邻甲氧基羰基苄氧基取代杯[4]芳烃衍生物的合成及其性能研究

杯芳烃是继冠醚、环糊精之后的第三代主体分子[1].据文献[2,3]报道,在杯[4]芳烃下沿酚氧原子上连接乙酸酯得到的四取代衍生物对Na+有很高的选择性,核磁与晶体结构研究均证实这是由于羧酸酯的羰基和酚氧基参与了对Na+的配位,而且配位基团所形成的包络空间大小与钠离子相匹配.一般认为,随着包络空间改变,对金属离子的识别作用会有所变化[4].但目前对这方面的工作并没有给予更多的重视.我们发现,用2-溴甲基苯甲酸甲酯与杯[4]芳烃反应,得到了一种新的四取代杯[4]芳烃衍生物[2]萃取研究结果表明,该化合物对钾离子有较好的选择性.此外,在合成该衍生物的过程中,还得到了另一新的二取代衍生物(3).     

Quantitative analysis of fluid inclusions in evaporites by ion chromatography

Natural salt minerals often contain inclusions of saturated salt solutions with diameters from 1 to> 100 μm. With the quantification of the composition of the fluid inclusions, the origin and metamorphism of the salt rocks can be interpreted. Hence, these data are important concerning the long-term safety of underground repositories in salt rocks [1]. For the extraction of the solutions in fluid inclusions with diameters 300 μm, an optical precision instrument was developed. For the simultaneous determination of Cl⁻, Br⁻, SO₄²⁻, Li⁺, Na⁺, K⁺, Mg²⁺ and Ca²⁺ two ion chromatographic systems with conductivity detection for cations and anions and additional photometric detection for Br⁻ were used. To prevent column overload, the Cl concentration must be less than 50 μg/ml in the measuring solution. The extracted samples (volumes> 0.1 μl) are diluted with demineralized water by a factor of 1 · 10⁴ (20-μl sample loops). The practical limit of determination for the measured elements is 0.01–0.3 μg/ml in the measuring solutions. By calculation of the anion and cation charge balance (molar equivalence), a relative error of <5% for the analysis of fluid inclusions was found.     

The synthesis of novel polysiloxanes with pendant hand-basket type calix[6]crowns and their transporting properties for metal ions in a liquid membrane

Two novel polysiloxanes with pendant hand-basket type calix[6]-1,3-crown-3 and calix[6]-1,4-crown-4 were prepared by hydrosilylation of p-tert-butylcalix[6]-(2′-allyloxymethyl)-1,3-crown-3 (CA[6]C3) and p-tert-butylcalix[6]-[2′-(ω″-undecenyloxymethyl)]-1,4-crown-4 (CA[6]C4) followed by condensation reaction with silanol-terminated polydimethylsiloxane. The monomeric calix[6]crowns and two calix[6]crown-based polysiloxanes were used as carriers in a bulk membrane. All carriers showed the transport rate of the cations decreased in the order Li⁺ < Na⁺ < K⁺. The flux of K⁺ for the monomeric calix[6]crown was higher than that for polymeric carrier. In comparison with other carriers, the transport rate of calix[6]crown-4-functionalized polysiloxanes (CA[6]C4PS) towards cesium ions were increased greatly. Competitive transport experiments known to be more useful in industrial fields also revealed to give high cesium transfer rate.     

