Sunxuehao

Silver-assisted gold catalysis was applied to alkynyl glycosyl carbonate donors for the synthesis of purine, pyrimidine, quinolin-2-one, and asparagine glycosides. It was demonstrated (40 examples) to be highly versatile for the synthesis of important types of N-glycosides. The method has been utilized for the synthesis of various 2’-modified nucleosides and the disaccharide dipeptide moiety of chloroviruses.

Abstract

The synthesis of N-glycosides from stable glycosyl donors in a catalytic fashion is still challenging, though they exist ubiquitously in DNA, RNA, glycoproteins, and other biological molecules. Herein, silver-assisted gold-catalyzed activation of alkynyl glycosyl carbonate donors is shown to be a versatile approach for the synthesis of purine and pyrimidine nucleosides, asparagine glycosides and quinolin-2-one N-glycosides. Thus synthesized nucleosides were subjected to the oxidation–reduction sequence for the conversion of Ribf- into Araf- nucleosides, giving access to nucleosides that are otherwise difficult to synthesize. Furthermore, the protocol is demonstrated to be suitable for the synthesis of 2’-modified nucleosides in a facile manner. Direct attachment of an asparagine-containing dipeptide to the glucopyranose and subsequent extrapolation to afford the dipeptide disaccharide unit of chloroviruses is yet another facet of this endeavor.

A layered double hydroxide-derived plasmonic Cu catalyst was synthesized for the photo-driven water-gas shift reaction (WGSR). Light-induced hot electrons led to efficient *H₂O activation and *H combination via a carboxyl pathway. High hydrogen production rate (114.35 μmol g_cat ⁻¹ s⁻¹) was realized at 200 °C through the plasmonic Cu-mediated strategy, representing state-of-the-art performance for (photo-)thermal WGSR catalyst at low temperatures.

Abstract

The activation of water molecules in thermal catalysis typically requires high temperatures, representing an obstacle to catalyst development for the low-temperature water-gas shift reaction (WGSR). Plasmonic photocatalysis allows activation of water at low temperatures through the generation of light-induced hot electrons. Herein, we report a layered double hydroxide-derived copper catalyst (LD-Cu) with outstanding performance for the low-temperature photo-driven WGSR. LD-Cu offered a lower activation energy for WGSR to H₂ under UV/Vis irradiation (1.4 W cm⁻²) compared to under dark conditions. Detailed experimental studies revealed that highly dispersed Cu nanoparticles created an abundance of hot electrons during light absorption, which promoted *H₂O dissociation and *H combination via a carboxyl pathway, leading to the efficient production of H₂. Results demonstrate the benefits of exploiting plasmonic phenomena in the development of photo-driven low-temperature WGSR catalysts.

A family of racemic polymers were induced into one-handed helices which were memorized after the chiral inducer was removed. The enantiomeric excess of one handed helix (ee _h) is up to 98 %. Interestingly, the switchable helix-induction is visible with the naked eye. Moreover, the one-handed helices exhibit enhanced stability with helicity discrimination and enantiomer separation abilities.

Abstract

Inspired by biological helices (e.g., DNA), artificial helical polymers have attracted intense attention. However, precise synthesis of one-handed helices from achiral materials remains a formidable challenge. Herein, a series of achiral poly(biphenyl allene)s with controlled molar mass and low dispersity were prepared and induced into one-handed helices using chiral amines and alcohols. The induced one-handed helix was simultaneously memorized, even after the chiral inducer was removed. The switchable induction processes were visible to naked eye; the achiral polymers exhibited blue emission (irradiated at 365 nm), whereas the induced one-handed helices exhibited cyan emission with clear circularly polarized luminescence. The induced helices formed stable gels in various solvents with helicity discrimination ability: the same-handed helix gels were self-healing, whereas the gels of opposite-handed helicity were self-sorted. Moreover, the induced helices could separate enantiomers via enantioselective crystallization with high efficiency and switchable enantioselectivity.

A high-curvature two-dimensional (2D) polymerization is proposed to form a single-layer 2D polymer network as a non-contacting ligand on the surface of nanoparticles for their stabilization and functionalization. The 2D polymer network coated on nanoparticle surfaces can be turned into a non-contact ligand showing excellent shape retention and high nanoparticle-surface accessibility.

Abstract

Two-dimensional polymers (2DPs), single-layer networks of covalently linked monomers, show perspectives as membranes and in electronics. However, 2D polymerization of monomers in orthogonal directions limited the formation of 2DPs on nanoparticles (NPs) with high surface curvatures. Here we propose a high-curvature 2D polymerization to form a single-layer 2DP network as a non-contacting ligand on the surface of NPs for their stabilization and functionalization. The high-curvature 2D polymerization of amphiphilic Gemini monomers was conducted in situ on surfaces of NPs with various sizes, shapes, and materials, forming highly cross-linked 2DPs. Selective etching of core–shell NPs led to 2DPs as a non-contact ligand of yolk-shell structures with excellent shape retention and high NP-surface accessibility. In addition, by copolymerization, the 2DP ligands can covalently link to other functional molecules. This work promotes the development of 2DPs on NPs for their functional modification.

