Preparation and characterization of luminescent cubic MCM-48 impregnated with an Eu3+ beta-diketonate complex

We report on the preparation of luminescent silica mesoporous molecular sieves (MCM-48) activated by the europium complex Eu(DBM)(3) . 2H(2)O (where DBM = dibenzoylmethane), using a simple wet impregnation method. Different concentrations of Eu(DBM)(3) . 2H(2)O were introduced into the MCM-48 cubic structure, and the resulting samples were washed with ethanol for different times. UV-Vis absorption measurements and thermogravimetric analysis were used to estimate the amount of Eu complex that has been incorporated within the pores of the MCM-48 host. The various samples were characterized by X-ray powder diffraction (XRD), infrared spectroscopy, diffuse reflectance (DR) and fluorescence measurements. The results reveal that Eu complexes have been successfully introduced into the pores of MCM-48 without disrupting the structure. All the impregnated MCM-48 materials show the typical red luminescence of Eu3+ when excited with a UV lamp. Shifts of the absorption maxima were observed in the DR and fluorescence excitation spectra and will be discussed in relation with guest-host interactions between the organic complex and the silica matrix. The decay profiles of the europium luminescence in the different samples were also measured and discussed.

Preparation and luminescence properties of the mesoporous MCM-41s intercalated with rare earth complex

Rare earth complex Eu(DBM)(3)phen (DBM: dibenzoylmethane, phen: 1.10-phenanthroline) hits been incorporated into unmodified MCM-41 and modified MCM-41s by aminopropyltriethoxysilane (APTES) or N-[(3-triethoxysilyl)propyl]ethylenediamine(TEPED). Thus, the assemblies of unmodified or modified MCM-41s with rare earth (RE) complex have been obtained. XRD spectra. NMR spectra. diffuse reflectance spectra. and the luminescence spectra were used to characterize the pure RE complex and the corresponding assemblies. The assemblies have better luminescence properties under UV irradiation. and their fluorescence lifetimes on the excited state are longer than that of the corresponding pure complex. The possible mechanisms are also discussed in the context.

Novel microporous silicates and mesoporous MCM materials derivatised with inorganic and organometallic complexes

Os materiais microporosos e mesoporosos são potenciais catalisadores heterogéneos. Os zeólitos e outros materiais microporosos do tipo zeolítico tradicionais, têm átomos tetracoordenados no esqueleto. Nos últimos anos, um vasto número de titanossilicatos contendo Ti(IV) hexacoordenado e Si(IV) tetracoordenado, com estruturas tridimensionais, têm sido alvo de grande interesse. Um dos objectivos desta tese foi preparar silicatos microporosos, contendo átomos metálicos com número de coordenação superior a quatro, e possuindo quer novas estruturas quer propriedades físicas e químicas interessantes. Neste contexto, foi preparado um novo ítriossilicato de sódio, AV-1, análogo do raro mineral montregianite, Na4K2Y2Si16O38·10H2O. Este material é o primeiro sólido microporoso que contem quantidades estequiométricas de sódio (e ítrio) no esqueleto. Foi, também, sintetizado um silicato de cério, AV-5, análogo estrutural do mineral montregianite com potencial aplicação em optoelectrónica. Nesta tese é, ainda, descrita a síntese e caracterização estrutural de um silicato de cálcio hidratado, AV-2, análogo do raro mineral rhodesite (K2Ca4Na2Si16O38.12H2O). Na continuação do trabalho desenvolvido em Aveiro na síntese de novos titanossilicatos surgiu o interesse de preparar novos zirconossilicatos microporosos por síntese hidrotérmica. Foram preparados dois novos materiais análogos dos minerais petarasite Na5Zr2Si3O18(Cl,OH)·2H2O (AV-3) e kostylevite, K2Si3O9·H2O (AV-8). Foram, também, obtidos análogos sintéticos dos minerais parakeldyshite e wadeite, por calcinação a alta temperatura de AV-3 e de umbite sintética. A heterogeneização de complexos organometálicos na superfície de materiais mesoporosos do tipo M41S permite associar a grande actividade catalítica e a presença de sítios activos localizados típicos dos complexos organometálicos, com a robustez e fácil separação, características dos materiais mesoporosos siliciosos. Nesta dissertação relata-se a derivatização dos materiais MCM-41 e MCM-48 através da reacção de [SiMe2{(h5-C5H4)2}]Fe e [SiMe2{(h5-C5H4)2}]TiCl2 com os grupos silanol das superfícies mesoporosas. Os materiais MCMs derivatizados com ansa-titanoceno foram testados na epoxidação de cicloocteno a 323 K na presença de hidrogenoperóxido de t-butilo. Estudou-se a heterogeneização dos sais de complexos com ligação metal-metal [Mo2(MeCN)10][BF4]4, [Mo2(m-O2CMe)2(MeCN)6][BF4]2 e [Mo2(m- O2CMe)2(dppa)2(MeCN)2][BF4]2 via imobilização nos canais do MCM-41. A imobilização dos catalisadores homogéneos na superfície do MCM-41 envolve a saída dos ligandos nitrilo lábeis, preferencialmente em posição axial, através da reacção com os grupos Si-OH da sílica. Verificou-se que a ligação Mo-Mo se mantém intacta nos produtos finais. É provável que estes materiais sejam eficientes catalisadores heterogéneos em reacções de polimerização. As técnicas de caracterização utilizadas nesta tese foram a difracção de raios-X de pós, a microscopia electrónica de varrimento, a espectroscopia de ressonância magnética nuclear do estado sólido (núcleos 13C, 23Na e 29Si), as espectroscopias de Raman e infravermelho com transformadas de Fourier, as análises termogravimétricas e as análises de adsorção de água e azoto.