碱金属离子与三肽复合物的气相裂解反应

为了探索侧链R基团对碱金属离子与多肽复合物气相裂解反应的影响, 采用电喷雾电离质谱法研究了碱金属离子Li⁺, Na⁺和K⁺分别与甘氨酸三肽(GGG)、 甘氨酰-苯丙氨酰-甘氨酸三肽(GFG)和甘氨酰-甘氨酰-苯丙氨酸三肽(GGF)形成的复合物的气相裂解反应. 质谱定性实验结果表明, Li⁺, Na⁺和K⁺与GGG, GFG或GGF在气相中可以形成稳定的复合物, 配合比为1∶1或2∶1. 竞争反应质谱图显示, GGG, GFG或GGF与碱金属离子形成的复合物的质谱峰丰度按Li⁺, Na⁺, K⁺顺序依次下降, 表明随着碱金属离子半径的增加, 它们与三肽的结合强度依次减弱. 碰撞诱导解离显示, 母体离子[GGG+Na]⁺, [GGF+Na]⁺和[GFG+Na]⁺ 的质心碰撞能量E(CM)₅₀数值分别为1.94, 1.76和1.63 eV. 通过质谱滴定法测得[GGG+Na]⁺, [GFG+ Na]⁺和[GGF+Na]⁺ 的结合常数lg\begin{array}{c}{K}_{a_1}\end{array}分别为5.30, 5.25和5.17. 质谱法定量结果进一步确认复合物的稳定性顺序为[GGG+Na]⁺>[GGF+Na]⁺>[GFG+Na]⁺, 表明由于空间位阻的影响, 侧链R基团含有苄基的GFG或 GGF与Na⁺的键合强度要小于侧链R全部为H的GGG. 串级质谱分析结果显示, 碱金属化的GGG断裂位点较多, 可解离出丰富的金属化a₂, b和y型碎片离子, 而碱金属化的GGF和GFG解离出的金属化y型离子较多, b型离子其次, 金属化a型离子几乎没有. 此外, 双碱金属化的GGF可解离出较多金属化y型离子. 复合物[GGF+Na]⁺的裂解曲线显示, 当碰撞能量为25 eV时, [y₂+Na-H]⁺ 和[b₂+Na+OH]⁺为主要碎片离子, 当碰撞能量>40 eV时, 只有[b₂+Na+OH]⁺ 碎片离子占有优势数量. 根据质子化三肽裂解机理可以推测, 钠化GFG裂解后生成含噁唑酮的[b₂+Na]⁺离子, 该离子经过一系列过渡态生成[a₂+Na]⁺(2-苄基-4-咪唑酮), 而不是常见的亚胺离子.     

碱金属阳离子对Cu+Y催化甲醇氧化羰基化性能影响的密度泛函理论研究

基于密度泛函理论方法构建并优化了CuMY(M为碱金属阳离子)分子筛的稳定构型, 采用速控步骤CO插入CH₃O形成CH₃OCO反应, 研究了碱金属阳离子对Cu⁺Y分子筛中活性中心周围电子环境及催化甲醇氧化羰基化合成碳酸二甲酯性能的影响. 计算结果表明, Li⁺, Na⁺和K⁺稳定落位于Y分子筛小笼中, 且随着金属离子半径的增大, CH₃OH, CO, CH₃O在CuMY上的吸附能和CO/CH₃O的共吸附能均逐渐增加, CO插入CH₃O反应的过渡态结构稳定性逐渐降低, 活化能逐渐上升, 相应的反应活性逐渐下降. 而落位在超笼中Ⅱ^*位的Rb⁺与Cs⁺则随着离子半径的增大, 反应过渡态的结构稳定性提高, 克服的活化能降低, 反应活性升高. 不同CuMY分子筛上催化活性顺序为CuLiY-Ⅰ'>CuCsY-Ⅱ^*>CuNaY-Ⅰ'>CuRbY-Ⅱ^*>CuKY-Ⅰ'>CuCuY-Ⅰ', 其中CuLiY-Ⅰ'分子筛克服速控反应的活化能垒(52.74 kJ/mol)最低.     

Gas-phase chemistry of nitrogen trifluoride NF3: structure and stability of its M–NF3 (M=H, Li, Na, K) complexes

The stationary points characterizing the potential energy profiles of the complex processes of the M⁺(M=H, Li, Na, K) and NF₃ were investigated by QCISD and B3LYP in conjunction with the 6-311+G(2d,2p) basis set. The optimized geometries and NBO analysis indicate that the complexes of M⁺(M=Li, Na, K) and NF₃ exist as ion-dipole molecules. But for H⁺ complexes, there are two stable isomers NF₃H⁺ and NF₂⁺–HF. The interaction distances of isomers follow the sequence H⁺< Li⁺< Na⁺< K⁺. The calculated affinity energies of the most stable isomers of H⁺, Li⁺, Na⁺, and K⁺ complexes exceed 20.1 kJ/mol, and these values suggest that the M⁺–NF₃ (M=H, Li, Na, K) complexes could be observed as stable species in gas phase, which supports Fujii's proposal that Li⁺ ion attachment mass spectrometry can serve as a conceivable technique to quantify the emissions of the NF₃.     

