｉｎ ｓｅｃｔｉｃｉｄｅｓ ,ｈｅｒｂｉｃｉｄｅｓａｎｄｆｕｎｇｉｃｉｄｅｓ .Ｉｎｖｉｅｗｏｆｔｈｅｐｏｓ ｓｉｂｌｅｉｎｆｌｕｅｎｃｅｏｆｆｌｕｏｒｉｎｅｓｕｂｓｔｉｔｕｔｉｏｎｏｎｔｈｅｂｉｏｌｏｇｉｃａｌａｃｔｉｖｉｔｙｏｆｏｒｇａｎｏｐｈｏｓｐｈｏｒｕｓｃｏｍｐｏｕｎｄｓｗｅｈａｖｅｔｕｒｎｅｄｏｕｒａｔｔｅｎｔｉｏｎｔｏｔｈｅｓｔｕｄｙｏｆｔｈｅｓｙｎｔｈｅｓｉｓａｎｄｂｉｏｌｏｇｉｃａ…     

Tandem Reaction of Deprotonation-Oxidation-Wittig Reaction: Stereoselective Synthesis of (E)-α,β-Unsaturated Enoates

Ｓｉｎｃｅｉｔｓｄｉｓｃｏｖｅｒｙ ,Ｗｉｔｔｉｇｒｅａｃｔｉｏｎｈａｓｂｅｃｏｍｅｏｎｅｏｆｐｒｉｍａｒｙｍｅｔｈｏｄｓｆｏｒｔｈｅｆｏｒｍａｔｉｏｎｏｆｃａｒｂｏｎ ｃａｒｂｏｎｄｏｕｂｌｅｂｏｎｄｓａｎｄｂｅｅｎｗｉｄｅｌｙｕｓｅｄｉｎｔｈｅｓｙｎｔｈｅｓｉｓｏｆｎａｔｕｒａｌｐｒｏｄｕｃｔｓ .1,2 Ｒｅｃｅｎｔｌｙ ,ｉｔｗａｓｆｏｕｎｄｔｈａｔｐｒｉｍａｒｙａｌｃｏｈｏｌｓｃａｎｕｎｄｅｒｇｏｔｈｅｔａｎｄｅｍｒｅａｃｔｉｏｎｏｆｏｘｉｄａｔｉｏｎ Ｗｉｔｔｉｇｒｅａｃｔｉｏｎｗｉｔｈｐｈｏｓ…     

Quantum chemical investigation on solvation of Ginkgolides

ＧｉｎｋｇｏｉｓａｋｉｎｄｏｆｔｒａｄｉｔｉｏｎａｌＣｈｉｎｅｓｅｈｅｒｂｓｗｈｉｃｈｈａｄｂｅｅｎｕｓｅｄｆｏｒｄｉｓｅａｓｅｔｒｅａｔｍｅｎｔｅｖｅｎｓｉｎｃｅ5000ｙｅａｒｓａｇｏｉｎＣｈｉｎａ.Ｉｎｍｏｄｅｒｎｍｅｄｉｃｉｎｅ,ｇｉｎｇｋｏｈａｓｂｅｅｎｔａｋｅｎａｓａｍｅｄｉｃｉｎｅｓｅｒｉｏｕｓｌｙｄｕｅｔｏｔｈｅｆａｃｔｔｈａｔｉｔｃａｎｂｅｕｓｅｄｔｏｔｒｅａｔａｌｏｔｏｆｄｉｓｅａｓｅｓｓｕｃｈａｓａｓｔｈｍａａｎｄｔｒａｃｈｅｉｔｉｓ.Ｐｈａｒｍａｃｏｌｏｇｉｃａｌｓｃｒｅｅｎｉ…     

Accurate Mass Determination of Amino Alcohols by Turboionspray／Time—of—Flight Mass Spectrometry

