A thiolated copper-hydride nanocluster with chloride bridging as a catalyst for carbonylative C-N coupling of aryl amines under mild conditions: a combined experimental and theoretical study.

Atomically precise copper nanoclusters (Cu NCs), an emerging class of nanomaterials, have garnered significant attention owing to their versatile core-shell architecture and their potential applications in catalytic reactions. In this study, we present a straightforward synthesis strategy for [Cu29(StBu)12(PPh3)4Cl6H10][BF4] (Cu29) NCs and explore their catalytic activity in the carbonylative C-N coupling reaction involving aromatic amines and N-heteroarenes with dialkyl azodicarboxylates. Through a combination of experimental investigations and density functional theory studies, we elucidate the radical mechanisms at play. The crucial step in the catalytic process is identified as the decomposition of diisopropyl azodicarboxylates on the surface of Cu29 NCs, leading to the generation of oxyacyl radicals and the liberation of nitrogen gas. Subsequently, an oxyacyl radical abstracts a hydrogen atom from aniline, initiating the formation of an aminyl radical. Finally, the aminyl radical reacts with another oxyacyl radical, culminating in the synthesis of the desired carbamate product. This detailed analysis provides insights into the intricate catalytic pathways of Cu29 NCs, shedding light on their potential for catalyzing carbonylative C-N coupling reactions.

Deciphering DNA nucleotide sequences and their rotation dynamics with interpretable machine learning integrated C3N nanopores.

A solid-state nanopore combined with the quantum transport method has garnered substantial attention and intrigue for DNA sequencing due to its potential for providing rapid and accurate sequencing results, which could have numerous applications in disease diagnosis and personalized medicine. However, the intricate and multifaceted nature of the experimental protocol poses a formidable challenge in attaining precise single nucleotide analysis. Here, we report a machine learning (ML) framework combined with the quantum transport method to accelerate high-throughput single nucleotide recognition with C3N nanopores. The optimized eXtreme Gradient Boosting Regression (XGBR) algorithm has predicted the fingerprint transmission of each unknown nucleotide and their rotation dynamics with root mean square error scores as low as 0.07. Interpretability of ML black box models with the game theory-based SHapley Additive exPlanation method has provided a quasi-explanation for the model working principle and the complex relationship between electrode-nucleotide coupling and transmission. Moreover, a comprehensive ML classification of nucleotides based on binary, ternary, and quaternary combinations shows maximum accuracy and F1 scores of 100%. The results suggest that ML in tandem with a nanopore device can potentially alleviate the experimental hurdles associated with quantum tunneling and facilitate fast and high-precision DNA sequencing.

Design of porphyrin-based frameworks for efficient visible light-promoted reduction of CO2 from dilute gas: Combined experimental and theoretical investigation.

The photocatalytic carbon dioxide reduction (CO2R) coupled with hydrogen evolution reaction (HER) constitutes a promising step for a sustainable generation of syngas (CO + H2), an essential feedstock for the preparation of several commodity chemicals. Herein, visible light/sunlight-promoted catalytic reduction of CO2 and protons to syngas using rationally designed porphyrin-based 2D porous organic frameworks, POF(Co/Zn) is demonstrated. Indeed, POF(Co) showed superior catalytic performance over the Zn counterpart with CO and H2 generation rates of 1104 and 3981 µmol g-1h-1, respectively. The excellent catalytic performance of Co-based POF is aided by the favorable transfer of photo-excited electrons from Ru-sensitizer to the CoII catalytic site, which is not feasible in the case of POF(Zn), revealed from the theoretical investigation. More importantly, the POF(Co) catalyzes the reduction of CO2 even from dilute gas (13% CO2), surpassing most reported framework-based photocatalytic systems. Significantly, the catalytic performance of POF(Co) was increased under natural sunlight conditions suggesting sunlight-promoted enhancement in syngas generation. The in-depth theoretical investigation further unveiled the comprehensive mechanistic pathway of the light-promoted concurrent CO and H2 generation. This work showcases the advantages of porphyrin-based frameworks for visible light/sunlight-promoted syngas generation by utilizing greenhouse gas (CO2) and protons under mild eco-friendly conditions.

Luminescent [CO2@Ag20(SAdm)10(CF3COO)10(DMA)2] nanocluster: synthetic strategy and its implication towards white light emission.

