溴代1-己基-3-甲基咪唑离子液体与丙酮的相互作用

1H and 13C NMR chemical shifts were determined to investigate the interactions of acetone with a room temperature ionic liquid 1-hexyl-3- methylimidazolium bromide C6mimBr at various mole fractions. Changes in chemical shifts of hydrogen nuclei and of carbon nuclei with the acetone concentration indicated the formation of hydrogen bond between anion of the ionic liquid and methyl protons of acetone. The NMR results were in good agreement with the ab initio computational results.     

1-甲基-3-己基咪唑碘的合成及在染料敏化太阳电池中的应用

利用高压釜使1-甲基咪唑和碘代正己烷直接反应生成离子液体1-甲基-3-己基咪唑碘, 并考察了温度对反应的影响. 结果表明, 升高反应温度, 可使1-甲基咪唑和碘代正己烷按化学计量比进行反应, 产率近100%, 该方法操作简单, 所得产品纯度高, 反应过程不需要使用有机溶剂, 且对环境友好. 同时还测量了I-3在1-甲基-3-己基咪唑碘和1-甲基咪唑混合液中的表观扩散系数及其所组成的染料敏化太阳电池的光伏性能.     

Enhancement of oxygen and methane solubility in 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide using carbon dioxide

The presence of CO(2) increases the solubility of O(2) and CH(4) in 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide at 25 degrees C and pressures to 13 bar.     

Low-temperature heat capacity of room-temperature ionic liquid, 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide

Heat capacities of liquid, stable crystal, and liquid-quenched glass of a room-temperature ionic liquid (RTIL), 1-hexyl-3-methylimidazolium bis(trifluromethylsulfonyl)imide were measured between 5 and 310 K by adiabatic calorimetry. Heat capacity of the liquid at 298.15 K was determined for an IUPAC project as (631.6 +/- 0.5) J K(-1) mol(-1). Fusion was observed at T(fus) = 272.10 K for the stable crystalline phase, with enthalpy and entropy of fusion of 28.34 kJ mol(-1) and 104.2 J K(-1) mol(-1), respectively. The purity of the sample was estimated as 99.83 mol % by the fractional melting method. The liquid could be supercooled easily and the glass transition was observed around T(g) approximately 183 K, which was in agreement with the empirical relation, T(g) approximately ((2)/(3)) T(fus). The heat capacity of the liquid-quenched glass was larger than that of the crystal as a whole. In the lowest temperature region, however, the difference between the two showed a maximum around 6 K and a minimum around 15 K, at which the heat capacity of the glass was a little smaller than that of crystal.     

Solubility and thermodynamic properties of acetaminophen in 1-hexyl-4-methylpyridinium bromide and water mixtures

The solubility data of acetaminophen in binary mixtures of 1-hexyl-4-methylpyridinium bromide and water were obtained over the temperature range from 293.15 to 313.15 K by using the gravimetric method under atmospheric pressure. Using the experimentally measured solubility values, the thermodynamic properties of dissolution, mixing and transfer processes were evaluated. The measured solubilities were correlated by the modified Wilson and the electrolyte non-random two liquid (E-NRTL) models.     

Synthesis and Photophysical Properties of 3,6-Diphenyl-9-hexyl-9H-carbazole Derivatives Bearing Electron Withdrawing Groups

3,6-Diphenyl-9-hexyl-9H-carbazole derivatives bearing electron withdrawing groups, such as the formyl or the nitro-group in 4-positions of the phenyl substituents, were prepared and characterized. Their photophysical properties were evaluated and compared with those of the unsubstituted counterpart 3,6-diphenyl-9-hexyl-9H-carbazole. The electron withdrawing groups bearing compounds exhibited considerable red shifts of the absorption and the emission maxima. While 3,6-di(4-nitrophenyl)-9-hexyl-9H-carbazole emitted in the orange region of the visible spectrum with its emission maximum peaking at 585 nm, 3,6-di(4-formylphenyl)-9-hexyl-9H-carbazole gave a pure blue emission with a luminescence quantum yield of 95% peaking at 450 nm. Observed features were explained using quantum mechanical calculations and organic light emitting diodes using the formylphenyl substituted compound as emissive layer were built demonstrating the practical applicability of this class of compounds.     