ＩｎｔｒｏｄｕｃｔｉｏｎＡｍｉｎｏａｌｃｏｈｏｌｓａｒｅａｎｉｍｐｏｒｔａｎｔｃｌａｓｓｏｆｃｏｍｐｏｕｎｄｓｉｎｓｙｎｔｈｅｔｉｃｏｒｇａｎｉｃｒｅａｃｔｉｏｎｓ .Ｔｈｅｉｒｍｏｌｅｃｕｌｅｓｔｒｕｃｔｕｒｅｓｂｅｃｏｍｅｕｎｓｔｅａｄｙｗｈｅｎａｎａｌｙｚｅｄｂｙｅｌｅｃｔｒｏｎｉｍｐａｃｔ(ＥＩ) .ＴｈｅｆｒａｇｍｅｎｔｓｏｂｔａｉｎｅｄｆｒｏｍＥＩａｒｅｕｓｕａｌｌｙａｓ ｓｉｇｎｅｄｔｏｎｅｕｔｒａｌｌｏｓｓｅｓｓｕｃｈａｓＨ2 Ｏ ,ＣＨ3 ＯＨ (Ｆｉｇ .1) .ＥＩｉｓｎｏｔａｕｓｅｆｕｌｍｅ…     

Microdetermination of Proteins by Enhanced Rayleigh Light Scattering Spectroscopy with Thorin

ＩｎｔｒｏｄｕｃｔｉｏｎＰｒｏｔｅｉｎｄｅｔｅｒｍｉｎａｔｉｏｎｉｓａｌｗａｙｓｉｍｐｏｒｔａｎｔｉｎｃｌｉｎｉｃａｌａｐｐｌｉｃａｔｉｏｎｓ .Ｎｅｗｍｅｔｈｏｄｓｉｎｃｌｕｄｉｎｇｓｐｃｅｔｒｏｐｈｏｔｏｍｅｔｒｙ ,1ｆｌｕｏｒｏｍｅｔｒｙ2 ａｎｄｃｈｅｍｉｌｕｍｉｎｉｃｅｎｃｅ3 ,4 ａｒｅｃｏｎｔｉｎｕｏｕｓｌｙｂｅ ｉｎｇｄｅｖｅｌｏｐｅｄ .Ｐａｓｔｅｒｎａｃｋｅｔａｌ.5,6ｄｅｖｅｌｏｐｅｄａｔｅｃｈ ｎｉｑｕｅｔｏｍｅａｓｕｒｅｔｈｅｉｎｔｅｎｓｉｔｙｏｆｓｃａｔｔｅｒｉｎｇｌｉｇｈｔｕｓｉ…     

Synthesis of Nanorods of Crystalline Co3O4Using Carbon Nanotubes as Templates

ＩｎｔｒｏｄｕｃｔｉｏｎＭａｔｅｒｉａｌｓｂａｓｅｄｏｎｃｏｂａｌｔｏｘｉｄｅｓｈａｖｅａｔｔｒａｃｔｅｄａｇｒｅａｔｉｎｔｅｒｅｓｔｉｎｖｉｅｗｏｆｔｈｅｉｒｐｏｔｅｎｔｉａｌａｐｐｌｉｃａｔｉｏｎｓｉｎｓｃｉｅｎｔｉｆｉｃａｎｄｔｅｃｈｎｏｌｏｇｉｃａｌｆｉｅｌｄｓ .1Ｔｈｅｙｈａｖｅｂｅｅｎｕｓｅｄｆｏｒｔｈｅｐｒｏｄｕｃｔｉｏｎｏｆｓｏｌｉｄ ｓｔａｔｅｓｅｎｓｏｒｓ ,2 ｈｅｔｅｒｏｇｅｎｅｏｕｓｃａｔａｌｙｓｔｓ ,3ｅｌｅｃｔｒｏｃｈｒｏｍｉｃｄｅｖｉｃｅｓ (ＥＣＤｓ) 4ａｎｄａｓｉｎｔｅ…     

Amperometric detection studies of Nafion/indium hexacyanoferrate film for the determination of electroinactive cations in ion chromatography

