冠醚螺吡喃化合物的合成和光致变色性质

合成了四个新的6位带不同取代基的含冠醚结构单元吲哚啉螺苯并吡喃化合物(5a-5d),研究了其光致变色性质和离子诱导光致变色作用及取代基的影响。结果表明冠醚能稳定螺吡喃开环形式,碱金属离子对冠醚螺吡喃的生色有诱导作用;6位为吸电子基团时,螺吡喃开环形式的稳定性增加,而6位为推电子基团时,螺吡喃开环形式的稳定性降低。另外,就稳定螺吡喃开环体的作用来说,吲哚啉环上的取代基效应和苯并吡喃环上的正好相反。     

Chloride ion conduction without water coordination in the pore of ClC protein

In the present work, we have found by an atomistic molecular dynamics simulation that hydrogen atoms originating from the residues of a prokaryotic ClC protein (EcClC) stabilize the chloride ion without water molecules in the pore of ClC protein. When the chloride ion conduction is simulated by pulling a chloride ion along the pore axis, the free energy barrier for chloride ion conduction is calculated to be low (4 kcal/mol), although the chloride ion is stripped of its hydration shell as it passes through the dehydrated pore region. The calculation of the number of hydrogen atoms surrounding the chloride ion reveals that water molecules hydrating the chloride ion are replaced by polar and non‐polar hydrogen atoms protruding from the protein residues. From the analysis of the pair interaction energy between the chloride ion and these hydrogen atoms, it is realized that the hydrogen atoms from the protein residues stabilize the chloride ion at the dehydrated region instead of water molecules, by which the energetic penalty for detaching water molecules from the permeating ion is compensated. © 2009 Wiley Periodicals, Inc. J Comput Chem, 2010     

Synthesis and metal ion complexing properties of novel chromogenic cryptands

Four novel chromogenic benzocryptands and one side-armed chromogenic cryptand have been synthesized and their complexing abilities for alkali metal cations are described.     

Block copolymers with Zwitterionic groups at specific sites: Synthesis and aggregation behavior in dilute solutions

Well‐defined linear diblock and triblock copolymers of styrene and isoprene, nearly symmetric in composition, with one or two sulfobetaine associogenic groups at the ends of the polymer chain or the junction points between blocks, were synthesized by anionic polymerization high‐vacuum techniques. The synthetic strategy used the combined initiation of polymerization with 3‐dimethylaminopropyllithium, living end‐capping with 1‐(4‐dimethylaminophenyl)‐1‐phenylethylene, and postpolymerization reaction with cyclopropanesultone. The association behavior of these macromolecules in dilute solutions in the nonpolar solvent CCl₄, good for both blocks, was studied by a number of methods, including static and dynamic light scattering and viscometry. The number and position of the associogenic groups dramatically influenced the association behavior of these model block copolymers. The end‐functionalized samples formed larger aggregates than the junction‐point‐functionalized ones. The difference was attributed to stronger excluded volume effects when the zwitterion group was located within the chain than when the group was at the chain end(s). © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 3791–3801, 2000     

H-type aggregation of functional metal ion sensing phthalocyanines: Synthesis,characterization and electrochemistry

