Organometallic Derivatives of Polyphosphazenes as Precursors for Metallic Nanostructured Materials

Co-polyphosphazenes containing anchored organometallic fragments are useful precursors for nanostructured metallic materials. Pyrolysis in air at 800°C yields metallic nanoparticles of the type, M°/M _x O _y /M _z (P _x O _y )/P₄O₇, depending on the metal used; i.e., M° when the metal is a noble metal, metal oxide when the metal is Cr, W and Ru, metallic pyrophosphate when M = Mn and Fe. The organic spacer of the polyphosphazene influences strongly the morphology of the pyrolytic product. The mechanism of formation of the nanostructured materials involves carbonization of the organic matter, which produces holes where the nanoparticles are grown. Reaction of the phosphorus polymeric chain with O₂ yield phosphorus oxide units, which act as a P₄O₇ matrix to stabilize the nanoparticles and/or P _x O _y ⁻ⁿ for the formation of metallic pyrophosphates. The method appears to be a general and versatile new route to metallic nanostructured materials. Dedicated to Professor Harry Allcock for his pioneering and persevering work on Polyphosphazene and their projection in another field as materials and recently nanomaterials.     

Organometallic Derivatives of Cyclotriphosphazene as Precursors of Nanostructured Metallic Materials: A New Solid State Method

The cyclic phosphazene trimers [N₃P₃(OC₆H₅)₅OC₅H₄N·Ti(Cp)₂Cl][PF₆] (3), [N₃P₃(OC₆H₄CH₂CN·Ti(Cp)₂Cl)₆][PF₆]₆ (4), [N₃P₃(OC₆H₄-Bu^t)₅(OC₆H₄CH₂CN·Ti(Cp)₂Cl)][PF₆] (5), [N₃P₃(OC₆H₅)₅C₆H₄CH₂CN·Ru(Cp)(PPh₃)₂][PF₆] (6), [N₃P₃(OC₆H₅)₅C₆H₄CH₂CN·Fe(Cp)(dppe)][PF₆] (7) and N₃P₃(OC₆H₅)₅OC₅H₄N·W(CO)₅ (8) were prepared and characterized. As a model, the simple compounds [HOC₅H₅N·Ti(Cp)₂Cl]PF₆ (1) and [HOC₆H₄CH₂CN·Ti(Cp)₂Cl]PF₆ (2) were also prepared and characterized. Pyrolysis of the organometallic cyclic trimers in air yields metallic nanostructured materials, which according to transmission and scanning electron microscopy (TEM/SEM), energy-dispersive X-ray microanalysis (EDX), and IR data, can be formulated as either a metal oxide, metal pyrophosphate or a mixture in some cases, depending on the nature and quantity of the metal, characteristics of the organic spacer and the auxiliary substituent attached to the phosphorus cycle. Atomic force microscopy (AFM) data indicate the formation of small island and striate nanostructures. A plausible formation mechanism which involves the formation of a cyclomatrix is proposed, and the pyrolysis of the organometallic cyclic phosphazene polymer as a new and general method for obtaining metallic nanostructured materials is discussed.     

CdS纳米粒子的室温固相反应制备及其光催化活性研究

以牛血清白蛋白为稳定剂,采用CdSO4.8H2O、硫脲和NaOH之间的室温固相反应制备了高分散立方晶相粒径为4~5 nm的CdS纳米颗粒。用X射线洐射(XRD)、透射电镜(TEM)和原子力显微镜(AFM)对CdS纳米颗粒的相组成,形貌和粒径等进行了表征。以甲基橙降解脱色为探针反应,研究了自然光照条件下,CdS纳米颗粒的光催化活性,即光催化剂用量,试液的pH值,光照及时间等与甲基橙脱色率的关系。在最佳光催化剂用量为0.2 g,最佳pH值为1时,太阳光照射1 min,甲基橙降解率可达99%以上,表明由室温固相反应制备的CdS纳米颗粒,具有优异的光催化活性。     

由锰尘和钛白废酸制备醋酸锰

叙述了以锰尘和钛白废酸为原料制备醋酸锰的方法,通过试验,对合成酸度、温度、原料配比、过滤的温度的影响等进行了讨论,并在试验的基础上得出了正确的工艺条件,生产出了达到化工部质量标准的产品.工艺简单合理,收率较好,对废酸、废料进行了综合利用,没有环境污染.     

