芘在玻璃基片表面的单层组装及其对有机铜盐的选择性传感

将多环芳烃芘经含三乙基四胺结构的连接臂化学单层组装于玻璃基质表面, 制备了一种荧光薄膜材料. 荧光测量结果表明, 醋酸铜、酒石酸铜、柠檬酸铜等有机铜盐可以显著猝灭薄膜荧光, 而且猝灭过程可逆; 硫酸铜、氯化铜、硝酸铜等无机铜盐对薄膜荧光影响不大; 醋酸锌、醋酸铅、醋酸钴、醋酸镍等其它醋酸盐对有机铜盐的检测影响轻微. 荧光寿命测定表明, 醋酸铜对上述薄膜荧光的猝灭遵循静态猝灭机制.     

Crystal structure of 4,7,13,16,21,24-hexaoxa-1,10-diazoniabicyclo [8.8.8]hexacosane nitrate-hydrogen nitrate perchlorate semihydrate

An adduct of 2.2.2-cryptand with nitric and perchloric acids of the [H₂(Crypt-222)· 0.52H₂O]²⁺·ClO ₄ ^? ·NO ₃ ^? ·HNO₃ composition (I) is prepared and characterized by single crystal X-ray diffraction. The triclinic structure of I (space group \(P\overline 1 \), a = 10.176 Å, b = 11.272 Å, c = 12.870 Å, α = 78.61°, β = 76.62°, γ = 79.88°, Z = 2) is solved by a direct method and refined in the full-matrix anisotropic approximation to R = 0.062 for all 3642 measured independent reflections (CAD-4 automated diffractometer, λMoK _α). The structure of I contains a dication of 2.2.2-cryptand in the endo-endo conformation, two hydrogen atoms at the protonated N atoms are directed inside the cavity which also includes a water molecule with a site occupation factor of 0.52. Tetrahedral ClO ₄ ^? anion in I is disordered. In I, the H atom of the NO ₃ ^? ·HNO₃ dimer is split over two close positions with occupation factors of 0.33 and 0.67; this dimer is joined by a very strong single disordered hydrogen bond N-O-H?O = N between the molecule of nitric acid and its anion.     

Study of the interaction between oxygen and bile salts

The interaction between molecular oxygen and bile salts, previously observed using chemiluminescence techniques, is studied in this paper by electrochemical techniques to further highlight the nature of the interaction. A shift of half-wave potential of the first polarographic wave for the reduction of molecular oxygen was observed in solutions in the presence of bile salts. The shift could be related to different phenomena, such as adsorption of bile salt molecules on the mercury electrode, irreversibility of the oxygen reduction reaction, pH of the solution. Experimental results suggest the exclusion of the above mentioned processes and outline the occurrence of a direct interaction between oxygen and bile salts, where the hydrophobic face of bile salt monomers and/or small aggregates are involved, enhancing so dismutation of superoxide ion produced at the electrode. The presence of bile salts in solutions containing triphenylphosphine oxide, a hydrophobic surfactant, increases also the wave of reduction of molecular oxygen. As a consequence bile salts, beside the well-assessed physiological roles, can behave as oxygen carrier and as antioxidant, preventing the oxidation of biological compounds by superoxide ion.     

New hydrazinium salts of benzene tricarboxylic and tetracarboxylic acids—preparation and their thermal studies

Some new hydrazinium salts of benzene tricarboxylic and tetracarboxylic acids have been prepared by neutralisation of these acids with hydrazine hydrate in aqueous medium and characterised by conductance measurement, IR spectral and thermal analyses. Hemimellitic acid (H₃hml) forms monohydrazinium salt, trimellitic acid (H₃tml) and trimesic acid (H₃tms), mono and dihydrazinium salts, and pyromellitic acid (H₄pml) all the four salts with hydrazine hydrate. Conductance study indicates their electrolytic nature. IR spectra of all the salts show NN stretching frequencies of the N₂H₅⁺ in the region of 960-990 cm⁻¹. The hemimellitate salt undergoes endothermic dehydrazination at 154 °C, trimellitates and pyromellitates in the range of 191-271 °C, and trimesates in the range of 267-332 °C. Trimesates decompose to give CO₂ around 337 °C. All the salts then undergo strong exothermic decomposition in the range of 517-595 °C via the formation of respective acid intermediates first, then arenes, yielding carbon residue. A comparison of the thermal behaviour of pure acids with that of their salts reveals the fact that the acids do not withstand high temperature like salts. They show sharp endotherms at their melting points and then they decompose exothermally before 400 °C to give carbon residue.     