Owing to the quantized size and associated discrete energy levels, atomically precise silver nanoclusters (Ag NCs) hold great potential for designing functional luminescent materials. However, the thermally activated non-radiative transition of Ag(I)-based NCs has faded the opportunities. To acquire the structurally rigid architecture of cluster nodes for constraining such transitions, a new synthetic approach is unveiled here that utilizes a neutral template as a cluster-directing agent to assemble twenty Ag(I) atoms that ensure the maximum number of surface-protecting ligand attachment possibilities in a particular solvent medium. The solvent polarity triggers the precise structural design to circumvent the over-reliance of the templates, which results in the formation of [CO2@Ag20(SAdm)10(CF3COO)10(DMA)2] NC (where SAdm = 1-adamantanethiolate and DMA = N,N-dimethylacetamide) exhibiting an unprecedented room-temperature photoluminescence emission. The high quantum yield of the generated blue emission ensures its candidature as an ideal donor for artificial light-harvesting system design, and it is utilized with the two-step sequential energy transfer process, which finally results in the generation of ideal white light. For implementing perfect white light emission, the required chromophores in the green and red emission regions were chosen based on their effective spectral overlap with the donor components. Due to their favorable energy-level distribution, excited state energy transfers occurred from the NC to ß-carotene at the initial step, then from the conjugate of the NC and ß-carotene to another chromophore, Nile Blue, at the second step via a sequential Förster resonance energy transfer pathway.

Recent Advancements in Devising Computational Strategies for Dual-Ion Batteries.

Dual-ion batteries (DIBs) have been considered a viable alternative to increasingly costly and hazard-prone lithium-ion batteries (LIBs), which have reached a level of saturation. DIBs differ from LIBs in the way that the cations and anions originate from the electrolyte, thus signifying the active role played by electrolyte. In this Review, the major developments in research in the field of DIBs are summarized with a major emphasis on computational approaches in this direction. The various computational methods for understanding and designing electrodes are discussed. The advancements in electrode and electrolyte design for efficient DIBs are highlighted. Further, the ways to investigate solid-electrolyte interphase formation through simulations to comprehend the role of various components are discussed. Finally, directions are given on which future computational research can be carried out to design futuristic DIBs to provide useful guidelines to the researchers to understand and design DIBs.

Template-assisted alloying of atom-precise silver nanoclusters: a new approach to generate cluster functionality.

To acquire the atomic design of new functional Ag(i) nanoclusters (NCs), a new synthetic approach of site-specific alloying has been unveiled, by which the neutral CO2 templated Ag20 core is confined through Cu containing two peripheral motif units. The impact of surface charge, size and shape of the template on the self-assembly of Ag(i) has been precisely controlled here for the first time and as a result, a similar pentagonal gyrobicupola-like Ag20 core is formed while varying the templates (S2-, CO3 2- and CO2). However, the surface charge generated on the Ag(i) core due to the presence of a neutral template opens up the possibility of this novel alloying process. The introduction of strongly interacted peripheral motif units (DMA-CuS-) on the Ag20 core enforces more rigidity in the skeleton that reduces the probability of non-radiative transition in the excited state by lowering the intramolecular vibration. In addition to this, the incorporation of electron-donating peripheral motif units modulates the frontier molecular arrangement that helps in attaining the synergy which would ultimately turn on the room-temperature emission properties. The electron-donating effect of the peripheral motif units further leads to a sharp reduction of the bandgap and the symmetric position of the heterometal in the cluster minimizes the intercluster distances which further influences the intercluster charge carrier transport. So, the precise structure-property correlation with this novel synthetic approach will pave the way for a well-functioning NC design.

An atomically precise silver nanocluster for artificial light-harvesting system through supramolecular functionalization.

Designing an artificial light-harvesting system (LHS) with high energy transfer efficiency has been a challenging task. Herein, we report an atom-precise silver nanocluster (Ag NC) as a unique platform to fabricate the artificial LHS. A facile one-pot synthesis of [Cl@Ag16S(S-Adm)8(CF3COO)5(DMF)3(H2O)2]·DMF (Ag16) NC by using a bulky adamantanethiolate ligand is portrayed here which, in turn, alleviates the issues related to the smaller NC core designed from a highly steric environment. The surface molecular motion of this NC extends the non-radiative relaxation rate which is strategically restricted by a recognition site-specific supramolecular adduct with ß-cyclodextrin (ß-CD) that results in the generation of a blue emission. This emission property is further controlled by the number of attached ß-CD which eventually imposes more rigidity. The higher emission quantum yield and the larger emission lifetime relative to the lesser numbered ß-CD conjugation signify Ag16 ∩ ß-CD2 as a good LHS donor component. In the presence of an organic dye (ß-carotene) as an energy acceptor, an LHS is fabricated here via the Förster resonance energy transfer pathway. The opposite charges on the surfaces and the matched electronic energy distribution result in a 93% energy transfer efficiency with a great antenna effect from the UV-to-visible region. Finally, the harvested energy is utilized successfully for efficient photocurrent generation with much-enhanced yields compared to the individual components. This fundamental investigation into highly-efficient energy transfer through atom-precise NC-based systems will inspire additional opportunities for designing new LHSs in the near future.

