Preparation and photoconductivity of ethylenediamine-bridged iron phthalocyanine polymer [PcFe(eda)]n

An ethylenediamine (eda)-bridged iron phthalocyanine (FePc) polymer [PcFe(eda)]_n was synthesized by the complexing of ethylenediamine and FePc. Through electric field poling, a novel low-dimensional [PcFe(eda)]_n-PVDF film was obtained. The characterization of the film by DSC, angle-dependents XPS, FT-IR Reflection Absorption Spectroscopy (FTIR-RAS) revealed that the planes of phthalocyanine rings were parallel to the film surface. The photoconductivities of the photoreceptors (P/Rs) made from polarized or unpolarized [PcFe(eda)]_n-PVDF film and different charge transfer materials were measued. It was found that the photoconductivities of P/Rs from [PcFe(eda)]_n were much better than those of P/Rs from FePc, and after the orientation of electric field, the photoconductivities of P/Rs from [PcFe(eda)]_n increased greatly. These changes were ascribed to the effects of the low dimension of the molecular and material structure. In ESR spectra, both the complexation of FePc and ethylenediamine and the polarization of electric field raised the charge carrier density, which suggesting that in low-dimensional materials the intramolecular and intermolecular charge transfer interactions may increase significantly, resulting in the improvement of photoconductivities. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 64: 1769–1774, 1997     

Optimum reaction conditions for polypyrrole film deposition with some iron(III) compounds

The optimum reaction conditions for the deposition of smooth conductive polypyrrole (PP) films were monitored using a quartz crystal microbalance technique. This is for oxidative polymerization of pyrrole with some iron(III) compounds. The FeCl₃ · 6H₂O/pyrrole system in aqueous solution at 20 ± 0.5°C was examined in some detail. The effect of the initial molar ratio of the reactants on the yield and the growth rate of the PP film deposition was studied. The optimum molar ratio was found to be approximately 2.4 ± 0.1. A comparison between the growth rate of the PP films was made when different iron(III) compounds were used. The rate is shown to be affected by the nature of the anions in these compunds.     

表面带磺酸基团的聚苯乙烯微球的制备及其对蛋白质的吸附

研究了运用分散聚合法,在乙醇/水混合介质中,制备2-丙烯酰胺基-2-甲基丙磺酸(AMPS)与苯乙烯(St)的共聚微球。运用红外、核磁共振、激光光散射和扫描电子显微镜对功能微球进行表征。阐述了该微球对牛血清蛋白(BSA)的吸附量与吸附时间和pH值的关系。结果表明:功能微球对BSA的吸附先随时间的增长而增大,一段时间后达到平衡吸附。当pH值接近BSA等电点(pI=4.7)时,BSA的吸附量达到最大值。     

Spectrophotometric study of the complexation equilibria of iron(III) with 3-hydroxypicolinic acid and determination of iron in pharmaceutical preparations

The complexation equilibria of iron(III) with 3-hydroxypicolinic acid (hypa) have been studied spectrophotometrically in 40% (v/v) ethanol—water medium at 25°C and an ionic strength of 0.1 M NaClO₄. The equilibria occurring in solution were established and the basic characteristics of the complexes formed were determined. The spectral study of the reaction solutions containing equimolar concentrations or an excess of one component in the pH range 1.5 to 10.5 gave the evidence for the formation of [FeLH]²⁺, [FeL]⁺ and [FeL₂]^? complex species, depending upon the pH of the medium (LH₂ symbolising the molecular form of hypa). The possible complex transitions that occur in solution were demonstrated using graphical and logarithmic analysis of the absorbance—pH graphs. A simple, rapid, sensitive and selective method for spectrophotometric determination of trace levels of iron(III) was proposed based on the formation of Fe(hypa)₂ complex at pH 5.5 (λ = 440 nm, ? = 1.5 × 10⁴ dm³ mol^?1 cm^?1). The interference of a large number of foreign ions was investigated. The method has been applied successfully to the analysis of multivitamin and mineral preparations containing iron.     