Ipso-nitration of carboxylic acids using a mixture of nitronium tetrafluoroborate,base and 1-hexyl-3,4,5-trimethyl-1H-imidazolium tetrafluoroborate

An eco-friendly and a simple ipso-nitration protocol for a series of aliphatic and (hetero)aromatic carboxylic acids using nitronium tetrafluoroborate, 1-hexyl-3,4,5-trimethyl-1H-imidazolium tetrafluoroborate and base is reported. While contrasted with recently known decarboxylative ipso-nitration strategies for the preparation of nitro compounds, this protocol does not require a toxic metal catalyst and harmful volatile organic solvents. Moreover, this method is perfect for a broad range of functional groups and affords exclusively the ipso-nitrated product in moderate to good yields.     

Long-chain dicarboxylic acids : II. Precipitation of aqueous 5-(and 6-)carboxy-4-hexyl-2-cyclohexen-1-yl octanoic acid solutions with metal ions

Aqueous dispersions of heavy-metal salts of 5-(and 6-)carboxy-4-hexyl-2-cyclohexen-1-yl octanoic acids, denoted by H₂D, were prepared by direct mixing of solutions of the metal nitrates with solutions of Na₂D. With any particular concentration of D²⁻ ion, it was found that the turbidity increased sharply when the concentration of a metal ion exceeded a certain value. This transition from low to high turbidity defined the boundary between stable and unstable soap suspensions, and the concentration of the added salt at which it occurred was labeled as critical transition concentration (ctc). Complete domains, showing the ctc values for different concentrations of dicarboxylate for thallium(I), magnesium, calcium, and lanthanum counterions, have been given. These transition boundaries are strongly dependent on pH. The mixing of calcium and lanthanum nitrates with a solution of Na₂D gave a suspension of solid particles, whereas immediate spontaneous emulsification occurred when thallium(I) and magnesium nitrates were used.     

Synthesis and Photophysical Properties of 3,6-Diphenyl-9-hexyl-9<Emphasis Type="Italic">H</Emphasis>-carbazole Derivatives Bearing Electron Withdrawing Groups

Summary. 3,6-Diphenyl-9-hexyl-9H-carbazole derivatives bearing electron withdrawing groups, such as the formyl or the nitro-group in 4-positions of the phenyl substituents, were prepared and characterized. Their photophysical properties were evaluated and compared with those of the unsubstituted counterpart 3,6-diphenyl-9-hexyl-9H-carbazole. The electron withdrawing groups bearing compounds exhibited considerable red shifts of the absorption and the emission maxima. While 3,6-di(4-nitrophenyl)-9-hexyl-9H-carbazole emitted in the orange region of the visible spectrum with its emission maximum peaking at 585 nm, 3,6-di(4-formylphenyl)-9-hexyl-9H-carbazole gave a pure blue emission with a luminescence quantum yield of 95% peaking at 450 nm. Observed features were explained using quantum mechanical calculations and organic light emitting diodes using the formylphenyl substituted compound as emissive layer were built demonstrating the practical applicability of this class of compounds.     

Effect of water, methanol, and acetonitrile on solvent relaxation and rotational relaxation of coumarin 153 in neat 1-hexyl-3-methylimidazolium hexafluorophosphate

The dynamics of solvent relaxation in ionic liquid (IL)-water, IL-methanol, and IL-acetonitrile mixtures have been investigated using steady state and picosecond time-resolved fluorescence spectroscopy. We have used Coumarin 153 (C-153) and 1-hexyl-3-methylimidazolium hexafluorophosphate ([hmim][PF(6)]) as fluorescence probe and IL, respectively. The steady-state emission spectra showed that the gradual addition of cosolvents increases the polarity of the mixtures. In neat [hmim][PF(6)] and all IL-cosolvent mixtures, solvation occurs in two well-separated time regimes within the time resolution of our instrument. A substantial portion of the solvation has been missed due to the limited time resolution of our instrument. The gradual addition of cosolvents decreases the viscosity of the medium and consequently solvation time also decreases. The decrease in solvation time is more pronounced on addition of acetonitrile compared to water and methanol. The rotational relaxation time of the probe is also decreasing with gradual addition of the cosolvents. The decrease in viscosity of the solution is responsible for the decrease in the rotational relaxation time of the probe molecule.     

