Interaction of 1-pyrenebutyrate with poly(vinylbenzo-18-crown-6) and poly(vinylbenzoglyme) in water

Binding constants of 1-pyrenebutyrate (PB^?, 1-pyrenecarboxylate and 1-pyrenevaleriate to the polysoap-type macromolecule poly(vinylbenzo-18-crown-6) (P18C6) and the poly(vinylbenzoglyme) PVBG (a polystyrene with two CH₃O(CH₂CH₂O)₂-substituents at the 3 and 4 position of each benzene ring) were determined spectrophotometrically (λ_m 342 nm for free PB^?, 348 nm for polymer-bound PB^?). The binding appears to follow Langmuir adsorption behaviour. Interaction with P18C6 is enhanced on adding crown ether-complexable cations, which converts the neutral polymer into a polycation. The enhanced binding is chiefly caused by lower values of $\text{1}\text{n}$ (minimum number of crown monomer units per bound PB^? molecule). This decreases at 25°C from $\text{1}\text{n}\text{= 25}$, for neutral P18C6, to 6.2 and 2.7 in the presence of 0.01 M CsCl and 0.1 M KCl, respectively. It is argued that the COO^? substituent of bound PB^? is probably located in the aqueous layer at the polymer-water interphase. Its presence close to the crown ligands enhances the binding of K⁺ or Cs⁺ cations to these ligands by forming crown-complexed ion pairs PB^?, M⁺ … P18C6. The typical excimer fluorescence emission peak of PB^? is observed when P18C6 in 0.1 M KCl is saturated with PB^?. Some of the binding measurements were carried out in ethanol-water mixtures.     

Effect of charge on anion and cation binding to poly(vinylbenzo-18-crown-6) in water

Complex formation constants, K, of cation to poly(vinylbenzo-18-crown-6) (P18C6) and to its monomeric analogue 4′-methylbenzo-18-crown-6 (MB 18C6) were measured in water potentiometrically or spectrophotometrically. The constants for Na⁺, K⁺ and Cs⁺ to P18C6, extrapolated to zero charge density, were found to be 2.4, 110 and 300 M^?1, respectively, and 27, 110 and ≈20 for MB18C6. Binding of K⁺ and of picrate anions to P18C6 was measured as a function of the number of K⁺ ions, Z, on the P18C6 chain. The charge effect (a decrease in K⁺ binding with increasing Z, and an increase in picrate binding) can be reasonably well-described by assuming the macroion to be a solvent- and ion-impenetrable sphere, the potential of which can be calculated by using a Debye-Huckel approximation. A linear plot is predicted and found (at least for picrate binding) between InK and Z, the slope yielding information on the radius of the P18C6 macroion. The cation effect on picrate binding to P18C6 was utilized to determine spectrophotometrically the order of binding of a series of cations to P18C6. The results were confirmed by using the dye, 2-(4′-hydroxybenzeneazo)benzoate which produces a much larger bathochromic shift on binding to P18C6 in water than does the picrate anion.     

Mass transfer study in a pulsed bed electrode - application to the electrodeposition of a poly(dibenzo-18-crown-6) film

The polymerization of dibenzo-18-crown-6 has been carried out in an electrochemical reactor containing a granular electrode percolated by a pulsed solution. The influence of different parameters (pulse frequency, permanent flow velocity of the electrolytic solution, particle diameter and bed height) on the mass transfer has been studied. A correlation between the reduced mass transfer coefficient and the Strouhal number has been established. The maximum mass transfer coefficient and the maximum Strouhal number have been determined as a function of the Galilee number. The correlation predicts well the mass transfer coefficient over a larger range of the variables than previously achieved.     

