Study on the Synthesis and Characterization of Novel Immobilized β-Cyclodextrin Polymer (Ⅰ)

A series of novel β-cyclodextrin polymers was synthesized by immobilization of β-cyclodextrin on the chloromethylated crosslinked polystyrene carriers. The synthetic conditions such as reaction time, temperature, molar feeding ratio of reactants, the degree of crosslinking of polystyrene and the catalysts used were studied in detail and the chemical and physical structures of the formed β-CDpolymers were characterized. Results show that the preparation method is simple and the amount of β-CD immobilized is high. As biomedical adsorbents, they were tested for removal of various endogenous and exogenous toxins such as phenols, aromatic amins, barbitals and unconjugated bilirubin. Results indicate that the adsorptión capacity for those toxins can be enhanced by the inclusion interaction among the β-CD, the substrate molecules and the β-CD polymers.     

Guest-Binding and Catalytic Properties of Immobilized β-Cyclodextrins

Abstract

Cyclodextrins¹(CyDs), cyclic oligomers of 6–8 glucose units, form inclusion complexes with guest compounds and have been used as catalyst for the selective syntheses.² Previously, immobilization of CyD with epichlorohydrin as crosslinking agent have been described.^3-4 Here, we report the first successful immobilization of β-CyD using various crosslinking agents. The guest binding abilities and the catalytic abilities of these immobilized β-CyDs are shown.     

Kinetics of Catalytic Hydrolysis of Potato Starch by Immobilized β-Amylase

The enzyme activity of immobilized β-amylase carried on active carbon and the reaction kinetics for hydrolysis of potatostarch catalyzed by the enzyme have been investigated. A kinetics model based on the overall reaction has been suggested and a reaction coefficient as a new parameter introduced. All of the kinetics parameters involved in the model, including the reaction coefficient, reaction order rate constant as well as the maximum reaction rate etc. at different temperatures have been obtained by using the modified Quasi-Newton optimization technique.     

Surface Roughness Characterization of Poly(methylmethacrylate) Films with Immobilized Eu(III) β-Diketonates by Fractal Analysis

The structural complexity of the 3-D surface of poly(methylmethacrylate) films with immobilized europium β-diketonates was studied by atomic force microscopy and fractal analysis. Fractal analysis of surface roughness revealed that the 3-D surface has fractal geometry at the nanometer scale. Poly(methylmethacrylate) (PMMA) as immobilization matrix is dense and uniform, and a tendency for formation of chain structures was observed. Fractal analysis can quantify key elements of 3-D surface roughness such as the fractal dimensions D _f determined by the morphological envelopes method of the Eu(DBM)₃ and Eu(DBM)₃ · dpp nanostructures, which are not taken into account by traditional surface statistical parameters.     

Preparation and Characterization of Macroporous Resin Immobilized Pd—Cu Bimetallic Cluster Catalysts

The Solvated Metal Atom Impregnation (SMAI) technique was employed to prepare macroporous resin immobilized Pd-Cu bimetallic cluster catalysts.The X-ray diffraction(XRD) and transmission electron micrograph(TEM) showed that Pd-Cu alloy was formed and the particle sizes of Pd-Cu clusters were very small,with average diameters<3nm.X-ray photoelectron spectroscopy indicated that both Pd and Cu were in zero-valent state.The catalytic activities of the macroporous resin immobilized Pd-Cu catalysts in hydrogenation of 4-methyl-3-penten-2-one were much greater than that of the carbon supported Pd-Cu catalysts.     

Syntheses Characterization of Chloro-cyclopentadienyltricarbonyl-molybdenum with β-Cyclodextrin Supramolecular

Organotransition metal complex have been extensively used as homogeneous catalysts in organic reactions and much effort has been paid to improve their activity and selectively. Cyclodextrins have been studied as a model of enzyme for selective catalysis. However, so far there are only a few reports on the inclusion compounds of organometallic complexes with cyclodextrins. Breslow et al.repored high acylation rates for β-CD using ferrocene derivatives and assumed β-CD substrate complexes as intermediate [1]..larad et al reported the preparation and propertics of cyclodextrin-ferrocen inclusion compounds as the first example of cyclodextrin inclusion compounds of organotransition metal complexes[2]. Song Le-Xin et al reported the supramolecular inclusion compound of β-cyclodextrin with cyclopentadieny-tricarbonylmanganese [3] .To our knowledge, there are no reports of inclusion compounds of β-CD with molybdenum organometallic complexes. In the present work we described the preparation and properties of the supramolecular of CpMo(CO)3Cl with β-CD in details.     

