Communications Chemistry最新文献

The presence of amino acids in comets and meteorites has long suggested that prebiotic molecules may have formed in space and contributed to the origins of life on Earth. Glycine, the simplest amino acid, has been identified in several extraterrestrial environments, although its detection in the interstellar medium, including prestellar cores and protostellar regions, remains elusive. Here, we investigate a novel catalytic pathway for glycine formation on silicate grains during relatively warm (> 150 K) stages of star formation. Using atomistic simulations, the feasibility of a Strecker-type synthesis and a direct neutral mechanism involving reactivity between formaldehyde, carbon monoxide and ammonia on forsterite surfaces, the major constituent of interstellar dust, is assessed. Results show that the Strecker pathway is limited by high activation barriers, whereas the proposed direct mechanism proceeds through low-energy surface-stabilized intermediates leading to spontaneous formation of glycine in a single-barrier exoergic process. Additionally, glycine strongly adsorbs onto the mineral surface and is unlikely to desorb under warm conditions. A vibrational analysis reveals that glycine formed through this pathway exhibits spectrally distinct features, including suppression and shifting of characteristic bands, which may account for its persistent non-detection in astronomical observations.

Accurate modeling of conical intersections is crucial in nonadiabatic molecular dynamics, as these features govern processes such as radiationless transitions and photochemical reactions. Conventional electronic structure methods, including Hartree-Fock, density functional theory, and their time-dependent extensions, struggle in this regime. Due to their single reference nature and separate treatment of ground and excited states, they fail to capture ground state intersections. Multiconfigurational approaches overcome these limitations, but at a prohibitive computational cost. In this work, we propose a modified Hartree-Fock framework, referred to as Convex Hartree-Fock, that optimizes the reference within a tailored subspace by removing projections along selected Hessian eigenvectors. The ground and excited states are then obtained through subsequent Hamiltonian diagonalization. We validate the approach across several test cases and benchmark its performance against time-dependent Hartree-Fock within the Tamm-Dancoff approximation.

Machine learning (ML) and artificial intelligence (AI) techniques are transforming the way chemical reactions are studied today. Datasets from high-throughput experimentation (HTE) are generated to better understand the reaction conditions crucial for outcomes such as yields and selectivities. However, it is often overlooked that datasets from such designed experiments possess a specific structure, which can be captured by a statistical model. Ignoring these data structures when applying ML/AI algorithms can result in misleading conclusions. In contrast, leveraging knowledge about the data-generating process yields reliable, interpretable, and comprehensive insights into reaction mechanisms. A particularly complex dataset is available for the Buchwald-Hartwig amination. Using this dataset, a statistical model for such HTE-generated chemical data is introduced, and a parameter estimation algorithm is developed. Based on the estimated model, new insights into the Buchwald-Hartwig amination are discussed. Our approach is applicable to a wide range of HTE-generated data for chemical reactions and beyond.

Native chemical ligation (NCL) has emerged as the most extensively employed chemoselective reaction in chemical protein synthesis (CPS). Nevertheless, the inherently low reactivity of peptide alkyl thioesters often necessitates the use of excessive nucleophilic additives in NCL to facilitate the reaction. Herein, we describe a rapid, and additive-free peptide ligation reaction between peptide thioacid and N-terminal cysteinyl peptide without epimerization in the present vinyl thianthrenium tetrafluoroborate (VTT). VTT promotes quantitative and chemoselective activation of fully unprotected C-terminal peptide thioacids into thioester intermediates, which demonstrate exceptional reactivity, facilitating rapid NCL in an additive-free manner with high yields. This additive-free strategy is fully compatible with post-ligation desulfurization, allowing for a streamlined one-pot process that enhances the overall efficiency and simplicity of CPS workflows. The effectiveness of this methodology is demonstrated by synthesizing hyalomin-3 from two fragments through a one-pot thioesterification-ligation-desulfurization protocol and ubiquitin through a one-pot C-to-N sequential three-segment condensation (six steps in one pot).

Helices are present in the most important biomolecules (i.e., RNA, DNA). Helices are formed in biology and the laboratory using subunits with information encoded based on molecular recognition. The production of abiotic helical structures is an ongoing goal in synthetic and materials chemistry and has involved the development of organic and metal-organic materials that rely on complementarity of noncovalent forces (e.g. hydrogen bonds, coordination bonds) for helix formation. Herein, we describe a series of supramolecular isomers of three hydrogen-bonded organic cocrystals involving components that self-assemble and show progression at the structural level from a zig-zag chain to a double helix and to a quadruple helix. The isomers constitute a form of trimorphism involving a binary cocrystal system and we show that the polymeric structures can be interconverted through solvent-mediated phase transformations. We demonstrate the cocrystal involving the double helix to possess components that undergo an intermolecular [2 + 2] photodimerization in the crystalline state.