聚(丙烯酸-共聚-苯并-18-冠醚-6-丙烯酰胺)的铯离子响应特性及其铯离子检测性能

制备了一种聚(丙烯酸-共聚-苯并-18-冠醚-6-丙烯酰胺)（PAB）线形共聚物,并系统研究了不同丙烯酸含量的PAB线形共聚物对铯离子的响应特性及其用于铯离子浓度检测的性能。结果表明,在不同浓度的铯离子溶液中,PAB线形共聚物的低临界溶解温度（LCST）会随着铯离子浓度增加向低温迁移;在实验范围内,当PAB线形共聚物中的丙烯酸质量分数为30%时,其铯离子响应特性最有利于水溶液中铯离子浓度的检测。通过系统实验研究,确立了PAB共聚物的LCST与水溶液中铯离子浓度的关系函数;利用该关系函数,可简单地通过测定未知铯离子浓度的PAB溶液LCST,即可推断出该溶液中的铯离子浓度。该研究为铯离子的便捷检测提供了新手段。     

Synthesis of poly(dibenzo-19-crown-6) via cyclopolymerization of diepoxide

Summary Synthesis and cyclopolymerization of 5,6;14,15-dibenzo- 1, 2; 18, 19-diepoxy- 4, 7, 10, 13, 16-pentaoxanonadeca- 5,14-diene (3) was carried out. The polymerization of 3 with tin tetrachloride and boron trifluoride etherate gave the polymers with lower molecular weight. Alternatively, triethylaluminium-water-acetylacetone (Vandenberg catalyst) was effective in preparing polymers of high molecular weight which were soluble in p-cresol and p-chlorophenol. The polymers were essentially composed of cyclic constitutional units corresponding to dibenzo-19-crown-6. The cation-binding ability of the polymer showed the highest selectivity for K⁺.     

Supramolecular assemblages from uranyl complexes of calixarenes and potassium complexes of 18-crown-6 or dibenzo-18-crown-6

Reaction of uranyl nitrate with p-tert-butyl[3.1.3.1]homocalixarene (L¹H₄) or p-tert-butylcalix[8]arene (L²H₈) has been carried out in the presence of KOH and 18-crown-6 (18C6) or dibenzo-18-crown-6 (db18C6), giving the supramolecular assemblages [K(db18C6)(H₂O)₂]₃ [{UO₂(L¹)}₂K(H₂O)₅] (1) and [K(18C6)(OH)₂][{(UO₂)₂(L²H₅)(OH)}{K(18C6)}] (2). Compound 1 comprises a sandwich, “complex-within-complex” assemblage in which two uranyl/calixarene complexes encompass a potassium/crown ether guest. A direct bond between uranyl and K(18C6) is present in 2, in which a columnar arrangement of alternate dimetallic calixarene complexes and potassium/crown ether species is formed.     

Restraining the associations of anthracene fluorophore by chemically linking to poly(methyl methacrylate)

Associations (dimer or aggregate) of anthracene (An) fluorophores tend to interrupt the monomer emission and reduce the quantum yield (Φ_PL); therefore, poly(methyl methacrylate) (PMMA) chain was used in this study to chemically link to anthracene and to block the mutual associations among the anthracene fluorophores. With this aim, the target polymers were prepared by anionic polymerizations with 9,10‐dibromoanthracene/s‐butyllithium as initiating system to proceed polymerizations of methyl methacrylate (MMA) directly or in the presence of 1,1‐diphenylethylene (DPE). Use of DPE before addition of MMA produces stable initiating anionic species and avoids potential side reactions during polymerization; however, it also introduces four β‐phenylene rings around the central anthracene ring, which interfere with the corresponding emission pattern and reduce the Φ_PL (32%) value due to potential interactions between phenylene rings and anthracene. On the contrast, polymerization without participation of DPE results in polymer with central anthracene ring directly connected to two PMMA chains, which gives clean vibronic emission pattern with limited association emissions and enhanced Φ_PL (52%) value. Physical blending of anthracene by PMMA is less efficient to restrain the associations and results in a film of lower Φ_PL (20%). © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Surface morphology evolution of poly(styrene-block-4-vinylpyridine) (PS-b-P4VP)(H) and poly(methyl methacrylate)-dibenzo-18-crown-6-poly(methyl methacrylate) (PMCMA) supramolecular film