Synthesis and Physical Characterization of β-Alkyl Oligoselenophenes

Russian Journal of General Chemistry - α-Conjugated oligoselenophenes are characterized by very low solubility in organic solvents. Their higher solubility may be achieved by introducing alkyl...     

Preparation and Characterization of Macroporous Resin Immobilized Pd－Cu Bimetallic Cluster Catalysts

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Production, Purification, and Characterization of a β-Glucosidase of Penicillium funiculosum NCL1

Penicillium funiculosum NCL1, a filamentous fungus, produced significantly higher levels of ??-glucosidase. The effect of initial pH, incubation temperature, and different carbon sources on extracellular ??-glucosidase production was studied in submerged fermentation. At 30?°C with initial pH 5.0, enzyme production was increased by 48-fold upon induction with paper mill waste, as compared to commercial cellulose powder. In zymogram analysis, four isoforms of ??-glucosidases were observed with wheat bran whereas a minimum of one isoform was observed with other carbon sources. A major ??-glucosidase (Bgl3A) with the apparent molecular weight of ~120?kDa, induced by paper mill waste, was purified 19-fold to homogeneity, with a specific activity of 1,796 U/mg. Bgl3A was a monomeric glycoprotein with 29% of neutral carbohydrate content. It showed optimum activity at pH 4.0 and 5.0, optimum temperature at 60?°C, and exhibited a half-life of 1?h at 60?°C. K _m of Bgl3A was found to be 0.057?mM with p-nitrophenyl ??-d-glucoside and V _max was 1,920 U/mg. The purified enzyme exhibited glucose tolerance with a K _i of 1.5?mM. Bgl3A readily hydrolyzed glucosides with ??-linkage. Bgl3A activity was enhanced (156%) by Zn²⁺ and was not affected by other metal cations and reagents. The supplementation of Bgl3A (5 U/mg) with Trichoderma reesei cellulase complex (5 FPU/mg) resulted in about 70% of enhanced glucose production, which emphasizes the industrial importance of Bgl3A.     

Synthesis and Characterization of Manganese Tetrafluoride β-MnF4

The crystal structure of β-MnF₄ has finally been elucidated. It crystallizes in the non-centrosymmetric space group R3c, no. 161, hR360, with the lattice parameters a = 19.390(3), c = 12.940(3) Å, V = 4213.3(14) ų, Z = 72, T = 100 K. It is a 4a × 4a superstructure of the VF₃ (FeF₃) structure type. The Mn atoms are coordinated octahedron-like by F atoms, of which two are bound terminal, while the other act as μ-bridging F atoms to other Mn atoms forming a three-dimensional infinite network structure which can be described by the Niggli formula ³_∞[MnF_4/2F_2/1]. Voids on the metal sites, which are occupied in the VF₃ structure, are grouped together in the shape of a “star” with approximate D_3h symmetry. We prepared β-MnF₄ photochemically according to the literature and obtained a phase-pure powder as evidenced by X-ray diffraction at room temperature. The lattice parameters are a = 19.566(3), c = 12.984(2) Å, V = 4304(1) ų. IR and Raman spectra recorded on the powder show that β-MnF₄ has also been obtained free of moisture, HF, and O₂⁺ containing compounds, however MnF₃ is likely present as a magnetic impurity. We observe thermal decomposition of MnF₄ to MnF₂ and not MnF₃.     

Characterization and mechanism study of micrometer-sized secondary assembly of β-cyclodextrin

We herein report a β-cyclodextrin-based secondary assembly (β-CD SA) obtained from an aqueous solution. It was found that the addition of a very small amount of organic molecule 2-phenyl-5-(4-diphenylyl) 1,3,4-oxadiazole (PBD) into an aqueous solution of 10 mM β-CD led to the formation of a micrometer-sized rodlike SA, which made the mixture turbid immediately. After careful characterization, the structure and the formation mechanism of the β-CD SA were suggested. PBD first induces β-CDs to form rigid nanotubes through head-to-head or tail-to-tail routes. Using the "solid" nanotubes as recrystallization centers, other β-CDs assembled to channel in the c axis direction and hexagonally aligned in the b axis direction, leading to the formation of a β-CD SA. In the β-CD SA, most of the β-CDs were not occupied by PBD. In the course of formation , intermolecular hydrogen-bonding plays a prominent role. The results reported herein would be helpful in constructing cyclodextrin-based architectures in water.     