Kinetic evaluation of the pyrolysis of high density polyethylene over H-AlMCM-41 material

The AlMCM-41 material with Si/Al=50 was synthesized by hydrothermal method, using cethyltrimethylammonium as template. The protonic H-AlMCM-41 acid form was obtained by ion exchange with ammonium chloride solution and subsequent calcination. The characterization of the material by several techniques showed that a good-quality MCM-41 material was obtained. High-density polyethylene (HDPE) has been submitted to thermal degradation alone, and in presence of the exchanged H-AlMCM-41 catalyst at a concentration of 1: 1 in mass (H-AlMCM-41/HDPE). The reactor was connected on line to a gas chromatograph connected to a mass spectrometer. This process was evaluated by thermogravimetry (TG), from 350 to 600degreesC, under helium dynamic atmosphere, with heating rates of 5.0; 10.0 and 20.0 degreesC/min. From TG curves, the activation energy, calculated using a multiple heating rate integral kinetic method, decreased from 225.5 KJ.mol(-1), for the pure polymer (HDPE), to 184.7 KJ.mol(-1), in the presence of the catalyst (H-AlMCM-41/HDPE).

Mesoporous bioglass/silk composite scaffolds for bone tissue engineering

In the past 20 years, mesoporous materials have been attracted great attention due to their significant feature of large surface area, ordered mesoporous structure, tunable pore size and volume, and well-defined surface property. They have many potential applications, such as catalysis, adsorption/separation, biomedicine, etc. [1]. Recently, the studies of the applications of mesoporous materials have been expanded into the field of biomaterials science. A new class of bioactive glass, referred to as mesoporous bioactive glass (MBG), was first developed in 2004. This material has a highly ordered mesopore channel structure with a pore size ranging from 5–20 nm [1]. Compared to non-mesopore bioactive glass (BG), MBG possesses a more optimal surface area, pore volume and improved in vitro apatite mineralization in simulated body fluids [1,2]. Vallet-Regí et al. has systematically investigated the in vitro apatite formation of different types of mesoporous materials, and they demonstrated that an apatite-like layer can be formed on the surfaces of Mobil Composition of Matters (MCM)-48, hexagonal mesoporous silica (SBA-15), phosphorous-doped MCM-41, bioglass-containing MCM-41 and ordered mesoporous MBG, allowing their use in biomedical engineering for tissue regeneration [2-4]. Chang et al. has found that MBG particles can be used for a bioactive drug-delivery system [5,6]. Our study has shown that MBG powders, when incorporated into a poly (lactide-co-glycolide) (PLGA) film, significantly enhance the apatite-mineralization ability and cell response of PLGA films. compared to BG [7]. These studies suggest that MBG is a very promising bioactive material with respect to bone regeneration. It is known that for bone defect repair, tissue engineering represents an optional method by creating three-dimensional (3D) porous scaffolds which will have more advantages than powders or granules as 3D scaffolds will provide an interconnected macroporous network to allow cell migration, nutrient delivery, bone ingrowth, and eventually vascularization [8]. For this reason, we try to apply MBG for bone tissue engineering by developing MBG scaffolds. However, one of the main disadvantages of MBG scaffolds is their low mechanical strength and high brittleness; the other issue is that they have very quick degradation, which leads to an unstable surface for bone cell growth limiting their applications. Silk fibroin, as a new family of native biomaterials, has been widely studied for bone and cartilage repair applications in the form of pure silk or its composite scaffolds [9-14]. Compared to traditional synthetic polymer materials, such as PLGA and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), the chief advantage of silk fibroin is its water-soluble nature, which eliminates the need for organic solvents, that tend to be highly cytotoxic in the process of scaffold preparation [15]. Other advantages of silk scaffolds are their excellent mechanical properties, controllable biodegradability and cytocompatibility [15-17]. However, for the purposes of bone tissue engineering, the osteoconductivity of pure silk scaffolds is suboptimal. It is expected that combining MBG with silk to produce MBG/silk composite scaffolds would greatly improve their physiochemical and osteogenic properties for bone tissue engineering application. Therefore, in this chapter, we will introduce the research development of MBG/silk scaffolds for bone tissue engineering.

