Quantitative Quaternization of Poly(4-Vinyl Pyridine)

Quaternization of poly(4-vinyl pyridine), (P4-VP) by common alkyl halides can be performed with relatively low (up to 65–70%) conversion yields. Here we describe fully quaternization of P(4-VP) with activated halides such as chloro 2-propanone and 2-chloroacetamide in dimethylformamide (DMF) at room temperature.     

Ion-specific swelling behaviors of partially quaternized poly(4-vinyl pyridine) gel

Swelling degrees of partially quaternized poly(4-vinyl pyridine) (p.q.P4VP) were measured as functions of the degree of quaternization (D.Q.: 5, 10, 15, 30, and 50 mol%), salt concentration (0–4 M), and salt species (KF, LiCl, NaCl, KCl, CsCl, MgCl₂, KBr, LiSCN, KSCN, Na₂SO₄, and MgSO₄) to study ion effects on the three kinds of interactions involved with p.q.P4VP in aqueous systems, i.e., electrostatic interaction, hydrogen bonding to the nitrogen of the pyridine ring, and hydrophobic interaction, as well as to estimate the relative contributions of the respective ion effects to gel swelling. Upon addition of salts at the lowest salt concentration studied (0.01 M), p.q.P4VP gels, except for one with D.Q.=10%, significantly deswelled depending on the counterion species; the lowest swelling degree was observed for the thiocyanates and the highest one for KF. In the higher salt concentration region (≧1 M) where electrostatic interactions might well be screened, however, some salt systems (e.g., LiCl, KSCN) showed swelling with increased salt concentration, contrary to the common behavior of usual ionic gels. These ion-specific swelling behaviors were interpreted as being caused by additive ionic effects on the three kinds of interactions.     

The synthesis and properties of adducts between poly(4-vinyl pyridine) and metal alkyls

Poly(4-vinyl pyridine) is used as a polymeric ligand to react with metal alkyls, Me_nM (n = 3, M = Al, Ga or In; n = 2, M = Cd or Zn) to form adducts. The adducts are characterized by solid state ¹³C NMR, infrared spectroscopy, microanalyses and differential scanning calorimetry (DSC). All the adducts are nonpyrophoric and thermally dissociable, so they may have potential both for use in adduct purification processes or for use as safer metal alkyl sources for Metal–Organic Chemical Vapor Deposition.     

Copper iodide nanoparticles on poly(4-vinyl pyridine) as new and green catalyst for multicomponent click synthesis of 1,4-disubstituted-l,2,3-triazoles in water

Poly(4-vinyl pyridine) supported nanoparticle of copper(Ⅰ) iodide is reported as a green and recyclable catalyst for the regioselective synthesis of 1,4-disubstituted-1H-1,2,3-triazoles from benzyl halides,sodium azide and terminal alkynes in water. This catalyst can be recovered by simple filtration and recycled up to 8 consecutive runs without any loss of its efficiency.     

Kinetics and steric limitation of quaternization of poly(4-vinylpyridine) with mesogenic ω-(4′-methoxy-4-biphenylyloxy)alkyl bromides

The kinetics and characteristics of the quaternization of poly(4-vinylpyridine) with very large alkylating agents are studied with the main aim to demonstrate the occurrence of a limitation of the reaction due to steric effect. Kinetics are carried out in sulfolane at different temperatures with two ω-(4'-methoxy-4-biphenylyloxy)alkyl bromides. An important limitation of the reaction is demonstrated: 30% of the pyridine groups are inaccessible at 333 K, 23% at 355.5 K, and 4% at 363 K. Post-quaternization experiments with butyl bromide of already partially quaternized P4VP also demonstrate this limitation. The occurrence of global steric hindrance and hydrophobic effects affecting the conformation of the chain in solution is proposed to explain the limited accessibility of the pyridine groups. The results question the classical neighboring group model generally used to describe the slowing down of the quaternization reaction with increasing quaternization ratio. The thermal stability of the quaternized polymers and the colors of the reaction medium are also discussed. © 1992 John Wiley & Sons, Inc.     

Glass transition of thin films of poly(2-vinyl pyridine) and poly(methyl methacrylate): nanocalorimetry measurements

Glass transitions were observed in thin films of poly(2-vinyl pyridine) (P2VP) and poly(methyl methacrylate) (PMMA) using a scanning nanocalorimetry technique which has both high sensitivity (10⁻⁹ J/K) and high scan rates (10⁴-10⁵ K/s). Samples were deposited by the spin-cast method. The thickness of samples was 100-400 nm. Glass transition temperature, obtained by nanocalorimetry, is shifted toward higher temperatures by 10-20 K and activation enthalpy of glass transition is shifted to lower values by factor of 2-4. The glass transition characteristics of both polymers are discussed in terms of the standard Tool-Narayanaswamy-Moynihan (TNM) multi-parameter model.     