An amperometric detector based on the chemical modification of Nafion and indium (III) hexacyanoferrate (II, III) thin film (Nafion/In-CN-Fe) onto a glassy carbon (GC) electrode, was first successfully used for the determination of electroinactive cations (Li⁺, Na⁺, K⁺, Rb⁺, Cs⁺, NH₄ ⁺) in single column ion chromatography (IC). A set of well-defined peaks of electroinactive cations was obtained. The detection limits of the cations are 8.9 × 10^–6 mol/L for Li⁺, 2.3 × 10^–6 mol/L for Na⁺, 5.2 × 10^–6 mol/L for K⁺, 4.8 × 10^–6 mol/L for Rb⁺, 4.0 ׶10^–6 mol/L for Cs⁺ and 5.3 × 10^–6 mol/L for NH₄ ⁺ at a single-to-noise ratio of 3. The proposed method was quick, sensitive and simple. The cations in rainwater and mineral water were successfully analyzed by this method.     

Affinity capillary electrophoresis and density functional theory study of noncovalent interactions of cyclic peptide [Gly6]‐antamanide with small cations

ACE and density functional theory were employed to study the noncovalent interactions of cyclic decapeptide glycine‐6‐antamanide ([Gly⁶]AA), synthetic derivative of native antamanide (AA) peptide from the deadly poisonous fungus Amanita phalloides , with small cations (Li⁺, Rb⁺, Cs⁺, NH₄⁺, and Ca²⁺) in methanol. The strength of these interactions was quantified by the apparent stability constants of the appropriate complexes determined by ACE. The stability constants were calculated using the nonlinear regression analysis of the dependence of the effective electrophoretic mobility of [Gly⁶]AA on the concentration of the above ions in the BGE (methanolic solution of 20 mM chloroacetic acid, 10 mM Tris, pH_MeOH 7.8, containing 0–70 mM concentrations of the above ions added in the form of chlorides). Prior to stability constant calculation, the effective mobilities measured at actual temperature inside the capillary and at variable ionic strength of the BGEs were corrected to the values corresponding to the reference temperature of 25°C and to the constant ionic strength of 10 mM. From the above ions, Rb⁺ and Cs⁺ cations interacted weakly with [Gly⁶]AA but no interactions of [Gly⁶]AA with univalent Li⁺ and NH₄⁺ ions and divalent Ca²⁺ ion were observed. The apparent stability constants of [Gly⁶]AA‐Rb⁺ and [Gly⁶]AA‐Cs⁺ complexes were found to be equal to 13 ± 4 and 22 ± 3 L/mol, respectively. The structural characteristics of these complexes, such as position of the Rb⁺ and Cs⁺ ions in the cavity of the [Gly⁶]AA molecule and the interatomic distances within these complexes, were obtained by the density functional theory calculations.     

Ionophores in Rubidium Ion‐Selective Membrane Electrodes

Binaphthyl‐based crown ethers incorporating anthraquinone, benzoquinone, and 1,4‐dimethoxybezene have been synthesized and tested for Rb⁺ selective ionophores in the poly(vinyl chloride) (PVC) membrane. The membrane containing NPOE gave a better Rb⁺ selectivity than those containing either DOA or BPPA as a plasticizer. The response was linear within the concentration range of 1.0×10^?5–1.0×10^?1 M and the slope was 54.7±0.5 mV/dec. The detection limit was determined to be 9.0×10^?6 M and the optimum pH range of the membrane was 6.0–9.0. The ISE membrane exhibits good selectivity for Rb⁺ over ammonium, alkali metal, and alkaline earth metal ions. Selectivity coefficients for the other metal ions, log K^Pot were ?2.5 for Li⁺, ?2.4 for Na⁺, ?2.0 for H⁺, ?1.0 for K⁺, ?1.2 for Cs⁺, ?1.6 for NH₄⁺, ?4.5 for Mg²⁺, ?5.0 for Ca²⁺,?4.9 for Ba²⁺. The lifetime of the membrane was about one month.     