Effects of mesostructured silica catalysts on the depolymerization of organosolv lignin fractionated from woody eucalyptus

Isolated and purified organosolv eucalyptus wood lignin was depolymerized at different temperatures with and without mesostructured silica catalysts (i.e., SBA-15, MCM-41, ZrO2-SBA-15 and ZrO2-MCM-41). It was found that at 300 oC for 1 h with a solid/liquid ratio of 0.0175/1 (w/v), the SBA-15 catalyst with high acidity gave the highest syringol yield of 23.0% in a methanol/water mixture (50/50, wt/wt). Doping with ZrO2 over these catalysts did not increase syringol yield, but increased the total amount of solid residue. Gas chromatography-mass spectrometry (GC-MS) also identified other main phenolic compounds such as 1-(4-hydroxy-3,5-dimethoxyphenyl)-ethanone, 1,2-benzenediol, and 4-hydroxy-3,5-dimethoxy-benzaldehyde. Analysis of the lignin residues with Fourier transform-Infrared spectroscopy (FT-IR) indicated decreases in the absorption bands intensities of OH group, C-O stretching of syringyl ring and aromatic C-H deformation of syringol unit, and an increase in band intensities associated with the guaiacyl ring, confirming the type of products formed.

Mesoporous silica- and silicon-based materials as carriers for poorly water soluble drugs

New chemical entities with unfavorable water solubility properties are continuously emerging in drug discovery. Without pharmaceutical manipulations inefficient concentrations of these drugs in the systemic circulation are probable. Typically, in order to be absorbed from the gastrointestinal tract, the drug has to be dissolved. Several methods have been developed to improve the dissolution of poorly soluble drugs. In this study, the applicability of different types of mesoporous (pore diameters between 2 and 50 nm) silicon- and silica-based materials as pharmaceutical carriers for poorly water soluble drugs was evaluated. Thermally oxidized and carbonized mesoporous silicon materials, ordered mesoporous silicas MCM-41 and SBA-15, and non-treated mesoporous silicon and silica gel were assessed in the experiments. The characteristic properties of these materials are the narrow pore diameters and the large surface areas up to over 900 m²/g. Loading of poorly water soluble drugs into these pores restricts their crystallization, and thus, improves drug dissolution from the materials as compared to the bulk drug molecules. In addition, the wide surface area provides possibilities for interactions between the loaded substance and the carrier particle, allowing the stabilization of the system. Ibuprofen, indomethacin and furosemide were selected as poorly soluble model drugs in this study. Their solubilities are strongly pH-dependent and the poorest (< 100 µg/ml) at low pH values. The pharmaceutical performance of the studied materials was evaluated by several methods. In this work, drug loading was performed successfully using rotavapor and fluid bed equipment in a larger scale and in a more efficient manner than with the commonly used immersion methods. It was shown that several carrier particle properties, in particular the pore diameter, affect the loading efficiency (typically ~25-40 w-%) and the release rate of the drug from the mesoporous carriers. A wide pore diameter provided easier loading and faster release of the drug. The ordering and length of the pores also affected the efficiency of the drug diffusion. However, these properties can also compensate the effects of each other. The surface treatment of porous silicon was important in stabilizing the system, as the non-treated mesoporous silicon was easily oxidized at room temperature. Different surface chemical treatments changed the hydrophilicity of the porous silicon materials and also the potential interactions between the loaded drug and the particle, which further affected the drug release properties. In all of the studies, it was demonstrated that loading into mesoporous silicon and silica materials improved the dissolution of the poorly soluble drugs as compared to the corresponding bulk compounds (e.g. after 30 min ~2-7 times more drug was dissolved depending on the materials). The release profile of the loaded substances remained similar also after 3 months of storage at 30°C/56% RH. The thermally carbonized mesoporous silicon did not compromise the Caco-2 monolayer integrity in the permeation studies and improved drug permeability was observed. The loaded mesoporous silica materials were also successfully compressed into tablets without compromising their characteristic structural and drug releasing properties. The results of this research indicated that mesoporous silicon/silica-based materials are promising materials to improve the dissolution of poorly water soluble drugs. Their feasibility in pharmaceutical laboratory scale processes was also confirmed in this thesis.

