Synthesis of an imidazolium-linked cyclophane from histamine

The synthesis and structural characterization of a dicationic imidazolium-linked cyclophane 7 is reported. In 7, two imidazolium units that have histamine dihydrochloride as a precursor are bridged by two 2,6-bis(bromomethyl)-pyridine.     

Synthesis of a biphenyl-based cyclophane via benzidine rearrangement of a constrained m-nitrophenol derivative

The benzidine rearrangement of a constrained m-nitrophenol derivative results in production of a cyclophane comprising a biphenyl group and a polyether tether connected at the 4,4′ positions.     

Template-directed synthesis of pyridazine-containing tetracationic cyclophane for construction of [2]rotaxane

Benefiting from its bent molecular structure, 3,6-pyridazinyl contained tetracationic cyclophane (1) is synthesized by template-directed method with high isolated yield up to 92%. This template-directed strategy is further utilized to efficiently construct [2]rotaxane.     

环番作为人工受体和人工酶的研究进展

本文综述了水溶液和有机溶液中环番作为人工受体包结有机分子的行为,重点综述了功能化环番作为人工酶的研究进展。     

Synthesis and guest-binding study of polytopic multi(cyclophane) hosts

Novel bis(cyclophanes) bearing glucosides and pentakis(cyclophanes) bearing glucosides were prepared as water-soluble hosts by connecting two or five macrocyclic skeletons, respectively. The guest-binding affinities of the present bis(cyclophanes) and pentakis(cyclophanes) toward a hydrophobic dye, 6-p-toluidinonaphthalene-2-sulfonate, were enhanced 13- and 1200-fold, respectively, relative to that by a corresponding monocyclic cyclophane, reflecting multivalency effects in macrocycles.     

TTF单元与苯单元构建的新型TTF环蕃的合成和性质

以4,5-二(2'-氰乙基硫基)-1,3-二硫杂环戊烯-2-硫酮为原料经甲醇钠消除一个氰乙基生成4-(2'-氰乙基硫基)-1,3-二硫杂环戊烯-2-硫酮的单钠盐, 生成的单钠盐再与1,4-二(氯甲基)苯反应生成4,4'-二(2-氰乙基硫基)-5,5'-(1,4-二亚甲基苯)-二(1,3-二硫杂环戊烯-2-硫酮). 接着在乙酸汞的作用下生成4,4'-二(2-氰乙基硫基)-5,5'-(1,4-二亚甲基苯)-二(1,3-二硫杂环戊烯-2-酮), 此化合物在亚磷酸三乙酯的作用下发生偶联反应, 生成由TTF单元和苯单元构建的新型四硫富瓦烯环蕃和另一种四硫富瓦烯衍生物. 并分别通过循环伏安法和化学氧化法对它们及其导电复合物的电化学性质和紫外光谱进行了研究. 还研究了这种新型四硫富瓦烯环蕃在金纳米颗粒表面自组装行为.     

Selective ion clefts based on a three-bridged [43]cyclophane

A variety of new three-bridged cyclophanes, clefts4–14, have been conveniently prepared, and their cation-binding properties have been examined. Compounds4–6 have a special affinity for alkali metal cations. Ethyl ester5 and methyl ester4 selectively formed 2:1 complexes with K⁺ and Na⁺ ions, respectively. Clefts11–13, which possess pyridyl groups, bind Ag⁺ cation exclusively.¹H NMR titration studies confirmed that11 or12, having 2- or 3-pyridyl groups, form a 1:1 complex with Ag⁺ cation, while13, with 4-pyridyl ligating groups, forms a 2:1 complex. Cleft10, with aminimide groups, also shows an affinity for Ag⁺ cation in a 2:1 ratio in a polar solvent, while it forms a 1:1 complex in a nonpolar solvent. The same solvent effect was observed for clefts13 and15c, which is discussed qualitatively.     