Synthesis, characterization and catalytic oxidation of tetrahydrofuran with 16-membered pentaazabis(macrocyclic) copper(II) complexes; {[Cu([16]aneN5)]2R}4+ (R = aromatic nitrogen–nitrogen linkers)

New square-planar bis(macrocyclic)dicopper(II) complexes containing phenylene bridges between 16-membered pentaaza macrocyclic subunits have been synthesized via in-situ one pot template condensation reaction (IOPTCR) of aromatic nitrogen-nitrogen linker (R = 1,4-phenylenediamine; benzidine; 4,4′-diaminodiphenylmethane; 4,4′-diaminodiphenylether; 4,4′-diaminodiphenylsulfone), formaldehyde, bis(1,3-diaminopropane)copper(II) perchlorate and 1,3-dibromopropane in a 1:4:2:2 molar ratio results in the formation of new series of binuclear copper(II) complexes; 1-phenyl- (1); 1,1′-phenyl- (2); 1,1′-diphenylmethan- (3); 1,1′-diphenylether- (4); 1,1′-diphenylsulfone- (5) bis(1,3,7,11,15-pentaazacyclohexadecane)copper(II)), {[Cu([16]aneN₅)]₂R}(ClO₄)₄″. The formation of the macrocyclic framework and the mode of bonding of the complexes have been confirmed by data obtained from elemental analyses, UV-visible, FT-IR, ¹H-NMR, electronic spectral studies, conductivity and magnetic susceptibility measurements. These bis(macrocyclic) complexes catalyzed efficiently the selective oxidation of tetrahydrofuran into tetrahydrofuran-2-one and a small amount of tetrahydrofuran-2-ol and 4-hydroxybutyraldehyde using dil. H₂O₂ as the oxidant.     

聚4-乙烯基吡啶与Cu(Ⅱ)离子配合过程及配合物的结构

采用粘度法确定了聚4-乙烯基吡啶(P4VP)在乙醇/水混合溶剂中的临界交迭浓度c*, 分别在稀溶液与亚浓溶液浓度范围内, 采用光谱法与电导滴定法研究了P4VP与Cu(II)离子的配合过程及配合物的结构, 通过红外光谱(FTIR)对配合物的化学结构进行了表征, 并用差示扫描量热法(DSC)测定了配合物的热性能. 结果表明, 对于相对分子质量为1.06×105的P4VP, 其c*为15 mmol•L−1(按P4VP中的链节量计算). 在稀溶液中P4VP与Cu(II)离子形成可溶性的分子内配合物, 表观配位数为9~10；在亚浓溶液中, P4VP与Cu(II)离子发生分子间配合作用, 由于配位交联, 形成不溶性的配合物P4VP-Cu(II), 配位数为3. P4VP与Cu(II)离子形成配合物后, 玻璃化温度明显提高.     

Preparation and characterization of SBA‐15 supported iron(II)‐bisimine pyridine catalyst for ethylene polymerization

2,6‐Diacetylpyridinebis (2,6‐diisopropylani) iron dichloride, a late‐transition metal catalyst for olefin polymerization, was supported on SBA‐15 successfully and the property of the supported catalyst was carefully studied. Ethylene polymerization was systematically investigated in the presence of MAO under various conditions employing this type of catalyst system. In general, after support, a decrease in the catalytic activity was observed and higher molecular weight and fibrous morphology of polyethylene were obtained. The “extrusion polymerization” phenomenon was observed in ethylene polymerization by using the supported catalyst system. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4830–4837, 2004     

Effects of chemical modifications on the swelling behaviors of poly (4-vinyl phenol) gel

Poly (4-vinyl phenol) (P4VPh) gels were prepared by crosslinking with a hydrophilic crosslinker [ethyleneglycoldiglycidylether (EGDGE)] and a hydrophobic one [diglycidyl 1,2-cyclohexane dicarboxylate (DGCHDC)], and the former gel was further modified by CH₃I or C₂H₅I to partially convert the hydrogen of phenol OH to the corresponding alkyl groups. Swelling behaviors of P4VPh gels, thus modified, were investigated to see how the hydrophobic groups introduced to the crosslinker and the polymer substrate affect the super salt resistivity to inorganic ions and the high water content (>90%) that have been observed for the original P4VPh gel. Water content and salt resistivity were unexpectedly preserved even for the modified gels. Effects of the chemical modifications on the gel swelling were only observed in the presence of hydrophobic solutes, i.e., tetrabutyl ammonium chloride and ionic surfactants. All these results strongly suggest that hydration around the polymer substrate in the gel phase is specifically stabilized, probably because of the coexistence of the hydrophobic hydration and the π-hydrogen-bonding hydration around the phenol ring.     