反气相色谱法测定离子液体1-己基-3-甲基咪唑三氟甲磺酸盐的热力学参数

采用反气相色谱法研究了343.15~373.15 K温度范围内离子液体1-己基-3-甲基咪唑三氟甲磺酸盐([HMIM]OTF)的热力学参数。根据18种探针溶剂的保留时间计算出探针溶剂与[HMIM]OTF之间的摩尔吸附焓、无限稀释的摩尔混合焓、摩尔蒸发焓、质量部分活度系数、Flory-Huggins相互作用参数及[HMIM]OTF的溶解度参数。结果表明,所选溶剂中正构烷烃、四氢呋喃、乙醚、环己烷和苯为[HMIM]OTF的不良溶剂;二氯甲烷、丙酮、氯仿、乙酸乙酯、四氯化碳、乙酸甲酯、甲苯和甲醇为[HMIM]OTF的良溶剂;运用外推法得到了室温(298.15 K)时[HMIM]OTF的溶解度参数为20.74 (J/cm³)^0.5。本研究为离子液体的应用及相关工作提供了参考。     

Thermophysical properties of 1-hexyl-3-methyl imidazolium based ionic liquids with tetrafluoroborate, hexafluorophosphate and bis(trifluoromethylsulfonyl)imide anions

The thermophysical properties of 1-hexyl-3-methyl imidazolium based hydrophobic room temperature ionic liquids (RTILs); with tetrafluoroborate (BF₄), hexafluorophosphate (PF₆), and bis(trifluoromethylsulfonyl)imide (Tf₂N) anions, namely density ρ (298.15 to 348.15) K, dynamic viscosity η (288.2 to 348.2) K, surface tension σ (298.15 to 338) K, and refractive index n_D (302.95 to 332.95) K have been measured. The coefficients of thermal expansion α_p values were calculated from the experimental density data using an empirical correlation. The thermal stability of all ILs is also investigated at two different heating rates (10 and 20) °C · min⁻¹) using thermogravimetric analyzer (TGA). The experimental results presented in this study reveal that the choice of anion type shows the most significant effect on the properties of ILs. The chloride and water contents of ILs (as impurities) are also investigated and reported in the present work.     

Conformations of the Ten-membered Ring in 5, 10-Secosteroids. III: (Z)-3β- and (Z)-3α-Hydroxy-5, 10-seco-1 (10)-cholesten-5-one Esters and (Z)-5, 10-seco-1 (10)-Cholestene-3, 5-dione

(Z)-3β-Acetoxy- and (Z)-3 α-acetoxy-5, 10-seco-1 (10)-cholesten-5-one ( 6a ) and ( 7a ) were synthesized by fragmentation of 3β-acetoxy-5α-cholestan-5-ol ( 1 ) and 3α-acetoxy-5β-cholestan-5-ol ( 2 ), respectively, using in both cases the hypoiodite reaction (the lead tetraacetate/iodine version). The 3β-acetate 6a was further transformed, via the 3β-alcohol 6d to the corresponding (Z)-3β-p-bromobenzoate ester 6b and to (Z)-5, 10-seco-1 (10)-cholestene-3, 5-dione ( 8 ) (also obtainable from the 3α-acetate 7a ). The ¹H-and ¹³C-NMR. spectra showed that the (Z)-unsaturated 10-membered ring in all three compounds ( 6a , 7a and 8 ) exists in toluene, in only one conformation of type C ₁, the same as that of the (Z)-3β-p-bromobenzoate 6b in the solid state found by X-ray analysis. The unfavourable relative spatial factors (interdistance and mutual orientation) of the active centres in conformations of type C ₁ are responsible for the absence of intramolecular cyclizations in the (Z)-ketoesters 6 and 7 ( a and c ).     

(10Z)- and (10E)-19-fluoro-1alpha,25-dihydroxyvitamin D3: an improved synthesis via 19-nor-10-oxo-vitamin D

An efficient synthetic route to (10Z)- and (10E)-19-fluoro-1alpha,25-dihydroxyvitamin D3 was developed. The key feature of this pathway is the introduction of a 19-fluoromethylene group to a (5E)-19-nor-10-oxo-vitamin D derivative. The 10-oxo-compound was obtained via a 1,3-dipolar cycloaddition reaction of (5E)-1alpha,25-dihydroxyvitamin D with in situ generated nitrile oxide followed by ring cleavage of the formed isoxazoline moiety with molybdenum hexacarbonyl. Conversion of the keto group of (5E)-19-nor-10-oxo-vitamin D to the E and Z fluoromethylene group was achieved through a two-step sequence involving a reaction of lithiofluoromethyl phenyl sulfone followed by the reductive desulfonylation of the alpha-fluoro-beta-hydroxy sulfone. The dye-sensitized photoisomerization of the (5E)-19-fluorovitamin D afforded the desired (5Z)-19-fluorovitamin D derivatives, (10Z)- and (10E)-19-fluoro-1alpha,25-dihydroxyvitamin D3.     

