Synthesis of novel linear exo-bidentate bispyridine ligands and their complexes with silver(i) tetrafluoroborate

Novel exo-bidentate ligands containing two -pyridyl fragments and their complexes with silver(i) tetrafluoroborate were synthesized.     

FT-Raman Study of Ionic Interactions in Lithium and Silver Tetrafluoroborate Solutions in Acrylonitrile

Solutions of silver and lithium tetrafluoroborate in acrylonitrile, over a range ofconcentrations between 0.5 and 4 mol-kg^–1, have been studied byFourier-transform Raman spectroscopy. The spectral regions studied include the solvent(C=dN) fundamental and the anion B-F symmetric stretching band. In AgBF₄solutions the absence of ionic pairing was demonstrated and the anion ₁(A ₁)remains as a single narrow band located at 764.7±0.1 cm^–1. Consequently, thesilver ion solvation number does not change in the range of concentrations studied,having a constant value of 3.54±0.10. However, a high level of ionic pairingwas observed in the corresponding solutions of LiBF₄. Three components weredetected in the tetrafluoroborate ₁(A ₁) band located at 766.0±0.4, 773.4±1.1,and 782.7±0.9 cm^–1, and assigned to spectroscopically free anions, ion pairs,and dimers, respectively. The solvation number of the lithium ion, which shouldbe three in the limit of infinite dilution, decreases as the salt concentrationincreases as a result of the ionic pairing. However, the ionic pairing of LiBF₄ inacrylonitrile is less than that previously observed in lithiumtrifluoromethanesulfonate (triflate) or lithium perchlorate.     

Characterization of carbon nanotubes and analytical methods for their determination in environmental and biological samples: A review

In the present paper, a critical overview of the most commonly used techniques for the characterization and the determination of carbon nanotubes (CNTs) is given on the basis of 170 references (2000–2014). The analytical techniques used for CNT characterization (including microscopic and diffraction, spectroscopic, thermal and separation techniques) are classified, described, and illustrated with applied examples. Furthermore, the performance of sampling procedures as well as the available methods for the determination of CNTs in real biological and environmental samples are reviewed and discussed according to their analytical characteristics. In addition, future trends and perspectives in this field of work are critically presented.     

Photochemically catalyzed ring opening of oxiranecarbonitriles and [3+2] cycloaddition with olefins: synthesis of polysubstituted tetrahydrofurans

Photoinduced electron transfer catalyzed ring opening of aryl-substituted oxiranecarbonitriles via C_β-O bond cleavage was achieved using 2,4,6-triphenylpyrylium tetrafluoroborate (TPT) as a sensitizer and subsequent [3+2] cycloaddition reaction with electron-rich olefins afforded polysubstituted tetrahydrofurans in good to moderate yields.     

离子液体修饰毛细管胶束电动色谱法分离测定槲皮素、绿原酸和异槲皮甙

建立了一种离子液体(1-乙基-3-甲基咪唑四氟硼酸盐,1E-3M I-TFB)修饰毛细管胶束电动色谱法分离测定异槲皮甙、绿原酸和槲皮素的方法。研究了缓冲溶液的酸度和浓度、牛磺胆酸纳的浓度以及1E-3M I-TFB对分离的影响。分离的最佳条件为:25 mmol/L硼砂-磷酸二氢钾(pH 9.0)-40 mmol/L牛磺胆酸钠-1‰(V/V)1E-3M I-TFB,电压16 kV。在优化条件下,3种分析物在11 m in内可以得到良好的分离。异槲皮甙、绿原酸和槲皮素的峰面积和浓度分别在0.02~0.40、0.02~0.20和0.08~0.60 g/L浓度范围内呈良好的线性;线性相关系数分别为0.9998、0.9988和0.9991;3种物质基于峰面积的相对标准偏差分别为:2.48%,2.56%和3.03%;基于迁移时间的相对标准偏差分别为1.12%、1.46%和1.59%;检出限(S/N=3)分别为:异槲皮甙,0.0050 g/L;绿原酸,0.0045 g/L;槲皮素,0.0040 g/L。将此方法应用于分离测定欧亚旋覆花中的异槲皮甙、绿原酸和槲皮素,取得良好结果。     

离子液体增塑的聚合物电解质

离子液体增塑的聚合物电解质;偏氟乙烯六氟丙烯共聚物;乙基甲基咪唑鎓四氟硼酸盐;微波合成;电学行为     

Synthesis and properties of novel polymers having S-methyldibenzothiophenium salt moieties

A polymer having dibenzothiophenium salt moieties [poly(sulfonium salt), 2 ] was prepared by the reaction of poly(2-vinyldibenzothiophene) ( 1 ) with CH₃I and AgBF₄ in CH₂ClCH₂Cl at room temperature for 24 h. The obtained polymer 2 was found to contain 71% of the methyldibenzothiophenium tetrafluoroborate unit. A monomer carrying the sulfonium salt moiety, i.e., 5-methyl-2-vinyldibenzothiophenium tetrafluoroborate ( 4 ), was independently prepared and subjected to radical polymerization to give a polymer ( 5 ) in 88% yield (methyldibenzothiophenium tetrafluoroborate unit: 79%). The thermal decompositions of 2 and 5 took place in two steps; the first step involved the formation of polymer 1 by demethylation. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1779–1784, 1998     

Solubilities and Ksp Values of the Less Soluble Anion Salts of “Nitron” (1,4-Diphenyl-3-anilino-1,2,4-triazoline)

Abstract

The solubilities and K_sp values at 25°C for the following anion salts of nitron are reported: VO₄ ⁼, Cro₄ ⁼, Cr₂O₇ ⁼,WO₄ ⁼, MoO₄ ⁼, BF₄ ^?, NO₃ ^?, NO₂ ^?, SeO₃ ⁼, S₂O₈ ⁼, SCN^?, Fe(CN)₆ ^?3, Fe(CN)₆ ^?4, Fe(CN)₅NO⁼, I^?, IO₄ ^?, CIO₃ ^?, CIO₄ ^?, BrO₃ ^?, and picrate^?. A total of 58 anions were tested.     

Synthesis of 2-oxazolines and related N-containing heterocycles using [Et2NSF2]BF4 as a cyclodehydration agent

The preparation of 2-oxazolines and related N-containing heterocycles from the corresponding hydroxyamides using XtalFluor-E ([Et₂NSF₂]BF₄) as a cyclodehydration agent is described. A wide range of heterocycles are obtained under mild conditions in good to excellent yields.     

Cloud point measurements of 1-butyl-2,3-dimethylimidazolium tetrafluoroborate with alcohols

Mutual solubility data of imidazolium-based ionic liquid, 1-butyl-2,3-dimethylimidazolium tetrafluoroborate ([bmmim][BF₄]) with the alcohols, 1-propanol, 2-propanol, 1-butanol, 1-pentanol, and 1-hexanol were obtained by a cloud point method. The upper critical solution temperatures of the ionic liquid and alcohol mixtures were determined from the mutual solubility data. The upper critical solution temperature of the binary mixtures gradually increased as the chain length of the alcohol increased. The mutual solubility data of binary systems ([bmmim][BF₄] + alcohols) have been correlated by the original UNIQUAC model as well as the extended and modified form of the UNIQUAC model. The temperature dependence of the mutual solubility data could be represented in terms of the temperature dependence of the binary energy parameters obtained from the correlation. Additionally the influence of water contamination on the ionic liquid mixture was shown experimentally by adding pure water into the binary mixture ([bmmim][BF₄] + 1-butanol).