We report, in this study, the preparation and physical characterization of the peripherally functionalized ionophore ligand, 4,5-bis(6-hydroxyhexan-3ylthio)-1,2-dicyanobenzene (1) and its branched thioalcohol-substituted phthalocyanines, 2,3,7,8,12,13,17,18-octakis{6-hydroxyhexan-3-ylthio)-metal (II) or (III) phthalocyanines {M{Pc[SCH(C₃H₇)(C₂H₅OH)]₈} {M = Pb(II) (2), Zn(II) (3), Cu(II) (4), Co(II) (5) and Mn(III), X = Cl⁻ (6)} which can selectively bind soft-metal ions such as silver (I) and palladium (II). It was observed by means of UV–Vis absorption spectrophotometry that the aggregates formed lead to a low solubility of the phthalocyanines in protic solvents, such as low molecular alcohols. However, the addition of AgNO₃ and Na₂PdCl₄ into a THF–MeOH solution of {M{Pc[SCH(C₃H₇)(C₂H₅OH)]₈X} {M = Pb(II) (2), Zn(II) (3), Cu(II) (4), Co(II) (5) and Mn(III), X = Cl⁻ (6)} induced optical changes, which indicated the formation of twisted H-type dimers (blue shift, face-to-face fashion) of {M{Pc[SCH(C₃H₇)(C₂H₅OH)]₈} complexes, bound by four PdCl₂ and AgNO₃ units in THF solution. Elemental analysis data, matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF/MS), FT-IR, ¹H, ¹³C NMR, and UV–Vis spectral data were used as complementary techniques. Voltammetry and in situ spectroelectrochemistry of the complexes were performed on Pt in DMSO/TBAP. The first reduction and oxidation processes of 5 were found to be split due to the presence of facile equilibria between the species coordinated differently at axial positions. The Mn(III)Pc(−2)X⁻ complex (6) displayed well-defined colour changes during its reduction processes. The redox behaviour of the Mn(III)Pc(−2)X⁻ complex was observed to be affected significantly by the existence of oxygen in solution due to the formation of μ-oxo MnPc species, Mn(III)Pc–O–PcMn(III). This effect was clarified well by in situ spectroelectrochemical measurements.     

Bis(crown ether) and Azobenzocrown Derivatives of Calix[4]arene. A Review of Structural Information from Crystallographic and Modelling Studies

The association within one molecule ofcalix[4]arene and crown ether moieties leads toligands with new complexing properties. In particular,calix[4]arene bis(crown-6) and some of itsderivatives have been shown to be highly selectiveextractants for caesium ions. This review presents thebackground of the study and the results of crystalstructure determinations and molecular modellingcalculations performed during the investigation of twomolecular families, the bis(crown ether) and theazobenzocrown derivatives of calix[4]arene.     

Design and evaluation of imidazolium cation-based ionic liquids having double-armed anions for selective cation conduction

A series of triple ionic compounds consisting of double armed anions and one cation were prepared as lithium cation conductive matrices. As anions, lithium borates derived from lithium-9-borabicyclo[3,3,1]nonane hydride were introduced. The sterically hindered borate anion structures prevented the crystallization of triple ionic compounds. Introduction of ethylene oxide chains attached to the borate anions led to lower glass transition temperature, and also improved ionic conductivity. A lithium transference number of 0.73 was observed in spite of the presence of ethylene oxide chains.     

Complex formation of hydronium ion with several crown ethers in 1,2-dichloroethane,acetonitrile, and nitrobenzene solutions

A conductance study concerning the interaction between hydronium ion and several crown ethers in acetonitrile, nitrobenzene and 1,2-dichloroethane solutions has been carried out at 25°C. The stability constants of the resulting 1:1 complexes in acetonitrile and nitrobenzene solutions were determined from the molar conductance-mole ratio data and found to vary in the order 18C6>DB30C10>DC18C6>DB18C6>DB21C7>DB24C8>B15C5. In 1,2-dichloroethane solution, the complexation process results in the dissociation of ion pairs. There is an inverse relationship between the stabilities of the complexes and the Gutmann donicity of the solvents. In nitrobenzene solution, some evidence for the formation of a 2:1 sandwich adduct between the smaller crowns (i.e., B15C5 and 18-crowns) are observed from the molar conductance-mole ratio data which is supported by the¹H NMR data.     