Well-ordered nanostructured polymeric supramolecular thin films were fabricated from the supramolecular assembly of poly(styrene-block-4-vinylpyridine) (PS-b-P4VP)(H⁺) and poly(methyl methacrylate)-dibenzo-18-crown-6-poly(methyl methacrylate) (PMCMA). A depression of cylindrical nanodomains was formed by the block of P4VP(H⁺) and PMCMA associates surrounded by PS. The repulsive force aroused from the incompatibility between the block of P4VP(H⁺) and PMCMA was varied through changing the molecule weight (M_w) of PMCMA, the volume fraction of the block of P4VP(H⁺), and annealing the film at high temperature. Increasing the repulsive force led to a change of overall morphology from ordered nanoporous to featureless structures. The effects of solvent nature and evaporation rate on the film morphology were also investigated. Further evolution of surface morphologies from nanoporous to featureless to nanoporous structures was observed upon exposure to carbon bisulfide vapors for different treatment periods. The wettability of the film surface was changed from hydrophilicity to hydrophobicity due to the changes of the film surface microscopic composition.     

Synthesis and properties of poly(dipropargyl-16-crown-5)

Summary We have synthesized a polyacetylene derivative, poly(dipropargyl-16-crown-5), through the cyclopolymerization of the corresponding monomer by metathesis catalysts. The polymer containing crown-ether units was characterized by spectroscopic and thermal techniques. The polymer structure is believed to be a cyclized from with both five- and sixmembered rings. The polymer exhibits high cation-binding properties and ionochromic effects. The order of the selectivity of alkali- metal cations for both the monomer and the polymer was found to be Na⁺>K⁺>Li⁺ and the polymer shows the largest red shift by approximately 40 nm in _max for Na⁺.     

Flow and thermal characteristics of cationic dyeable nylon 6/cationic dyeable poly(ethylene terephthalate) polyblended polymers and filaments

Cationic dyeable nylon 6 (CD‐N6) and cationic dyeable poly(ethylene terephthalate) (CD‐PET) polymers were extruded (in the proportions of 75/25, 50/50, 25/75) from one melt twin‐screw extruders to prepare three CD‐N6/CD‐PET polyblended polymers and then spin filaments. The molar ratio of 5‐sodium sulfonate dimethyl isophthalate (5‐SSDMI) for CD‐N6 and CD‐PET polymers were 2.01% and 2.04%, respectively. This study investigated the flow and thermal characteristics of CD‐N6/CD‐PET polyblended polymers and filaments using gel permeation chromatography (GPC), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), potentiometer, a rheometer, the density gradient, wide‐angle X‐ray diffraction (WAXD), and extension stress–strain measurement. Flow behavior of CD‐N6/CD‐PET polyblended polymers exhibited negative‐deviation blends (NDB), and the 50/50 blend of CD‐N6/CD‐PET showed a minimum value of the melt viscosity. Experimental results of the DSC indicated CD‐N6 and CD‐PET molecules formed an immiscible system. Particularly, a double endothermic peak was observed from CD‐N6, CD‐PET and their polyblended filaments. The tenacity of CD‐N6/CD‐PET polyblended filaments decreased initially and then increased as the CD‐PET content increased. Crystallinities and densities of CD‐N6/CD‐PET polyblended filaments were the linear relation with the blend ratio. The miscibility parameter μ values of CD‐N6/CD‐PET all samples were less than zero. It indicated the electrostatic repulsion was evident between CD‐N6 and CD‐PET molecules. From the experimental data, the CD‐N6 and CD‐PET polymers were identified to be immiscible. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2049–2056, 2007     

Crystal structure and fluorescence behavior of N,N'-bis (1-naphthylmethyl)-diazonia-18-crown-6 diisothiocyanate