Novel Diglycolamic Acid Functionalized Iron Oxide Particles for the Mutual Separation of Eu(III) and Am(III)

Iron oxide (Fe₃O₄) particles functionalized with diglycolamic acid (Fe-DGAH) were synthesized and characterized by TG-DTA, X-Ray diffraction,¹H NMR, and scanning electron microscopy (SEM). The extraction behavior of Am(III) and Eu(III) in Fe-DGAH was studied from dilute nitric acid medium to examine the feasibility for the mutual separation of trivalent actinides and lanthanides using Fe-DGAH. For this purpose, the effect of various parameters such as the duration of equilibration and concentrations of europium, nitric acid, and diethylenetriaminepentaacetic acid (DTPA) in the aqueous phase on the distribution ratio (K_d) of Am(III) and Eu(III) was studied. The conditions needed for the efficient separation of Am(III) from Eu(III) were optimized using DTPA. The distribution ratio of ?10⁴ mL/g was obtained for both Am(III) and Eu(III) at pH 3, and it decreased with an increase in the concentration of nitric acid. However, a separation factor of Eu(III) over Am(III) of ?150 was achieved in the presence of DTPA. Rapid sorption of metal ions in the initial stages of equilibration followed by the establishment of equilibrium occurred within 2 h. The sorption data were fitted to the Langmuir adsorption model, and the apparent europium sorption capacity was determined to be ?50 mg/g. The study indicated the feasibility of using Fe-DGAH particles for magnetic separation of Eu(III) from Am(III) with high separation factors.     

The surface modification of magnetic poly(methyl acrylate) microspheres with dendron and application in Au(III) adsorption

An improved suspension polymerization method for preparation of the magnetic poly(methyl acrylate) microspheres (mPMA‐DVB) was investigated. Through subsequent reaction with methyl acrylate (MA) and ethylenediamine (EDA), the magnetic poly(methyl acrylate) microspheres with dendron surface was obtained, and the magnetic poly(methyl acrylate) microspheres with dendron surface reacted with carbon bisulfide and sodium hydroxide to create sodium dithiocarbamate. Following, the resultant magnetic microspheres with dendron surface modification were used to adsorb Au(III) from aqueous solution. The result showed that the capacity of amino groups on the surface of the mPMA microspheres increased from 1.67 mmol/g for the magnetic polymer microspheres with G₀ dendron to 4.35 mmol/g with G₃ dendron, and the adsorption capacity rose from 0.1981 g/g with G₀ dendron to 0.7853 g/g with G₃ dendron. The effects of solution pH, the adsorption temperature, the adsorption time, and the initial concentration of Au(III) on the adsorption of Au(III) were studied, the optimum pH for Au(III) adsorption was found at pH = 1, the adsorption capacity achieved the maximum in 60 min, and the adsorption process was endothermic reaction and conformed to pseudo‐second‐order kinetic models. Furthermore, the adsorption process was in accordance with the Langmuir model. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Oxidation of 3-methylindole catalyzed by cobalt(II)phthalocyanines covalently bound to polyorganosiloxane

Two kinds of cobalt(II)phthalocyanines covalently bound to polyorganosiloxane (POS) were prepared to be applied as catalysts for the oxidation of 3-methylindole in organic solvents. The catalytic activity of the POS whose carboxyl residues were methyl-esterified was high compared with that of the POS which has carboxyl residues. The former polymeric atalyst exhibited higher catalytic activity than monomolecular phthalocyanine, indicating an appearance of effects of polymer chains. The factors which influence the catalytic oxidation, e.g., polymer conformations, basicity of solvents, and equilibrium involving phthalocyanine monomer and the dimer, are discussed. It has become apparent that polymer conformation influences catalytic activity and that the catalytic activity of the POS, whose main chains are mobile, is high.     

Synthesis of a new iron(III) porphyrin acrylate-styrene copolymer and its catalysis for hydroxylation of cyclohexane

A new iron(III) porphyrin acrylate-styrene copolymer, P[(PorFe)A-S], was synthesized by the reaction of iron(III) porphyrin acrylate with styrene and characterized by UV-Vis, Infrared spectra (IR), inductively coupled plasmaatomic emission spectrometry (ICP) and molecular weight determination. Its catalytic activity in the hydroxylation of cyclohexane for model cytochrome P450 in the P[(PorFe) A-S]-O₂-ascrobate-thiosalicylic acid system has been studied. It was found that the P[(PorFe)A-S] has a higher catalytic activity than non-supported iron(III) porphyrin and its high catalytic activity remained in reuse. The catalytic activity of P[(PorFe)A-S] was discussed in the view of the microenvironment of iron(III) porphyrin. It is proposed that the catalytic activity of the P[(PorFe)A-S] may be further enhanced by construction of a homophase catalytic system containing the iron(III) porphyrin acrylate-styrene copolymer. Translated from Acta Scientiarum Naturalium Universitatis Sunyatseni, 2006, 45(1): 61–63 [译自: 中山大学学报 (自然科学版)]     

