Jia Huo

Hollow Ferrocenyl Coordination Polymer Microspheres with Micropores in Shells Prepared by Ostwald Ripening

Hollow microspheres with pores in their shells have received much attention owing to their hierarchically porous structures and advanced applications in electrochemical capacitive energy storage, hydrogen storage, drug delivery, sensing, and catalysis. For example, Lou et al. reported that hollow SnO2 nanospheres with nanoporous shells showed high reversible charge capacity and good cycling performance. Zhu et al. investigated the drug-delivery properties of hollow silica spheres with mesoporous shells and found that the hollow microspheres were able to store significantly more molecules with higher release rates than conventional mesoporous silica. Template synthesis is one of the most-used strategies to prepare hierarchically hollow microspheres, especially for pores inside the shells. Braun and co-workers have prepared hollow ZnS microspheres with mesoporous shells using dual templates assembled by lyotropic liquid crystals on the surfaces of silica or polystyrene colloidal templates. Liu et al. have produced organic–inorganic hybrid hollow nanospheres with microwindows on the shells templated by tricopolymer aggregates. The template method is general to prepare hollow microspheres with pores in the shells, but expensive and tedious post-treatment processes, such as solvent extraction, thermal pyrolysis, or chemical etching, and resultant fragile frameworks, limit or even impair its applicability. 3, 4] As a result, it remains an important challenge to develop a convenient and template-free method to prepare hollow microspheres with porous shells. Porous coordination polymers are highly ordered porous multifunctional materials prepared by linking metal ions or metal oxide clusters with multidentate organic ligands without any additional template. Construction of shells of hollow materials with porous coordination polymers is an especially promising approach to design hollow microspheres with porous shells through a template-free method and to endow materials with multifunctionality, such as electric, magnetic, and optical properties. Herein, we report the formation of hollow coordination polymer microspheres with microporous shells by a one-pot solvothermal reaction without any additional template; the shells are constructed of iron-based ferrocenyl coordination polymers. We confirm that the Ostwald ripening mechanism is responsible for the formation of hollow cavities with controllable size. Hollow iron-based ferrocenyl coordination polymer microspheres (Fe-Fc-HCPS) were synthesized by a solvothermal reaction of FeCl3·6H2O with 1,1’-ferrocenedicarboxylic acid (H2FcDC) in N,N-dimethyl formamide (DMF; Figure 1a). The precipitate was collected by centrifugation and washed several times with DMF and CHCl3. The reaction temperature, reaction time, and molar ratio of reactants play important roles in the formation of hollow spherical particles. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), and optical microscopy (OPM) were

Templated preparation of porous magnetic microspheres and their application in removal of cationic dyes from wastewater.

Porous magnetic microspheres with large particle size (350-450 microm) were prepared with sulfonated macroporous polydivinylbenzene as a template. The preparation process included ferrous ion exchange and following oxidation by hydrogen peroxide. The results showed that the weight fraction of magnetic nanoparticles exceeded 20 wt% in microspheres after the preparation process was repeated three times. X-ray diffraction profiles indicated that the crystalline phase of as-formed magnetic nanoparticles was magnetite (Fe(3)O(4)). TEM images revealed rod-like magnetite crystal after the first oxidation cycle, however, the crystal morphologies were transferred into random shape after more oxidation cycles. The applicability of porous magnetic microspheres for removal of cationic dyes from water was also explored. The results exhibited that basic fuchsin and methyl violet could be quickly removed from water with high efficiency. More importantly, the magnetic microspheres could be easily regenerated and repeatedly employed for wastewater treatment. Therefore, a novel methodology was provided for fast removal cationic dyes from wastewater.

Electrochemical assessment of the interaction of dihydrogen phosphate with a novel ferrocenyl receptor.

A novel ferrocene-based amide has been synthesized by condensation reaction and characterized by (1)H NMR and UV-vis spectroscopies. The electrochemical properties and anion recognition properties of the ferrocene-based amide were investigated by the CV and UV-vis techniques. An interesting phenomenon was revealed by CV: a second oxidative peak, and the first oxidative peak decreased. Therefore, an effective dihydrogen phosphate recognition sensor is expected from this compound in the future.

Hyperbranched Ferrocenyl Polymer Film with High Charge Transport Efficiency

The electrochemical behaviors of hyperbranched poly(ferrocenyl-methylsilane) (HPFMS) and linear oligo(ferrocenyldimethylsilane) (LOFS) films were studied systematically by cyclic voltammetry and chronocoulometry under different polymer coverage and solvents. Both poly(ferrocenylsilanes) show stable cyclic voltammographs in LiClO 4 solutions. Compared with LOFS films, HPFMS films exhibit higher charge transport efficiency because of their hyperbranched structure: peak current ( i p) and apparent diffusion coefficient ( D app) for HPFMS films are larger than those for LOFS films, especially at high polymer coverage (3.8 x 10 (-11) vs 3.9 x 10 (-12) cm2/s for HPFMS and LOFS film at the coverage of 2.1 x 10 (-6) mol Fc/cm2). The conceptual models of electrode processes for HPFMS and LOFS films were proposed to account for higher charge transport efficiency of HPFMS films. It is also found that a solvent with the appropriate solubility parameter and polarity, lower viscosity, and higher dielectric constant is in favor of charge transport through polymer films, which is consistent with the proposed model of electrode process for HPFMS films. These results imply that hyperbranched ferrocenyl polymers have the potential to be excellent chemical sensor materials with convenient synthesis and high sensitivity.

