Formation of the Inclusion Complex of Orange II with β-Cyclodextrin and Its Photostability

Inclusion complex of Orange II with β-Cyclodextrin (β-CD) and the anti-photolysis effect under UV-light were investigated. The molar ratio of inclusion complex of β-Cyclodextrin and Orange Ⅱ is 1∶1. The formation constant K=1.236×103 L/mol was determined by the UV and Fluorescence spectra respectively, which was quite in accordance with the calculation with a modified Benesi-Hildbrand equation. The inclusion complex was characterized by the IR spectra and the molar ratio of inclusion complex is 1∶1 too. The formation constant K=1.266×103 L/mol was determined by 1 H NMR analysis and was nearly the same by UV and fluorescence spectra. The photocatalytic decolorization rate of Orange Ⅱ solutions containing β-CD and TiO2 was smaller by 51.9% than that of the Orange Ⅱ solutions only containing TiO2, while in the case of direct photolysis of Orange Ⅱ solutions, β-CD can lower the photolysis rate by 48.1% under UV-light. This result indicates β-CD can inhibit the photolysis and photocatalytic decolorization of Orange Ⅱ under UV-light. The β-CD inclusion complex was found to be persistent to UV-light photolysis.     

Synthesis of Novel Chitosan Microspheres Grafted with β-Cyclodextrins and Their Adsorption for Iodine for Antibacterial Activities

The novel chitosan microspheres grafted with β cyclodextrins (CMGC) were prepared by means of the reaction of chitosan microspheres and mono-(6-p-tosyl)- β-cyclodextrins (β-CD-OTs-6). β-CD-OTs-6 were gained by the reaction of p toluenesulfonyl chloride (TsCl) and β-cyclodextrins (β-CDs). Their structures were proved by Fourier transform infrared spectral analysis (FT-IR), X ray powder diffraction analysis, and ^13C NMR; the configuration of CMGC was characterized by scanning electron micrograph (SEM) and transmittance electron micrograph (TEM). The inclusion complex of CMGC with iodine was prepared and its inclusion ability was studied. The experimental results showed that some iodine was included with CMGC and formed a stable inelusion. The stable complex of CMGC and iodine (CMGC-I) shows good antibacterial effect.     

Research of Inclusion Complexation of 4,4'-Thiodiphenol Effected by β-Cyclodextrin in Aqueous Solutions and the Effect on Photodegradation

The inclusion behavior of 4,4′ -Thiodiphenol (TDP),a typical bisphenol and endocrine disruptor,reacts with β-cyclodextrin (β-CD) in aqueous solutions has been investigated by means of UV absorption spectrum and quantum-chemical calculation with Gaussian 98 software. The results show that the inclusion behavior of TDP is quite different in acidic solutions (pH 5.9) from that in alkaline solutions (pH 10.0). This behavior difference is attributed to the different formula structures in aqueous solutions at acidic and alkaline pH values that are demonstrated by quantumchemical modeling and calculation. TDP forms a 1∶1 β-CD inclusion complex in aqueous solutions. The equilibrium constant K was calculated to be 553.49 L/mol at pH 5.9 and 1 318.20 L/mol at pH 10.0 respectively for the inclusion complex reaction by using the modified Benesi-Heldbrand equation. After inclusion TDP's structure is changed especially at the inclusion part with the bond order becoming larger,which results in inhibitive photodegradation during direct photooxidation and H2O2 assisted photooxidation.     

Research of Inclusion Complexation of 4,4＇-Thiodiphenol Effected by β-Cyclodextrin in Aqueous Solutions and the Effect on Photodegradation

The inclusion behavior of 4, 4＇ -Thiodiphenol （TDP）, a typical bisphenol and endocrine disruptor, reacts with β-cyclodextrin （β-CD） in aqueous solutions has been investigated by means of UV absorption spectrum and quantum-chemical calculation with Gaussian 98 software. The results show that the inclusion behavior of TDP is quite different in acidic solutions （pH 5.9） from that in alkaline solutions （pH 10.0）. This behavior difference is attributed to the different formula structures in aqueous solutions at acidic and alkaline pH values that are demonstrated by quantum- chemical modeling and calculation. TDP forms a 1 ： 1 fl-CD inclusion complex in aqueous solutions. The equiiibrium constant K was calculated to be 553.49 L/mol at pH 5.9 and 1 318.20 L/mol at pH 10.0 respectively for the inclusion complex reaction by using the modified Benesi-Heldbrand equation. After inclusion TDP＇s structure is changed especially at the inclusion part with the bond order becoming larger, which results in inhibitive photodegradation during direct photooxidation and H2O2 assisted photooxidation.     