锕系元素在熔盐体系中的电化学及萃取特性研究进展

熔融盐是一类非水溶剂,分为高温熔盐、室温熔盐和低温熔盐。 作为反应介质和电解介质,因其优良性能,可以溶解很多难溶于水的活泼金属。 近年来,该领域的研究热点是将熔盐作为干法后处理的电解质分离和回收锕系元素。 本文综述了锕系元素在高温熔盐中的电化学行为、热力学等物理特性,介绍了近几年室温离子液体(RTILs)的研究进展及锕系元素在RTILs中萃取特性的最新研究成果,展望了熔盐体系未来的研究方向。     

Polyfluoroorganotrifluoroborates and -difluoroboranes: interesting materials in fluoroorgano and fluoroorgano-element chemistry

The aimed introduction of the polyfluoroorgano groups (4-C₅F₄N), C₆F₁₃C₂H₄, and C₂F₅ into methoxy group-containing boron electrophiles is reported. The new compounds obtained after transformations K[(4-C₅F₄N)BF₃], (4-C₅F₄N)BF₂, K[C₆F₁₃C₂H₄BF₃], C₆F₁₃C₂H₄BF₂, K[(C₂F₅)₂B(OMe)₂], and K[(C₂F₅)₂BF₂] were isolated and characterised. Additionally some of their precursors as there are Li(4-C₅F₄N), Li[(4-C₅F₄N)B(OMe)₃], (4-C₅F₄N)B(OH)₂ and the by-products Li[(4-C₅F₄N)₂B(OMe)₂], (4-C₅F₄N)₂BOH, and K[(4-C₅F₄N)₂BF₂] are described. The usefulness of polyfluoroorganodifluoroboranes for introducing polyfluoroorgano groups into hypervalent FEF bonds is demonstrated by the synthesis of [C₆F₅(4-C₅F₄N)I][BF₄] and [p-FC₆H₄(trans-CF₃CFCF)I][BF₄].     

A viscometric study of tuning micellar morphology by organic additives

The micellar morphology in aqueous 0.2 M sodium dodecyl sulfate (SDS) solutions has been studied in the simultaneous presence of organic salts (anilinium hydrochloride, AHC; ortho-toluidine hydrochloride, oTHC; para-toluidine hydrochloride, pTHC) and aliphatic alcohols (n-butanol, C₄OH; n-pentanol, C₅OH; n-hexanol, C₆OH; n-heptanol, C₇OH), aliphatic amines (n-butylamine, C₄NH₂; n-pentylamine, C₅NH₂; n-hexylamine, C₆NH₂; n-heptylamine, C₇NH₂), or hydrocarbons (n-hexane, C₆H; n-heptane, C₇H) by viscosity measurements under Newtonian flow conditions at 30 °C. Addition of alcohols and amines causes micellar growth which is found to be dependent upon chain length of the additive and nature of organic salt counterion. It is observed that amines are more effective in increasing the viscosity of the system if added in pure 0.2 M SDS solution, while SDS + pTHC system was found versatile when alcohols were added to this system. The increased viscosity or the micellar growth is explained in terms of the site of solubilization of the respective additive and the interaction of the additive with micellar surface and salt counterion present in the head group region. Hydrocarbons are nearly ineffective in inducing micellar growth and can be used as ‘micellar destroyer’ for the grown micelles. The additives used are found effective in tuning the environment of the micelle which is reflected in viscosity behavior. This work may find use in micellar ultrafiltration as well as in mimicking the natural cell, which has several aspects common with the micelle.     

Regioselectivity in 2-X-pyrazine aminations by O-mesitylenesulfonylhydroxylamine

The regioselectivity of 2-X-pyrazine aminations by O-mesitylenesulfonylhydroxylamine was studied experimentally and the results are discussed from the viewpoint of electronic and steric factors. DFT calculations are consistent with the reaction proceeding according to an S_N2 mechanism.     

Crystal structure of 1,3-dialkyldiazolium bromides

Systematic X-ray diffraction study of the crystal structures of 1,3-dialkylimidazole-based ionic liquids containing the Br⁻ anion was performed. Analysis of the influence of the nature of the cation on the formation of a hydrogen bond system and the supramolecular arrangement of ions demonstrated that not only CH⋯Br contacts but also anion—π-system and CH—π-system interactions exist in the crystalline state. Conclusions were drawn on the character of changes in the melting point in a series of bromide ionic liquids containing the imidazolium cation. Dedicated to Academician O. M. Nefedov on the occasion of his 75th birthday. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 1916–1925, November, 2006.     

Activity and Osmotic Coefficients from the Emf of Liquid Membrane Cells. X. Tris(Ethylenediamine) Cobalt(III) Nitrate, Perchlorate, and Chloride

Activity coefficients of [Co(en)₃](NO₃)₃ and [Co(en)₃](ClO₄)₃, to be compared with [Co(en)₃]Cl₃ and the corresponding lanthanum salts previously studied, are determined. [Co(en)₃]Cl₃ data are revised. Ion interaction strengths vary in the same order found for La³⁺, i.e., as if nitrate and perchlorate ions were of smaller and larger size, respectively, than chloride ions; however, the differences are much smaller than in lanthanum salts. Tris(ethylenediamine)cobalt III and lanthanum nitrate, chloride, and perchlorate—like the corresponding hexacyanoferrate(III) and hexacyanocobaltate(III) salts, but contrary to sulfate salts—behave as if [Co(en)₃]³⁺ were smaller in size than La³⁺. In the dilute regions, [Co(en)₃](NO₃)₃ displays negative deviations from the limiting slope, a kind of behavior typical for 2:2, 2:3, 3:2, and 3:3 electrolytes, but unnoticed earlier for 3:1 or 1:3 electrolytes. Pitzer's equation parameters able to provide accurate activity and osmotic coefficients for [Co(en)₃](NO₃)₃, [Co(en)₃](ClO₄)₃, and, revised, [Co(en)₃]Cl₃ are reported.