Characterization of Galactosyl-neoglycoalbumin~1 by MALDI-TOF-MS

It was reported there was a membrane receptor, hepatic binding protein (HBP), which resides only at the cell surface of mammalian hepatocytes, selectively bind galactose- terminated glycoprotein for transporting to hepatic lysosomes1. According to this discovery, a special analog ligand, galactosyl-neoglycoalbumin(NGA), was prepared as hepatic targeting drug carrier and hepatic screening agents. The ligand was synthesized by covalent coupling of carbohydate bifunctional reagent, 2-imino-2-et…     

Metathesis of 1-Heptene over Tungsten Catalyst Immobilized on Polymers

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New Approaches for Preparation of β-CDP-PAN and its Characterization

A new type of Electrorheological materials made of an inclusive complex, which was synthesized by the means of molecular self-assembly, show a stronger electrorheological effec than that ofβ-cyclodextrin cross-linking polymer (β-CDP). Three approaches, named liquid-phase, solid-phase and liquid-solid-phase method, are respectively proposed to prepareβ-CDP-PAN, and show that both of the solid-phase and liquid-solid-phase methods are simple and convenient. The inclusion complex was characterized by the fluorescence spectrophotometer, IR and XRD confirming that the naphthalene ring of 1-(2-pyridlazo)-2-naphthol (PAN) was included in the glycopyranose unit ofβ-CDP.     

Synthesis and Characterization of β—Cyclodextrin Bonded Metal Porphyrins

Reactions of 5-(p-aminophenyl)-10,15,20-triphenyl porphyrin (1) with Ru3(CO)12 or M(OCOCH3)2 (M=Ni,Mn) afforded metalloporphyrins(4-6),respectively.6-Deoxy-6-io-do-β-cyclodextrin(2) and mono(6-O-trifluoromethanesulfonyl) permethylated β-cyclodextrin(3) reacted with complexes 4-6 to give β-cyclodextrin bonded metal porphyrins (7-9) and permethylated β-cyclodextrin bonded me-tal porphyrins (10-12) respectively.These new complexes were identified by MS,IR,UV-visible and ^1H NMR spectra,and elemental analysis.     

Characterization of β-cyclodextrin inclusion complex with procaine hydrochloride by 1H NMR and ITC

The inclusion of local anesthetic drug procaine hydrochloride by β-cyclodextrin was investigated by 1D and 2D proton NMR spectroscopy and isothermal titration calorimetry (ITC) at 298 K. The stoichiometry of the complex was determinate by the method of continuous variation, using the chemical induced shift of both host and guest protons. The association constant K, of the obtained complex was calculated and found to be 293.17 M^?1. Rotating frame NOE spectroscopy, was used to ascertain the solution geometry of the host–guest complex. The result reveals that the procaine molecule penetrates into the β-cyclodextrin cavity with the aromatic ring. The energetics of complexation process is investigated by ITC technique. The analysis indicates that the complexation of procaine by β-CD is an exothermic process and show that both enthalpy and entropy contribute to the binding process. The obtained value for the association constant is in good agreement with that obtained from NMR.     

Molecular Recognition of Immobilized Supramolecular Complex of Ironporphyrin and β-CD Polymer as an Analogue for Peroxidase

The immobilized supramolecular inclusion complex of FeTPPS4 and -CD polymer was applied as a mimesis of peroxidase, and its molecular recognition for twenty substrates was studied. As the space structure;CD interior cavities, high selectivity was obtained by immobilized mimetic enzyme. p-Chlorophenic acid was identified as an optimal substrate in the system tested.     

Efficient Immobilization of Porcine Pancreatic α-Amylase on Amino-Functionalized Magnetite Nanoparticles: Characterization and Stability Evaluation of the Immobilized Enzyme

The potential of the modified magnetic nanoparticles for covalent immobilization of porcine pancreatic α-amylase has been investigated. The synthesis and immobilization processes were simple and fast. The co-precipitation method was used for synthesis of magnetic iron oxide (Fe₃O₄) nanoparticles (NPs) which were subsequently coated with silica through sol–gel reaction. The amino-functionalized NPs were prepared by treating silica-coated NPs with 3-aminopropyltriethoxysilane followed by covalent immobilization of α-amylase by glutaraldehyde. The optimum enzyme concentration and incubation time for immobilization reaction were 150 mg and 4 h, respectively. Upon this immobilization, the α-amylase retained more than 50 % of its initial specific activity. The optimum pH for maximal catalytic activity of the immobilized enzyme was 6.5 at 45 °C. The kinetic studies on the immobilized enzyme and its free counterpart revealed an acceptable change of K_m and V_max. The Km values were found as 4 and 2.5 mM for free and immobilized enzymes, respectively. The V_max values for the free and immobilized enzymes were calculated as 1.75 and 1.03 μmol mg^?1 min^?1, in order, when starch was used as the substrate. A quick separation of immobilized amylase from reaction mixture was achieved when a magnetically active support was applied. In comparison to the free enzyme, the immobilized enzyme was thermally stable and was reusable for 9 cycles while retaining 68 % of its initial activity.