Strategic Design of Mg-Centered Porphyrin Metal-Organic Framework for Efficient Visible Light-Promoted Fixation of CO2 under Ambient Conditions: Combined Experimental and Theoretical Investigation.

The sunlight-driven fixation of CO2 into valuable chemicals constitutes a promising approach toward environmental remediation and energy sustainability over traditional thermal-driven fixation. Consequently, in this article, we report a strategic design and utilization of Mg-centered porphyrin-based metal-organic framework (MOFs) having relevance to chlorophyll in green plants as a visible light-promoted highly recyclable catalyst for the effective fixation of CO2 into value-added cyclic carbonates under ambient conditions. Indeed, the Mg-centered porphyrin MOF showed good CO2 capture ability with a high heat of adsorption (44.5 kJ/mol) and superior catalytic activity under visible light irradiation in comparison to thermal-driven conditions. The excellent light-promoted catalytic activity of Mg-porphyrin MOF has been attributed to facile ligand-to-metal charge transfer transition from the photoexcited Mg-porphyrin unit (SBU) to the Zr6 cluster which in turn activates CO2, thereby lowering the activation barrier for its cycloaddition with epoxides. The in-depth theoretical studies further unveiled the detailed mechanistic path of the light-promoted conversion of CO2 into high-value cyclic carbonates. This study represents a rare demonstration of sunlight-promoted sustainable fixation of CO2, a greenhouse gas into value-added chemicals.

Solvent-Dependent Photophysical Properties of a Semiconducting One-Dimensional Silver Cluster-Assembled Material.

Unraveling the total structure of the atom-precise silver cluster-assembled materials (CAMs) is extremely significant to elucidating the structure-property correlation, but it is a very challenging task. Herein, a new silver CAM is synthesized by a facile synthetic pathway with a unique distorted elongated square-bipyramid-based Ag11 core geometry. The core is protected by two different kinds of the surface protecting ligands (adamantanethiolate and trifluoroacetate) and connected through a bidentate organic linker. The crystallographic data show that this material embraces a one-dimensional periodic structure that orchestrates by various noncovalent interactions to build a thermally stable supramolecular assembly. Further characterization confirms its n-type semiconducting property with an optical band gap of 1.98 eV. The impact of an adamantanethiol-protected silver core on the optical properties of this type of periodic framework is analyzed by the UV-vis absorbance and emission phenomena. Theoretical calculations predicted that the occupied states are majorly contributed by Ag-S. Solvent-dependent photoluminescence studies proved that a polar solvent can significantly perturb the metal thiolate and thiolate-centered frontier molecular orbitals that are involved in the electronic transitions.

Recent Trends in Electrode and Electrolyte Design for Aluminum Batteries.

Due to the drawbacks in commercially known lithium-ion batteries (LIB) such as safety, availability, and cost issues, aluminum batteries are being hotly pursued in the research field of energy storage. Al being abundant, stable, and possessing high volumetric capacity has been found to be attractive among the next generation secondary batteries. Various unwanted side reactions in the case of aqueous electrolytes have shifted the attention toward nonaqueous electrolytes for Al batteries. Unlike LIBs, Al batteries are based on intercalation/deintercalation of ions on the cathode side and deposition/stripping of Al on the anodic side during the charge/discharge cycle of the battery. Hence, to provide a clear understanding of the recent developments in Al batteries, we have presented an overview concentrating on the choice of suitable cathodes and electrolytes involving aluminum chloride derived ions (AlCl4 -, AlCl2 +, AlCl2+, etc.). We elaborate the importance of innovation in terms of structure and morphology to improve the cathode materials as well as the necessary properties to look for in a suitable nonaqueous electrolyte. The significance of computational modeling is also discussed. The future perspectives are discussed which can improve the performance and reduce the manufacturing cost simultaneously to conceive Al batteries for a wide range of applications.