Esterification of stearic acid with p-cresol over modified Indian bentonite clay catalysts

The esterification of stearic acid with p-cresol using modified Indian bentonite clay catalysts has been reported. The reaction was studied over exchanged clays, acid activated clays, exchanged acid activated clays, aluminium pillared clay, aluminium pillared acid activated clay, molecular sieve Al-MCM-41, zeolite H beta, ZrO2, S-ZrO2, p-TSA, montmorillonite K10, and montmorillonite KSF in o-xylene for 6 h. The catalysts were characterized by X-ray diffraction and surface area measurements. The acidity was determined by n-butylamine back-titration method and DRIFTS after pyridine adsorption. Acid activated Indian bentonite (AAIB) was found to be a better catalyst compared to other catalysts in the esterification of stearic acid with p-cresol.

Meso-Structured Silica-Nafion Hybrid Membranes for Direct Methanol Fuel Cells

A series of novel organic-inorganic hybrid membranes have been prepared employing Nafion and acid-functionalized meso-structured molecular sieves (MMS) with varying structures and surface area. Acid-functionalized silica nanopowder of surface area 60 m(2)/g, silica meso-structured cellular foam (MSU-F) of surface area 470 m(2)/g and silica meso-structured hexagonal frame network (MCM-41) of surface area 900 m(2)/g have been employed as potential filler materials to form hybrid membranes with Nafion framework. The structural behavior, water uptake, proton conductivity and methanol permeability of these hybrid membranes have been investigated. DMFCs employing Nafion-silica MSU-F and Nafion-silica MCM-41 hybrid membranes deliver peak-power densities of 127 mW/cm(2) and 100 mW/cm(2), respectively; while a peak-power density of only 48 mW/cm(2) is obtained with the DMFC employing pristine recast Nafion membrane under identical operating conditions. The aforesaid characteristics of the hybrid membranes could be exclusively attributed to the presence of pendant sulfonic acid groups in the filler, which provide fairly continuous proton-conducting pathways between filler and matrix in the hybrid membranes facilitating proton transport without any trade-off between its proton conductivity and methanol crossover. (C) 2012 The Electrochemical Society. DOI: 10.1149/2.036211jes] All rights reserved.

Mesostructured-aluminosilicate-Nafion hybrid membranes for direct methanol fuel cells

Organic-inorganic hybrid membranes are prepared from Nafion and acid functionalized aluminosilicate with varying structures and surface areas. Acid-functionalized mesostructured aluminosilicate with cellular foam framework (Al-MSU-F type) of surface area 463 m(2) g(-1), acid-functionalized aluminosilicate molecular sieves (Al-HMS type) of surface area 651 m(2) g(-1) and acid-functionalized mesostructured aluminosilicate with hexagonal network (Al-MCM-41 type) of surface area 799 m(2) g(-1) have been employed as potential filler materials to form hybrid membranes with Nafion. The structural behavior, water uptake, ion-exchange capacity, proton conductivity and methanol permeability of the hybrid membranes are extensively investigated. Direct methanol fuel cells (DMFCs) with Al-HMS-Nafion and Al-MCM-41-Nafion hybrid membranes deliver respective peak power-densities of 170 mW cm(-2) and 246 mW cm(-2), while a peak power-density of only 48 mW cm(-2) is obtained for the DMFC employing pristine recast-Nafion membrane under identical operating conditions. The unique properties associated with hybrid membranes could be exclusively attributed to the presence of pendant sulfonic-acid groups in the filler materials, which provide proton-conducting pathways between the filler and matrix in the hybrid membranes, and facilitate proton transport with adequate balance between proton conductivity and methanol permeability. (C) 2012 Elsevier Ltd. All rights reserved.

Development of the heterogeneous catalysts for the production of levulinic acid from furfuryl alcohol

207 p.