Polyphosphazenes as Solid Templates for the Formation of Monometallic and Bimetallic Nanostructures

A simple synthetic route to monometallic and bimetallic nanostructured materials is presented. Pyrolysis of the organometallic iron co-polyphosphazenes, [{[N = P(R₁)₂]_0.8[N = P(OC₆H₄CH₂CN[Fe])₂]_0.15}{PF₆}_0.32]_n (1) and [{[N = P(R₁)₂]₀₅₅[N = P(OC₆H₄CH₂CN[Fe])₂]_0.2}{PF₆}_0.32]_n (2) with R₁ = OC₁₂H₈ [Fe] = CpFe(dppe)⁺ Cp = η−C₅H₅, dppe = PPh₂(CH₂)₂PPh₂ in air affords nanoparticles of the iron pyrophosphate Fe₂Fe₅(P₂O₇)₄, while the pyrolysis of both copolymers in air and in the presence of TlPF₆ yield bimetallic Tl, Fe nanostructures. The polyphosphazene acts as a hybrid organic–inorganic template. By carbonization, the organic part of the polymer provides holes where the metallic centers grow while the inorganic P = N acts as precursor for the formation of phosphorus oxides, which form the metal pyrophosphates or the stabilizing matrix. Pyrolysis of organometallic polyphosphazene polymers containing two organometallic fragments is discussed as a new and general method for obtaining bimetallic nanostructured materials.     

纳米改性聚合物材料研究进展

综述了纳米改性聚合物材料的研究进展,包括纳米粒子的结构与性质,纳米粒子的表面改性,纳米粒子对聚合物的改性机理和方法及纳米技术在高分子材料领域中的应用。     

有机金属先驱体分解制备铟和氧化铟纳米颗粒

介绍了有机金属先驱体In(η5-C5H5)分解制备铟(In)和氧化铟(In2O3)纳米颗粒的实验方法,并利用透射电子显微镜(TEM)观察制备的In和In2O3纳米颗粒的微观结构.     

非离子表面活性剂在纳米粒中的应用

综述了聚合物纳米粒和固体脂质纳米粒的有关研究进展,重点对非离子表面活性剂在聚合物纳米粒和固体脂质纳米粒制备方法、表面修饰中的应用进行了介绍,指出了非离子表面活性剂在纳米粒研究和应用中具有广阔的前景。     

一步法制备新型荧光聚合物纳米粒子

采用一步细乳液聚合法将荧光单体4-甲胺基-9-(2-烯丙基)-1,8-萘二甲酰亚胺(MANI)共价键结合进聚合物纳米粒子中.光谱特性研究证明了MANI已经成功结合进人纳米粒子中.更重要的是,因为MANI通过共价键的方式结合进聚合物纳米粒子中,可以有效避免产生染料泄漏现象.并且可以通过控制纳米粒子中MANI的含量,来获得...     

利用废锰矿制硫酸锰的研究

采用废锰矿湿法制硫酸锰、用SO2对废锰矿进行硫酸盐化处理，用硫铁矿对废锰矿进行硫酸盐化处理等工艺路线进行实验，利用废锰矿制取硫酸锰，取得了良好的效果。不但使有限的资源得到充分利用，为企业增加经济效益，而且减少了环境污染。     

Synthesis and Microstructural Investigations of Organometallic Pd(II) Thiol-Gold Nanoparticles Hybrids

In this work the synthesis and characterization of gold nanoparticles functionalized by a novel thiol-organometallic complex containing Pd(II) centers is presented. Pd(II) thiol, trans, trans-[dithiolate-dibis(tributylphosphine)dipalladium(II)-4,4′-diethynylbiphenyl] was synthesized and linked to Au nanoparticles by the chemical reduction of a metal salt precursor. The new hybrid made of organometallic Pd(II) thiol-gold nanoparticles, shows through a single S bridge a direct link between Pd(II) and Au nanoparticles. The size-control of the Au nanoparticles (diameter range 2–10 nm) was achieved by choosing the suitable AuCl₄ ⁻/thiol molar ratio. The size, strain, shape, and crystalline structure of these functionalized nanoparticles were determined by a full-pattern X-ray powder diffraction analysis, high-resolution TEM, and X-ray photoelectron spectroscopy. Photoluminescence spectroscopy measurements of the hybrid system show emission peaks at 418 and 440 nm. The hybrid was exposed to gaseous NO _x with the aim to evaluate the suitability for applications in sensor devices; XPS measurements permitted to ascertain and investigate the hybrid –gas interaction.     

Bioadhesive Nanoparticles for Local Drug Delivery

Local drug delivery is an effective strategy for achieving direct and instant therapeutic effects. Current clinical treatments have fallen short and are limited by traditional technologies. Bioadhesive nanoparticles (NPs), however, may be a promising carrier for optimized local drug delivery, offering prolonged drug retention time and steadily maintained therapeutic concentrations. In addition, the possibility of clinical applications of this platform are abundant, as most polymers used for bioadhesion are both biodegradable and biocompatible. This review highlights the major advances in the investigations of polymer-based bioadhesive nanoparticles and their innumerable applications in local drug delivery.     