Development of a decaaza‐cyclophane stationary phase for high‐performance liquid chromatography

A new stationary phase for high‐performance liquid chromatography was prepared by covalently bonding a heteroatom‐bridged cyclophane onto silica gel using 3‐aminopropyltriethoxysilane as the coupling reagent. The structure of the new material was characterized by infrared spectroscopy, elemental analysis, and thermogravimetric analysis. The linear solvation energy relationship method was successfully employed to evaluate the new phase with a set of 25 solutes, and compared with octadecylsilyl and p‐tert‐butyl‐calix[4]arene bonded stationary phases. The retention characteristics of the new phase are similar to the octadecylsilyl and conventional calixarene phases, and it also has distinctive features. In addition, the chromatographic behavior of the phase was illustrated by eluting alkylbenzenes and inorganic anions in the reversed‐phase mode and anion‐exchange mode, respectively. Thus, multi‐interaction mechanisms and mixed‐mode separation of the new phase can very likely guarantee its promising application in the analysis of complex samples. The column has been successfully employed for the analysis of triazines in milk, and it is demonstrated to be a competitive alternative analytical method for the determination of triazine herbicide residues.     

新型三(四硫富瓦烯)环蕃的合成和性质

利用四(3'-碘丙硫基)四硫富瓦烯和四硫富瓦烯二钠盐反应合成新的三(四硫富瓦烯)环蕃, 并通过循环伏安法和化学氧化法分别对其氧化还原性质和紫外光谱进行了研究.     

Interplay of Charge Transfer, Dimensionality, and Amide Hydrogen Bond Network Adaptability in TCNQF4 Complexes of EDO-TTF-CONH2 and EDT-TTF-CONH2

[EDO-TTF-CONH₂][TCNQF₄], triclinic system, space group P-1, a=8.2479(12) Å, b=12.282(2) Å, c=12.6842(18) Å, α=113.850(17)°, β=106.420(17)°, γ=90.284(19)°, V=1116.8(4) ų; and [EDT-TTF-CONH₂]₂[TCNQF₄], triclinic system, space group P-1, a=6.5858(9) Å, b=11.699(2) Å, c=12.2281(18) Å, α=104.000(19)°, β=93.611(17)°, γ=98.279(19)°, V=899.9(3) ų, whose π-donor molecules, (ethylenedioxo)-carbamoyltetrathiafulvalene and (ethylenedithio)-carbamoyltetrathiafulvalene, respectively, differ solely by the nature of the chalcogen atoms in their outer ethylene dichalcogeno bridge, yet form very different charge-transfer complexes with the same π-acceptor. [EDO-TTF-CONH₂^•+]₂ [TCNQF₄^•−]₂ is a diamagnetic insulating ionic salt with a three-dimensional rock-salt-type structure based on discrete dimers while in the semi-conducting mixed-valence complex, [EDT-TTF-CONH₂]₂^•+[TCNQF₄^•−], the mixed-valence dimers aggregate into infinite chains interspersed within parallel rows of non-interacting radical anions. It is shown how the robust and adaptable supramolecular amide hydrogen bond tweezers-like motifs common to the two solids simply comply to the 3-to-1 dimensionality reduction upon substitution of O for S.     

Surface plasmon resonance study on binding interactions of multivalent cyclophane hosts with immobilized guests

Guest‐binding affinities of water‐soluble cyclophane heptadecamer (1) and pentamer (2) with immobilized guests such as 1‐pyrenylmethylamine (PMA) and 2‐(1‐ naphthyl)ethylamine (NEA) were investigated by surface plasmon resonance (SPR) measurements. As a typical example, the binding constants (K) for 1 and 2 with the immobilized PMA as a guest were evaluated to be 2.5 × 10⁷ and 2.7 × 10⁶ M^?1, respectively, and were much larger than that of a monocyclic reference cyclophane (K, 2.5 × 10⁴ M^?1). Interestingly, in the complexation of 1 and 2 with the immobilized guests, more favorable association and dissociation rate constant values (k_a and k_d, respectively) were observed in comparison with those for the monocyclic cyclophane, reflecting multivalent effects in macrocycles. The multivalent effects in macrocycles as well as molecular recognition abilities of the cyclophane oligomers were confirmed even when the guest molecules were immobilized on SPR sensor chip surfaces. Copyright © 2009 John Wiley & Sons, Ltd.     