气相中碱金属离子与丝氨酸、 亮氨酸和赖氨酸五肽复合物的裂解反应

为了探索金属离子对含有不同侧链的多肽气相解离的影响, 采用质谱法研究了碱金属离子Li⁺, Na⁺, K⁺, Rb⁺和Cs⁺分别与丝氨酸、 亮氨酸和赖氨酸五肽(分别简写为S5, L5和K5)形成的复合物的裂解反应. 质谱定性结果表明, 5种碱金属离子均可以在气相中与丝氨酸、 亮氨酸和赖氨酸五肽形成配合比为1∶1 和2∶1的非共价复合物; 竞争反应结果表明, 随着碱金属离子半径的增加, 它们与3种五肽的结合能力逐渐减弱. 质谱定量结果表明, K⁺与丝氨酸、 亮氨酸和赖氨酸五肽复合物的结合常数分别为8.94×10⁴, 2.83×10⁴和2.50×10³ L/mol, 表明K⁺与五肽复合物的结合强度按照丝氨酸、 亮氨酸和赖氨酸的顺序依次减小. 含不同侧链碱金属离子-五肽复合物的碰撞诱导解离结果表明, 复合物的碎裂主要发生在骨架上, 丝氨酸五肽复合物最易碎裂, 亮氨酸五肽复合物其次, 赖氨酸五肽复合物则较难碎裂, 且3种复合物的侧链断裂情况也呈现明显差异. 此外, 研究了Na⁺与亮氨酸五肽复合物所产生的碎片离子, 分析了不同离子之间的来源关系, 并以Dunbar的复合物理论模型为依据, 推测在碎裂过程中, 碱金属离子可能向五肽的碳端或氮端偏移. 质谱碎片分析结果表明, 在2∶1的非共价复合物中, 第一个碱金属离子与五肽上4个酰胺键的羰基结合, 第二个碱金属离子与五肽的羧基氧原子结合.     

Vibrational spectra and microstructure of poly(ε-caprolactone)/siloxane biohybrids doped with lithium triflate

Fourier Transform infrared (FT-IR) and Raman (FT-Raman) spectroscopies and Scanning Electron Microscopy (SEM) were used to investigate ionic association, hydrogen bonding and morphology in a family of sol–gel derived lithium triflate (LiCF₃SO₃)-doped di-urethane cross-linked poly(ε-caprolactone) (PCL(530))/siloxane hybrid electrolytes. The materials studied, with compositions ∞ > n  0.5 (where n – composition – expresses the molar ratio of PCL(530) ester repeat units per Li⁺ ion), are non-porous and homogeneous. The Li⁺ ions interact with the urethane and ester carbonyl oxygen atoms within the whole range of salt concentration analyzed, promoting the formation of hydrogen-bonded aggregates. The composition dependence of the relative concentration of “free” anions and coordinated anions (weakly coordinated anions, ion pairs or [Li(CF₃SO₃)₂]⁻ triplets, aggregates I ([Li₂(CF₃SO₃)]⁺) and aggregates II ([Li₃(CF₃SO₃)]²⁺) in all the samples is in perfect agreement with the values of the room temperature ionic conductivity reported previously.     

Development of low-cost metal oxide pH electrodes based on the polymeric precursor method

In this work, the polymeric precursor method was used to prepare low-cost solid-state sensors for pH determination based on iridium oxide as the main pH sensitive material. The iridium content was reduced with addition of TiO₂, forming the binary system IrO_x–TiO₂, whose electroanalytical properties were evaluated in comparison with a commercial glass pH electrode. The minimum iridium content which gave suitable results was 30 mol%, and the electrode presented Nernstian and fast response in the pH range from 1 to 13, with no hysteresis effect observed. Besides, the electrode showed high selectivity in the presence of alkali ions as Li⁺, Na⁺ or K⁺. The amount of iridium in the prepared electrodes was very small (<0.1 mg), supporting the efficiency of this method on the simple preparation of functional low-cost pH electrodes.     

Separation and indirect detection by capillary zone electrophoresis of ppb (w/w) levels of aluminum ions in solutions of multiple cations

Solutions of multiple cations in aqueous solutions at concentrations as low as 200 ppb were analyzed by capillary zone electrophoresis. Aluminum ions were cleanly separated from Li⁺, K⁺, Ca²⁺, Cr³⁺, Zn²⁺, CU²⁺, and other ions less than 6 min after injection of the solution on a 50 cm × 50 μm I.D. uncoated fused-silica capillary column at 15 kV. Indirect detection at 204 nm was carried out using a pH 2.8 background electrolyte containing 5.2 mM ephedrine as a UV-absorbing co-ion and 4.7 mM -hydroxyisobutyric acid as a completing counter ion. Mobilities for Al³⁺ and 14 other complexed cations were determined for this electrolyte.     

