Search

Carbon dioxide anion radical (CO 2 •- ) can act as a versatile single electron reductant, but its generation pathways are quite limited. Herein, we demonstrate that oxalic acid (OA) could be effectively and continuously utilized to produce CO 2 •- over Bi(C 2 O 4 )OH, a novel photocatalyst, under light irradiation. Bi(C 2 O 4 )OH would proceed with self-redox reactions under the light irradiation producing CO 2 •- , through the oxidation of C 2 O 4 2- . OA in the solution could recoordinate with Bi 3+ , thus maintaining the structure of the photocatalysts and the stability of the reactions. Benefiting from the fast reaction between CO 2 •- and O 2 in forming • O 2 - , hydrogen peroxide (H 2 O 2 ) would be efficiently produced (219.0 μmol/h). This study proposes a novel approach for harnessing OA containing wastewater and explores its potential application in the efficient production of H 2 O 2 .

Keto sugar nucleotides (KSNs) are common and versatile precursors to various deoxy sugar nucleotides, which are substrates for the corresponding glycosyltransferases involved in the biosynthesis of glycoproteins, glycolipids, and natural products. However, there has been no KSN synthesized chemically due to the inherent instability. Herein, the first chemical synthesis of the archetypal KSN TDP-4-keto-6-deoxy-d-glucose ( 1 ) is achieved by an efficient and optimized route, providing feasible access to other KSNs and analogues, thereby opening a new avenue for new applications.

Magnon-mediated spin flow in magnetically ordered insulators enables long-distance spin-based information transport with low dissipation. In the materials studied to date, no anisotropy has been observed in the magnon propagation length as a function of propagation direction. Here, we report measurements of magnon spin transport in a spinel ferrite, magnesium aluminum ferrite MgAl 0.5 Fe 1.5 O 4 (MAFO), which has a substantial in-plane 4-fold magnetic anisotropy. We observe spin diffusion lengths > 0.8 μm at room temperature in 6 nm films, with spin diffusion lengths 30% longer along the easy axes compared to the hard axes. The sign of this difference is opposite to the effects just of anisotropy in the magnetic energy for a uniform magnetic state. We suggest instead that accounting for anisotropy in exchange stiffness is necessary to explain these results. These findings provide an approach for controlling magnon transport via strain, which opens new opportunities for designing magnonic devices.

In this study, electrodeposition combined with anodization was employed to prepare a nanoporous tin oxide film on a pure copper substrate. It was found that annealing temperature played a critically significant role in regulating the crystallinity, pore size, and contents of different oxidation states of the anodized tin oxide film to affect the electrochemical performance. The study verified that SnO x films treated by optimized annealing at 500 °C with precisely controlling the nanoporous morphology and crystallinity displayed competitive specific capacitance at an appropriate ratio of Sn 4+ to Sn 2+ . A maximum specific capacitance of 86.2 mF/cm 2 could be achieved at this temperature, and the capacitance retention rate still exceeded 90% even after 8000 charge-discharge cycles. With properly designed annealing treatment, we implemented tin film anodization to obtain an optimized electrode with significantly enhanced electrochemical performance, which shows a promising application in the electrochemical field to prepare electrodes.

Emergent quantum phenomena in electronically coupled two-dimensional heterostructures are central to next-generation optical, electronic, and quantum information applications. Tailoring electronic band gaps in coupled heterostructures would permit control of such phenomena and is the subject of significant research interest. Two-dimensional polymers (2DPs) offer a compelling route to tailored band structures through the selection of molecular constituents. However, despite the promise of synthetic flexibility and electronic design, fabrication of 2DPs that form electronically coupled 2D heterostructures remains an outstanding challenge. Here, we report the rational design and optimized synthesis of electronically coupled semiconducting 2DP/2D transition metal dichalcogenide van der Waals heterostructures, demonstrate direct exfoliation of the highly crystalline and oriented 2DP films down to a few nanometers, and present the first thickness-dependent study of 2DP/MoS 2 heterostructures. Control over the 2DP layers reveals enhancement of the 2DP photoluminescence by two orders of magnitude in ultrathin sheets and an unexpected thickness-dependent modulation of the ultrafast excited state dynamics in the 2DP/MoS 2 heterostructure. These results provide fundamental insight into the electronic structure of 2DPs and present a route to tune emergent quantum phenomena in 2DP hybrid van der Waals heterostructures.

Our previous studies with shishijimicin A resulted in the total synthesis of this scarce marine natural product and a number of its simpler analogues endowed with picomolar potencies against certain cancer cell lines. Herein, we describe the design, synthesis, and biological evaluation of four linker-drugs, anticipating the construction of antibody-drug conjugates (ADCs) as the ultimate goal of this research program. Using a common payload, the assembly of these linker-drugs utilized different linkers and attachment points, providing opportunities to probe the optimal molecular design of the intended ADCs as targeted cancer therapies. In the course of ADC generation and in vitro evaluation, we identified two linker-drugs with a promising in vitro plasma stability profile and excellent targeted cytotoxicity and specificity. Conjugation of shishijimicin A enediyne payloads through their phenolic moiety represents a novel approach to enediyne ADC creation, while the pharmacological profiles of at least two of the generated ADCs compare well with the profiles of the corresponding clinically approved ADC Kadcyla.

A streamlined total synthesis of the naturally occurring antitumor agents trioxacarcins is described, along with its application to the construction of a series of designed analogues of these complex natural products. Biological evaluation of the synthesized compounds revealed a number of highly potent, and yet structurally simpler, compounds that are effective against certain cancer cell lines, including a drug-resistant line. A novel one-step synthesis of anthraquinones and chloro anthraquinones from simple ketone precursors and phenylselenyl chloride is also described. The reported work, featuring novel chemistry and cascade reactions, has potential applications in cancer therapy, including targeted approaches as in antibody-drug conjugates.

The total synthesis of the rare but extremely potent antitumor agent shishijimicin A has been achieved via a convergent strategy involving carboline disaccharide 3 and hydroxy enediyne thioacetate 4.

The first total syntheses of taiwaniadducts B, C, and D have been accomplished. Two diterpenoid segments were prepared with high enantiopurity, both through Ir-catalyzed asymmetric polyene cyclization. A sterically demanding intermolecular Diels-Alder reaction promoted by Er(fod)3 assembled the scaffold of taiwaniadducts B and C. A carbonyl-ene cyclization forged the cage motif of taiwaniadduct D at a late stage, providing over 200 mg of this compound.

A divergent approach was developed toward the total synthesis of taiwaniaquinoids. An advanced intermediate 5a with trans A/B ring junction was concisely assembled by employing a Bi(OTf)3-catalyzed cationic cyclization and a Wolff-type ring contraction as key steps. This common intermediate was readily converted to racemic taiwaniaquinones A and F and taiwaniaquinols B and D, respectively.