N,N'-bis (1-naphthylmethyl)-diaza-18-crown-6 (1) showed weak emissions, suggesting that photoinduced electron transfer (PET) from the amine group to the excited naphthalene occurs. The PET fluoroionophore (1) was found to display unique photophysical properties in the presence of a guest cation. Single crystals of the HNCS salt of 1 were grown from 1 and NH(4)SCN. The crystal structure of the HNCS salt of 1 was elucidated by X-ray crystallographic analysis. The HNCS salt of 1 consists of a 1·2H(+) and 2NCS(-) ion pair. The 1·2HNCS salt gave an emission band at 332 nm. Complexation of 1 with HNCS increased the fluorescence intensity of the host by a factor of 29. The emission enhancement of 1 with HNCS was caused by the proton which dissociates from HNCS.     

Highly Efficient Cooperative Membrane Transport of Lead(II) Ions by Aza-18-crown-6 and Palmitic Acid

Abstract

A chloroform membrane system containing a given mixture of aza-18-crown-6 and palmitic acid was applied for the uphill transport of Pb²⁺ ions. In the presence of P₂O₇ ^4? ion as a suitable metal ion acceptor in the receiving phase, the amount of lead ion transported across the liquid membrane after 100 minutes is 89.1 ± 1.3%. The selectivity and efficiency of lead transport from aqueous solutions containing other cations such as Zn²⁺, Cu²⁺, Ni²⁺, Co²⁺, Fe²⁺, Pd²⁺, and Ag⁺ ions were investigated. In the presence of S₂O₃ ^2? ion as a proper masking agent in the source phase, the interfering effects of Cu²⁺ ion were diminished drastically.     

富马酰基桥联双冠醚的晶体结构及其对金属离子的选择键合

通过母体冠醚环(苯并氮杂-15-冠-5)与富马酰氯反应,合成了一种新型的富马酰基桥连的双冠醚,其单晶结构经X-射线单晶衍射仪测定;继而采用溶剂萃取法考察了其对金属离子(Li~+、Na~+、K~+、Rb~+、Cs~+、Ag~+、Tl~+)的识别能力。结果显示,该双冠醚对Li~+具有较高的萃取率和选择性。     

A combined radical/cationic synthetic route for poly(styrene-g-isobutylene) and poly(styrene-g-isobutylene-co-isoprene)

Summary A synthetic route for graftcopolymers, in which the poly(styrene-co-2-acetoxy-2-(4-vinylphenyl)propane) was synthesized via a radical pathway is described. The resulting macroinitiator was used to initiate the cationic homopolymerization of isobutylene and the cationic copolymerization of isobutylene with isoprene. The resulting polymers were characterised with common methods such as ¹H/¹³C-NMR, IR and GPC. Received: 30 July 2001/ Revised version:3 December 2001/ Accepted: 3 December 2001     

Aqueous lubricating properties of charged (ABC) and neutral (ABA) triblock copolymer chains

Application of charged polymer chains as additives for lubricating neutral surfaces in aqueous environment, especially via polymer physisorption, is generally impeded by the electrostatic repulsion between adjacent polymers on the surface. In this study, we have investigated the adsorption and aqueous lubricating properties of an amphiphilic triblock copolymer, comprised of a neutral poly(ethylene glycol) (PEG) block, a hydrophobic poly(2-methoxyethyl acrylate) (PMEA) block, and a charged poly(methacrylic acid) (PMAA) block, namely PEG-b-PMEA-b-PMAA. After adsorption onto a nonpolar hydrophobic surface from aqueous solution, an equal and homogeneous mixture of neutral PEG and charged PMAA chains is formed on the surface, with an adsorbed polymer mass comparable to its fully neutral counterpart, PEG-b-PMEA-b-PEG. The lubricity of PEG-b-PMEA-b-PMAA showed significant improvement compared to fully charged polymer chains, e.g. poly(acrylic acid)-block-poly(2-methoxyethyl acrylate) (PAA-b-PMEA), which is attributed to dilution of charged moieties on the surface and subsequent improvement of the lubricating film stability.     

