Vibrational Study on the Local Structure of Post‐Synthesis and Hybrid Mesoporous Materials: Are There Fundamental Distinctions?

Organic-inorganic mesoporous materials of the MCM-41 type are important materials that can be prepared by either post-synthesis or one-pot synthesis procedures. A complete control of the characteristics at a local level is of the utmost importance in view of the applications of such materials. However, there are not many studies relating such features with synthetic approaches. In this work, we prepared samples by post-synthesis derivatization of materials from Si-based MCM-41, with bidentate nitrogen ligands bearing one or two silylated arms, and by one-pot synthesis of organic-inorganic hybrid materials. The bulk properties of the two kinds of materials were comparable. Diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy and Raman spectroscopy were used to investigate the local environment, namely, the number of OH groups and distribution of SiO(4) units (large and small ring units). Hydrophilicity correlates with both the type of organic moiety used (mono- or disilylated), as well as with the synthetic procedure. The same vibrational studies showed how the structure in the channels changes as a function of pressure, reflecting the low mechanical stability of the mesoporous materials.     

From chemistry to materials, design and photophysics of functional terbium molecular hybrids from assembling covalent chromophore to alkoxysilanes through hydrogen transfer addition

Two silica-based organic-inorganic hybrid materials composed of phenol (PHE) and ethyl-p-hydroxybenzoate derivatives (abbreviated as EPHBA) complexes were prepared via a sol-gel process. The active hydroxyl groups of PHE/EPHBA grafted by 3-(triethoxysilyl)-propyl isocyanate (TESPIC) through hydrogen transfer reaction were used as multi-functional bridged components, which can coordinate to Tb³⁺ with carbonyl groups, strongly absorb ultraviolet and effectively transfer energy to Tb³⁺ through their triplet excited state, as well as undergo polymerization or crosslinking reactions with tetraethoxysilane (TEOS), for anchoring terbium ions to the silica backbone. For comparison, two doped hybrid materials in which rare-earth complexes were just encapsulated in silica-based sol-gel matrices were also prepared. NMR, FT-IR, UV/vis absorption and luminescence spectroscopy were used to investigate the obtained hybrid materials. UV excitation in the organic component resulted in strong green emission from Tb³⁺ ions due to an efficient ligand-to-metal energy transfer mechanism.     

Nanometer fluorescent hybrid silica particle as ultrasensitive and photostable biological labels

Nanometer-sized fluorescent hybrid silica (NFHS) particles were prepared for use as sensitive and photostable fluorescent probes in biological staining and diagnostics. The first step of the synthesis involves the covalent modification of 3-aminopropyltrimethoxysilane with an organic fluorophore, such as fluorescein isothiocyanate, under N2 atmosphere for getting a fluorescent silica precursor. Then the NFHS particles, with a diameter of well below 40 nm, were prepared by controlled hydrolysis of the fluorescent silica precursor with tetramethoxysilane (TMOS) using the reverse micelle technique. The fluorophores are dispersed homogeneously in the silica network of the NFHS particles and well protected from the environmental oxygen. Furthermore, since the fluorophores are covalently bound to the silica network, there is no migration, aggregation and leakage of the fluorophores. In comparison with common single organic fluorophores, these particle probes are brighter, more stable against photobleaching and do not suffer from intermittent on/off light emission (blinking). We have used these newly developed NFHS particles as a fluorescent marker to label antibodies, using silica immobilization method, for the immunoassay of human alpha-fetoprotein (AFP). The detection limit of this method was down to 0.05 ng mL(-1) under our current experimental conditions. We think this material would attract much attention and be applied widely in biotechnology.     

有机-无机杂化一维纳米材料的合成及其二次转化

近十年来,随着纳米科技的发展,有机．无机杂化一维纳米材料的设计合成与应用成为了自然科学领域的研究热点．本文综述了由有机小分子与无机组分杂化而成的一维纳米材料的合成方法,包括水热／溶剂热法、共沉淀法、非水相溶胶凝胶法、模板法、后嵌入法等．并对有机一无机杂化一维纳米材料的二次转化,如通过二次转化获得功能性一维氧化物、碳氮化物、硫属化合物及高分子杂化纳米材料,进行了讨论与展望．     

Thermal degradation of epoxy-silica organic-inorganic hybrid materials

Degradation kinetics of organic-inorganic hybrid materials based on epoxy resin were investigated by thermogravimetric analysis (TGA). The hybrid materials were prepared from diglycidyl ether of bisphenol A (DGEBA) and 3-glycidyloxypropyltrimethoxysilane (GLYMO) polymerised simultaneously by poly(oxypropylene)diamine (Jeffamine D230). Nanometric level of homogeneity in the hybrids was verified by electron microscopy. Energy of activation of degradation for the hybrids with varying inorganic content, as well as for the unmodified epoxy-amine system, was determined by the isoconversional Kissinger-Akahira-Sunose method, and was found to be significantly higher for the hybrid materials than for the unmodified epoxy-amine system. The degradation process was described by empirical kinetic models. The results indicated that presence of the inorganic network influences the mechanism of degradation of organic phase. Greater thermal stability of hybrid materials was confirmed by other parameters obtained from TGA curves.     