Oxidative Precipitation Synthesis of Calcium-Doped Manganese Ferrite Nanoparticles for Magnetic Hyperthermia

Superparamagnetic nanoparticles are of high interest for therapeutic applications. In this work, nanoparticles of calcium-doped manganese ferrites (Ca_xMn_1−xFe₂O₄) functionalized with citrate were synthesized through thermally assisted oxidative precipitation in aqueous media. The method provided well dispersed aqueous suspensions of nanoparticles through a one-pot synthesis, in which the temperature and Ca/Mn ratio were found to influence the particles microstructure and morphology. Consequently, changes were obtained in the optical and magnetic properties that were studied through UV-Vis absorption and SQUID, respectively. XRD and Raman spectroscopy studies were carried out to assess the microstructural changes associated with stoichiometry of the particles, and the stability in physiological pH was studied through DLS. The nanoparticles displayed high values of magnetization and heating efficiency for several alternating magnetic field conditions, compatible with biological applications. Hereby, the employed method provides a promising strategy for the development of particles with adequate properties for magnetic hyperthermia applications, such as drug delivery and cancer therapy.     

Macromolecular Superstructures: A Future Beyond Single Chain Nanoparticles

Over the last 100 years polymer chemistry has flourished in all areas and enabled control over synthetic polymer architectures – including chain lengths, dispersity and monomer sequences. Compared to the architectures of biomacromolecules, these scientific achievements mainly took place on the level of primary structures. The plethora of functions carried out by proteins in nature, however, does not only result from their primary structure, but from its folding into perfectly defined 3D structures. Striving towards a similar architectural control and function in synthetic polymers, the field of single chain nanoparticles (SCNPs) emerged. In this review, we analyze the state of the art and identify what is currently standing between polymer chemistry and perfectly controlled synthetic macromolecular architectures. Based on the current challenges in the field of SCNPs, we discuss potential avenues to break today's barriers and explore future applications reaching beyond the current-state-of-the-art.     

Influence of Emulsifiers on the Formation and Crystallization of Solid Lipid Nanoparticles

The production of solid lipid nanoparticles by means of hot homogenization uses two different techniques: emulsification (liquid state) and crystallization (solid state). Both these processes depend on many parameters, such as composition, energy input, or geometry of the emulsification device. In former investigations known from the literature, the influence of the emulsifier concentration and the potential of controlling the polymorphic forms of the solidified particles were not investigated in detail. Here, these two factors were analyzed on the example of palm oil particles stabilized with emulsifiers suitable for foods. The influence of the emulsifier concentration on the resulting droplet and particle sizes is very high, up to a certain level. However, beside this influence, the polymorphic form of the solidified particles can be controlled by the right choice of emulsifier type and concentration.     

微通道内载紫杉醇固体脂质纳米粒制备及工艺优化

目的:制备载紫杉醇固体脂质纳米粒。方法:微通道内采用溶剂扩散法制备脂质纳米粒,并通过正交优化制备工艺。结果:制备的纳米粒稳定性良好,平均粒径为(129.87±2.91)nm,包封率为(3.11±0.06)%,载药率为(43.67±0.24)%。结论:本研究制备的载药固体脂质纳米粒载药特性与重复性良好。     

聚合物纳米微球分离纯化棘白霉素B母核方法研究

以聚合物纳米微球为层析介质,采用HPLC检测方法,开发高纯度棘白霉素B母核的分离纯化工艺,并对层析条件进行优化。结果表明,当选择Uni PS 30型聚合物纳米微球为层析介质、上样量为1.2g·(100g介质)-1、以体积分数为3%的乙醇进行洗脱、流速为12mL·min-1时,得到的棘白霉素B母核纯度大于98%。建立了高纯度棘白霉素B母核的分离纯化工艺,流程简单、可行,为该产品产业化开发提供了一定的理论基础。     

在T型微通道内制备固体脂质纳米粒(SLN)的实验研究

研究了一种用T型微通道制备固体脂质纳米粒(solid lipid nanoparticles,SLN)的新方法.以softisan100(C_(10)～C_(18)的混合脂)丙酮溶液作为脂相,以Poloxamer 188水溶液为水相,用注射泵分别将脂相和水相注入T型通道的主道和支道内,两相在交叉口接触后形成明显的相界面,并继续沿主道向前流动.脂相中丙酮通过相界面迅速向水相扩散,随着流体的向前运动,脂相中脂的浓度不断增大至过饱和而形成固体脂质纳米粒(SLN).实验考察了两相流速和微通道尺寸对SLN粒径大小和粒径分布的影响.结果表明:在实验条件下,制得的SLN粒径在110～350 nm之间,多分散性指数小于0.24;T型通道交叉口的流场分布受两相相对流速的影响,并直接影响成粒规律,在不出现两相返混条件下,保持水相流速不变,SLN粒径随脂相流速增大而增大;保持脂相流速不变,粒径随水相流速的增大略有增大;通道尺寸越小所制得粒径也越小.