Increasing nitrate (NO₃^-) concentration in water bodies due to anthropogenic activities has become a leading environmental challenge of the 21st century. Electrochemical nitrate reduction reaction (eNO₃RR) offers a sustainable solution by simultaneously removing nitrates and producing ammonia, a valuable feedstock. However, eNO₃RR possesses significant challenges, such as efficiency, competing reactions, product selectivity, catalyst stability, etc. This review article highlights the importance of eNO₃RR, its mechanistic pathway, in-situ/operando techniques to understand the mechanistic pathway, reactor design, analytical challenges in product estimation, and catalyst designing strategies. This work uniquely integrates in-situ studies, mechanistic insights, and design principles to establish clear structure-activity correlations for advancing eNO₃RR catalysts. We conclude with current challenges and prospects to guide future research toward efficient and selective catalysts for eNO₃RR-driven ammonia production.

Many hydrogenation reactions still depend on noble-metal catalysts, which limits their broader use because of high cost and supply concerns. Developing effective catalysts from abundant materials that operate under mild reaction conditions remains a significant challenge. Here, we show the preparation of a copper silicate catalyst using an ammonia evaporation method that delivers exceptional performance in converting nitroarenes to anilines. The catalyst maintains high activity and stability, providing yields above 99 percent under mild conditions. Structural and surface analyses reveal well-dispersed copper species whose combined contributions promote both hydrogen activation and substrate conversion. This behaviour enables a cost-effective and sustainable alternative to noble-metal catalysts. The material also demonstrates robust recyclability, retaining activity over repeated use, and scale-up tests confirm its practical viability. These results highlight the promise of copper-based systems for efficient and industrially relevant hydrogenation processes.

Light-driven dissipative self-assembly has garnered substantial attention due to its precise spatiotemporal controllability. However, achieving synergistic integration of spatial manipulation fidelity, architectural programmability, and dynamic reconfigurability within a free-standing platform remains a formidable challenge. Herein, we report a light-driven hierarchical dissipative self-assembly paradigm with temporally programmable fluorochromism, achieved through molecular-engineered coordination of dynamic macrocyclic host-guest interactions within sustainable cellulose matrices. Protonated vinylpyridium-derived merocyanine is designed and synthesized to construct light-controlled differential binding architectures with cucurbiturils. This system demonstrates quantitatively reversible interconversion between spiropyran and merocyanine states through alternating photoactivation (475 nm) and thermal relaxation. Structural modulation of host-guest stoichiometry between 1:2 and 1:1 induces nanoscale morphological switching between spherical and cuboid assemblies, accompanied by time-resolved fluorescence chromism. Leveraging the inherent affinity between cucurbiturils and cellulose nanofibrils, we engineered light-fueled hierarchical architectures into freestanding cellulosic papers, exhibiting self-erasing transient photowriting and multilevel anti-counterfeiting functions. The non-covalent host-guest architecture and reprocessable cellulose matrix synergistically enable material recyclability. This spatiotemporally programmed dissipative self-assembly system pioneers sustainable cellulose platforms for adaptive optoelectronics and smart sensing.

This work presents a visual growth strategy based on water-induced phase transitions, which enables real-time tracking and structural regulation of Cs₄PbBr₆-to-CsPbBr₃ microcrystal transformation under ambient conditions without the need for high-energy beams or vacuum. Driven by the difference in the dissolution rates of CsBr and PbBr₂ in water, the slow progression of the reaction interface allows clear observation of crystal morphology evolution under a conventional fluorescence microscope. The microcrystals obtained through strategy possess highly regular structural morphology and superior optical properties. In the experiments, micron-scale-wire exhibiting size-dependent polarized emission and bulk-microcrystals supporting multimode lasing emission were successfully constructed. Further analysis revealed the significant influence of crystal size on excited-state dynamics, cavity mode selectivity, and emission characteristics, thereby establishing a direct link between structural visual regulation and functional photon output. This work delivers mechanistic insights and experimental evidence for controllable fabrication of low-threshold lasers and polarized light-emitting devices.