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A novel effervescence-assisted dispersive liquid-liquid microextraction method has been developed for the determination of four fungicides in apple juice samples. In this method, a solid effervescent agent is added into samples to assist the dispersion of extraction solvent. The effervescent agent is environmentally friendly and only produces an increase in the ionic strength and a negligible variation in the pH value of the aqueous sample, which does not interfere with the extraction of the analytes. The parameters affecting the extraction efficiency were investigated including the composition of effervescent agent, effervescent agent amount, formulation of effervescent agent, adding mode of effervescent agent, type and volume of extraction solvent, and pH. Under optimized conditions, the method showed a good linearity within the range of 0.05-2 mg/L for pyrimethanil, fludioxonil, and cyprodinil, and 0.1-4 mg/L for kresoxim-methyl, with the correlation coefficients >0.998. The limits of detection for the method ranged between 0.005 and 0.01 mg/L. The recoveries of the target fungicides in apple juice samples were in the range of 72.4-110.8% with the relative standard deviations ranging from 1.2 to 6.8%.

The simultaneous determination of four strobilurin fungicides (picoxystrobin, kresoxim-methyl, trifloxystrobin, and azoxystrobin) in cotton seed by combining acetonitrile extraction and dispersive liquid-liquid microextraction was developed prior to GC with electron capture detection. Several factors, including the type and volume of the extraction and dispersive solvents, extraction condition and time, and salt addition, were optimized. The analytes were extracted with acetonitrile from cotton seed and the clean-up was carried out by primary secondary amine. Afterwards, 60 μL of n-hexane/toluene (1:1, v/v) with a lower density than water was mixed with 1 mL of the acetonitrile extract, then the mixture was injected into 7 mL of distilled water. A 0.1 mL pipette was used to collect a few microliters of n-hexane/toluene from the top of the aqueous solution. The enrichment factors of the analytes ranged from 36 to 67. The LODs were in the range of 0.1 × 10(-3) -2 × 10(-3) mg/kg. The relative recoveries varied from 87.7 to 95.2% with RSDs of 4.1-8.5% for the four fungicides. The good performance of the method, compared with the conventional pretreatments, has demonstrated it is suitable for determining low concentrations of strobilurin fungicide residues in cotton seed.

Novel lanthanide selenidostannate polymers containing the soft-base Sn2Se6 ligand, (H3O)n[La(tepa)(μ-1κ2:2κ2-Sn2Se6)]n (1), [{Nd(tepa)(μ-OH)}2(μ-1κ:2κ-Sn2Se6)]n (2), and [{Gd(tepa)(μ-OH)}2(μ-1κ:2κ-Sn2Se6)]n·nH2O (3) (tepa = tetraethylenepentamine) were prepared by treating lanthanide oxides with Sn and Se using pentadentate polyamine tepa as a second ligand under solvothermal conditions. In 1, the La3+ ion is coordinated by a tepa ligand to form an unsaturated [La(tepa)]3+ unit, and the [Sn2Se6]4– anion acts as a tetradentate bridging ligand with four terminal Se atoms to connect the [La(tepa)]3+ units into a coordination polymeric anion [La(tepa)(μ-1κ2:2κ2-Sn2Se6)–]n. The μ-1κ2Se1,Se2:2κ2Se5,Se6 bridging mode in 1 is a new coordination mode for the Sn2Se6 unit to LnIII centers. In 2 and 3, the lanthanide ion is coordinated by a tepa ligand, and two [Ln(tepa)]3+ (Ln = Nd, Gd) ions are joined by two μ-OH bridges to form dinuclear cations. Behaving as a bidentate μ-Sn2Se6 ligand with the trans-terminal Se atoms, the Sn2Se6 units connect the [{Ln(tepa)(μ-OH)}2]4+ cations into neutral coordination polymers [{Ln(tepa)(μ-OH)}2(μ-Sn2Se6)]n. The coordination modes μ-1κ2Se1,Se2:2κ2Se5,Se6 in 1 and μ-1κSe1:2κSe5 in 2 and 3 are related to the metal size of the lanthanide(III) ions. In addition, as an ethylenepolyamine with higher denticity, the pentadentate tepa exhibits a significantly different influence on the structures of the solvothermally synthesized Ln selenidostannates compared to the bidentate ethylenediamine and tridentate diethylenetriamine. Compounds 1–3 are semiconductors with well-defined band gaps of 1.95–2.34 eV.

The lanthanide selenidogermanates [{Eu(en)3}2(μ-OH)2]Ge2Se6 (1), [{Ho(en)3}2(μ-OH)2]Ge2Se6 (2), and [{Ho(dien)2}2(μ-OH)2]Ge2Se6 (3) (en = ethylenediamine, dien = diethylenetriamine) were solvothermally prepared by the reactions of Eu2O3 (or Ho2O3), germanium, and selenium in en and dien solvents respectively. Compounds 1–3 are composed of selenidogermanate [Ge2Se6]4– anion and dinuclear lanthanide complex cation [{Ln(en)3}2(μ-OH)2]4+ (Ln = Eu, Ho) or [{Ho(dien)2}2(μ-OH)2]4+. The [Ge2Se6]4– anion is composed of two GeSe4 tetrahedra sharing a common edge. The dinuclear lanthanide complex cations are built up from two [Ln(en)3]3+ or [Ho(dien)2]3+ ions joined by two μ-OH bridges. All lanthanide(III) ions are in eight-coordinate environments forming distorted bicapped trigonal prisms. In 1–3, three-dimensional supramolecular networks of the anions and cations are formed by N–H···Se and N–H···O hydrogen bonds. To the best of our knowledge, 1–3 are the first examples of selenidogermanate salts with lanthanide complex counter cations.

A one-pot three-component reaction of 2-naphthol, aldehyde, urea or amide catalyzed by the molybdophosphoric acid (heteropolyacid) to afford 1-amidoalkyl-2-naphthols is described, which is high yield with simple work-up.

The new selenidostannates (IV) and (V) are hydrothermally synthesized in the presence or absence of KSCN, respectively.

In aqueous solution, Co2+ and Ni2+ ions can be coordinated not only by polyamines but also by As2S3 or AsS3 units as in (III) and (IV).

The first selenidogermanate salts with lanthanide complex counter cations (IVa, b) and (V) crystallize in the monoclinic space group P21/n with Z = 2.

Manganese triacetate was introduced as a new reagent for radical cyclization of substituted aminothioureas. Bis-(1,2,4-triazolyl)-3-disulfides were generated in 10 min under microwave irradiation.

A simple method for the synthesis of 3-aryl-1,5-bis(2-hydroxyaryl)pentane-1,5-diones is developed by one-pot reaction involving 2-hydroxyacetophenone and arylaldehyde in aqueous potassium hydroxide.