Neutron diffraction studies of ions in aqueous solution

The effect of ions on the structure of water is discussed in terms of results for ionic hydration as derived from neutron diffraction isotopic substitution experiments. Results are presented for alkali ions (Li⁺, Na⁺ and K⁺), alkaline earth ions (Mg²⁺, Ca²⁺ and Sr²⁺) and for the anions Cl⁻, ClO⁻₄) and NO⁻₃, from which it is inferred that the water structure is disrupted more by cations with higher charge density.     

离子水化过程的核磁共振研究——二-(2-乙基己基)膦酸-长链醇-煤油-水体系

本文利用无水皂化萃取剂加水生成微乳状液研究离子水化的新方法,研究了酸性膦酸酯D₂EHPA(碱金属盐)-ROH-煤油-水体系中,通过对水质子化学位移变化的规律来研究碱金属的水合作用,所得结果与环烷酸体系相似。当[M⁺]/[H₂O]从100/1向1/100变化时,可以看到配位水的化学位移比缔合水(即正常液体水)向低场移动近2ppm,这比通常在浓盐水溶液中观察到的差值提高了一个数量级。当[M⁺]/[H₂O]大于100/1时,配位水的化学位移随阳离子不同而趋于不同的极限值,其顺序为NH₄⁺(6.76)>Li⁺(6.60)>Na⁺(5.96)>K⁺(5.40)。 从不同体系NMR图峰形和半高宽度Δv_1/2的变化,可以观察到阴离子的结构和组成对离子的水化作用有较大的影响。有关阴离子水合情况的研究工作正在进行中。     

On the affinities of ammonia and water for Li, Na and K

The affinities of ammonia for Na⁺ and K⁺, recently determined experimentally, have been computed by the ab initio SCF method using ended polarized gaussian basis sets and shown to be satisfactory Furthermore, the corresponding values computed at the same level of accuracy for the three cations Li⁺, Na⁺, K⁺ and the two ligands NH₃ and H₂O are shown to yield the order Li⁺ > Na⁺ > K⁺ for each ligand and NH₃ > H₂O for each ion, in agreement with experiment. An analysis of the factors involved in the binding provides a consistent rationalization of these regularities and of some observed correlations.     

Infrared spectroscopic study of solid films of poly(ethylene glycol) doped with cations

The infrared spectra of solid films, prepared on a silicon plate of poly(ethylene glycol) doped with various cations (Li⁺, Na⁺, K⁺, Ca²⁺ and Ba²⁺), have been measured. The spectral analysis indicates that the films are non-crystalline and essentially amorphous. The polymer chain is significantly disordered by assuming diverse conformational states. The interaction between the ether oxygens of the polymer and the cation, as estimated from the C---O stretching wavenumber, is correlated to the size of the cation; the interaction is stronger for the cation with larger size.     

Plasticizer-free microspheres for ionophore-based sensing and extraction based on a methyl methacrylate-decyl methacrylate copolymer matrix

Plasticizer-free methyl methacrylate-decyl methacrylate (MMA-DMA) microspheres were prepared under mild, non-reactive conditions using a high-throughput particle generator. The particles were perfectly smooth and monodisperse, with a particle diameter of approximately 10.0 μm. In order to evaluate the suitability of the polymer as a matrix for bulk extraction processes, lipophilic sensing components were incorporated into the particles. Particles contained either a H⁺-selective chromoionophore (ETH 5294) only (type 1), or a K⁺-selective ionophore (BME-44), anionic sites (NaTFPB), and ETH 5294 (type 2). Type 1 particles responded according to an anion–proton coextraction mechanism and demonstrated Hofmeister selectivity by showing a preference for more lipophilic sample anions (ClO₄⁻>NO₃⁻>Cl⁻). Particles of type 2 functioned by way of an ion-exchange equilibrium and demonstrated a functional response for K⁺, with a dynamic range from 10⁻¹–10⁻⁴ M K⁺. These particles also exhibited selectivity comparable to that previously reported for analogous particles made from bis(2-ethylhexyl sebacate) (DOS)-plasticized poly(vinyl chloride) (PVC) and DMA-DOS. In addition, the behavior of both types1 and 2 particles was in agreement with analogous thin film optical sensors (optodes) prepared from MMA-DMA. With the advent of ionophore-based plasticizer-free microspheres a wide variety of ions may potentially be assessed using various popular bead-based sensing strategies, such as lab-on-a-chip technologies, bundled optical fiber arrays, and flow cytometry, without experiencing the deleterious effects resultant of plasticizer leaching.     