Organic nanocrystals grown in sol-gel matrices: new hybrid organic-inorganic materials for optics

We have developed a simple and generic preparation of stable organic nanocry stals grown in gel-glass matrices. The synthesis of these hybrid organic-inorganic materials is based on the confined nucleation and growth of organic phases in the pores of dense gels. For bulk nanocomposite samples, narrow size distributions of particles (10–20 nm in diameter) are obtained. We have extended this method to the preparation of organic nanocrystals embedded in sol-gel thin films prepared by spin-coating. For all these nanocomposite materials, we have significantly increased the dye stability and obtained promising optical properties: luminescence, non-linear optical properties or photochromism. Moreover, we have also demonstrated basic working principles of a new type of fluorescent nanosensor through the preparation of organic luminescent nanocrystals grown in silicate films.     

荧光团杂化纳米SiO2微球作为生物标记探针的应用研究

近年来 ,无机发光量子点[1,2 ] 、荧光纳米乳液微球[3 ,4 ] 及发光团掺杂 Si O2 纳米粒子[5] 等纳米荧光探针的出现 ,为生物标记提供了新的发展领域 .将有机染料以共价方式包埋在 Si O2 中所得的复合材料具有独特的光学性质 ,然而其在生物标记方面的应用并未得到重视[6 ,7] .本实验通过控制荧光团修饰的硅烷前体在反相胶束体系中的水解缩合 ,合成了用于生物染色和诊断的高灵敏度、高稳定性的新型荧光团杂化纳米 Si O2 微球 ( NFHS微球 ) .在 NFHS微球中 ,荧光团以共价方式地均匀分散在 Si O2 网络结构中 ,避免了与外界体系中溶解氧的…     

Solid-state 13C NMR studies on organic-inorganic hybrid zeolites

A novel type of organic-inorganic hybrid zeolite with organic lattice (ZOL) is studied in detail by solid-state (13)C magic angle spinning nuclear magnetic resonance (MAS NMR). The (13)C MAS NMR measurements employing several pulse sequences quantitatively demonstrate that methylene groups are really incorporated in the framework, although they are partially cleaved into methyl groups. The organic species in ZOL materials are open for adsorbates, which is evidenced by the (13)C MAS NMR measurements for an n-hexane-adsorbing ZOL material. This finding strongly suggests that organic moieties are incorporated as a zeolite framework, indicating that ZOL is not a physical mixture of a carbon-containing amorphous aggregate and a conventional zeolite but a true organic-inorganic hybrid zeolite.     

有机-无机杂化氧化硅基介孔材料

有机基团可以通过嫁接或共聚的方法引入到氧化硅基介孔材料的孔表面或材料的骨架中,形成表面结合型和桥键型两大类有机-无机杂化氧化硅基介孔材料.本文综述了有机-无机杂化氧化硅基介孔材料的最新研究进展,介绍了其合成方法、应用及潜在的应用领域,详细总结了目前已报道的有机-无机杂化氧化硅基介孔材料的种类,展望了桥键型有机-无机杂化氧化硅基介孔材料的发展及应用前景.     

Synthesis and characterizations of anion exchange organic-inorganic hybrid materials based on poly(2,6-dimethyl-1,4-phenylene oxide) (PPO)

A series of poly(2,6-dimethyl-1,4-phenylene oxide) (PPO)-based organic-inorganic hybrid materials for anion exchange were prepared through sol-gel process of polymer precursors PPO-Si(OCH₃)₃. PPO-Si(OCH₃)₃ were obtained from the reaction of bromomethylated PPO with 3-aminopropyl-trimethoxysilane (A1110). These polymer precursors then underwent hydrolysis and condensation with additional A1110 to generate hybrid materials. The reaction to produce polymer precursors was identified by FTIR; while FTIR, TGA, XRD, SEM, as well as conventional ion exchange capacity (IEC) measurements were conducted for the structures and properties of the prepared hybrids. TGA results show that this series of hybrid materials possess high thermal stability; XRD and SEM indicate that the prepared hybrid materials are amorphous and the inorganic and organic contents show good compatibility if the ratio between them is proper. The IEC values of the hybrid materials due to the amine groups range from 1.13 mmol/gBPPO (material i) to 4.80 mmol/gBPPO (material iv).     