反式-9, 10-二氢-9, 10-二(1-萘基)-9, 10-菲二醇的包合现象 与晶体结构

按文献方法合成了一个螯形主体分子,反式-9,10-二氢-9,10-二(1-萘基)-9,10-菲二醇。研究发现该主体可以和一些含氮杂环化合物形成一定比例的晶体包合物。用X-射线衍射分析二环己胺包合物的晶体结构表明,包合物中主客体之间存在O-H…N氢键相互作用,客体分子包合在主体分子形成的空腔中。     

Densities and dynamic viscosities of the binary system (water + 1-hexyl-3-methylimidazolium bromide) at different temperatures

Densities and viscosities were measured for pure ionic liquid [C₆mim][Br] (1-hexyl-3-methylimidazolium bromide) and the binary system (water + [C₆mim][Br]) at 0.1 MPa and in the (293.15 to 333.15) K range. The excess molar volume and viscosity deviation were calculated and correlated by Redlich–Kister polynomial expansions. The fitting parameters and the standard deviations were determined.     

Evidence for homo-conjugation between two revolving 14pi-electron systems in 10b-methyl-10c-[2-(10b,10c-dimethyl-10b,10c-dihydropyrenyl)]-10b,10c-dihydropyrene

Ring contraction followed by an elimination reaction on anti-9-methyl-18-trans-2-(10b,10c-dimethyl-10b,10c-dihydropyrenyl)-2,11-dithia[3,3]metacyclophane gave the desired compound 10b-methyl-10c-[2-(10b,10c-dimethyl-10b,10c-dihydropyrenyl)]-10b,10c-dihydropyrene. 1H NMR spectroscopic analysis indicated a ring current effect over a considerable distance from the macro-molecular plane of each of the aromatic rings with the two pi systems freely rotating. Bathochromic shifts and peak broadening in its electronic spectrum clearly supports the presence of through-space pi-pi interactions between the two aromatic rings. This should serve as a good model to verify homo-conjugation effect in such a novel system where the two pi systems are freely revolving.     

Determination of 5-(3-Chlorophenyl)-4-hexyl-2,4-dihydro-3H-1,2,4-triazole-3-thione in Mouse Brain Tissue by Microwave-Assisted Extraction and High-Performance Liquid Chromatography with Fluorescence Detection

A sensitive and selective method was developed for the determination of 5-(3-chlorophenyl)-4-hexyl-2,4-dihydro-3H-1,2,4-triazole-3-thione (TP-315), an antiepileptic compound, in the tissue homogenate of mouse brains by microwave-assisted extraction and high performance liquid chromatography with fluorescence detection by use of an external standard. The analyses were performed on a C₁₈ column using a mobile phase consisting of 60% acetonitrile in water. Fluorescence detection was performed at an excitation wavelength of 263 nm and an emission wavelength of 411 nm. The method provided a high extraction yield with recoveries exceeding 90%. The precision values expressed by intra- and inter-day relative standard deviations were lower than 5%. The validated procedure was employed to develop a brain concentration profile after intraperitoneal administration of a single oral dose equal to 300 mg per kg of body weight. The time to the maximum anticonvulsant action of TP-315 in a mouse maximal electroshock-induced seizure test was 30 min after administration.     

Potentiometric and theoretical studies of the carbonate sensors based on 3-bromo-4-hexyl-5-nitrotrifluoroacetophenone

Novel carbonate ionophore, trifluoroacetophenone derivative (TFA) substituted by two acceptor substituents in the phenyl ring (3-bromo-4-hexyl-5-nitrotrifluoroacetophenone), was synthesized. Solvent polymeric membrane sensors based on this ionophore exhibited heightened selectivity to carbonate ions in the presence of the most important interfering anions. A wide range of potentiometric properties were studied and compared with those of sensors based on mono-substituted ionophores. Special attention was paid to pH dependence of sensor responses and to elaboration of appropriate conditions for carbonate analysis. A segmented-sandwich membrane method was applied for determination of the stoichiometry of ionophore-carbonate complexes, which was determined to be 1:3, and apparent complex formation constants which were 14.4 and 13.6 for DOS- and NPOE-plasticized membranes, respectively. Theoretical studies on TFA derivatives by semi-empirical (AM1 and PM3) and ab initio(6-31+G*) methods were performed, considering different types of possible ionophore-ion interactions. The formation of hydrogen bonds between carbonate and hydrated TFA was proved to be much more favourable in terms of energy compared to tetrahedral nucleophilic adducts that earlier were postulated to being formed in the membrane phase. The final conclusion on the mechanism of carbonate sensing by TFA-based solvent polymeric membrane sensors was made on the basis of computational data and detailed analysis of the literature.