Ability of iron(III)‐loaded carboxylated polyacrylamide‐grafted sawdust to remove phosphate ions from aqueous solution and fertilizer industry wastewater: Adsorption kinetics and isotherm studies

Iron(III)‐loaded carboxylated polyacrylamide‐grafted sawdust was investigated as an adsorbent for the removal of phosphate from water and wastewater. The carboxylated polyacrylamide‐grafted sawdust was prepared by graft copolymerization of acrylamide and N,N′‐methylenebisacrylamide onto sawdust in the presence of an initiator, potassium peroxydisulfate. Iron(III) was strongly attached to the carboxylic acid moiety of the adsorbent. The adsorbent material exhibits a very high adsorption potential for phosphate ions. The coordinated unsaturated sites of the iron(III) complex of polymerized sawdust were considered to be the adsorption sites for phosphate ions, the predominating species being H₂PO ions. Maximum removal of 97.6 and 90.3% with 2 g L^?1 of the adsorbent was observed at pH 2.5 for an initial phosphate concentration of 100 and 250 μmol L^?1, respectively. The adsorption process follows second‐order kinetics. Adsorption rate constants as a function of concentration and temperature and kinetic parameters, such as ΔG^±, ΔH^±, and ΔS^±, were calculated to predict the nature of adsorption. The L‐type adsorption isotherm obtained in the sorbent indicated a favorable process and fitted the Langmuir equation model well. The adsorption capacity calculated by the Langmuir adsorption isotherm gave 3.03 × 10^?4 mol g^?1 of phosphate removal at 30°C and pH 2.5. The isosteric heat of adsorption was also determined at various surface loadings of the adsorbent. The adsorption efficiency toward phosphate removal was tested using industrial wastewater. Different reagents were tested for extracting phosphate ions from the spent adsorbent. About 98.2% of phosphate can be recovered from the adsorbent using 0.1M NaOH. Alkali regeneration was tried for several cycles with a view to recover the adsorbed phosphate and also to restore the adsorbent to its original state. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2541–2553, 2002     

Effect of polymer compositions on the fabrication of poly(ortho‐ester) microspheres for controlled release of protein

Eight kinds of self‐catalyzed poly(ortho‐esters) (POEs) are used to fabricate bovine serum albumin (BSA)‐containing microspheres using a W/O/W double‐emulsion solvent extraction/evaporation method. All eight kinds of POE polymers used in this study are shown able to form microspheres under proposed fabrication conditions. The surface morphology and inner structure of the microspheres are analyzed using scanning electron microscopy (SEM). The microspheres have a size range from 64.7 to 120.2 μm. POE with a higher viscosity leads to bigger microspheres. It was found that the POE composition has a significant effect on BSA release profiles. POEs, which are more hydrophilic and contain a greater amount of glycolide or lactate (latent acid), yield higher BSA release rates. Specifically, POE containing 1,6‐hexanediol diglycolide (HD‐diGL) microspheres have the highest BSA release rate after a 20‐day test through a combination of surface erosion and diffusion mechanisms. POE containing a high percentage of the trans‐cyclohexanedimethanol (CDM) segment tends to yield microspheres with a lower release rate because of its hydrophobic nature. It was also found that the BSA release rate is more rapid at 37°C than at 22°C because of faster polymer degradation and water penetration at 37°C. Experimental results suggest that various protein release rates can be achieved by using different compositions of POEs. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1630–1642, 2001     

Tailorable polyelectrolyte protein complex based on poly(aspartic acid) and bovine serum albumin

Protein–polyelectrolyte complexes (PPC) are playing an important role in a variety of chemical and biological processes, such as protein separation, enzyme stabilization, and polymer drug delivery. The present investigation is focused on evaluation of the PPC formation between a synthetic polypeptide (poly(aspartic acid) – PAS) and a natural protein (bovine serum albumin – BSA). The PPC obtained from PAS and BSA in different ratio was investigated by corroboration of various techniques of characterization as: spectroscopy, microscopy, thermogravimetric analysis, dynamic light scattering (DLS), and zeta potential determination, measurements which were performed in static and/or dynamic conditions. The static contact angle of the sample films was also determined in order to evaluate the changes brought upon surface free energy of the prepared PPCs in interdependence with the complexes composition. The critical conditions for complex formation in BSA–polyelectrolyte systems were underlined. The phenomenon was better evidenced in case of a ratio of 1/1 wt between the two polymers, both in static and/or dynamic conditions.     