Preparation and applications of hybrid organic-inorganic monoliths: a review

This review presents an overview of the properties of hybrid organic-inorganic monolithic materials and summarizes the recent developments in the preparation and applications of these hybrid monolithic materials. Hybrid monolithic materials with porosities, surface functionalities, and fast dynamic transport have developed rapidly, and have been used in a wide range of applications owing to the low cost, good stability, and excellent performance. Basically, these materials can be divided into two major types according to the chemical composition: hybrid silica-based monolith (HSM) and hybrid polymer-based monolith (HPM). Compared to the HPM, HSM monolith has been attracting most wide attentions, and it is commonly synthesized by the sol-gel process. The conventional preparation procedures of two type's hybrid organic-inorganic monoliths are addressed. Applications of hybrid organic-inorganic monoliths in optical devices, capillary microextraction (CME), capillary electrochromatography (CEC), high performance liquid chromatography (HPLC), and chiral separation are also reviewed.     

Organic-inorganic hybrid mesoporous silicas: functionalization, pore size, and morphology control

Topological design of mesoporous silica materials, pore architecture, pore size, and morphology are currently major issues in areas such as catalytic conversion of bulky molecules, adsorption, host-guest chemistry, etc. In this sense, we discuss the pore size-controlled mesostructure, framework functionalization, and morphology control of organic-inorganic hybrid mesoporous silicas by which we can improve the applicability of mesoporous materials. First, we explain that the sizes of hexagonal- and cubic-type pores in organic-inorganic hybrid mesoporous silicas are well controlled from 24.3 to 98.0 A by the direct micelle-control method using an organosilica precursor and surfactants with different alkyl chain lengths or triblock copolymers as templates and swelling agents incorporated in the formed micelles. Second, we describe that organic-inorganic hybrid mesoporous materials with various functional groups form various external morphologies such as rod, cauliflower, film, rope, spheroid, monolith, and fiber shapes. Third, we discuss that transition metals (Ti and Ru) and rare-earth ions (Eu(3+) and Tb(3+)) are used to modify organic-inorganic hybrid mesoporous silica materials. Such hybrid mesoporous silica materials are expected to be applied as excellent catalysts for organic reactions, photocatalysis, optical devices, etc.     

有机-无机杂化骨修复材料

寻找理想的骨修复材料一直是骨科领域的研究热点之一。骨修复材料已由最初单纯取代天然骨组织的惰性材料向具有诱导骨组织再生功能的生物活性材料发展,其中有机-无机杂化材料由于有机和无机组分在分子/纳米水平的复合使其能够最大程度地实现二者的优势互补和协同优化,近年来受到广泛关注。本文着重介绍了有机-无机杂化骨修复材料近些年来的研究进展,并对其发展趋势进行了展望。     

Functionalizing inorganic solids: towards organic-inorganic nanostructured materials for intelligent and bioinspired systems

The design, preparation, and properties of organic-inorganic hybrid compounds are described and discussed with respect to their potential uses as intelligent and bioinspired materials. Several synthesis strategies based on intercalation in 2D solids, the grafting of organic groups onto silica and silicates, and the self-assembly of organo-silica materials are presented, focusing on the soft procedures that are used to modify the functionality of the inorganic substrates. The combination of both organic and inorganic moieties at the nanometer level forms the basis for preparing multifunctional solids that are provided with specific functions in response to different types of stimuli. In some cases these resemble materials that are found in biological systems. Examples include organic-inorganic membranes that are based on intercalated macrocyclic compounds and bi-layer vesicles that consist of alkyl long-chains arranged either in the confined region of layered silicates or as self-organized organo-silica micelles. The role of certain hybrid materials such as membranes provides a different approach to the development of artificial liposomes and other mimetic systems that have an organic-inorganic composition and nanostructural organization. Their potential uses for DDS or DNA-dense phases are also discussed and novel alternatives to bioinspired systems development are proposed.     