Synthesis of Glycidyl Ether of Poly(bisphenol-A 1,1′-ferrocene dicarboxylate) and Its Electrochemical Behavior

A novel ferrocene-based epoxy compound of the glycidyl ether of poly(bisphenol-A 1,1′-ferrocene dicarboxylate) (GEPBFC) was synthesized and the electrochemical behavior of its films and solutions was investigated by cyclic voltammetry (CV). It was found that the GEPBFC films and solutions present different CV behavior in different solvents and the swelling ability of the solvent is the main factor that affects the CV behavior of GEPBFC films. The kinetic parameters of the film-electrode process, including the surface transfer coefficient, the apparent diffusion coefficient and the standard rate constant in LiClO4 ethanol solution, were calculated, and the corresponding electrode-process mechanism was discussed.

Recent Research Progress in the Synthesis of Polyphosphazene and Their Applications

In the past five decades, many new types of polymers, containing nitrogen and phosphorus atoms as a significant part of the polymer backbone, have been synthesized. This paper reviews the developments in the field of polyphosphazenes and their applications. In this paper, synthesis, characterization, functionalization and practical applications of polyphosphazenes are described.

Study on Poly(ferrocenylsilane) and Its Promotive Effect to Decomposition of Ammonium Perchlorate

S OLID propellant is one of the most significant ingredients used in rockets. The burning rate of propellant is a vital parameter for rocket design. A promising method to enhance the burning rate of propellants is to use burning-rate promoters (BRPs). BRPs have become increasingly important and are receiving more attention recently due to their successful use in solid propellant burning-rate enhancement. Generally, there are several kinds ofBRPs; transitionmetal oxides, nanometal particles, metal chelate, ferrocene, and its derivatives. Transition metal oxide BRPs are cheap, but the burning-rate improvement of propellant is limited. The addition of nanometal particles can enhance the burning rate because nanometal particles have large specific surface areas and higher surface energy. However, nanometal particles are difficult to disperse well and passivation is needed for their surface to prevent spontaneous combustion in air [1]. Organic metal chelate BRPs, such as copper organic chelate and Plumbum iron double metal chelate, can greatly enhance the burning rate due to their good dispersion in propellants. Ferrocene and its derivatives have attracted much attention for their fascinating properties as BRPs [2]. They have been widely used in composite propellant, especially to enhance the burning rate of butyl hydroxide propellant, which contains ammonium perchlorate (AP) and aluminum powder. When ferrocene and its derivatives are used as BRPs, they are easy to migrate during storage. This migration affects their application in propellants. In this Note, we explore the possibility of using a series of poly(ferrocenylsilanes) with highmolecular weights as BRPs.

Recent Research Progress in the Synthesis of Polyphosphazene Elastomers and Their Applications

Polyphosphazenes elastomers have major utilization as fire resistant materials, gas kits, O-rings, electrical insulation, oil-resistant hoses, foam, ceramics, especially helicopter, air craft, aerospace, military and navy hardware applications. Tremendous achievements have been obtained for the synthesis and applications of polyphosphazenes. In this review, we highlighted the types, synthesis, characterization and applications of polyphosphazenes elastomers.

Synthesis of a Novel Ferrocene-Based Epoxy Compound and Its Electrochemical Behavior

A novel ferrocene-based epoxy compound was synthesized. It was characterized by 1H-NMR and FT-IR. The influence of different solvents and potential scan rates on the cyclic voltammetry (CV) behavior of the resultant compound was investigated. The relationship between the peak currents and potential scan rates indicates that the charge transport of the resultant ferrocene-based epoxy compound obeys Ficks Law.

Synthesis and Characterization of Poly(bis(ethyl salicylate)phosphazenes) and Poly(bis(ethyl salicylate diethylamino)phosphazenes) and Their Hydrolytic Degradation

The polydichlorophosphazenes were synthesized from hexachlorocyclotriphosphazenes by ring opening polymerization in the presence of AlCl3 as a catalyst. Poly[bis(ethyl salicylate)phosphazenes] (PESP) and poly[bis(ethyl salicylate diethylamino)phosphazenes] (PESDEAP) were synthesized via macromolecular substitution reactions using ethyl salicylate and (or) diethylamine as side groups. The synthesis results were proved by nuclear magnetic resonance (1H NMR, and 31P NMR) and gel permeation chromatography. In addition, the hydrolytic degradation of PESP and PESDEAP was investigated at constant temperature in neutral medium.