稀土(Er, Nd, Yb, Pr, Ho, Sm)有机/无机杂化材料的制备及发光性能研究

目前，国内外对于铕和铽等稀土配合物的可见区发光和应用都有大量研究，但对具有近红外发光（800-1700 nm）性能的稀土配合物的研究还处于起步阶段。由于稀土的近红外发光在光纤通讯、激光系统及诊断学等方面应用具有特殊的优点，越来越引起人们的兴趣和重视。 稀土近红外发光配合物的致命弱点是其光、热和化学稳定性较差，从而限制了其在很多领域的实际应用。而溶胶－凝胶材料和介孔材料具有良好的光、热和化学稳定性，能改善客体分子的结构环境和化学微环境，从而能有效提高客体分子的发光性能。因此，本论文将具有优良近红外发光性能的稀土配合物分别与上述两种基质复合，从实验和理论研究稀土近红外发光杂化材料的性能和应用价值，制备出具有良好稳定性的高效稀土近红外发光杂化材料，以期为光纤通讯、激光等领域提供潜在的候选材料。围绕这一宗旨，开展了如下工作： 通过原位技术分别得到了掺杂和嫁接[Ln(dbm)3phen]化合物（Ln = Er, Nd, Yb）的杂化凝胶材料，Ln-D-P gel和Xerogel-Ln。通过对其近红外发光性能的研究，表明材料中配体能很好的保护稀土离子，并将能量有效的传递给稀土离子。采用Judd-Ofelt理论对所得部分材料进行了光谱分析，基于实验数据和理论分析表明其具有潜在的光放大和激光应用价值。 选择了两种含全氟化烷基链的β-二酮配体Hhfth和Htfnb，通过功能化的phen-Si配体，将三元配合物[Ln(hfth)3phen] (Ln = Er, Nd, Yb, Sm)和[Pr(tfnb)3phen]成功共价嫁接到介孔MCM-41和SBA-15杂化材料中，得到的衍生材料Ln(hfth)3phen–MCM-41、Pr(tfnb)3phen–MCM-41和Ln(hfth)3phen–SBA-15、Pr(tfnb)3phen–SBA-15都保持了高度有序的介孔p6mm结构，并展现出稀土离子特征的近红外发射。所得稀土配合物功能化的材料的发射光谱能完全覆盖对光通讯极具应用价值的1300-1600nm区域。 通过对Er(dbm)3phen–M41(X, Y) (X = 1~14, Y = 3, 6, 12, 18, 24 h)材料系统的比较研究，选择了X = 12, Y = 6作为合成目标材料的优化参数，通过功能化的phen-Si配体将[Ln(dbm)3phen]配合物共价嫁接于有序介孔MCM-41和SBA-15中(Ln = Er, Nd, Yb)，所得两类材料Ln(dbm)3phenM41和Ln(dbm)3phenS15都保持了很好的介孔有序性，并具有良好的近红外发光性能。通过对Ln(dbm)3phenM41和Ln(dbm)3phenS15两类材料发光行为的比较，以及两类材料中稀土离子的含量及孔结构的分析，推出以SBA-15为载体得到的材料在相对发光强度和荧光寿命上，均比以MCM-41为载体的材料有所提高。 通过对8－羟基喹啉配体进行改性，合成了具有双功能的配体Q-Si，继而合成了共价嫁接8－羟基喹啉衍生物的介孔杂化材料Q–SBA-15，其形貌均一，并具有高度有序的介孔p6mm结构。通过配体交换反应，得到了嫁接稀土喹啉配合物的具有近红外发光性能的介孔杂化材料LnQ3–SBA-15 (Ln = Er, Nd, Yb)，其仍然保持高度有序的介孔结构，且外形呈现与母体材料Q–SBA-15相似的弯曲圆柱状。激发配体的吸收，LnQ3–SBA-15材料都分别展现出相应稀土离子特征的近红外发射，并详细分析和讨论了所得介孔杂化材料的近红外发光性能。

