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Acremolactone B is a pyridine‐containing azaphilone‐type polyketide. The first total synthesis of this molecule was achieved on a gram scale, based on an aza‐6π electrocyclization–aromatization strategy for construction of the tetra‐substituted pyridine ring. A bicyclic intermediate was expeditiously prepared by using [2+2] photocycloaddition and chemoselective Baeyer–Villiger oxidation, which was further elaborated to a densely substituted aza‐triene. An electrocyclization–aromatization cascade was utilized to forge the tetracyclic core of this natural product, and the side chain was introduced through diastereoselective acylation and reduction. [ABSTRACT FROM AUTHOR]

Supported metal nanoparticles are used as heterogeneous catalysts but often deactivated due to sintering at high temperatures. Confining metal species into a porous matrix reduces sintering, yet supports rarely provide additional stabilization. Here, we used the silanol‐rich layered zeolite IPC‐1P to stabilize ultra‐small Rh nanoparticles. By adjusting the IPC‐1P interlayer space through swelling, we prepared various architectures, including microporous and disordered mesoporous. In situ scanning transmission electron microscopy confirmed that Rh nanoparticles are resistant to sintering at high temperature (750 °C, 6 hrs). Rh clusters strongly bind to surface silanol quadruplets at IPC‐1P layers by hydrogen transfer to clusters, while high silanol density hinders their migration based on density functional theory calculations. Ultimately, combining swelling with long‐chain surfactant and utilizing metal‐silanol interactions resulted in a novel, catalytically active material—Rh@IPC_C22. [ABSTRACT FROM AUTHOR]

We report an Ag1 single‐atom catalyst (Ag1/MnO2), which was synthesized from thermal transformation of Ag nanoparticles (NPs) and surface reconstruction of MnO2. The evolution process of Ag NPs to single atoms is firstly revealed by various techniques, including in situ ETEM, in situ XRD and DFT calculations. The temperature‐induced surface reconstruction process from the MnO2 (211) to (310) lattice plane is critical to firmly confine the existing surface of Ag single atoms; that is, the thermal treatment and surface reconstruction of MnO2 is the driving force for the formation of single Ag atoms. The as‐obtained Ag1/MnO2 achieved 95.7 % Faradic efficiency at −0.85 V vs. RHE, and coupled with long‐term stability for electrochemical CO2 reduction reaction (CO2RR). DFT calculations indicated single Ag sites possessed high electronic density close to Fermi Level and could act exclusively as the active sites in the CO2RR. As a result, the Ag1/MnO2 catalyst demonstrated remarkable performance for the CO2RR, far surpassing the conventional Ag nanosized catalyst (AgNP/MnO2) and other reported Ag‐based catalysts. [ABSTRACT FROM AUTHOR]

It is highly desirable but challenging to optimize the structure of photocatalysts at the atomic scale to facilitate the separation of electron–hole pairs for enhanced performance. Now, a highly efficient photocatalyst is formed by assembling single Pt atoms on a defective TiO2 support (Pt1/def‐TiO2). Apart from being proton reduction sites, single Pt atoms promote the neighboring TiO2 units to generate surface oxygen vacancies and form a Pt‐O‐Ti3+ atomic interface. Experimental results and density functional theory calculations demonstrate that the Pt‐O‐Ti3+ atomic interface effectively facilitates photogenerated electrons to transfer from Ti3+ defective sites to single Pt atoms, thereby enhancing the separation of electron–hole pairs. This unique structure makes Pt1/def‐TiO2 exhibit a record‐level photocatalytic hydrogen production performance with an unexpectedly high turnover frequency of 51423 h−1, exceeding the Pt nanoparticle supported TiO2 catalyst by a factor of 591. [ABSTRACT FROM AUTHOR]

The photocatalytic CO2 reduction reaction (CRR) represents a promising route for the clean utilization of stranded renewable resources, but poor selectivity resulting from the competing hydrogen evolution reaction (HER) in aqueous solution limits its practical applicability. In the present contribution a photocatalyst with hydrophobic surfaces was fabricated. It facilitates an efficient three‐phase contact of CO2 (gas), H2O (liquid), and catalyst (solid). Thus, concentrated CO2 molecules in the gas phase contact the catalyst surface directly, and can overcome the mass‐transfer limitations of CO2, inhibit the HER because of lowering proton contacts, and overall enhance the CRR. Even when loaded with platinum nanoparticles, one of the most efficient HER promotion cocatalysts, the three‐phase photocatalyst maintains a selectivity of 87.9 %. Overall, three‐phase photocatalysis provides a general and reliable method to enhance the competitiveness of the CRR. [ABSTRACT FROM AUTHOR]