生物基超韧聚乳酸复合材料的制备与性能

采用来源于可再生资源的聚醚酰胺弹性体（PEBA）增韧聚乳酸（PLA）制备超韧聚乳酸（PLA/PEBA-GMA）复合材料.为了提高PEBA与PLA之间的相容性,选择极性单体甲基丙烯酸缩水甘油酯（GMA）、共接枝单体乙烯基吡咯烷酮（NVP）及引发剂过氧化二异丙苯（DCP）对PEBA进行接枝改性制备PEBA-GMA.研究了接枝单体组分的用量（m/g）对PLA/PEBA-GMA复合材料性能的影响.研究发现,随着接枝单体组分用量的提高,复合材料的缺口冲击强度逐渐增大,当接枝单体组分GMA,NVP和DCP的用量分别为2.5,2.5和0.25 g时,复合材料的冲击强度高达88.6 kJ/m²,断裂伸长率为164.1%.研究表明,在熔融共混过程中,聚乳酸的端基（—OH和—COOH）与PEBA-GMA上环氧基团发生反应,有效改善两相间的界面相容性,随着接枝单体组分比例的提高,分散相PEBA-GMA的粒子尺寸逐渐减小且分布均匀.     

Poly(4-vinylpyridinium tribromide) as metal-free, green and recoverable oxidizing polymer for the chemoselective oxidation of sulfides into sulfoxides

Poly(4-vinylpyridinium tribromide) was prepared from poly(4-vinylpyridin) and used for the selective oxidation of a variety of sulfides to the corresponding sulfoxides.The oxidation reaction was carried out heterogeneously in acetone/water,as green solvent, at room temperature.     

Preparation, structure and catalytic activity of copper(II) complexes of novel 4,4′-BOX ligands

This Letter details the synthesis of two new 4,4′-bisoxazoline (BOX) ligands. The copper(II) complex of one of the new ligands is structurally determined. The catalytic performance of the copper(II) complexes of the novel ligands, and that of our recently described phenyl AraBOX ligand in Diels-Alder reactions are reported. We have used the structural information to propose an explanation of a curious variation in the diastereoselectivity obtained in the case of one ligand complex.     

Synthesis and Characterization of an Unexpected Asymmetric Binuclear Copper（Ⅰ） Complex Containing 4-Vinyl-pyridine

The asymmetric binuclear copper(I) complex [Cu₂(dppm)₂(C₇H₇N)(μ‐HCOO)](NO₃) (dppm=Ph₂PCH₂PPh₂, C₇H₇N=4‐vinyl‐pyridine) has been prepared and characterized by physicochemical and spectroscopic methods. The complex is photoluminescent at room temperature. It crystallizes in triclinic system, space group P‐1 with a= 1.2719(3) nm, b=1.8637(4) nm, c=1.1656(2) nm, a=97.16(3)°, β= 104.94(3)″, γ=89.39(3)°, V=2.648.1(9) nm³, D_c= 1.390 g.m^?3, Z=2, μ=0.974 mm^?1, R=0.0483 for 5716 independently observed reflections with I>2δ(I). The structure consists of [Cu₂(dppm)₂(C₇H₇N)(μ‐HCOO)]⁺cations and nitrate anions. The copper atoms show different coordination modes: Cu(1) displays a distorted trigonal and Cu(2) a tetrahedred geometry.     

Electroless Deposition of Copper on Poly(tetrafluoroethylene) Films Modified by Plasma-Induced Surface Grafting of Poly(4-vinylpyridine)

Argon plasma-pretreated poly(tetrafluoroethylene) (PTFE) films were solution coated with a thin layer of poly(4-vinyl pyridine) (P4VP). Subsequent exposure of the films to argon plasma resulted in the grafting of P4VP on the PTFE films. Electroless plating of copper could be carried out effectively on the P4VP-grafted PTFE (P4VP-g-PTFE) surface after PdCl₂ activation and in the absence of SnCl₂ sensitization (the Sn-free process). The catalytic processes of the electroless plating of copper in the presence and absence of sensitization by SnCl₂ were also compared. The effect of glow discharge conditions on the P4VP concentration and the adhesion strength of the electrolessly deposited copper was investigated. The T-peel adhesion strength of the electrolessly deposited copper with the graft-modified PTFE film was improved in the absence of SnCl₂ sensitization and could reach about 3 N/cm. PdCl₂ activation and electroless deposition of copper could not be carried out on the pristine or the Ar plasma-treated PTFE surface in the absence of prior sensitization by SnCl₂. X-ray photoelectron spectroscopic (XPS) analysis revealed that the electrolessly deposited copper delaminated from the P4VP-g-PTFE film by cohesive failure inside the PTFE film.     