Diastereomeric differentiation of peptides with CuII and FeII complexation in an ion trap mass spectrometer

Complexation by transition metal ions (CuII and FeII) was successfully used to differentiate the diastereomeric YAGFL, YDAGFL and Y(D)AGF(D)L pentapeptides by electrospray ionization-ion trap mass spectrometry in the positive ion mode using low-energy collision conditions. This distinction was allowed by the stereochemical effects due to the (D)Leu/(L)Leu and the (D)Ala/(L)Ala residues yielding various steric interactions which direct relative dissociation rate constants of the binary [(M - H) + MeII]+ complexes (Me = Cu or Fe) subjected to low-energy, collision-induced dissociation processes. The interpretation of the collision-induced dissociation spectra obtained from the diastereomeric cationized peptides allowed the location of the deprotonated site(s), leading to the postulation of ion structures and fragmentation pathways for both the [(M - H) + CuII]+ and [(M - H) + FeII]+ complexes, which differed significantly. With CuII, consecutive fragmentations, initiated by the decarboxylation at C-terminus, were favored relative to sequence product ions. On the other hand, with FeII, competitive fragmentations resulting in abundant sequence product ions and significant internal losses were preferred. This could be explained by different localizations of the negative charge, which directs the orientation of both the [(M - H) + CuII]+ and [(M - H) + FeII]+ binary complexes fragmentations. Indeed, the free negative charge of the [(M - H) + CuII]+ ions was mainly located at one oxygen atom: either at the C-terminal carboxylic group or, to a minor extent, at the Tyr phenol group (i.e. zwitterionic forms). On the other hand, the negative charge of the [(M - H) + FeII]+ ions was mainly located at one of the nitrogen atoms of the peptide backbone and coordinated to FeII (i.e. salt non-zwitterionic form).Moreover, this study reveals the particular behavior of CuII reduced to CuI, which promotes radical losses not observed from the peptide-FeII complexes. Finally, this study shows the analytical potentialities of the complexation of transition metal ions with peptides providing structural information complementary to that obtained from low-energy, collision-induced dissociation processes of protonated or deprotonated peptides.     

Chiral complexation and aggregation of bilirubin with serum albumin at a liquid/liquid interface

The chiral complexation of bilirubin (BR) with bovine and human serum albumin (BSA and HSA), and the aggregation of the complexes at the heptane+chloroform(5:1)/water interface were studied via UV/Vis absorption and circular dichroism (CD) measurements in combination with the centrifugal liquid membrane (CLM) method. The interfacial adsorptivities of BR, BSA and their complexes were also studied by performing interfacial tension measurements at the interface. The changes in the absorbances and the induced CD amplitudes of the interfacial BR-BSA complex provided insights into the mechanism of the conformational enantioselective complexation at the interface, and indicated that the chiral conversion induced by the complexation with BSA was from the P(+) form to the M(-) form of BR. The broadening of the 450 nm band and the appearance of a new shoulder at 474 nm further supported the formation of aggregates of the complexes at the interface. The dependence of the CD amplitude on the molar ratio of BSA to BR revealed that the composition of the complex was 1:1 BSA:BR. The probable interfacial reaction scheme was proposed, and the affinity constant of BR-BSA at the interface was found to be 4.67 x 10(8) M(-2). The interfacial complexation and aggregation of BR and HSA were weaker than those of the BR-BSA complex due to the different BR binding positions adopted for BSA and HSA and the binding effect of chloroform.     

Polymerized ionic liquids: Effects of counter‐anions on ion conduction and polymerization kinetics