Photopolymerization of Methyl Methacrylate Sensitized by Tris(2,2′-bipyridine)iron(III)

The photopolymerization of methyl methacrylate (MMA) sensitized by tris(2,2′-bipyridine)iron(III ) complex, [Fe(bpy)₃]³⁺, was studied at 35°C in the presence of an electron donor, triethylamine (TEA) with UV radiation of wavelength 254nm. The initial rate of polymerization, R_p, shows a linear dependence on [MMA] with an exponential value of 1·18±0·04. R_p varies linearly with the square root of the photosensitizer concentration up to 2·00×10^-4moll^-1, and above this concentration, R_p decreases with the increase of photosensitizer concentration. The rate of polymerization is not affected by the concentration of the co-initiator, [TEA]. A suitable mechanism for the reaction is proposed to explain the kinetics of the reaction. © 1997 SCI.     

Catalytic oxidation of olefins with hydrogen peroxide catalyzed by [Fe(III)(salen)Cl] complex covalently linked to polyoxometalate

The catalytic activity of a hybrid compound [Fe(salen)-POM] (1) consisting of Fe(III)(salen)Cl [H₂salen = N,N′-bis(salicylidene)ethylenediamine] complex covalently linked to a Keggin type polyoxometalate, K₈SiW₁₁O₃₉, (POM) was studied in the oxidation of various olefins in acetonitrile, using hydrogen peroxide as oxygen source. While, [Fe(salen)-POM] catalyst showed moderate to good catalytic activity and product selectivity in the oxidation reactions, the complex Fe(III)(salen)Cl showed poor catalytic activity in these reactions. The effect of other parameters such solvent, oxidant, temperature and the metal type in Schiff base complex were also investigated.     

Review of the hydrolysis of iron(III) and the crystallization of amorphous iron(III) hydroxide hydrate

Hydrolysis of ferric solutions leads initially to mono- and dinuclear species which interact to produce further species of higher nuclearity. These polynuclear species age eventually to either crystalline compounds or to an amorphous precipitate (amorphous iron(III) hydroxide hydrate). Amorphous iron(III) hydroxide hydrate is thermodynamically unstable and gradually transforms to α-FeO(OH) and α-Fe₂O₃. These crystalline products form by competing mechanisms and the proportion of each in the final product depends on the relative rates of formation. The master variable governing the rates at which these compounds form is pH. Other important factors are temperature and the presence of additives. Most additives retard the transformation and by suppressing formation of α-FeO(OH) lead to an increase in the amount of α-Fe₂O₃ in the product; some additives also directly promote formation of the latter compound. Metal ions can oftxen replace a proportion of Fe in the α-FeO(OH) and α-Fe₂O₃ lattices. At high enough concentrations they can induce formation of additional phases. Additives may also modify the morphology of the crystalline products.     

Single-layer white polymer light-emitting diodes based on an iridium (III) complex containing alkyltrifluorene picolinic acid

To explore the relationship between the electronic properties of a host/dopant system and obtain a high-efficiency single-dopant white polymer light-emitting device two novel blue-emitting cyclometalated iridium (III) complexes of (dfppy)₂Ir(Tfl-pic) and (dfppy)₂Ir(Brfl-pic) have been synthesized and characterized, where dfppy is 2-(2,4-difluorophenyl)pyridine, Tfl-pic and Brfl-pic are picolinic acid derivatives containing trialkylfluorene and dibromoalkylfluorene units bridged with an alkoxy chain, respectively. Both iridium (III) complexes exhibited blue emission in dichloromethane solution and their neat films, and possessed good dispersibility and thermal properties. Two different devices using (dfppy)₂Ir(Tfl-pic) as a single component emitter and a blend of poly(N-vinylcarbazole) and 2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole as the host matrix were fabricated. Improved white emission was obtained by adjusting the electron injection layer leading to efficient exciplex emission.     