硝基苯胺类非线性光学化合物的高压合成

提出了用氯代硝基苯和胺的高压芳香族亲核取代反应一步合成硝基苯胺类非线 性光学化合物的方法。并筛选出一些具有较高二阶非线性光学活性的化合物。     

新型四四硫富瓦烯环蕃的合成和性质

利用2,3-二(2-氰基乙硫基)-6,7-二烷硫基四硫富瓦烯在甲醇钠的作用下消除一个保护基团生成四硫富瓦烯单钠盐, 与1,4-二氯甲基苯反应, 形成“单桥”-双(四硫富瓦烯)衍生物, 生成的“单桥”-双(四硫富瓦烯)衍生物再次在甲醇钠的作用下消除剩下的保护基团, 形成“单桥”-双(四硫富瓦烯)衍生物二钠盐, 最后与二溴代烷反应形成新型四四硫富瓦烯环蕃, 并通过循环伏安法和化学氧化法分别对其氧化还原性质和紫外光谱进行了研究.     

Ultra-high pressure LC determination of glucosamine in shrimp by-products and migration tests of chitosan films

Chitosan, a multiple applications molecule, was isolated from shrimp by-products by fermentation. The amount of chitosan in the solid fraction of the fermented extract was measured after its conversion in the respective glucosamine units. The procedure includes an acid hydrolysis (110 °C, 4 h with HCl 8 M) and a derivatization with 9-fluorenylmethyl chloroformate (Fmoc-Cl). Ultra-high-pressure liquid chromatography method was developed and optimized. Excellent peaks resolution was achieved in just 10 min. The method was evaluated in what concerns to validation parameters such as linearity, repeatability, quantification limit, and recovery. Migration tests of films prepared with chitosan were carried out in two simulants: ultrapure water and ethanol 95% (v/v).     

Probing the Electrostatic Barrier of Tetrathiafulvalene Dications using a Tetra-stable Donor–Acceptor [2]Rotaxane

A tetra-stable donor–acceptor [2]rotaxane 1 ⋅4PF₆ has been synthesized. The dumbbell component is comprised of an oxyphenylene (OP), a tetrathiafulvalene (TTF), a monopyrrolo-TTF (MPTTF), and a hydroquinone (HQ) unit, which can act as recognition sites (stations) for the tetra-cationic cyclophane cyclobis(paraquat-p-phenylene) (CBPQT⁴⁺). The TTF and the MPTTF stations are located in the middle of the dumbbell component and are connected by a triethylene glycol (TEG) chain in such a way that the pyrrole moiety of the MPTTF station points toward the TTF station, while the TTF and MPTTF stations are flanked by the OP and HQ stations on their left hand side and right hand side, respectively. The [2]rotaxane was characterized in solution by ¹H NMR spectroscopy and cyclic voltammetry. The spectroscopic data revealed that the majority (77 %) of the tetra-stable [2]rotaxane 1 ⁴⁺ exist as the translational isomer 1 ⋅MPTTF⁴⁺ in which the CBPQT⁴⁺ ring encircles the MPTTF station. The electrochemical studies showed that CBPQT⁴⁺ in 1 ⋅MPTTF⁴⁺ undergoes ring translation as result of electrostatic repulsion from the oxidized MPTTF unit. Following tetra-oxidation of 1 ⋅MPTTF⁴⁺, a high-energy state of 1 ⁸⁺ was obtained (i.e., 1 ⋅TEG⁸⁺) in which the CBPQT⁴⁺ ring was located on the TEG linker connecting the di-oxidized TTF²⁺ and MPTTF²⁺ units. ¹H NMR spectroscopy carried out in CD₃CN at 298 K on a chemically oxidized sample of 1 ⋅MPTTF⁴⁺ revealed that the metastable state 1 ⋅TEG⁸⁺ is only short-lived with a lifetime of a few minutes and it was found that 70 % of the positively charged CBPQT⁴⁺ ring moved from 1 ⋅TEG⁸⁺ to the HQ station, while 30 % moved to the much weaker OP station. These results clearly demonstrate that the CBPQT⁴⁺ ring can cross both an MPTTF²⁺ and a TTF²⁺ electrostatic barrier and that the free energy of activation required to cross MPTTF²⁺ is ca. 0.5 kcal mol⁻¹ smaller as compared to TTF²⁺.     

