Synthesis of double-shelled periodic mesoporous organosilica nanospheres/MIL-88A-Fe composite and its elevated performance for Pb2+ removal in water

Herein, we report the synthesis of double-shelled periodic mesoporous organosilica nanospheres/MIL-88A-Fe (DSS/MIL-88A-Fe) composite through a hydrothermal method. To survey the structural and compositional features of the synthesized composite, a variety of spectroscopic and microscopic techniques, including FT-IR, XRD, BET, TEM, FE-SEM, EDX, and EDX-mapping, have been employed. A noteworthy point in this synthesis procedure is the integration of MOF with PMO to increase the adsorbent performance, such as higher specific surface area and more active sites. This combination leads to achieving a structure with an average size of 280 nm and 1.1 μm long attributed to DSS and MOF, respectively, microporous structure and relatively large specific surface area (312.87 m²/g). The as-prepared composite could be used as an effective adsorbent with a high adsorption capacity (250 mg/g) and quick adsorption time (30 min) for the removal of Pb²⁺ from water. Importantly, DSS/MIL-88A-Fe composite revealed acceptable recycling and stability, since the performance in Pb²⁺ removal from water remained above 70% even after 4 consecutive cycles.

Recent advanced development of metal-loaded mesoporous organosilicas as catalytic nanoreactors

Ordered periodic mesoporous organosilicas have been widely applied in adsorption/separation/sensor technologies and the fields of biomedicine/biotechnology as well as catalysis. Crucially, surface modification with functional groups and metal complexes or nanoparticle loading has ensured high efficacy and efficiency. This review will highlight the current state of design and catalytic application of transition metal-loaded mesoporous organosilica nanoreactors. It will outline prominent synthesis approaches for the grafting of metal complexes, metal salt adsorption and in situ preparation of metal nanoparticles, and summarize the catalytic performance of the resulting mesoporous organosilica hybrid materials. Finally, the potential prospects and challenges of metal-loaded mesoporous organosilica nanoreactors are addressed.

Controlling Particle Morphology and Pore Size in the Synthesis of Ordered Mesoporous Materials

Ordered mesoporous materials have attracted considerable attention due to their potential applications in catalysis, adsorption, and separation technologies, as well as biomedical applications. In the present manuscript, we aim at a rational design to obtain the desired surface functionality (Ti and/or hydrophobic groups) while obtaining short channels (short diffusion paths) and large pore size (>10 nm). Santa Barbara Amorphous material SBA-15 and periodic mesoporous organosilica PMO materials are synthesized using Pluronic PE 10400 (P104) surfactant under mild acidic conditions to obtain hexagonal platelet-like particles with very short mesochannels (300–450 nm). The use of expanders, such as 1, 3, 5-trimethylbenzene (TMB) and 1, 3, 5-triisopropylbenzene (TIPB) were tested in order to increase the pore size. TMB yielded in the formation of vesicles in all the syntheses attempted, whereas P104 combined with TIPB resulted both in expanded (E) E-SBA-15 and E-PMO with 12.3 nm pore size short channel particles in both cases. Furthermore, the synthesis method was expanded to the incorporation of small amount of Ti via co-condensation method using titanocene as titanium source. As a result, Ti-E-SBA-15 was obtained with 15.5 nm pore size and isolated Ti-sites maintaining platelet hexagonal morphology. Ti-PMO was obtained with 7.8 nm and short channels, although the pore size under the tried synthesis conditions could not be expanded further without losing the structural ordering.

Environmental friendly method of the epoxidation of limonene with hydrogen peroxide over the Ti-SBA-15 catalyst

This work presents the studies on the epoxidation of limonene to 1,2-epoxylimonene with hydrogen peroxide and over the titanium-silicate Ti-SBA-15 catalyst. The main object of the research was a solvent effect on the epoxidation process. The influence of solvents, such as: methanol, toluene, propan-2-ol (isopropyl alcohol), acetonitrile and ethanol has been studied. Furthermore, the influence of temperature in the range of 0-120°C and the reaction time in the range of 0.25-48 h have been investigated. Gas chromatography and iodometric titration methods were used to establish the products of this process and amount of the unreacted hydrogen peroxide. 1,2-Epoxylimonene, 1,2-epoxylimonene diol, perillyl alcohol, carvone and carveol have been determined as the main products of this process. All these compounds are very valuable raw materials for organic syntheses, medicine or cosmetic and food industry.