Selective complexation of alkali metal ions and nanotubular cyclopeptides: a DFT study

A density functional theory based on interaction of alkali metal cations (Li⁺, Na⁺, K⁺, Rb⁺ and Cs⁺) with cyclic peptides constructed from 3 or 4 alanine molecule (CyAla3 and CyAla4), has been investigated using mixed basis set (C, H, O, Li⁺, Na⁺ and K⁺ using 6-31+G(d), and the heavier cations: Rb⁺ and Cs⁺ using LANL2DZ). The minimum energy structures, binding energies, and various thermodynamic parameters of free ligands and their metal cations complexes have been determined with B3LYP and CAM-B3LYP functionals. The order of interaction energies were found to be Li⁺ > K⁺ > Na⁺ > Rb⁺ > Cs⁺ and Li⁺ > Na⁺ > K⁺ ? Rb⁺ > Cs⁺, calculated at CAM-B3LYP level for the M/CyAla3 and M/CyAla4 complexes, respectively. Their selectivity trend shows that the highest cation selectivity for Li⁺ over other alkali metal ions has been achieved on the basis of thermodynamic analysis. The main types of driving force host–guest interactions are investigated, the electron-donating O offers lone pair electrons to the contacting LP* of alkali metal cations.     

Tungsten oxide bronzes with alkali metals

Single-phase samples of tungsten bronzes M _x WO₃ (M = K⁺, Rb⁺, Cs⁺) are prepared by solid-state synthesis. The reversibility of the M_0.33WO₃/M⁺-solid electrolyte interface is studied subject to the alkali metal nature and humidity over a wide temperature interval. The exchange current density at 24°C and 58%-relative humidity is 3.6 × 10^?4 A/cm² for the Rb_0.33WO₃/Rb⁺-solid electrolyte interface; 2.2 × 10^?4 A/cm² for the Cs_0.33WO₃/Cs⁺-solid electrolyte interface; and 1.3 × 10^?4 A/cm² for the K_0.33WO₃/K⁺-solid electrolyte interface. A correlation between the reversibility of the bronze|solid electrolyte interface, which is characterized by the exchange current density, and the rate of potential equilibration in sensor systems, where the bronze is a reference electrode, is revealed. Ionic component of the conductivity of the synthesized tungsten oxide bronzes is measured at a background of the predominant electronic conductivity. The ionic conductivity is three orders of magnitude lower than the electronic conductivity; it decreases in the series Rb_0.33WO₃ > Cs_0.33WO₃ > K_0.33WO₃, amounting to 2.3 × 10^?2, 2.1 × 10^?3, and 2 × 10^?4 S cm^?1, respectively. The working capacity of the M_0.3WO₃ bronzes as reference electrodes in sensor systems for carbon dioxide detection is evaluated. The plots of the cell potential vs. the CO₂ concentration in the electrochemical cells are linear, their slopes (59 ± 1 mV/decade) are characteristic for one-electron process. The fastest response to changes in the CO₂ concentration was obtained with the sensor system that used Rb_0.33WO₃ as reference electrode.     

Synthesis of novel chromogenic azocalix[4]arenemonoquinones and their binding with alkali metal cations

Five new chromogenic azocalix[4]arenemonoquinones have been synthesized, characterized and examined for their interaction with alkali metal cations (Li⁺, Na⁺, K⁺, Rb⁺ and Cs⁺) by UV-visible spectroscopic and cyclic voltammetric techniques. It has been determined that 4a selectively exhibits a significant bathochromic shift in its UV-visible spectrum on interaction with potassium ion in comparison to its treatment with other alkali metal cations. The binding stoichiometry of 4a and potassium ion was established to be 1:1 with an association constant of 3.27 × 10⁴ M^?1. Cyclic voltammetric experiments in 4:1 dichloromethane-acetonitrile also revealed a significant anodic shift (ΔE _(1/1′) = 115 mV) of the original redox waves of 4a on interaction with potassium ion.     