~1H NMR Investigation of Supramolecular Complex between β-Cyclodextrin and Cholesterol

A supramolecular complex between β-cyclodextrin and cholesterol was synthesized and characterized via proton 1H NMR spectroscopy. In the supramolecular complex,the stoichiometric proportion of β-cyclodextrin to cholesterol is 1:2. The possible conformation of the supramolecular complex was depicted according to the chemical shift variance of proton 1H NMR of the host and guest molecules inside the inclusion complex. Removal efficiency of cholesterol complexed by β-cyclodextrin in our work is increased to a remarkable extent. This result can be applied in the field of drug development to reduce cholesterol in blood and other human organs.     

Characterization and photoluminescence properties of ultrafine copper molybdate (α-CuMoO4) powders prepared via a combustion-like process

We report a simple method for preparing copper(II) molybdate (CuMoO₄) powders via a combustion-like process. A gel was first prepared by the polymerizable complex method, where citric acid was used as a complexing and polymerizing agent and nitric acid was used as an oxidizing agent. The thermal decomposition behavior of the (CuMo)-precursor gel was studied by thermogravimetry–differential thermal analysis (TG–DTA), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). We observed that the crystallization of CuMoO₄ powder was completed at 450°C. The obtained homogeneous powder was composed of grains with sizes in the range from 150 to 500 nm and exhibited a specific surface area of approximately 5 m2/g. The average grain size increased with increasing annealing temperature. The as-prepared CuMoO₄ crystals showed a strong green photoluminescence emission at room temperature under excitation at 290 nm, which we mainly interpreted on the basis of the Jahn-Teller effect on [MoO₄2- ] complex anions. We also observed that the photoluminescence intensity increased with increasing crystallite size.     

Synthesis of a symmetrical tetrasubstituted cucurbit[6]uril and its host-guest inclusion complex with 2,2′-bipyridine

Synthesis of a symmetrical tetrasubstituted cucurbit[6]uril has been achieved by using the diether of dimethylglycoluril (1) and the dimmer of glycoluril (2). The structure of the symmetrical tetramethylcucurbit[6]uril (TMeQ[6]) has been determined by single crystal X-ray diffraction, ^1H NMR spectroscopy and ESMS. The ^1H NMR spectra of 2,2‘-bipyridine added to TMeQ[6] reveal that the host-guest inclusion complex was easily formed.     

Preparation and Structural Characterization of Polystyrene-Rectorite Nanocornposites

The polystyrene/reetorite nanocomposites were prepared by free radical polymerization of styrene containing dispersed organophilic rectorite. The structures and thermal properties of these hybrids have been investigated by X-ray diffraction (XRD), fourier transform infrared (FT-IR), positron annihilation spectroscopy (PAS) and thermal gmvimetric analysis (TGA) techniques. It was found that exfoliation of reetorite in polystyrene (PS) matrix was achieved. The average free-volume radius in the PS/clay nanocomposites is generally same as that in PS. Along with increment of reetorite contents, the interface between reetorite and polystyrene matrix increases, and the free-volume concentration decreases obviously. And the polystyrene nanocomposites have higher thermal deeomrosition temoemture than oure PS.     

Synthesis,Characterization, and Luminescence Properties of a Multi-benzoic Acid Rare Earth Complex Applied to Fluorescence Nanometer and Micrometer Fiber

The design and synthesis of a novel multi-benzoic acid ligand and the luminescence properties of the rare earth complex with the ligand and Eu3 ＋were focused on. The composition and structure of ligand and complex were characterized by Fourier transform infrared（ FT-IR） spectroscopy,1H nuclear magnetic resonance（1H NMR） techniques, and element analysis. The luminescent properties,heat resistant performance,morphology and distribution in fibers of the complex were also measured. The fluorescent spectra indicate that as-synthesized complex owns excellent luminescent properties. The maximum relative fluorescence intensity of the complex is more than 7 000. The thermo-gravimetric analysis（ TGA） results confirm that the initial degradation temperature of as-synthesized complex is at 413 ℃. Transmission electron microscope（ TEM） and field-emission scanning electron microscope（ FESEM） photos show that the particle size of assynthesized complex is 50-60 nm,and can be uniformly distributed in fiber. Based on these results, it can be concluded that the synthesized complex has excellent luminescent properties, good thermal stability,and extensively application prospect.     