A novel imidazolium‐containing monomer, 1‐[ω‐methacryloyloxydecyl]‐3‐(n‐butyl)‐imidazolium (1BDIMA), was synthesized and polymerized using free radical and controlled free radical polymerization followed by post‐polymerization ion exchange with bromide (Br), tetrafluoroborate (BF₄), hexafluorophosphate (PF₆), or bis(trifluoromethylsulfonyl)imide (Tf₂N). The thermal properties and ionic conductivity of the polymers showed a strong dependence on the counter‐ions and had glass transition temperatures (T_g) and ion conductivities at room temperature ranging from 10 °C to −42 °C and 2.09 × 10⁻⁷ S cm⁻¹ to 2.45 × 10⁻⁵ S cm⁻¹. In particular, PILs with Tf₂N counter‐ions showed excellent ion conductivity of 2.45 × 10⁻⁵ S cm⁻¹ at room temperature without additional ionic liquids (ILs) being added to the system, making them suitable for further study as electro‐responsive materials. In addition to the counter‐ions, solvent was found to have a significant effect on the reversible addition‐fragmentation chain‐transfer polymerization (RAFT) for 1BDIMA with different counter‐ions. For example, 1BDIMATf₂N would not polymerize in acetonitrile (MeCN) at 65 °C and only achieved low monomer conversion (< 5%) at 75 °C. However, 1BDIMA‐Tf₂N proceeded to high conversion in dimethylformamide (DMF) at 65 °C and 1BDIMABr polymerized significantly faster in DMF compared to MeCN. NMR diffusometry was used to investigate the kinetic differences by probing the diffusion coefficients for each monomer and counter‐ion in MeCN and DMF. These results indicate that the reaction rates are not diffusion limited, and point to a need for deeper understanding of the role electrostatics plays in the kinetics of free radical polymerizations. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 1346–1357     

双功能聚合物基质阳离子交换固定相的制备及其在离子色谱中的应用

离子色谱是分离分析阳离子型化合物的重要手段之一。高效阳离子交换固定相的制备研究对离子色谱技术的发展具有重要的意义。该文以丙烯酸和顺丁烯二酸酐为单体,2-巯基乙基磺酸钠为巯基改性剂,提出了聚合物基质微球巯基改性自由基聚合修饰方法,用以制备新型双功能的阳离子交换固定相。该固定相以羧基和磺酸基为功能基,仅用简单的强酸淋洗液便可以实现常规阳离子的基线分离。利用色谱学模型,对金属离子和有机胺的保留行为进行了研究。采用梯度淋洗模式,可在24 min内实现10种阳离子的分离,表明固定相具有优异的色谱性能。"巯基-烯"修饰方法简单、高效。此外,通过调节巯基改性剂的比例能够实现对固定相交换能力的调控。     

Synthesis and metal ion complexation of spin labeled 18-crown-6 ethers containing an acridone or an acridine fluorophore unit

Double (spin and fluorescence) labeled pyrroline derivatives of crown ethers containing an acridone or an acridine fluorophore unit (1 and 2) and their diamagnetic analogues (3 and 4) were synthesized. Their fluorescent behavior as well as their complexation properties toward selected metal ions (Na⁺, K⁺, Mg²⁺, Ca²⁺, Zn²⁺) were examined.     

Four generations of water-soluble dendrimers with 9 to 243 benzoate tethers: synthesis and dendritic effects on their ion pairing with acetylcholine, benzyltriethylammonium, and dopamine in water

Water-soluble benzoate-terminated dendrimers of four generations (from G0 with 9 branches to G3 with 243 branches) were synthesized and fully characterized. They form water-soluble assemblies by ion-pairing interactions with three cations of medicinal interest (acetylcoline, benzyltriethylammonium, and dopamine), which were characterized and investigated by 1H NMR spectroscopy, whereas such interactions do not provoke any significant shift of 1H NMR signals with the monomeric benzoate anion. The calculated association constants confirm that the dendritic carboxylate termini reversibly form ion pairs and aggregates. Diffusion coefficients and hydrodynamic diameters of the dendrimers, as well as changes thereof on interaction with the cations, were evaluated by DOSY experiments. The lack of increase of dendrimer size on addition of the cations and the upfield shifts of the 1H NMR signals of the cation indicate encapsulation within the hydrophobic dendrimer interiors together with probable backfolding of the benzoate termini.     