The production of CH3OH from the photocatalytic CO2 reduction reaction (PCRR) presents a promising route for the clean utilization of renewable resources, but charge recombination, an unsatisfying stability and a poor selectivity limit its practical application. In this paper, we present the design and fabrication of 0D/2D materials with polymeric C3N4 nanosheets and CdSe quantum dots (QDs) to enhance the separation and reduce the diffusion length of charge carriers. The rapid outflow of carriers also restrains self‐corrosion and consequently enhances the stability. Furthermore, based on quantum confinement effects of the QDs, the energy of the electrons could be adjusted to a level that inhibits the hydrogen evolution reaction (HER, the main competitive reaction to PCRR) and improves the selectivity and activity for CH3OH production from the PCRR. The band structures of photocatalysts with various CdSe particle sizes were also investigated quantitatively to establish the relationship between the band energy and the photocatalytic performance. [ABSTRACT FROM AUTHOR]

Abstract: A hundred years on, the energy‐intensive Haber–Bosch process continues to turn the N2 in air into fertilizer, nourishing billions of people while causing pollution and greenhouse gas emissions. The urgency of mitigating climate change motivates society to progress toward a more sustainable method for fixing N2 that is based on clean energy. Surface oxygen vacancies (surface Ovac) hold great potential for N2 adsorption and activation, but introducing Ovac on the very surface without affecting bulk properties remains a great challenge. Fine tuning of the surface Ovac by atomic layer deposition is described, forming a thin amorphous TiO2 layer on plasmon‐enhanced rutile TiO2/Au nanorods. Surface Ovac in the outer amorphous TiO2 thin layer promote the adsorption and activation of N2, which facilitates N2 reduction to ammonia by excited electrons from ultraviolet‐light‐driven TiO2 and visible‐light‐driven Au surface plasmons. The findings offer a new approach to N2 photofixation under ambient conditions (that is, room temperature and atmospheric pressure). [ABSTRACT FROM AUTHOR]

Abstract: We report the total syntheses of daphenylline (1), daphnipaxianine A (5), and himalenine D (6), three Daphniphyllum alkaloids from the calyciphylline A subfamily. A pentacyclic triketone was prepared by using atom‐transfer radical cyclization and the Lu [3+2] cycloaddition as key steps. Inspired by the proposed biosynthetic relationship between 1 and another calyciphylline A type alkaloid, we developed a ring‐expansion/aromatization/aldol cascade to construct the tetrasubstituted benzene moiety of 1. The versatile triketone intermediate was also elaborated into 5 and 6 through a C=C bond migration/aldol cyclization approach. [ABSTRACT FROM AUTHOR]

Nanotubular Fe2O3 is a promising photoanode material, and producing morphologies that withstand high-temperature calcination (HTC) is urgently needed to enhance the photoelectrochemical (PEC) performance. This work describes the design and fabrication of Fe2O3 nanotube arrays that survive HTC for the first time. By introducing a ZrO2 shell on hydrothermal FeOOH nanorods by atomic layer deposition, subsequent high-temperature solid-state reaction converts FeOOH-ZrO2 nanorods to ZrO2-induced Fe2O3 nanotubes (Zr-Fe2O3 NTs). The structural evolution of the hematite nanotubes is systematically explored. As a result of the nanostructuring and shortened charge collection distance, the nanotube photoanode shows a greatly improved PEC water oxidation activity, exhibiting a photocurrent density of 1.5 mA cm−2 at 1.23 V (vs. reversible hydrogen electrode, RHE), which is the highest among hematite nanotube photoanodes without co-catalysts. Furthermore, a Co-Pi decorated Zr-Fe2O3 NT photoanode reveals an enhanced onset potential of 0.65 V (vs. RHE) and a photocurrent of 1.87 mA cm−2 (at 1.23 V vs. RHE). [ABSTRACT FROM AUTHOR]

The total syntheses of ileabethoxazole, pseudopteroxazole, and seco-pseudopteroxazole, three antituberculosis diterpenoids that had been isolated from Pseudopterogorgia elisabethae, were accomplished in a collective fashion. A cascade alkyne carbopalladation/Stille reaction was exploited to construct a triene precursor with suitable geometry. A fully substituted arene was then assembled through a key 6π electrocyclization/aromatization sequence, and served as an advanced common intermediate. Two radical cyclizations led to the formation of the five- and six-membered rings of ileabethoxazole and pseudopteroxazole, respectively, with the desired stereochemistry, and a straightforward side-chain elongation delivered seco-pseudopteroxazole. [ABSTRACT FROM AUTHOR]