Ultra-fast synthesis of hierarchical SAPO-11 molecular sieves with the assistance of hydroxyl radicals.

Considering the traditional time-consuming synthesis route and diffusion-limited micropore system of SAPO-11 (i.e., SAPO-11W), a hydroxyl radical assisted method has been developed to prepare hierarchical SAPO-11 within 5 min (i.e., SAPO-11M). Compared to previous reports, the unique contribution is to induce hydroxyl radicals by exposing carbon materials to microwave irradiation in an oxygen-containing atmosphere. Carbon materials play a dual role as mesopore filler and hydroxyl radical initiator. When employed to prepare deoxygenation catalysts for stearic acids, a higher selectivity for C15-C18 and isomers is observed due to the mild acidity of SAPO-11M. The Lewis-rich acidity of SAPO-11M exhibits an electron deficiency to interact with the hydroxyl oxygen atoms and promotes the hydrodeoxygenation of stearic acids with excellent atom economy. These results are important for opening up a new prospect of synthesizing SAPO molecular sieves (e.g., SAPO-11 and SAPO-5) by an efficient and facile route.

A surface modification strategy to prepare hierarchical Beta molecular sieves for glucose dehydration.

In order to balance the contradiction between mesopore introduction and loss of microporosity, a surface modification strategy is proposed by selectively adsorbing organic alkaline molecules on Beta molecular sieves before NaOH etching. Organic alkaline molecules adsorb on framework aluminum sites and the protective function of organic bases is affected by the adsorption configuration and physical barrier effect of organic bases. Organic alkaline molecules serve as a protective agent to increase the bond length of Al-O bonds. Therefore, the as-synthesized hierarchical Beta molecular sieves have more acid sites due to the preservation of aluminum atoms. When employed as catalysts in the dehydration reaction of glucose, 5-hydroxymethylfurfural (5-HMF) is obtained under the synergistic effect of Brønsted and Lewis acid sites. The unique contribution is to realize the porosity regulation and alleviate the acidity loss of Beta molecular sieves. These results are important to broaden the application fields of aluminum-silicon molecular sieves especially for large molecule-engaged acid catalyzed reactions.

Heterogeneous Carbon Nitrides Photocatalysis Multicomponent Hydrosulfonylation of Alkynes To Access ß-Keto Sulfones with the Insertion of Sulfur Dioxide in Aerobic Aqueous Medium.

Although hydrosulfonylation of alkynes is an ideal process to generate ß-keto sulfones, such an approach is rarely implemented. Here we reported a facile and efficient graphitic carbon nitride (p-g-C3N4) photocatalyzed hydrosulfonylation of alkynes with the insertion of sulfur dioxide in aerobic conditions. Controlled experiments and ESR results indicated both the superoxide radicals and valence band holes played an important role in the reaction. Further isotope experiments confirmed the oxygen atom of the products comes from H2O, while the O2 plays an important role in the reaction by quenching the DABCO radical cation. The metal-free heterogeneous semiconductor is fully recyclable at least 6 times without significant reducing activity. Furthermore, this reaction could be carried out under solar light irradiation and was applicable for a large-scale reaction with conserved results.

Multifunctional Fe3O4@C-based nanoparticles coupling optical/MRI imaging and pH/photothermal controllable drug release as efficient anti-cancer drug delivery platforms.

Multifunctional nanomedicines featuring high drug loading capacity, controllable drug release and real-time self-monitoring are attracting increasing attention due to their potential to improve cancer therapeutic efficacy. Herein, a new kind of Fe3O4@C-based nanoparticles modified with isoreticular metal organic frameworks (IRMOF-3), folic acid (FA) and detachable polyethylene glycol (PEG) under tumor microenvironment was developed. The core-shell structured Fe3O4@C was synthesized via the one-pot solvothermal reaction and the IRMOF-3 layers were coated on the outer shell of Fe3O4@C through layer-by-layer coating method. The FA and PEG were conjugated on the surface of nanoparticles by reacting with the amine groups provided by IRMOF-3. The as-synthesized nanoparticles showed stable photothermal effect, superparamagnetic properties and blue fluorescence characteristic under 360 nm irradiation. The in vitro experiments showed that the drug loaded nanoparticles exhibit pH-dependent drug release property, and PEGylation was proved effective in suppressing burst drug release (only 8.0% of drugs were released within 95 h). The confocal laser scanning microscopy study revealed that the as-synthesized nanoparticles could serve as a cell imaging agent and the cell internalization can be significantly enhanced after FA modified. The IRMOF-3 modified nanoparticles showed negligible cytotoxicity and the drug loaded nanoparticles showed pH/photothermal-stimuli enhanced cytotoxicity in vitro. It is believed that the present smart drug delivery platforms will hold great potential in imaging guided drug delivery and cancer therapy.

Advanced Carbon-based Nanoplatforms Combining Drug Delivery and Thermal Therapy for Cancer Treatment.

Anticancer treatment has become a research highlight in recent years. Despite several techniques have been developed and applied in the clinic, this area still meets great challenges in the construction of smart anticancer devices with accurate targeting, controlled release and microenvironment response properties. Most of the carbon-based materials are biocompatible, possessing abundant and tunable pore structures and particularly large surface areas. These properties make them suitable materials as drug carriers. In addition, some carbon-based materials are capable of absorbing near-infrared radiation (NIR) and have highly efficient photothermal effects. The generated heat in situ can be used to kill cancer cells in short time on the position. This review describes the recent and significant application of four kinds of carbon materials including carbon nanotubes, graphene, carbon dots and mesoporous carbon for drug delivery and photothermal therapy. After a short introduction of the structures and properties of these materials, the construction and application of these nanoplatforms in drug delivery, photothermal therapy or their combination will be summarized and discussed in depth. In addition, other carbon allotropes as drug carriers will be introduced briefly. Finally, the risk assessments and the perspectives and challenges of these materials used in cancer therapies are enclosed.

Boosting Size-Selective Hydrogen Combustion in the Presence of Propene Using Controllable Metal Clusters Encapsulated in Zeolite.

A strategy is presented for making metal clusters encapsulated inside microporous solids selectively accessible to reactant molecules by manipulating molecular sieve size and affinity for adsorbed molecules. This expands the catalytic capabilities of these materials to reactions demanding high selectivity and stability. Selective hydrogen combustion was achieved over Pt clusters encapsulated in LTA zeolite (KA, NaA, CaA) in a propene-rich mixture obtained from propane dehydrogenation, showing pore-size dependent selectivity and coking rate. Propene tended to adsorb at channels or external surfaces of zeolite, interfering the diffusion of hydrogen and oxygen. Tailoring the surface of LTA zeolite with additional alkali or alkaline earth oxides contributed to narrowing zeolite pore size and their affinity for propene. The thus-modified Pt@KA catalyst displayed excellent hydrogen combustion selectivity (98.5 %) with high activity and superior anti-coking and anti-sintering properties.