In situ ESR and UV/vis spectroelectrochemical study of eosin Y upon reduction with and without Zn(II) ions.

The electroreduction of eosin Y on a platinum electrode in deaerated slightly acidic aqueous 0.1 mol L(-1) potassium chloride medium is followed in situ by electron spin resonance (ESR) spectroscopy and UV/Vis spectroscopy. The electrochemical formation of a semiquinone radical is proved by both the appearance of an absorbing band at 408 nm, and a strong ESR signal observed during a negative-going scan. The system is also studied in the presence of Zn(II) ions due to its importance for understanding the growth mechanism of nanostructured ZnO/Eosin Y hybrid films by electrodeposition; under such conditions the ESR and UV/Vis response of the semiquinone radical is not observed. Zinc (II) ions form a complex with the dye, which is reduced by a fast two-electron process.     

Dispersion of functional tetraphenylporphyrin-ligated metal into ultra-thin flexible acrylate films. 2. Oxygen-uptake properties

Cobalt(II) meso-tetraphenylporphyrin (CoTPP)/acrylate hybrid thin films were prepared by CoTPP sublimation and reactive monomer evaporation onto the glass substrate in vacuum conditions. Deposited CoTPP/acrylate thin films were in situ photopolymerized. The oxygen-uptake behaviors of CoTPP/acrylate films were investigated by means of sorption measurements, monitored by gravimetric means, and analyzed using dual mode sorption model. The loading percent of CoTPP in the film was adjusted up to 60% by controlling the CoTPP sublimation rate. The thickness of the CoTPP/acrylate hybrid film was about 200 nm and oxygen-uptake data obtained from the sorption measurements indicated that CoTPP molecules in the CoTPP/acrylate hybrid films were able to bind oxygen molecules reversibly.     

New antitumor hybrid materials based on PtIV organic complex and polymer nanoparticles consisting of N-vinylpyrrolidone and (di)methacrylates

1. Download : Download high-res image (44KB)
2. Download : Download full-size image

     

A multilayered approach to approximating solute polarization

A hybrid multilayered "ONIOM"-type approach to solvation is presented in which the basic free energy of hydration is taken from the Poisson Boltzmann method and the contribution to the solute polarization is taken from a quantum mechanical implementation of the Born method. The method has been tested on the 52 neutral molecules used in the AM1-SM2 parameterization, and the polarized continuum method is taken as the standard by which the results are assessed. Regression analysis shows that the method gives a small improvement over the standard Poisson Boltzmann method or a dramatic improvement over the Born method. The system presented here represents one of the more straightforward applications of the multilayered approach to solvation, but other more sophisticated approaches are discussed.     

纳米CeO_2/PMMA杂化材料的制备与表征

采用在位分散聚合法制备了纳米CeO2 /PMMA杂化材料.XRD分析表明,杂化材料是无定形的.SEM分析表明,杂化材料中CeO2 含量不同,材料的断面形貌明显不同,随CeO2 含量的增加,杂化材料由韧性断裂向脆性断裂转变.EDS面分析表明,Ce在杂化材料中分布均匀.实验表明,随CeO2 含量的增加,杂化材料的透过率和溶解性降低     

Entrapping of Push-Pull Zwitterionic Chromophores in Hybrid Matrices for Photonic Applications

A new class of heterocycle-based push-pull chromophores showing enhanced nonlinear properties characterized by an aromatic and highly zwitterionic ground state and a quinoid/neutral excited state have been synthesized to be incorporated in sol-gel hybrid systems. This class of compounds shows very large first molecular hyperpolarizabilities ( as high as 27000 × 10^–48 esu) and is a promising candidate for photonic applications where large second order non-linearities are required. In spite of their very large hyperpolarizability and chemical and thermal stability, these chromophores are decomposed in presence of light and oxygen (photobleaching) and are sensitive to acidic environments due to the carbanionic nature of the donor moiety. A hybrid matrix, based on N-[(3-trimethoxysilyl)propyl]ethylenediamine and 3-glycidoxypropyltrimethoxysilane, has been specifically designed to allow the incorporation of such zwitterionic compounds assuring at the same time a good temporal stability of the optical properties. Amine functionalisation has been found very effective in reducing the photobleaching by acting on these chromophores via the singlet oxygen. Second harmonic generation has been observed on poled films, and an order parameter, , of 0.17 has been estimated. The nonlinear coefficient d_eff of the samples has been thus estimated at a value two times larger than for d₁₁ of quartz that, from literature data, is about 0.335 pm/V.     