稀土/高聚物杂化材料的制备及发光性能的研究

本论文旨在开发能使无机材料和有机材料的功能互补、协同优化的无机/有机复合发光材料的制备方法，并研究其发光性质，以发展一类新型的高性能发光材料。首先基于无机组份与有机组份的物理和化学性质的差异，采用能保持其性质均不改变的低温软化学合成法-溶胶-凝胶技术，无机组份选择具有优良光、热稳定性的SiO_2，有机组份选择具有和无机SiO_2相似折射率和优良力学性能的丙烯酸类如甲基丙烯酸甲酯(MMA)和甲基丙烯酸羟乙酯(HEMA)，采用两步溶胶-凝胶法和在交联剂3-(三甲氧基硅)丙基甲基丙烯酸酯(MSMA)存在下快速制备了两种杂化基质材料SiO_2/P(MMA-MSMA)和SiO_2/P(HEMA-MSMA)。由于使用两步溶胶-凝胶法，大大缩短了溶胶的成胶时间，所得杂化材料具有良好的光学透明性。实验结果表明，在基质材料中形成了无机网络和聚合物网络，无机相和有机相之间存在着强的化学键，两相间无明显的界面，即形成了互穿网络，粒子的尺寸在100 nm以内，属于纳米材料。由于原位聚合物与无机SiO_2基质同时生成，不仅使杂化基质材料具有一定的韧性，而且可有效降低无机SiO_2凝胶基质的热聚集和光损耗，是制备复合发光材料的优良基质材料。由于TiO_2基质具有较低的声子能量(可降低发光组份的非辐射跃迁几率)，也是一种良好的基质材料。研究了在DMF存在下透明TiO_2凝胶基质的快速制备方法。由于DMF上的氮原子可和Ti-OH上羟基形成氢键，从而大大降低了钛酸丁酯的水解速率，避免了钛酸丁酯直接水解时沉淀的出现，通过调节DMF的用量，可以在不同时间内制备透明的TiO_2凝胶。凝胶经热处理后，其结构从无定型态转变为锐钛矿相，经800℃热处理后己全部转变为会红石相。此制备方法不仅快速，而且比现有的溶胶-凝胶法制备金红石相TiO_2的温度至少降低了200℃。基于高分子聚合物聚乙烯醇缩丁醛(PVB)具有良好的成膜性能，采用旋转涂敷法制备了SiO_2/PVB杂化膜，通过调节溶胶的粘度和匀胶的速度，可以制备不同厚度的薄膜，为杂化发光膜的制备提供了依据。基于1,1,4,4-四苯基-1,3-丁二烯(TPB)在蓝光波段其有优良的发光性能，制备了掺杂TPB的SiO_2凝胶，并研究其在溶胶-凝胶过程中光谱性质的变化。由于凝胶基质的“笼保护”效应，掺杂于溶胶-凝胶基质中的TPB具有较高的热稳定性，其热分解温度达460℃。TPB具有较高的猝灭浓度，相对于它的氯仿溶液，TPB在凝胶基质中猝灭浓度提高2～3个数量级。另外，在凝胶基质中比其在氯仿溶液中具有较长的荧光寿命，这对于此类发光材料的实用化具有重要意义。基于基质的组成、微结构及化学环境，可影响发光组份之间的相互作用和能量传递规律，制备了双掺UO_2~(2+)和Eu~(3+)的TiO_2凝胶。由于在TiO_2凝胶基质中Eu~(3+)的激发光谱和UO_2~(2+)的发射光谱具有较大的光谱重叠，研究了它们之间的能量传递机制。实验结果表明，在TiO_2凝胶中，存在着UO_2~(2+)向Eu~(3+)的能量传递过程，其能量转移效率和能量转移速率随Eu~(3+)浓度的增大而增大。通过对Stern-Volmer曲线的分析，得出Eu~(3+)对UO_2~(2+)荧光的猝灭机制主要为稳态猝灭机制，此研究为丌发新的发光材料提供了科学依据。为克服传统溶胶-凝胶法制备光功能材料时预先掺杂法的缺点和局限，缩短制备光功能材料的周期，基于溶胶-凝胶水解、缩聚的特点和稀土配合物的形成规律，首次提出应用两步溶胶-凝胶法于SiO_2基质中快速原位合成了稀土配合物的方法。它是即在用盐酸作为酸性催化剂水解一定时间的溶胶中，加入六次甲基四胺作为碱性催化剂。六次甲基四胺的加入，一方面，加快了凝胶的形成，另一方面，使溶胶的介质逐步适合配合物的形成，最终在凝胶基质的形成中原位合成了稀土配合物。由于采用两步溶胶-凝胶法，缩短了凝胶时间，可在数小时内制备出透明含原位配合物的湿凝胶。采用荧光光谱、吸收光谱、IR光谱及荧光寿命测量等手段，对原位合成稀土配合物的过程进行了跟踪表征。实验结果表明，对于水杨酸-Tb~(3+)配合物的原位合成，在溶胶阶段无配合物的形成，此时，水杨酸向Tb~(3+)的能量传递属于分子间能量传递过程，即扩散控制的碰撞过程；在湿凝胶中，Tb~(3+)与水杨酸形成了配合物，在紫外光激发下，通过水杨酸向Tb~(3+)的分子内能量转移，发出Tb~(3+)强烈的特征荧光。此复合光功能材料制备技术，具有一定的创新性和实用价值。应用上述两步溶胶一凝胶法于SiO_2及SiO_2/聚合物杂化基质中快速原位合成了稀土β-二酮、芳香羧酸及杂环配体phen配台物，并制备了稀土配合物SiO_2/PVB杂化发光薄膜。原位稀土配合物在紫外光激发下发出其相应稀土离子的特征谱线，和纯配合物相比，其激发光谱变为-不对称的宽带，发射光谱表现出较少的劈裂：山于杂化基质的保护作用，原位合成的稀土配合物具有较好的光稳定性和热稳定性；由于原位合成的配合物被固定于基质的微孔中，在IR光谱上，其相关振动吸收较弱；配合物的名义掺杂在0.6 mol%时，发光强度随掺杂浓度的增加而增加，无浓度猝灭现象；SEM表明，含有原位合成的配合物的材料，具有一定的均匀性，粒子尺寸在纳米级范围。为发展多种无机基质稀土有机配合物光功能材料的复合技术，拓宽无机/有机光功能材料的制备方法，首次采用离子交换法将稀土配合物Eu(DBM)_3phen和Tb(AA)_3phen嵌入到层状化合物α-磷酸氢锆(α-ZrP)中，制备了嵌有稀土配合物的组装体，并研究了组装体的光物理性质。基于层状化合物的结构特点，首先将对甲氧基苯胺(PMA)嵌入层状化合物中，得到预组装体，使层间距变大，然后再通过离子交换的方式，制得含有稀土配合物的组装体。XRD光谱和紫外-可见吸收光谱证明配合物组装进了层状化合物中。在紫外光激发下，组装体发出相应稀土离子的特征谱线；和纯配合物粉末相比，其激发光谱发生一定的蓝移，而其发射光谱则表现出较少的劈裂；由于基质的保护作用，组装体中的配合物具有较高的荧光寿命和发光效率。研究、制备了改性MCM-41与稀土配合物Eu(DBM)_3phen的复合组装体发光材料，并研究了组装体的发光性质。由于羟基的高能振动将极大地猝灭稀土离子的荧光发射，所以采用3-氨丙基三乙氧基硅烷、N-[(3-三乙氧基硅)]丙基乙二胺和4-(三乙氧基硅)丁氰三种硅烷化试剂对介孔分子筛MCM-41内壁羟基进行了修饰。组装体在紫外光激发下发出稀土离子的特征谱线，经氨丙基三乙氧基硅烷改性后的组装体，其发光强度约为未改性MCM-41前组装体的9倍，说明了经改性后，减少了基质中的羟基含量，降低了因羟基的高能振动而引起的非辐射跃迁几率，提高了组装体的荧光强度；对不同的改性剂的改性效果的研究表明，经4-(三乙氧基硅)丁氰改性、N-[(3-三乙氧基硅)]丙基乙二胺改性和3-氨丙基三乙氧基硅烷改性MCM-41改性后的的组装体的荧光强度依次增加，同时，稀土离子在其中的荧光寿命也依次增加。以上复合技术为研究和开发具有高效、长寿命的复合发光材料提供了新的可能。为满足不同条件下材料的要求，选择具有优良发光性能的稀土配合物，将其引入P(MAA-St)共聚物的合成过程中，制备了质轻、透明性好的掺杂有稀土配合物的透明发光树脂，并研究了发光树脂的光物理性质。透明发光树脂具有良好的透光性，密度在1.2 g/cm~3；在紫外光照射下，树脂发出稀土离子强烈的特征荧光，在掺杂浓度不大于4wt%时，发光强度随掺杂浓度的增大而增大。稀土配合物在发光树脂中较其在乙醇溶液中具有较长的荧光寿命。与其相应的纯配合物的乙醇溶液相比，稀土配合物在发光树脂中的周围环境极性增大，格位对称性升高。