Molecular self-assembly behavior of mono[6-O-6-(4-carboxyl-phenyl)]-β-CD in solution and solid state

A novel modified cyclodextrin, mono[6-O-6-(4-carboxyl-phenyl)]-]-β-CD (1), has been synthesized by the reaction of mono[6-(p-toluenesulfonyl)]-β-CD with 4-hydroxybenzoate, and its molecular self-assembly behavior in both solution and solid state was studied by means of crystallography, NMR spectroscopy and microcalorimetry. The results indicate that the bezoic acid groups are successively penetrated intermolecularly into the adjacent β-CD cavities to form helical columnar supramolecules in the solid state. As compared with crystal, the similar self-assembly behavior of 1 in aqueous solution has also been confirmed by the ^1H ROESY spectroscopy. Thermodynamically, the formation of polymeric supramolecules by modified CD in aqueous solution is mainly driven by entropy changes.     

Synthesis and molecular recognition properties of a novel chemical modified P-cyclodextrin

A new fluorescent chemosensor, a kind of P-cyclodextrin (CD) modified with N' N-dimethylamino-chalcone, was synthesized. The photophysical behavior and the molecular recognition of this compound were investigated by fluorescence spectroscopy. The results show that there exists an "in-out" movement of appended chalcone group from cyclodextrin cavity for "large dimension guest molecule such as 1-adamantanecarboxylic acid. But the long-chained guests such as cationic surfactants can be inserted into the CD cavity as a spacer to form a ternary inclusion complex with the CD cavity and the chalcone moiety.     

Enhancement of thermal stability and UV resistance of halloysite nanotubes using zinc oxide functionalization via a solvent-free approach

The aim of this study was to synthesize and evaluate the thermal properties and ultraviolet(UV)resistance of zinc oxide-functionalized halloysite nanotubes(HNT–ZnO).The HNT–ZnO was synthesized using a facile solvent-free route.The properties of the HNT–ZnO nanofillers were characterized using zeta-potential measurement,X-ray diffraction(XRD),field-emission scanning electron microscopy(FESEM),transmission electron microscopy(TEM),Fourier transform infrared spectroscopy(FTIR),and thermogravimetric analysis(TGA).The immobilization of ZnO nanoparticles onto HNT is feasible even at the lowest mass ratio of HNT/ZnO.The TGA results indicate that the thermal stability of the HNT–ZnO nanofillers is higher than that of the HNT.Furthermore,UV?Vis diffuse reflectance spectroscopy(UV-DRS)results show that the HNT–ZnO achieve a total reflectance as high as approximately 87.5%in the UV region,as compare with 66.9%for the HNT.In summary,the immobilization of ZnO onto HNT is a viable approach for increasing the thermal stability and improving the UV shielding of HNT.     

Synthesis and Property Studies of Transparent Resins Containing Rare Earth Complex Eu(Ⅲ) (TTA)_2(MA)_2 Phen·H_2O

A new rare earth complex Eu(Ⅲ)(TTA)2(MA)2Phen·H2O was synthesized and characterized by element analysis, FTIR, UV, thermal analysis, and fluorescence spectra. The strong fluorescence and high thermal stability of Eu(Ⅲ)(TTA)2(MA)2Phen·H2O were used to modify resin. The copolymer containing europium was prepared by copolymerization of Eu(Ⅲ) and styrene/α-methylacrylic acid, and characterized by FTIR and fluorescence spectra. The fluorescence spectra showed that the copolymer was a sort of materials with good ...     

Efficient photo-assisted Fenton oxidation treatment of multi-walled carbon nanotubes

In this paper,a new and efficient way to oxidize and functionalize the multi-walled carbon nanotubes (MWNTs) has been developed by using a combination of ultraviolet (UV) irradiation and Fenton oxida-tion process,namely UV/Fenton oxidation treatment. Comparing with conventionally individual Fenton oxidation treatment of MWNTs,UV/Fenton combined treatment improved the etching rates and effi-ciencies and hence reduced the time for surface modification of MWNTs,which was proved to be an effective method in etching and functionalizing CNTs. The formation of new functional groups,struc-tural changes and thermal stability during oxidation period were characterized by Fourier transform infrared spectroscopy (FTIR),Raman spectroscopy and could be clarified by thermogravimetric analy-sis (TGA),which showed that it was under UV irradiation conditions that MWNTs could be rapidly functionalized with hydroxyl,carbonyl and carboxyl groups in the presence of Fenton reagents,origi-nating from the increase in the gross HO· concentration and the existent synergetic effect when using UV irradiation combing with Fenton oxidation process. Introduction of such new oxygen-containing functional groups was attributed to attacks of HO· on defect sites and unsaturated bonds of C=C in the MWNTs sample,which should play an important role in accounting for the FTIR and Raman spectral changes.     