Ion-exchange properties of hypercrosslinked polystyrene impregnated with methyl orange

A novel bipolar stationary phase (HCPS–MO) was prepared by impregnation of hypercrosslinked polystyrene (HCPS) with methyl orange (MO; 4-dimethylamino-4′-sulfoazobenzene) and its ion-exchange properties were studied. Simultaneous separation of cations and anions on HCPS–MO is possible, although it behaves preferentially as a cation-exchanger. Unusual selectivity of HCPS-MO for alkali and alkaline-earth metal cations: Na⁺+K⁺+4⁺+ and Mg²⁺2+2+2+ was observed. The effect of temperature on retention of alkali and alkaline-earth metal cations was studied. Separation of Na⁺, K⁺, Rb⁺, NH₄⁺, Cs⁺, Mg²⁺ and Ca²⁺ on HCPS–MO with diluted cerium(III) nitrate solution as an eluent in single run is presented.     

Construction of a nano-rectangular Zn-Nd complex with near-infrared luminescent response towards metal ions

One 6-metal Zn-Nd complex[Zn₂Nd₄L₂(OAc)₁₀(OH)₂(CH₃OH)₂](1)with Schiff base ligand bis(3-methoxysalicylidene)ethylene-1,2-phenylenediamine(H₂L)was constructed,and it has nanoscale rectangular structure(8×11×28 A).Excited by ligand-centered absorption bands,1 shows NIRemission of Nd³⁺ion.Interestingly,1 exhibits lanthanide luminescent response towards metal ions,especially to alkali metal ions(Li⁺,Na⁺ and K⁺)at ppm level.     

NMR Study on the Hydration of Ions in Microemulsion——Bis-2-Ethylhexyl Phosphoric Acid-Alcohol-Kerosine-Water System

In the present investigation we have observed the proton shift of water of hydration of metal ions in a microemulsion formed by adding water gradually front 0.05% to 20% to a moisture-free bis-2-ethflhexyl phosphoric acid-alcohol-kerosine sistem saponified by metallic sodium,so that the mole ratio of concentration (M )/V(H2O) can be varied from 100:1 to 1:100.Under such conditions,we have obtained the lirni's of SME for various cations as follows 6.78PPm(NH4 ),6.80(Li ).5.96(Na ).6.40(K ),in comparison with the proton shift of liquid water,H2O=4.80PPm.     

Spectroscopic, mass spectrometry, and semiempirical investigations of a new 2-(2-methoxyethoxy)ethyl ester of Monensin A and its complexes with monovalent cations

A new 2-(2-methoxyethoxy)ethyl ester of Monensin A (MON7) has been synthesized and its capability of complex formation with Li⁺, Na⁺, and K⁺ cations has been studied by ESI MS, ¹H and ¹³C NMR, FT-IR, and PM5 semiempirical methods. ESI mass spectrometry indicates that MON7 forms complexes with Li⁺, Na⁺, and K⁺ of exclusively 1:1 stoichiometry which are stable up to cv = 70 V. The formation of complexes between MON7 and Na⁺ cations is strongly favored. Starting from about cv = 90 V fragmentation of the respective complexes is observed, primarily characterized by several dehydration steps. The structures of the MON7 complexes with Li⁺, Na⁺, and K⁺ cations are stabilized by intramolecular hydrogen bonds in which the OH groups are always involved. The structures are visualized and discussed in detail. It has been proved that the formation of a pseudo crown ring structure formed by MON7 is preferred in complexes with Na⁺ cations.     

Novel lithocholaphanes: Syntheses, NMR, MS, and molecular modeling studies

Novel head-to-head lithocholaphanes 6 and 11 have been synthesized via precursors 1–5 and 7–10 with overall good yields, and characterized by ¹H, ¹³C, and ¹⁵N NMR spectroscopy, ESI-TOF mass spectrometry, thermal analysis, and molecular modeling. In addition, the binding abilities of 6 and 11 towards alkali metal cations have been investigated via competitive complexation studies using equimolar mixtures of Li⁺, Na⁺, K⁺, and Rb⁺-cations, and cholaphanes 6 and 11. The formation of cation–cholaphane adducts was detected by ESI-TOF mass spectrometry. The trends in these comparative binding studies are nicely reproduced theoretically with PM3 energetically optimized structures of 6 and 11 and their interaction energies with alkali metal cations calculated by molecular mechanics. Cholaphane 11 possessing a peptoid type structural fragment, –(CH₂CONHCH₂CH₂)₂O–, as a coordination sphere, shows binding tendency towards lithium and sodium cations, whereas 6 possessing an ester type, –(CH₂OCOCH₂)₂O–, moiety and a bigger cavity size than 11, shows merely a tendency towards bigger alkali metal cations, potassium and rubidium.