多氟稀土（Sm、Tb）有机配合物的合成及发光性质的研究

本文合成了几种多氟β-二酮配合物，并将其引入无机／有机杂化基质及中孔分子筛材料中，从而制备了发光性能良好的杂化材料。选用新型的多氟β-二酮作为有机配体，合成了几种衫、试配合物，通过IR、1H NMR等手段证实了配合物的生成，并研究了其发光性质。首次得到了以4,4,5,5,6,6,6-七氟-1-2-噻吩基）-1-已二酮（HTH）为配体的衫的配合物单晶（Sm（HT）3Phen），解析了其结构，结果表明其配位多面体为三角十二面体。将多氟三元配合物Tb（Tfacac）3phen通过溶胶一凝胶过程掺杂到γ-缩水甘油丙基醚三甲氧基硅烷（GPTMS）改性的有机／无机杂化基质中，制备了有机／无机杂化发光块状材料一及其薄膜材料；研究了稀土配合物在未改性基质和改性基质中的发光性质，以及不同基质对发光性能的影响，结果发现该杂化材料最大激发峰位相对于纯配合物发生了蓝移，且激发谱带变窄；考察了两种基质中配合物掺杂浓度对杂化材料的发光强度的影响，结果表明。稀土配合物在改性基质中比在未改性基质中掺杂浓度提高了。比较了粉末材料与相应薄膜的发光性能，发现薄膜材料巴的发光强度和荧光寿命有所降低，表明材料的不同状态对其发光性能有一定的影响。制备了中孔分子筛MCM-41及GPTMS、TMSPMC改性的有机／无机杂化中孔材料。回时成功地将稀土配合物Sm（HTH）3Phen、Tb（Tfacac）3Phen组装到MCM-41及两种改性的MCM-41中，合成了担载新型稀土有机配合物的无机-有机杂化中孔发光材料。通过对稀土配合物及其在分子筛中的荧光光谱分析，发现激发光谱发生了蓝移；而且不同的改性剂对不同的稀土配合物的影响不同。并制得了发光色纯度较高的稀土-TMSPMC-MCM-41复合发光体。