Synthesis of poly(butyl methacrylate) in three-component cationic microemulsions

The polymerization of butyl methacrylate in three-component microemulsions prepared with the cationic surfactant dodecyltrimethlammonium bromide is reported here as a function of monomer and surfactant content in parent microemulsions, type and concentration of initiator, and temperature. Fast reaction rates and high conversions are achieved in all cases. Final latexes are bluish-opaque and stable, and contain spherical particles with diameters in the range of 20 to 30 nm, depending on composition of the parent microemulsions and reaction conditions. Each of these particles is composed of a few macromolecules of high molecular weight (2 to 4 × 10⁶ Dalton). Both particle size and average molecular weight remain constant throughout the reaction, suggesting a continuous nucleation mechanism. Analysis of the molecular weight distribution indicates that the controlling termination mechanism is chain-transfer to monomer. © 1996 John Wiley & Sons, Inc.     

Structure and properties of hydrophobic cationic poly(vinyl alcohol)

A new class of derivatives of poly(vinyl alcohol) (PVA) was prepared through hydrophobic cationic modification. The structure and composition of PVA grafted with glycidyl‐N‐alkyl‐N,N‐dimethyl‐ammonium chloride (DA) (PVA‐ graft ‐DA) was confirmed with Fourier transform infrared spectral analysis and ¹H NMR spectral analysis. The stress‐strain curves of PVA‐ graft ‐DA samples all exhibited an elastic deformation stress plateau, and strain hardening behavior can be observed, indicating the transition of PVA from brittle fracture to ductile fracture. Compared with virgin PVA, the relaxation peak (T_g) of PVA‐ graft ‐DA shifted to a lower temperature. With increasing alkyl chain length and grafting ratio of DA, T_g decreased, and PVA‐ graft ‐DA exhibited a gradually decreasing storage modulus over the whole temperature range of testing due to the relatively weak intermolecular hydrogen bonding and increasing flexibility of molecular chains by introduction of long alkyl chains. PVA crystallites were not affected by grafting with DA, while the crystallization temperature and crystallinity of PVA were improved and the grain size decreased. On grafting with DA, the fracture surface of PVA changed from a smooth surface to regularly distanced striations, displaying much obvious character of tough fracture, indicating that appropriate intermolecular association of the hydrophobic groups facilitated the formation of physical entanglement of molecular chains to strengthen and toughen the PVA matrix. PVA‐ graft ‐DA showed a significant decreasing surface tension with polymer concentration, while the surface tension of PVA‐ graft ‐DA12 dropped most dramatically and declined with increasing grafting ratio of DA12, indicating improvement of the surface activity of PVA by introduction of hydrophobic alkyl chains and hydrophilic cationic groups. Copyright © 2011 Society of Chemical Industry     

On the Mechanism of n-Butyl Vinyl Sulfide Formation with [K(18-crown-6)SBu] as catalyst

n-Butyl mercaptane reacts with acetylene in the presence of [K(18-cr-6)SBu] as catalyst to give n-butyl vinyl sulfide. In toluene the reaction is of zero^th order with respect to BuSH and first order with respect to [K(18-cr-6)SBu]. The reaction rate depends on the solvent in the following order: toluene > triglyme ≈ BuSH ≈ dioxane ≫ BuOH. In toluene, BuOH added in equimolar amounts accelerates the reaction indicating a complex formation [K(18-cr-6) (BuOH)SBu] with a higher catalytic activity. [K(18-cr-6)SBu] is monomeric in the solid state with d(K–S) = 3.051(2) Å. Potassium is displaced out of the mean plane defined by the six oxygen atoms of the crown ether by 0.626(3) Å. [K(18-cr-6)SBu] is a strong electrolyte in alcohols but practically no electrolytic dissociation takes place in solvents with low dielectric constants such as toluene and n-butyl mercaptane. From the results a reaction mechanism is derived with the addition of non-dissociated [K(18-cr-6)SBu] to acetylene as the rate-determining step.