Lewis acid InBr3-catalyzed arylation of diorgano diselenides and ditellurides with arylboronic acids.

A novel Lewis acid InBr3-catalyzed direct cross-coupling reaction of arylboronic acids with diorgano diselenides and ditellurides without any additive has been developed. The reactions generated the corresponding unsymmetrical diorgano monoselenides and monotellurides in good to excellent yields. The method has advantages of broad substrate scope, simple operation, mild reaction conditions and high effectiveness.

Recyclable Merrifield resin-supported organocatalysts containing pyrrolidine unit through A3-coupling reaction linkage for asymmetric Michael addition.

Merrifield resin-supported pyrrolidine-based chiral organocatalysts A-D through A(3)-coupling reaction linkage have been developed and found to be highly effective catalysts for the Michael addition reaction of ketones with nitrostyrenes. The reactions generated the corresponding products in good yields (up to 92%), excellent enantioselectivities (up to 98% ee), and high diastereoselectivities (up to 99:1 dr). In addition, the catalysts can be reused at least five times without a significant loss of catalytic activity and stereoselectivity.

Indium-catalyzed highly efficient three-component coupling of aldehyde, alkyne, and amine via C-H bond activation.

In this paper, indium(III) chloride was found to be a highly effective catalyst for the three-component coupling reactions of aldehydes, alkynes, and amines (A(3)-coupling) via C-H activation. The reactions could be applied to both aromatic and aliphatic aldehydes and alkynes. Nearly quantitative yields of the desired products were obtained in most cases.

Iron-catalyzed ligand-free three-component coupling reactions of aldehydes, terminal alkynes, and amines.

A tri-umph in many respects: The iron-catalyzed ligand-free, one-pot three-component coupling reactions of aldehydes, terminal alkynes, and amines in the presence of 4 A molecular sieves yields the corresponding propargylamines in good to excellent yields, displays a broad substrate scope, and is economical and environmentally friendly (see scheme).

Synthesis of amido black diazoaminoazobenzene and its application to the spectrophotometric determination of micrograms of cadmium.

A new azoamino reagent amido black diazoaminoazobenzene (ABDAB) has been synthesized, and found to be a good chromogenic reagent for cadmium. In pH 10.4 Na(2)B(4)O(7)NaOH buffer solution cadmium reacts with ABDAB to form an orange-red chelate (1:2), exhibiting an absorption maximum at 520 nm.

Asymmetric aldol reactions catalyzed by efficient and recyclable silica-supported proline-based peptides.

A series of silica-supported proline-based peptides were synthesized and applied as catalysts for direct asymmetric intermolecular aldol reactions. Among these, a peptide with two L-proline units was found to be the most efficient one for the asymmetric aldol reactions between acetone and aromatic aldehydes. The reactions generated the corresponding products with satisfactory isolated yields (up to 97%) and enantiomeric excesses (up to 96%) in the presence of this catalyst (5 mol %).

[The spectroscopic study on the interaction between edible pigment and human serum albumin in two-phase aqueous systems].

In polyethylene glycol 2000 (PEG)-(NH4)2SO4-edible pigment two-phase aqueous systems, the spectroscopic behaviour of the complexes of edible pigment and human serum albumin in PEG phase was investigated. Effects of different acidity, quantities of PEG and salt, reaction time, and coexistent matter on the determination of systems were discussed. Experimental results show that compared to BS spectra, the maximum wavelength of the complex of human serum albumin shifted to the red by 13 nm in buffer solution at pH 8, the maximum binding number of 40 was measured by molar ratio method, and the apparent molar absorptivity was 9.

[Study on determination of trace nitrite and reaction mechanism by two-wavelength negative absorption-catalytic spectrophotometry].

A new method was proposed for the determination of trace nitrite by two wavelength negative absorption catalytic spectrophotometry based on the catalysis of nitrite on the oxidation fading reaction of acridine orange by potassium bromate in phosphoricacid medium. The additive value of negative absorbances at two wavelengths was linear to the nitrite concentration in the range of 1.0 x 10(-5)-5.

[The spectroscopic behaviour and extraction separation of Cu(II), La(III), U(VI) and Ce(IV) in two-phase aqueous systems].

In polyethylene glycol 2000 (PEG)-(NH4)2 SO4-extractant (sodium diethyldithiocarbamate, DDC) two-phase aqueous systems, spectroscopic behaviour of complexes of Cu(II), La(III), U(VI) and Ce(IV) with DDC as the extractant in PEG phase and general water phase was investigated. Comparing to DDC spectrophotometry, the new method has the advantage that the maximum wavelength of complex of Cu(II) shifts to red wavelength. Extraction mechanism and existing form of complexes of metal ions in PEG phase were studied.

[Determination of 2,4-dinitrochlorobenzene in environmental water by primary-secondary wavelengths new spectrophotometry].

In basic solution, dinitrochlorobenzene may react on pyridine to form a purplish red compound. In this paper with the absorption property of a suspended liquid against light a new analytical method as primary-secondary wavelengths spectrophotometry was studied to determine trace dinitrochlorobenzene in environmental water. In 0-50 microg dinitrochlorobenzene/25 mL, the calculation curve is very stable and hardly affected by environment conditions.

The Sonogashira coupling reaction catalyzed by ultrafine nickel(0) powder.

The Sonogashira coupling reaction catalyzed by ultrafine nickel(0) powder has been developed; terminal alkynes couple with aryl, alkenyl iodide and aryl bromide in the presence of cuprous iodide, triphenylphosphine, potassium hydroxide and ultrafine particle nickel(0) to provide the corresponding cross-coupling products with high yields.

[Determination of trace amounts of nitrite and reaction mechanism by triple-wavelength spectrophotometry].

A new method was proposed for the determination of nitrite ion by triple-wavelength spectrophotometry. This limits ranges of determination are 0-0.560 mg.

[Spectrophotometric determination of nitrite ion with acridine red based on the nitrosation reaction].

A new spectrophotometric method for the determination of nitrite ion was studied. The method is based on the nitrosation reaction of acridine red with nitrite ion in hydrochloric acid medium. The decolorization of acridine red by the reaction with nitrite was used to spectrophotometric determination at 525 nm.

[Study on the separation and spectroscopic characteristics of titanium and lauthanum in two-phase aqueous systems].

In Polyethylene glycol-ammonium sulfate-chrome azurol S two-phase aqueous systems, the liquid-liquid extraction behavior of Ti(IV), Zr(IV) and La(III) with chrome azurol S as the extractant was investigated. Experimental result indicated that the complex of La(III) with CAS was almost completely extracted by the PEG phase, Zr(IV) partly extracted, while Ti(IV) was not extracted from the aqueous solution of pH 4.5-7.