基于环蕃类分子的铁氰化钾电化学存储和释放

通过利用合成的环蕃类化合物1与单壁碳纳米管(SWNTs)间的π-π共轭相互作用,将化合物1固定在SWNTs的表面,制备了1-SWNT修饰电极.利用化合物1氧化态和还原态与铁氰化钾分子之间不同强度的主客体相互作用,实现了铁氰化钾分子在1-SWNT修饰电极表面的电化学可控吸附和解吸.循环伏安和XPS实验结果表明,在本研究采用的实验条件下,铁氰化钾分子在电极表面20s内即可达到吸附平衡;当电极在0.70V下极化1000s后,大多数吸附的铁氰化钾可从电极表面解吸.基于此,制备了铁氰化钾的可控存储和释放的电化学器件,该器件不但可以重复进行铁氰化钾分子的存储和释放,而且多次重复操作表现出较好的稳定性和重现性.本研究在发展具有特殊用途的电化学纳米器件,例如分子搬运器、电化学开关等研究中具有重要意义.     

The synthesis of spirophanes from a pentaerythrityl core

Various thia- and oxa-spirobicyclic cyclophanes were synthesized from a pentaerythrityl building block and appropriate dithiols/bisphenols.     

Ultra-high pressure direct syntheses of bis(imidazolium-3-yl)alkane dichlorides

The ultra-high pressure Menshutkin reaction of N-substituted imidazoles and α,ω-dichloroalkanes provides access to a wide variety of bis(imidazoliumyl)alkane dichlorides in an efficient, one-pot process. Although the substitution reactions of dichloromethane at ambient pressure can be exceedingly slow, at 1.9 GPa, syntheses are usually quantitative in under 24 h. Reactions involving congested imidazole starting materials, that otherwise terminate after formation of the mono-imidazolium salt, are driven to the bis-imidazolium salt at 1.9 GPa. The rates of reaction increase with α,ω-dichloroalkane chain length, decrease with increasing bulk and imidazole N-substituent length, and the reactions of the more hindered imidazoles are more sensitive to the pressure-rate enhancement.     

Modelling of a high pressure calorimeter

The evaluation of the latent heat and enthalpy of fusion of food systems in the case of high pressure–low temperature processing is important for modelling purposes as well as for technical applications. A high pressure calorimeter has been designed for this purpose. The high pressure calorimeter was used to evaluate the latent heat during a pressure scan at constant temperature. It permits to measure the heat of phase transitions and to obtain the relationship between the initial freezing temperature T _ifp and the average pressure while the phase transition is going on. This work presents a modelling of results obtained from an experimental approach using a high pressure calorimeter and from a mathematical model developed from existing data on the phase change of pure water. The modelling work consisted in evaluating the latent heat measured in previous tests from computations taking into account the dependence of the latent heat of fusion of water on pressure. Models predicting the amount of frozen water in a food matrix under atmospheric conditions were used to determine the initial amount of frozen water in the sample. Then a stepwise procedure was operated in a program to reproduce the pressure rise occurring during a high pressure calorimeter test. The amount of melted ice at each pressure step was calculated using conventional ice fraction models, which were adapted to pressure dependence of the initial freezing temperature and the dependence of the latent heat pressure. The comparison was satisfactory, especially at low temperatures.