Chemistry of Mesoporous Organosilica in Nanotechnology: Molecularly Organic-Inorganic Hybridization into Frameworks

Organic-inorganic hybrid materials aiming to combine the individual advantages of organic and inorganic components while overcoming their intrinsic drawbacks have shown great potential for future applications in broad fields. In particular, the integration of functional organic fragments into the framework of mesoporous silica to fabricate mesoporous organosilica materials has attracted great attention in the scientific community for decades. The development of such mesoporous organosilica materials has shifted from bulk materials to nanosized mesoporous organosilica nanoparticles (designated as MONs, in comparison with traditional mesoporous silica nanoparticles (MSNs)) and corresponding applications in nanoscience and nanotechnology. In this comprehensive review, the state-of-art progress of this important hybrid nanomaterial family is summarized, focusing on the structure/composition-performance relationship of MONs of well-defined morphology, nanostructure, and nanoparticulate dimension. The synthetic strategies and the corresponding mechanisms for the design and construction of MONs with varied morphologies, compositions, nanostructures, and functionalities are overviewed initially. Then, the following part specifically concentrates on their broad spectrum of applications in nanotechnology, mainly in nanomedicine, nanocatalysis, and nanofabrication. Finally, some critical issues, presenting challenges and the future development of MONs regarding the rational synthesis and applications in nanotechnology are summarized and discussed. It is highly expected that such a unique molecularly organic-inorganic nanohybrid family will find practical applications in nanotechnology, and promote the advances of this discipline regarding hybrid chemistry and materials.

Effect of the grafting agent on the structure and catalytic performance of Ti-MCM-22

Ti-MCM-22 prepared by grafting with Ti(OEt)₄ has more Ti(iv) at Td sites than those prepared with Ti(OPr)₄ and Ti(OBu)₄, and gives higher catalytic activities in cyclohexene and cyclooctene epoxidation using t-butylhydrogen peroxide as the oxidant.

Biphasic Synthesis of Large-Pore and Well-Dispersed Benzene Bridged Mesoporous Organosilica Nanoparticles for Intracellular Protein Delivery

Large pore (4.6-7.6 nm) and well-dispersed benzene bridged mesoporous organosilica nanoparticles with uniform particle size of ≈50 nm are prepared via a biphasic approach. They can be directly used as nanocarriers without surface modification for the intracellular delivery of therapeutic proteins.

Highly effective design strategy for the heterogenisation of chemo- and enantioselective organocatalysts

The covalent heterogenisation of cinchonine and 1,4-diazabicyclo[2.2.2]octane within a range of mesoporous silicas affords highly selective and active organocatalysts.

Direct-synthesis method towards copper-containing periodic mesoporous organosilicas: detailed investigation of the copper distribution in the material

A direct synthesis method to incorporate Cu in ethane-bridged PMOs is presented. EPR and TEM reveal the immobilization and distribution of Cu in the material.

Biodegradable ethylene-bis(propyl)disulfide-based periodic mesoporous organosilica nanorods and nanospheres for efficient in-vitro drug delivery

Periodic mesoporous organosilica nanorods and nanospheres are synthesized from 1,4-bis(triethoxysilyl)ethylene and bis(3-ethoxysilylpropyl)disulfide. The nanosystems present the long-range order of the hexagonal nanostructure. They are degraded in simulated physiological conditions. The loading and release of doxorubicin with these nanosystems are both pH dependent. These nanoparticles are endocytosed by breast cancer cells and are very efficient for doxorubicin delivery in these cells.