Oxidation of Stereo‐regular Poly(styrene‐co‐4‐methylstyrene) by Cobalt(II) Acetate Tetrahydrate/Sodium Bromide Catalyst

Chemical modification on the stereo‐regular poly(styrene‐co‐4‐methylstyrene) (sPS‐PMS) was attempted in this study. Metallocene copolymerization of styrene (St) and 4‐methylstyrene (MSt) was performed by using η⁵‐pentamethylcyclopentadienyl‐titanium(IV)tributoxide (Cp*Ti(OBu)₃)/methylaluminoxane (MAO)/tri‐iso‐butylaluminum (TIBA) catalyst in the bulk state. Cobalt(II) catalyst was then applied to oxidize the benzylic methyl group on the MSt units of the resulting sPS‐PMS copolymer. Both aldehyde and carboxylic acid in the oxidized products were resolved by the FTIR and ¹H NMR. The oxidized sPS‐PMSs exhibit a low and a high‐temperature T_g and T_m corresponding to the transitions in the amorphous and the crystalline regions. Hydrogen‐bond and polar interactions between the aldehyde and carboxylic acids tend to interrupt the regular chain packing of the oxidized sPS‐PMS, resulting in the lowering of T_m with oxidation level. The oxidized sPS‐PMS showed better adhesion to glass fiber than pure sPS‐PMS copolymer as evaluated from the respective SEM fractured micrographs.     

聚环氧乙烷与聚2-乙烯基吡啶混物的导电率及高氯酸锂的增容作用

研究了聚环氧乙烷(PEO)/聚2-乙烯基吡啶(P2VP)的共混物分别经LiCLO₄、四氰基代苯醌二甲烷(TCNQ)及两者共同掺杂后其共混物的离子、电子及混合导电率。当PEO与P2VP的重量比分别为6/4、5/5及4/6时,共混物的混合导电率大于相应的离子及电子导电率的总和,呈现协同效应。从共混物外观的研究发现LiCLO₄能作为PEO/P2VP共混体系的增容剂。     

Complexes of Co(II), Ni(II) and Cu(II) with lapachol

Complexes of naturally occurring hydroxynaphtho-quinone, lapachol (2-hydroxy-3(3-methyl-2-buthenyl)-1,4-naphthoquinone = HL) with Co(II), Ni(II) and Cu(II) have been prepared by reaction of the corresponding acetates with the ligand (HL) in ethanol. The molecular and crystal structures were determined for [CoL₂(EtOH)₂] (1), [NiL₂(EtOH)₂] (2), and [CuL₂(py)₂] (3). In all cases the deprotonated lapachol behaves as chelating bidentate ligand. The complexes were also characterized by elemental analyses, cyclic voltammetry, and FAB-MS.     

Bis(imino)pyridine palladium(II) complexes: Synthesis, structure and catalytic activity

Bis(imino)pyridine palladium(II) complexes 3-6 were synthesized by two different methods. The structure of complexes 3 and 4 has been confirmed by X-ray structure analysis. The catalytic studies show that bis(imino)pyridine palladium(II) complexes are highly efficient catalysts in the Suzuki-Miyaura reaction and the complex 4 was used to catalyze the synthesis of fluorinated liquid crystalline compounds via Suzuki coupling reaction.     

Stereoregular control of poly(4‐vinyl pyridine) on free radical polymerization by using the inclusion complex with randomly methylated β‐cyclodextrin

Highly heterotactic poly(4‐vinyl pyridine)s (P4VPs) with the fraction of mr content (f_mr) > 0.81 were synthesized by free radical polymerization of 4‐vinyl pyridine (4VP) with randomly methylated β‐cyclodextrin (β‐RMCD) in acidic aqueous media of HNO₃ and CF₃COOH at 40 °C. The heterotacticity of P4VP strongly depended on the neutralization of 4VP. The complete neutralization of 4VP with HNO₃ or CF₃COOH increased the heterotacticity of P4VP, whereas atactic P4VP was obtained in water. The partial decomposition of β‐RMCD by HCl reduced the heterotacticity of P4VP (f_mr ≈ 0.74). The structures of inclusion complexed monomers were determined by Job's plot, 2D NMR with nuclear Overhauser enhancement spectroscopy analyses, and simulation by MM2. The 1:2 complex with [β‐RMCD]:[4VP] with meso placement of 4VPs in β‐RMCD was formed when 4VP was completely neutralized with acid, whereas the 1:1 complex was formed in water. The mechanism of heterospecific control by using β‐RMCD was proposed. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012