A composite microporous gel polymer electrolyte prepared by ultra-violet cross-linking

A new type of composite microporous gel polymer electrolyte was prepared by directly coating the hydrolyzed prepolymers onto PVdF microporous membrane, and then polymerizing and cross-linking with ultra-violet (UV). Their chemical, thermal, surface microscopic configuration, swelling ability and electrochemical properties have been investigated for various prepolymer’s solution concentrations. The swelling ability and ionic conductivity of the membrane supporting hybrid gel electrolyte (MSHGE) could reach an extreme point at 0.15 g/ml of the prepolymer’s solution. It is thought that their performance can be affected by the surface microscopic configuration and the quality of coated copolymer. The Arrhenius-type relationship was observed in the temperature dependence of ionic conductivity. The ionic conductivity of MSHGE (PVdF-15) at room temperature can reach 6.18 × 10⁻³ S cm⁻¹, and its electrochemical stability window is about 4.9 V.     

Sulfur Encapsulated in a TiO2‐Anchored Hollow Carbon Nanofiber Hybrid Nanostructure for Lithium–Sulfur Batteries

A hollow carbon nanofiber hybrid nanostructure anchored with titanium dioxide (HCNF@TiO₂) was prepared as a matrix for effective trapping of sulfur and polysulfides as a cathode material for Li–S batteries. The synthesized composites were characterized and examined by X‐ray diffraction, nitrogen adsorption–desorption measurements, field‐emission scanning electron microscopy, scanning transmission electron microscopy, and electrochemical methods such as galvanostatic charge/discharge, rate performance, and electrochemical impedance spectroscopy tests. The obtained HCNF@TiO₂–S composite showed a clear core–shell structure with TiO₂ nanoparticles coating the surface of the HCNF and sulfur homogeneously distributed in the coating layer. The HCNF@TiO₂–S composite exhibited much better electrochemical performance than the HCNF–S composite, which delivered an initial discharge capacity of 1040 mA h g^?1 and maintained 650 mAh g^?1 after 200 cycles at a 0.5 C rate. The improvements of electrochemical performances might be attributed to the unique hybrid nanostructure of HCNF@TiO₂ and good dispersion of sulfur in the HCNF@TiO₂–S composite.     

Superhydrophobic Polypropylene Surfaces Prepared with TiO2 Nanoparticles Functionalized by Dendritic Polymers

Hybrid inorganic–organic nanomaterials have received increasing interest due to the possibility of implementing different functions and characteristics within a single material. Their functionalities are a consequence of the synergy of the properties of distinct building blocks and are related to their varied natures and spatial locations. In this work, we present the development of superhydrophobic properties on polypropylene (PP) surfaces using hybrid nanomateriales from TiO₂ nanoparticles (NPs) and dendronized polymers. The dendron acryl Behera's amine was successfully grafted on the TiO₂ NP surfaces by Surface‐Initiated Atom Transfer Radical Polymerization (SI‐ATRP) and a core‐brush material was obtained. Finally, PP substrates were coated with NP hybrids to produce superhydrophobic surfaces with water contact angles of over 158 degrees. Controlling the organic silane concentration on the TiO₂ NPs allowed the dendronized process to be driven and thereby permitted the selection of specific wettability properties on PP substrate surfaces with high water adhesion or self‐cleaning conditions. This dendronized effect with consequent steric congestion of the polymeric brushes on the NPs changed their behaviors from Wenzel to the Cassie Baxter state. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 2019–2029     

New 3 D Tubular Porous Structure of an Organic–Zincophosphite Framework with Interesting Gas Adsorption and Luminescence Properties

A new 3D tubular zinc phosphite, Zn₂(C₂₂H₂₂N₈)_0.5(HPO₃)₂?H₂O ( 1 ), incorporating a tetradentate organic ligand was synthesized under hydro(solvo)thermal conditions and structurally characterized by single‐crystal X‐ray diffraction. Compound 1 is the first example of inorganic zincophosphite chains being interlinked through 1,2,4,5‐tetrakis(imidazol‐1‐ylmethyl)benzene to form a tubular porous framework with unusual organic–inorganic hybrid channels. The thermal and chemical stabilities, high capacity for CO₂ adsorption compared to that for N₂ adsorption, and interesting optical properties of LED devices fabricated using this compound were also studied.