Au (310)@Cu truncated ditetragonal prisms (DTPs) enhance the activity and selectivity for CO₂ electromethanation. Elemental mapping analysis shows Cu surface layers are uniformly distributed on the Au {310} facets of the DTPs. Operando Fourier transform infrared spectra show reactive adsorbed *CO as the main intermediate. CO stripping experiments reveal the high-index facets enhance the *CO formation followed by rapid desorption or hydrogenation.

Abstract

The chemical selectivity and faradaic efficiency of high-index Cu facets for the CO₂ reduction reaction (CO₂RR) is investigated. More specifically, shape-controlled nanoparticles enclosed by Cu {hk0} facets are fabricated using Cu multilayer deposition at three distinct layer thicknesses on the surface facets of Au truncated ditetragonal nanoprisms (Au DTPs). Au DTPs are shapes enclosed by 12 high-index {310} facets. Facet angle analysis confirms DTP geometry. Elemental mapping analysis shows Cu surface layers are uniformly distributed on the Au {310} facets of the DTPs. The 7 nm Au@Cu DTPs high-index {hk0} facets exhibit a CH₄ : CO product ratio of almost 10 : 1 compared to a 1 : 1 ratio for the reference 7 nm Au@Cu nanoparticles (NPs). Operando Fourier transform infrared spectroscopy spectra disclose reactive adsorbed *CO as the main intermediate, whereas CO stripping experiments reveal the high-index facets enhance the *CO formation followed by rapid desorption or hydrogenation.

Harvesting of multiple hot holes has been demonstrated using Au nanospheres for the plasmonic photocatalytic oxidative scission of olefin to carbonyls through a step-down process. Interband photoexcitation of Au nanospheres beyond a threshold intensity leads to a spurt in hot-carrier generation, enabling multifold enhancement in substrate activation compared to a dark process.

Abstract

Using visible photoexcitation of gold nanospheres we successfully demonstrate the simultaneous harvesting of plasmon-induced multiple hot holes in the complete oxidative scission of the C=C bond in styrene at room temperature to selectively form benzaldehyde and formaldehyde, which is a reaction that requires activation of multiple substrates. Our results reveal that, while extraction of hot holes becomes efficient for interband excitation, harvesting of multiple hot holes from the excited Au nanospheres becomes prevalent only beyond a threshold light intensity. We show that the alkene oxidation proceeded via a sequence of two consecutive elementary steps; namely, a binding step and a cyclic oxometallate transition state as the rate-determining step. This demonstration of plasmon-excitation-mediated harvesting of multiple hot holes without the use of an extra hole transport media opens exciting possibilities, notably for difficult catalytic transformations involving multielectron oxidation processes.

Nature Nanotechnology, Published online: 26 January 2023; doi:10.1038/s41565-022-01284-0

This Review illustrates opportunities for the nanophotonics community when adopting machine learning approaches.

Nature Chemistry, Published online: 26 January 2023; doi:10.1038/s41557-022-01124-7

Current strategies for photoinduced olefin metathesis lack wavelength tunability. Now, plasmonic nanoparticles have been used to activate latent ruthenium catalysts, enabling light-induced olefin metathesis in the infrared range with several advantages when compared with conventional heating. Implementing this approach in ring-opening metathesis polymerization resulted in photoresponsive polymer–nanoparticle composites with enhanced mechanical properties.

An array of well-controlled Au single particles or oligomers was printed on an electrode surface, and used as a high-throughput platform to investigate the plasmon enhanced electrochemiluminescence (ECL) at the single-nanoparticle level. This ECL microscopy can visualize and quantify the electrochemical reactions of multiple individual NPs from wide-field imaging simultaneously.

Abstract

Plasmon-enhanced electrochemiluminescence (ECL) at the single-nanoparticle (NP) level was investigated by ECL microscopy. The Au NPs were assembled into an ordered array, providing a high-throughput platform that can easily locate each NP in sequential characterizations. A strong dependence of ECL intensity on Au NP configurations was observed. We demonstrate for the first time that at the single-particle level, the ECL of Ru(bpy)₃ ²⁺-TPrA was majorly quenched by small Au NPs (<40 nm), while enhanced by large Au ones (>80 nm) due to the localized surface plasmon resonance (LSPR). Notably, the ECL intensity was further increased by the coupling effect of neighboring Au NPs. Finite Difference Time Domain (FDTD) simulations conformed well with the experimental results. This plasmon enhanced ECL microscopy for arrayed single NPs provides a reliable tool for screening electrocatalytic activity at a single particle.