Polyisobutene-poly(methylmethacrylate) interpenetrating polymer networks: synthesis and characterization

Interpenetrating polymer networks (IPNs) combining polyisobutene (PIB) and poly(methyl methacrylate) (PMMA) networks were prepared using a in situ strategy. PIB networks were formed by isocyanate—alcohol addition between the hydroxyl end groups of telechelic dihydroxy-polyisobutene and an isocyanate cross-linker, catalyzed by dibutyltindilaurate (DBTDL). PMMA networks were obtained from free-radical co-polymerization of methyl methacrylate (MMA) with ethylene glycol bismethacrylate (EGDM) in the presence of dicyclohexyl peroxydicarbonate (DCPD) as the initiator. The synthesis of each network during the IPN formation was followed by FTIR spectroscopy. The highest degree of interpenetration is obtained by forming the PIB network first. The corresponding transparent IPNs exhibit two mechanical relaxation temperatures as determined by Dynamic mechanical thermal analysis (DMTA), corresponding to those of PMMA and PIB enriched phases. Mechanical properties of PIB networks are tremendously improved by the presence of PMMA network in such IPN architecture.     

Ethanosolv pretreatment of barley straw with iron(III) chloride for enzymatic saccharification

BACKGROUND: Barley straw is a potential lignocellulosic biomass for the production of bioethanol because of its high cellulose and hemicelluloses content. Ethanosolv pretreatment catalyzed with inorganic acids has some undesirable effects, and thus, inorganic salts, such as FeCl₃, were studied as the catalyst in order to enhance enzymatic digestibility. RESULTS: The addition of 0.1 mol L^?1 FeCl₃ (Iron(III) chloride) had a particularly strong effect on the enzymatic digestibility, reaching a value as high as 89%, with cellulose recovery as high as 90% after the ethanosolv pretreatment. The enzymatic digestibility was 89% and 55% after the addition of 0.1 mol L^?1 FeCl₃ and H₂SO₄ (adjusted to the same pH), respectively. The enzymatic hydrolysis rate was significantly accelerated as the ethanosolv temperature increased, reaching the highest enzymatic digestibility of 89% after 72 h at 170 °C. The concentrations of HMF(5‐hydroxy‐2‐ methyl furfural) and furfural were 0.011 and 0.148 g L^?1 in the hydrolysate during FeCl₃‐ethanosolv treatment, which were lower than the concentrations quantified during H₂SO₄‐ethanosolv treatment. After the pretreatment, 88.5% of FeCl₃ was removed through the filtration process. CONCLUSION: The addition of several inorganic salts significantly accelerated enzymatic digestibility in the ethanosolv. FeCl₃ had a particularly strong effect on enzymatic digestibility and cellulose recovery. The formation of HMF and furfural and the remaining amount of FeCl₃ were investigated, and FeCl₃ had no effect on the subsequent processes after pretreatment. Copyright © 2010 Society of Chemical Industry     

Synthesis and characterization of poly(N-vinyl pyrrolidone-alt-maleic anhydride): Conjugation with bovine serum albumin

Alternate N-vinyl pyrrolidone/maleic anhydride (NVPMA) copolymers were obtained by radical solution polymerization in dioxane with various MA contents in the monomer feed. The conversion of each monomer was monitored by proton nuclear magnetic resonance spectroscopy (¹H NMR), and the kinetics investigation showed that both monomers had identical polymerization rates if both monomers were present in the reaction mixture. The presence of excess NVP in the polymerization medium increased the kinetics of the polymerization and the molar masses of the resulting polymers. This increase was attributed to a cosolvent effect due to NVP, which is a better solvent for the polymer than dioxane. The hydrolysis rate constant of the polymers increased with pH, and NVPMA copolymers were more prone to hydrolysis (by a factor 10) than the methyl vinyl ether ones. Finally, the immobilization of bovin serum albumin (BSA) was investigated. A 25 mM phosphate buffer (pH 5.5) was the best medium to covalently bind 5 BSA molecules onto a 29 kDa NVPMA copolymer and 13 BSA molecules onto a 58 kDa sample, with grafting efficiencies > 90%. Noncovalent interactions with the hydrolyzed form of the polymer and BSA occured at pHs lower than the isoelectric point of BSA, and the resulting complexes were insoluble in water. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 3327–3337, 2001