稀土配合物掺杂的中孔杂化发光材料的制备及其表征

稀土配合物由于具有优良的窄带发光性能和较长的荧光寿命，因而在光电学领域比如激光材料或者荧光标记上引起了广泛的兴趣和应用。吸附在固体表面的稀土配合物的发光性质得到了广泛的研究。MCM-48中孔材料是M41S家族中的一种，具有直径20-30A三维结构的中孔孔道，比MCM-41的一维结构孔道更有优势，比如它可以最大可能的避免客体分子的堆积现象。因此本论文中我们研究了将稀土（Eu3+）β-二酮（DBM＝dibenzoylmethane）配合物掺杂到纯硅MCM-48以及三种有机基团嫁接的有机－无机杂化MCM-48的孔道中去，得到了各种不同的杂化中孔发光材料。首先烧结后的MCM-48被装载稀土Eu（OBM）3'2H2O配合物之后。XRD结果说明稀土配合物被组装到了MCM-48中，其有序结构因为稀土配合物的进入而受到一定的影响，但是样品仍保持了MCM-48的立方相结构。分别通过吸收光谱和热失重的方法计算了掺杂后的发光MCM-48样品进行洗涤后留在MCM一48中配合物的量。固体漫反射光谱在紫外区有一个OBM配体的Sn基态能级（π）到S1激发态能级份＊）的电子跃迁形成的吸收宽带。可见区还观察到E护”离子的4f-4畴征吸收线。与稀土配合物中的OBM配体相比，掺杂MCM-48样品的Sn-S1吸收带均发生蓝移，反映了S1能级向高能方向移动。然后采用了室温两步合成法合成MCM-48，模板剂的去除采用了溶剂萃取法。最佳掺杂浓度为6.98×10-3 mol/l；同时最佳掺杂时间为24小时。在同样的掺杂条件下，稀土配合物在基质中的掺杂量MCM-48＞MCM-41＞＞SiO2。萃取之后的MCM-48在外形上近乎于球形，粒子的直径在0.7-1.2μm之间。粒子显现出多孔的海绵状表面形态，并且具有晶体结构外形，呈菱形十二面体被削去顶端立方体的结构。而且在粒子的表面观察到了类似螺旋结构的孔道，我们认为这是MCM一48所特有的双螺旋型三维孔道结构，这是到目前为止首次报道利用扫描电镜观察到中孔分子筛的孔道结构。荧光光谱结果观察到了激发峰的最大值由于纳米粒子效应出现的蓝移现象。不同基质中的发射系数QZ和04比较可知配合物在三种基质SiO2、MCM-41和MCM-48中环境的极性相差不大。掺杂到中孔MCM-48材料中的稀土配合物的热稳定性比在MCM-41中强，这是由于MCM-48的三维孔道对配合物的保护作用。室温条件下合成的MCM-48分子筛利用后合成嫁接的方法[post-synthesis grajng（PSG）]进行表面修饰，修饰剂选用了带有功能性乙烯基的VTES，链长最短的MTES以及带有氨基的长链NTSED。稀土Eu（DBM）3'2H2O配合物被组装到杂化中孔分子筛材料中。红外光谱与2951核磁共振光谱表明MCM-48的表面被成功的接枝上了有机M下任S，盯任s，N丁s任D基团。与MCM-48相比，MCM-48-R的表面积、孔体积和孔径的减少有以下NTSED＞VTES＞MTES的顺序。这也许是修饰的有机基团不同的链的长度不同的原因。稀土配合物在这三种有机一无机杂化基质环境的极性比纯硅MCM-48要增大。同时配合物在三种基质的中的QZ的值及发光效率的顺序为：MCM-48-MTES＜MCM-48-VTES＜MCM-48-NTSED，说明MCM-48经过三种有机硅氧烷修饰之后孔道极性也遵循同样的顺序，可以认为这是由于三种有机基团的链长的不同造成的，链长越长则修饰之后孔道极性增大的就越多。最后通过溶胶一凝胶过程利用提拉法（Dip-coating method）制备了具有中孔结构的SiO2-CTAB-Tb（acac）3透明发光薄膜（Mesostructed Iuminescence thin film，略为MLTF），稀土配合物利用原位合成（In-situ）的办法掺入到透明薄膜中。对薄膜进行热处理过程表明薄膜中的稀土配合物在50℃的时候开始形成。XRO结果表明稀土离子及有机配体的掺入对薄膜中孔相的结构没有太大的影响，荧光薄膜仍保持层状结构。红外光谱结果说明制备的中孔薄膜是由CTAB和硅氧烷聚合物组成的复合薄膜。荧光薄膜的发射光谱给出了Th3+离子的特征发射峰，荧光薄膜中有机配体与丁b离子之间发生了能量传递现象。因为在热处理过程中有机配体逐渐代替了开始与Tb离子配位的OH基团，使得二者间的能量传递更加有效，从而导致了荧光的增强。