Design and properties of functional hybrid organic-inorganic membranes for fuel cells

This critical review presents a discussion on the major advances in the field of organic-inorganic hybrid membranes for fuel cells application. The hybrid organic-inorganic approach, when the organic part is not conductive, reproduces to some extent the behavior of Nafion where discrete hydrophilic and hydrophilic domains are homogeneously distributed. A large variety of proton conducting or non conducting polymers can be combined with various functionalized, inorganic mesostructured particles or an inorganic network in order to achieve high proton conductivity, and good mechanical and chemical properties. The tuning of the interface between these two components and the control over chemical and processing conditions are the key parameters in fabricating these hybrid organic-inorganic membranes with a high degree of reproducibility. This dynamic coupling between chemistry and processing requires the extensive use and development of complementary ex situ measurements with in situ characterization techniques, following in real time the molecular precursor solutions to the formation of the final hybrid organic-inorganic membranes. These membranes combine the intrinsic physical and chemical properties of both the inorganic and organic components. The development of the sol-gel chemistry allows a fine tuning of the inorganic network, which exhibits acid-based functionalized pores (-SO(3)H, -PO(3)H(2), -COOH), tunable pore size and connectivity, high surface area and accessibility. As such, these hybrid membranes containing inorganic materials are a promising family for controlling conductivity, mechanical and chemical properties (349 references).     

Photochromic organic-inorganic hybrid materials

Photochromic organic-inorganic hybrid materials have attracted considerable attention owing to their potential application in photoactive devices, such as optical memories, windows, photochromic decorations, optical switches, filters or non-linear optics materials. The growing interest in this field has largely expanded the use of photochromic materials for the purpose of improving existing materials and exploring new photochromic hybrid systems. This tutorial review summarizes the design and preparation of photochromic hybrid materials, and particularly those based on the incorporation of organic molecules in organic-inorganic matrices by the sol-gel method. This is the most commonly used method for the preparation of these materials as it allows vitreous hybrid materials to be obtained at low temperatures, and controls the interaction between the organic molecule and its embedding matrix, and hence allows tailoring of the performance of the resulting devices.     

Silica-based mesoporous organic-inorganic hybrid materials

Mesoporous organic-inorganic hybrid materials, a new class of materials characterized by large specific surface areas and pore sizes between 2 and 15 nm, have been obtained through the coupling of inorganic and organic components by template synthesis. The incorporation of functionalities can be achieved in three ways: by subsequent attachment of organic components onto a pure silica matrix (grafting), by simultaneous reaction of condensable inorganic silica species and silylated organic compounds (co-condensation, one-pot synthesis), and by the use of bissilylated organic precursors that lead to periodic mesoporous organosilicas (PMOs). This Review gives an overview of the preparation, properties, and potential applications of these materials in the areas of catalysis, sorption, chromatography, and the construction of systems for controlled release of active compounds, as well as molecular switches, with the main focus being on PMOs.     

Synergetic Spin Crossover and Fluorescence in One‐Dimensional Hybrid Complexes

Hybrid materials integrated with a variety of physical properties, such as spin crossover (SCO) and fluorescence, may show synergetic effects that find applications in many fields. Herein we demonstrate a promising post‐synthetic approach to achieve such materials by grafting fluorophores (1‐pyrenecarboxaldehyde and Rhodamine B) on one‐dimensional SCO Fe^II structures. The resulting hybrid materials display expected one‐step SCO behavior and fluorescent properties, in particular showing a coupling between the transition temperature of SCO and the temperature where the fluorescent intensity reverses. Consequently, synergetic effect between SCO and fluorescence is incorporated into materials despite different fluorophores. This study provides an effective strategy for the design and development of novel magnetic and optical materials.     

Mesoporous hybrids containing Eu complexes covalently bonded to SBA-15 functionalized: Assembly, characterization and photoluminescence

A novel series of luminescent mesoporous organic-inorganic hybrid materials has been prepared by linking Eu³⁺ complexes to the functionalized ordered mesoporous SBA-15 which was synthesis by a co-condensation process of 1,3-diphenyl-1,3-propanepione (DBM) modified by the coupling agent 3-(triethoxysilyl)-propyl isocyanate (TEPIC), tetraethoxysilane (TEOS), Pluronic P123 surfactant as a template. It was demonstrated that the efficient intramolecular energy transfer in the mesoporous material Eu(DBMSi-SBA-15)₃phen mainly occurred between the modified DBM (named as DBM-Si) and the central Eu³⁺ ion. So the Eu(DBMSi-SBA-15)₃phen showed characteristic emission of Eu³⁺ ion under UV irradiation with higher luminescence quantum efficiency. Moreover, the mesoporous hybrid materials exhibited excellent thermal stability as the lanthanide complex was covalently bonded to the mesoporous matrix.