Cation exchange, interlayer spacing, and thermal analysis of Na/Ca-montmorillonite modified with alkaline and alkaline earth metal ions

Na-montmorillonites were exchanged with Li⁺, K⁺, Rb⁺, Cs⁺, Mg²⁺, Ca²⁺, Sr²⁺, and Ba²⁺, while Ca-montmorillonites were treated with alkaline and alkaline earth ions except for Ra²⁺ and Ca²⁺. Montmorillonites with interlayer cations Li⁺ or Na⁺ have remarkable swelling capacity and keep excellent stability. It is shown that metal ions represent different exchange ability as follows: Cs⁺?>?Rb⁺?>?K⁺?>?Na⁺?>?Li⁺ and Ba²⁺?>?Sr²⁺?>?Ca²⁺?>?Mg²⁺. The cation exchange capacity with single ion exchange capacity illustrates that Mg²⁺ and Ca²⁺ do not only take part in cation exchange but also produce physical adsorption on the montmorillonite. Although interlayer spacing d ₀₀₁ depends on both radius and hydration radius of interlayer cations, the latter one plays a decisive role in changing d ₀₀₁ value. Three stages of temperature intervals of dehydration are observed from the TG/DSC curves: the release of surface water adsorbed (36?C84?°C), the dehydration of interlayer water and the chemical-adsorption water (47?C189?°C) and dehydration of bound water of interlayer metal cation (108?C268?°C). Data show that the quantity and hydration energy of ions adsorbed on montmorillonite influence the water content in montmorillonite. Mg²⁺-modified Na-montmorillonite which absorbs the most quantity of ions with the highest hydration energy has the maximum water content up to 8.84%.     

Facilitated Transfer of Alkali Metal Ions by a Tetraester Derivative of Thiacalix[4]arene at the Liquid–Liquid Interface

The facilitated transfer of alkali metal ions (Na⁺, K⁺, Rb⁺, and Cs⁺) by 25,26,27,28‐tetraethoxycarbonylmethoxy‐thiacalix[4]arene across the water/1,2‐dichloroethane interface was investigated by cyclic voltammetry. The dependence of the half‐wave transfer potential on the metal and ligand concentrations was used to formulate the stoichiometric ratio and to evaluate the association constants of the complexes formed between ionophore and metal ions. While the facilitated transfer of Li⁺ ion was not observed across the water/1,2‐dichloroethane interface, the facilitated transfers were observed by formation of 1 : 1 (metal:ionophore) complex for Na⁺, K⁺, and Rb⁺ ions except for Cs⁺ ion. In the case of Cs⁺ a 1 : 2 (metal:ionophore) complex was obtained from its special electrochemical response to the variation of ligand concentrations in the organic phase. The logarithms of the complex association constants, for facilitated transfer of Na⁺, K⁺, Rb⁺, and Cs⁺, were estimated as 6.52, 7.75, 7.91 (log β₁°), and 8.36 (log β₂°), respectively.     

Facilitated Ion‐Transfer of Sodium Cation by (Anthraquinone‐1‐yloxy) methane‐15‐crown‐5 Across the Water/1,2‐Dichloroethane Microinterface

The transfer of sodium cation facilitated by (anthraquinone‐1‐yloxy) methane‐15‐crown‐5 (L) has been investigated at the water/1,2‐dichloroethane microinterface supported at the tip of a micropipette. The diffusion coefficient of (anthraquinone‐1‐yloxy) methane‐15‐crown‐5 obtained was (3.42±0.20)×10^?6 cm² s^?1. The steady‐state voltammograms were observed for forward and backward scans due to sodium ion transfer facilitated by L with 1 : 1 stoichiometry. The mechanism corresponded to an interfacial complexation (TIC) and interfacial dissociation (TID) process. The association constant was calculated to be log β_o=11.08±0.03 in the DCE phase. The association constant of other alkali metals (Li⁺, K⁺, Rb⁺) were also obtained.     

An Imine‐Based Molecular Cage with Distinct Binding Sites for Small and Large Alkali Metal Cations

The synthesis of a cylindrical, imine‐based cage composed of two trimeric metallamacrocycles is described. The cage acts as a heterotopic receptor for alkali metal cations. The small cations Li⁺, Na⁺, and K⁺ bind to the outside of the cage with good selectivity for Li⁺, whereas the larger cations Rb⁺ and Cs⁺ are bound inside the cage to form unusual π complexes with a good selectivity for Cs⁺. Negative heterotopic cooperativity between the two binding sites is observed. The complexation of Cs⁺ is associated with a color change, which enables the cage to be used as a specific sensor for Cs⁺.