Ionic-Liquid-Based Heterogeneous Covalent Triazine Framework Cobalt Catalyst for the Direct Synthesis of Methyl 3‑Hydroxybutyrate from Propylene Oxide

β-Hydroxy esters are considered as potential building blocks for the production of fine chemicals and potential drug molecules in various industries. Developing an efficient and recyclable catalyst for the synthesis of β-hydroxy esters is challenging. Here we report the first ionic-liquid-based heterogenized cobalt catalyst, [imidazolium-CTF]­[Co­(CO)₄], for the direct ring-opening carbonylation of propylene oxide to methyl 3-hydroxybutyrate (MHB) with 86% selectivity (>99% conversion)

Intense Red-Emitting Upconversion Nanophosphors (800 nm-Driven) with a Core/Double-Shell Structure for Dual-Modal Upconversion Luminescence and Magnetic Resonance in Vivo Imaging Applications

In this study, intense single-band red-emitting upconversion nanophosphors (UCNPs) excited with 800 nm near-infrared (NIR) light are reported. When a NaYF₄:Nd,Yb active-shell is formed on the 12.7 nm sized NaGdF₄:Yb,Ho,Ce UCNP core, the core/shell (C/S) UCNPs show tunable emission from green to red, depending on the Ce³⁺ concentration under excitation with 800 nm NIR light. Ce³⁺-doped C/S UCNPs (30 mol %) exhibit single-band red emission peaking at 644 nm via a ⁵F₅ → ⁵I₈ transition of Ho³⁺. A high Nd³⁺ concentration in the shell results in strong absorption at around 800 nm NIR light, even though the shell thickness is not large, and small-sized C/S UCNPs (16.3 nm) emit bright red light under 800 nm excitation. The formation of a thin NaGdF₄ shell on the C/S UCNPs further enhances the upconversion (UC) luminescence and sub-20 nm sized core/double-shell (C/D-S) UCNPs exhibit 2.8 times stronger UC luminescence compared with C/S UCNPs. Owing to the strong UC luminescence intensity and Gd³⁺ ions on the surface of nanocrystals, they can be applied as a UC luminescence imaging agent and a T₁ contrast agent for magnetic resonance (MR) imaging. In vivo UC luminescence and high-contrast MR images are successfully obtained by utilizing the red-emitting C/D-S UCNPs

Dendrite-Embedded Platinum–Nickel Multiframes as Highly Active and Durable Electrocatalyst toward the Oxygen Reduction Reaction

Pt-based nanoframe catalysts have been explored extensively due to their superior activity toward the oxygen reduction reaction (ORR). Herein, we report the synthesis of Pt–Ni multiframes, which exhibit the unique structure of tightly fused multiple nanoframes and reinforced by an embedded dendrite. Rapid reduction and deposition of Ni atoms on Pt–Ni nanodendrites induce the alloying/dealloying of Pt and Ni in the overall nanostructures. After chemical etching of Ni, the newly formed dendrite-embedded Pt–Ni multiframes show an electrochemically active surface area (ECSA) of 73.4 m² g_Pt^–1 and a mass ORR activity of 1.51 A mg_Pt^–1 at 0.93 V, which is 30-fold higher than that of the state-of-the-art Pt/C catalyst. We suggest that high ECSA and ORR performances of dendrite-embedded Pt–Ni multiframes/C can be attributed to the porous nanostructure and numerous active sites exposed on surface grain boundaries and high-indexed facets

Radially Phase Segregated PtCu@PtCuNi Dendrite@Frame Nanocatalyst for the Oxygen Reduction Reaction

Pt-based alloy nanoframes have shown great potential as electrocatalysts toward the oxygen reduction reaction (ORR) in fuel cells. However, the intrinsically infirm nanoframes could be severely deformed during extended electro-cyclings, which eventually leads to the loss of the initial catalytic activity. Therefore, the structurally robust nanoframe is a worthy synthetic target. Furthermore, ternary alloy phase electrocatalysts offer more opportunities in optimizing the stability and activity than binary alloy ones. Herein, we report a robust PtCuNi ternary nanoframe, structurally fortified with an inner-lying PtCu dendrite, which shows a highly active and stable catalytic performance toward ORR. Remarkably, the PtCu@PtCuNi catalyst exhibited 11 and 16 times higher mass and specific activities than those of commercial Pt/C

A Covalent Triazine Framework, Functionalized with Ir/N-Heterocyclic Carbene Sites, for the Efficient Hydrogenation of CO₂ to Formate

Functionalizing the recently developed porous materials such as porous organic frameworks and coordination polymer networks with active homogeneous catalytic sites would offer new opportunities in the field of heterogeneous catalysis. In this regard, a novel covalent triazine framework functionalized with an Ir­(III)-N-heterocyclic carbene complex was synthesized and characterized to have a coordination environment similar to that of its structurally related molecular Ir complex. Because of the strong σ-donating and poor π-accepting characters of the N-heterocyclic carbene (NHC) ligand, the heterogenized Ir-NHC complex efficiently catalyzes the hydrogenation of CO₂ to formate with a turnover frequency of up to 16 000 h^–1 and a turnover number of up to 24 300; these are the highest values reported to date in heterogeneous catalysis for the hydrogenation of CO₂ to formate

京都大学瀬戸臨海実験所振興会水族館月報 No. 115

Additional file 1. Supporting information

Synergistic Effect of Detection and Separation for Pathogen Using Magnetic Clusters

Early diagnosis of infectious diseases is important for treatment; therefore, selective and rapid detection of pathogenic bacteria is essential for human health. We report a strategy for highly selective detection and rapid separation of pathogenic microorganisms using magnetic nanoparticle clusters. Our approach to develop probes for pathogenic bacteria, including Salmonella, is based on a theoretically optimized model for the size of clustered magnetic nanoparticles. The clusters were modified to provide enhanced aqueous solubility and versatile conjugation sites for antibody immobilization. The clusters with the desired magnetic property were then prepared at critical micelle concentration (CMC) by evaporation-induced self-assembly (EISA). Two different types of target-specific antibodies for H- and O-antigens were incorporated on the cluster surface for selective binding to biological compartments of the flagella and cell body, respectively. For the two different specific binding properties, Salmonella were effectively captured with the O-antibody-coated polysorbate 80-coated magnetic nanoclusters (PCMNCs). The synergistic effect of combining selective targeting and the clustered magnetic probe leads to both selective and rapid detection of infectious pathogens