Periodic mesoporous organosilica with ionic liquid framework as a novel fiber coating for headspace solid-phase microextraction of polycyclic aromatic hydrocarbons

Periodic mesoporous organosilica based on alkylimidazolium ionic liquid (PMO-IL) was prepared and used as a highly porous fiber coating material for solid-phase microextraction (SPME). The prepared nanomaterial was immobilized onto a stainless steel wire for fabrication of the SPME fiber. The fiber was evaluated for the extraction of some polycyclic aromatic hydrocarbons (PAHs) from aqueous sample solutions in combination with gas chromatography-mass spectrometry (GC-MS). A one at-the-time optimization strategy was applied for optimizing the important extraction parameters such as extraction temperature, extraction time, ionic strength, stirring rate, and desorption temperature and time. In optimum conditions, the repeatability for one fiber (n=3), expressed as relative standard deviation (R.S.D.%), was between 4.3% and 9.7% for the test compounds. The detection limits for the studied compounds were between 4 and 9 pg mL(-1). The developed method offers the advantage of being simple to use, with shorter analysis time, lower cost of equipment, thermal stability of fiber and high relative recovery in comparison to conventional methods of analysis.

Periodic Mesoporous Organosilicas: from simple to complex bridges; a comprehensive overview of functions, morphologies and applications

Periodic Mesoporous Organosilicas (PMOs) were developed in 1999 and are basically ordered templated mesoporous organosilicas, prepared by the combination of a surfactant as template and a silsesquioxane as the organosilica precursor. They were one of the first examples of the so-called "hybrid" organic/inorganic materials. In the years that followed, an amazing variety of functional groups, morphologies and applications has been developed. Some of these high-end applications, like low-k buffer layers in microelectronics, chiral catalysts, chromatographic supports, selective adsorbents and light-harvesting devices, have clearly shown their potential. In this review, we will give a comprehensive overview of all these different functionalities and applications that have been created for Periodic Mesoporous Organosilicas.

Highly ordered periodic mesoporous organosilica nanoparticles with controllable pore structures

A general synthetic procedure for highly ordered and well-dispersed periodic mesoporous organosilica (PMO) nanoparticles is reported based on a single cationic surfactant cetyltrimethylammonium bromide (CTAB) and simple silica sources with organic bridging groups via an ammonia-catalyzed sol-gel reaction. By changing the bridging group in the silica sources, the pore structures of the as-made particles with three-dimensional hexagonal (P6(3)/mmc), cubic (Pm3n), two-dimensional hexagonal (P6mm), and wormlike structure were evidenced by powder X-ray diffraction analysis (XRD) and transmission electron microscopy (TEM). The size range of the nanoparticles can be adjusted from 30 nm to 500 nm by variation of the ammonia concentration or the co-solvent content of the reaction medium. The PMO nanoparticles with high concentration of organic groups in the framework offered good thermal stability, good dispersion in low polarity solvent and high adsorption of small hydrophobic molecules. Finally, the dye functionalized PMO nanoparticles show low cytotoxicity and excellent cell permeability, which offers great potential for biomedical applications.

Why PMO? Towards functionality and utility of periodic mesoporous organosilicas

Creative synthetic chemistry has endowed the class of periodic mesoporous organosilica materials, dubbed PMO, with a variety of new and exciting compositions, properties, and functions since its inception a decade ago. Using a handful of recent trendsetting case histories, the multidisciplinary applications of PMO materials in chemistry and physics, materials science and engineering, biology, and medicine are demonstrated in a most powerful way. In doing so, this Review aims to inspire more collaborative and ambitious endeavors in the second decade of PMO research.

Direct synthesis and fluorescent imaging of bifunctionalized mesoporous iodopropyl-silica

The cocondensation of 3-iodopropyltrimethoxysilane and tetraethoxysilane with an additional substituted trimethoxysilane (RTMS) in the presence of Pluronic P123 and hydrogen iodide yields bifunctionalized mesoporous silica. The pore-size distribution of these materials depends on the nature of the RTMS additive. Excellent results in terms of a narrow pore-size distribution were obtained with methyltrimethoxysilane. A particularly interesting bifunctionalized mesoporous material is formed by the coinclusion of iodopropyl and aminopropyl moieties. The complementary reactivity of these two functional groups is demonstrated by the selective labeling of the amino-iodo-functionalized mesoporous silica with 2-hydroxy-substituted Nile red and fluorescein isothiocyanate, allowing further characterization of the functional group distribution by confocal laser scanning microscopy.