载液组成对于卵白蛋白在非对称流场流分离通道中膜吸附和聚集行为的影响

非对称流场流分离技术对于蛋白质等生物大分子的分析具有温和、分离范围广的特点。然而,在场流分离通道中,受载液组成的影响而产生的蛋白质与通道膜的相互作用和蛋白质在通道内的聚集行为,会影响分析物的回收率和尺寸形态,这些现象一定程度上限制了场流分离仪器的进一步应用。该文研究了载液组成对于卵白蛋白在非对称流场流分离中膜吸附和聚集行为的影响。考察了不同pH （6.2、7.4、8.2）、阳离子种类（Na⁺、K⁺、Mg²⁺）及多种离子强度（0~0.1 mol/L）等条件对卵白蛋白洗脱过程的影响。结果表明a）载液的离子强度越大,卵白蛋白的吸附和聚集行为越严重;b） pH和蛋白质的等电点pI的相对大小决定了蛋白质的表面电荷,从而影响蛋白质的吸附聚集行为;c）二价阳离子Mg²⁺更易引发通道中蛋白质的吸附和聚集。这些结果有助于今后使用非对称流场流分离技术分析蛋白质样品时,改善载液组成以获得更高的回收率,降低蛋白质聚集作用,对AF4更广泛地应用于蛋白质生化分析中有较好的参考价值。     

Synthesis and evaluation of a novel pyrenyl-appended triazole-based thiacalix[4]arene as a fluorescent sensor for Ag ion

New fluorescent chemosensors 1,3-alternate-1 and 2 with pyrenyl-appended triazole-based on thiacalix[4]arene were synthesized. The fluorescence spectra changes suggested that chemosensors 1 and 2 are highly selective for Ag⁺ over other metal ions by enhancing the monomer emission of pyrene in neutral solution. However, other heavy metal ions, such as Cu²⁺, and Hg²⁺ quench both the monomer and excimer emission of pyrene acutely. The ¹H NMR results indicated that Ag⁺ can be selectively recognized by the triazole moieties on the receptors 1 and 2 together with the ionophoricity cavity formed by the two inverted benzene rings and sulfur atoms of the thiacalix[4]arene.     

Complexation of CH3Hg+ with chloride,sulfate and carbonate in NaClO4: construction of thermodynamic models

The complexation of CH₃Hg⁺ with major ions present in sea and estuary waters (Cl^?, SO₄^2? and CO₃^2?) was studied potentiometrically in an NaClO₄ medium in the ionic strength range 0.1–3.0 mol dm^?3 at 25 °C. The potentiometric data, treated with non‐linear least squares computer programs, led us to establish the formation of the species CH₃HgCl in equilibrium with chloride, CH₃Hg(SO₄)^? species with sulfate and no complex with carbonate. The stoichiometric stability constants obtained at the different ionic strengths were correlated by means of the modified Bromley methodology (MBM) to determine the corresponding thermodynamic constants and interaction parameters. This study is the second of a series designed to simulate, using the MBM thermodynamic model, the behaviour of methylmercury in different conditions of sea and estuary waters. In the first study of the series, the hydrolysis equilibria of methylmercury in NaClO₄ ionic media were established. Copyright © 2002 John Wiley & Sons, Ltd.     

La10-x(SiO4)6O3-1.5x的合成及其导电性能的研究

利用溶胶-凝胶法在800 ℃合成了硅酸盐氧基磷灰石La10-x(SiO4)6O3-1.5x(x=0,0.17,0.33,0.50和0.67),经XRD表征所得产品为磷灰石相.以电化学阻抗谱研究了硅酸盐氧基磷灰石的导电性能,体系的电导率随着间隙氧和阳离子空位数量的增多而加大,La9.33(SiO4)6O2的电导率较La9.5(SiO4)6O2.25大,是由于前者有较多的阳离子空位所致,700 ℃时La10(SiO4)6O3的电导率为7.98×10-3 S·cm-1,比La9.33(SiO4)6O2的电导率提高了5倍.氧分压从105～1 Pa变化时电导率保持不变,证明硅酸盐氧基磷灰石在较宽的氧分压范围内为O2-导电.