In order to selectively target malignant cells and eliminate severe side effects of conventional chemotherapy, biocompatible and redox-responsive hollow nanocontainers with tumor specificity were fabricated. The mechanized nanocontainers were achieved by anchoring mechanically interlocked molecules, i.e., [2]rotaxanes, onto the orifices of hollow mesoporous silica nanoparticles via disulfide bonds as intermediate linkers for intracellular glutathione-triggered drug release. The [2]rotaxane employed was mainly composed of U.S. Food and Drug Administration approved tetraethylene glycol chains, α-cyclodextrin, and folic acid. In this study, folate groups on the mechanized hollow nanocontainers act as both the tumor-targeting agents and stoppers of the [2]rotaxanes. Detailed investigations showed that anticancer drug doxorubicin loaded mechanized nanocontainers could selectively induce the apoptosis and death of tumor cells. The drug-loaded nanocontainers enhanced the targeting capability to tumor tissues in vitro and inhibited the tumor growth with minimal side effects in vivo. The present controlled and targeted drug delivery system paves the way for developing the next generation of nanotherapeutics toward efficient cancer treatment.

In this work, a series of Pd/Fe 2 O 3 catalysts were synthesized, characterized, and evaluated for the hydrodeoxygenation (HDO) of m-cresol. It was found that the addition of Pd remarkably promotes the catalytic activity of Fe while the product distributions resemble that of monometallic Fe catalyst, showing high selectivity toward the production of toluene (C−O cleavage without saturation of aromatic ring and C−C cleavage). Reduced catalysts featured with Pd patches on the top of reduced Fe nanoparticle surface, and the interaction between Pd and Fe, was further confirmed using X-ray photoelectron spectroscopy (XPS), scanning transmission electron microscopy (STEM), and X-ray absorption near edge fine structure (XANES). A possible mechanism, including Pd assisted H 2 dissociation and Pd facilitated stabilization of the metallic Fe surface as well as Pd enhanced product desorption, is proposed to be responsible for the high activity and HDO selectivity in Pd−Fe catalysts. The synergic catalysis derived from Pd−Fe interaction found in this work was proved to be applicable to other precious metal promoted Fe catalysts, providing a promising strategy for future design of highly active and selective HDO catalysts.

CO 2 methanation was investigated on 5% and 0.5% Ru/Al 2 O 3 catalysts (Ru dispersions: ~18% and ~40%, respectively) by steady-state kinetic measurements and transient DRIFTS-MS. Methanation rates were higher over 5% Ru/Al 2 O 3 than over 0.5% Ru/Al 2 O 3. The measured activation energies, however, were lower on 0.5% Ru/Al 2 O 3 than on 5% Ru/Al 2 O 3. Transient DRIFTS-MS results demonstrated that direct CO 2 dissociation was negligible over Ru. CO 2 has to first react with surface hydroxyls on Al 2 O 3 to form bicarbonates, which, in turn, react with adsorbed H on Ru to produce adsorbed formate species. Formates, most likely at the metal/oxide interface, can react rapidly with adsorbed H forming adsorbed CO, only a portion of which is reactive toward adsorbed H, ultimately leading to CH 4 formation. The unreactive CO molecules are in geminal form adsorbed on low-coordinated sites. The measured kinetics are fully consistent with a Langmuir-Hinshelwood type mechanism in which the H-assisted dissociation of the reactive CO* is the rate-determining step (RDS). The similar empirical rate expressions (4= 20.1 20.3−0.5) and DRIFTS-MS results on the two catalysts under both transient and steady-state conditions suggest that the mechanism for CO 2 methanation does not change with Ru particle size under the studied experimental conditions. Kinetic modeling results further indicate that the intrinsic activation barrier for the RDS is slightly lower on 0.5% Ru/Al 2 O 3 than on 5% Ru/Al 2 O 3. Due to the presence of unreactive adsorbed CO on lowcoordinated Ru sites under reaction conditions, the larger fraction of such surface sites on 0.5% Ru/Al 2 O 3 than on 5% Ru/Al 2 O 3 is regarded as the main reason for the lower rates for CO 2 methanation on 0.5% Ru/Al 2 O 3 .

Ap hotoelectrochemical method for the C À H alkylation of heteroarenes with organotrifluoroborates has been developed. The merger of electrocatalysis and photoredox catalysis provides ac hemical oxidant-free approach for the generation and functionalization of alkylr adicals from organotrifluoroborates.Avariety of heteroarenes were functionalized using primary,s econdary,a nd tertiary alkyltrifluoroborates with excellent regio-and chemoselectivity.

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Supported Au nanoparticles (Au NPs) have been identified as highly selective catalysts for the chemoselective hydrogenation reaction potential for advanced and greener syntheses of many special and fine chemicals in organic chemistry, but their potential for applications has been hampered by their generally observed low activity arising from the intrinsic nobleness of gold to H2 activation. This work deals with a synergy between Au NPs and their carrying Pt entities in Pt-on-Au nanostructures (coded as Pt m ∧Au, m denoting the atomic Pt/Au ratio) for hydrocinnamaldehyde production in the chemoselective hydrogenation of cinnamaldehyde. Pt m ∧Au immobilized on a noninteracting SiO2 support (Pt m ∧Au/SiO2) showed activity 1–2 orders of magnitude higher than that of monometallic Pt/SiO2 and Au/SiO2 catalysts. The high activity of Pt m ∧Au nanostructures also remained distinct on interacting support materials such as Al2O3 and carbon and when varying the reaction temperature, H2 pressure, or both. Kinetic assessments suggest that the hydrogenation reaction could occur according to a Langmuir–Hinshelwood mechanism, in which cinnamaldehyde adsorbed on the Au surface was attacked by hydrogen atoms activated by Pt entities in the nanostructured Pt m ∧Au catalysts. Pt dispersion or the size of the Pt entities and Pt–Au boundary, as well, strongly affected this synergic catalysis.

Metal nanoparticles (NPs) from colloidal synthesis are advantageous in fundamental catalysis research because of their precisely controlled size and morphology but unfortunately are usually contaminated with residues from the organic stabilizer essentially required in the synthesis. These residues could modify the surface property and disturb the catalysis intrinsic to "clean" NPs. Herein, polyvinylpyrrolidone (PVP)-stabilized Au NPs (4.7 ± 1.0 nm) from colloidal synthesis were immobilized on SiO 2 support and subjected to ultraviolet-ozone (UVO) treatment to remove the residues. Hydrogenation reactions of p-chloronitrobenzene (p-CNB) and cinnamaldehyde (CAL) were conducted to probe consequences of the stabilizer removal on the catalytic properties of Au NPs. Measurements by FTIR and XPS revealed a controlled removal and degradation of PVP according to the UVO-treatment duration. Careful HRTEM analysis disclosed that both the size and morphology of Au NPs remained unchanged after the UVO-treatment. Residual PVP significantly improved the activity of Au NPs for p-CNB hydrogenation but lowered the activity for CAL hydrogenation. Continued selectivity changes of CAL hydrogenation to favor the reaction at the CC bond were observed on increasing the removal degree of the residues. The UVO-cleaned Au NPs were also "restabilized" with PVP and other stabilizers by adsorption in aqueous solution. Comparison of the catalytic properties of these Au NPs involving different stabilizers with those of the UVO-cleaned ones enabled a comprehension of the stabilizer impacts on the hydrogenation catalysis of Au NPs.