Effect of niobium alloying level on the oxidation behavior of titanium aluminides at 850°C

This work addresses the alloying of titanium aluminides used in aircraft engine applications and automobiles. The oxidation resistance behavior of two titanium aluminides of α₂ + γ(Ti₃Al + TiAl) and orthorhombic Ti₂NbAl, recognized as candidates for high-temperature applications, was investigated by exposure of the alloys for 100 h in air. Thus, oxidation resistance was expressed as the mass gain rate, whereas surface aspects were analyzed using scanning electron microscopy in conjunction with energy-dispersive X-ray spectroscopy, and the type of oxidation products was analyzed by X-ray diffraction and Raman spectroscopy. The orthorhombic Ti₂NbAl alloy was embrittled, and pores and microcracks were formed as a result of oxygen diffusion through the external oxide layer formed during thermal oxidation for 100 h.     

Hydrogen absorption properties of amorphous (Ni0.6Nb0.4−yTay)100−xZrx membranes

Ni based amorphous materials have great potential as hydrogen purification membranes. In the present work the melt spun(Ni_(0.6)Nb_(0.4-y)Ta_y)_(100-x)Zr_x with y=0, 0.1 and x=20, 30 was studied. The result of X-ray diffraction spectra of the ribbons showed an amorphous nature of the alloys. Heating these ribbons below T 400 °C, even in a hydrogen atmosphere(1-10 bar), the amorphous structure was retained. The crystallization process was characterized by differential thermal analysis and the activation energy of such process was obtained. The hydrogen absorption properties of the samples in their amorphous state were studied by the volumetric method,and the results showed that the addition of Ta did not significantly influence the absorption properties, a clear change of the hydrogen solubility was observed with the variation of the Zr content. The values of the hydrogenation enthalpy changed from ~37 k J/mol for x=30 to ~9 k J/mol for x=20. The analysis of the volumetric data provides the indications about the hydrogen occupation sites during hydrogenation, suggesting that at the beginning of the absorption process the deepest energy levels are occupied, while only shallower energy levels are available at higher hydrogen content, with the available interstitial sites forming a continuum of energy levels.     

A Composite of Crosslinked and Quaternized Poly (4-vinylpyridine) and Polypyrrole as a Potential Candidate for the Detection of Low Humidity

1 Results Despite rapid progress in the development of resistive-type humidity sensors, the detection of low humidity is still a problem[1, 2]. In this study, poly(4-vinylpyridine) was crosslinked and quaternized with 1,4-bromobutane to form a polyelectrolyte humidity sensitive film on interdigitated gold electrodes, which was further coated with a layer of polypyrrole by a facile method of vapor phase polymerization process. The composite so prepared was characterized by UV-vis spectroscopy and scanning electron microscopy. It was found that the impedance of the composite changed linearly with humidity in the range of 0～60%RH with good sensitivity. In addition, it exhibited a fast response (t90%: ≈33 s and ≈110 s for adsorption and desorption, respectively) and a relative small hysteresis (≈5%RH). The effect of concentration and ratio of oxidizing agent and dopingagent, temperature of vapor phase polymerization of pyrrole on the humidity sensitive properties of the composite have been investigated. The sensitive mechanism of the composite was also explored. The composite of conducting PPy and polyelectrolyte has great potential as a candidate sensitive material forlow humidity detection.     

Amplified optical transduction of proteins derived from Mo6S9-xIx nanowires

We demonstrate that Mo6S9-xIx nanowires(MoSI NWs) enable the detection of proteins with cytochrome c as a model protein using UV-vis spectrometry.The association of cytochrome c with the nanowires was verified by scanning electroctron microscopy,X-ray photoelectron,light scattering and micro-FTIR spectroscopies.Our results show that MoSI NWs is a promising nanostructure material for the development of ultrasensitive sensors for detecting proteins.The new MoSI NW derived amplification bioassay is expected to provide a straightforward and effective strategy for protein analysis and biosensor construction.     

Synthesis and characterization of bifunctional terbium complex-based nanoparticles

Novel bifunctional terbium complex-based nanoparticles were developed using a modified Stber method and a layer-by-layer assembly process. A magnetic core of Fe3O4 nanoparticles was coated with a silica shell to form the first layer. Then a ternary Tb3+ complex (TESPPA-Tb), which acted as a luminescent marker, was covalently bound to the silica surface by stable Si-O-Si bonds. The TESPPA monomer was synthesized by binding pyridine 2,6-dicarboxylic acid to 3-aminopropyltriethoxysilane, which was used as a ligand for coordination with the Tb3+ ions. An outer shell of silica was applied to the nanoparticles to allow for versatility with surface functionalization. The nanoparticles were characterized by X-ray powder diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy, ultravioletvisible spectroscopy, vibration sample magnetometer, and photoluminescence spectroscopy. The bifunctional nanoparticles exhibited favorable superparamagnetic behavior and photoluminescence properties of Tb3+. These nanoparticles have potential applications in biolabeling, bioseparation, immunoassays, and pathogenic diagnosis.