Accounts of Chemical Research最新文献

{"title":"Crystalline Covalent Triazine Frameworks and 2D Triazine Polymers: Synthesis and Applications","authors":"Yumei Ren, Shuai Yang and Yuxi Xu*, ","doi":"10.1021/acs.accounts.4c0072910.1021/acs.accounts.4c00729","DOIUrl":"https://doi.org/10.1021/acs.accounts.4c00729https://doi.org/10.1021/acs.accounts.4c00729","url":null,"abstract":"<p >Covalent triazine frameworks (CTFs) are a novel class of nitrogen-rich conjugated porous organic materials constructed by robust and functional triazine linkages, which possess unique structures and excellent physicochemical properties. They have demonstrated broad application prospects in gas/molecular adsorption and separation, catalysis, energy conversion and storage, etc. In particular, crystalline CTFs with well-defined periodic molecular network structures and regular pore channels can maximize the utilization of the features of CTFs and promote a deep understanding of the structure–property relationship. However, due to the poor reversibility of the basic reaction for constructing the triazine unit and the traditional harsh synthesis conditions, it remains a considerable challenge to synthesize crystalline CTFs with diverse molecular structures, and there is still a significant lack of understanding of their polymerization mechanism, which limits their precise structural design, large-scale preparation, and practical applications. As the basic building block of bulk crystalline CTFs, two-dimensional triazine polymers (2D-TPs) which ideally have single-atom thickness have also aroused intensive interest due to their ultrathin 2D sheet morphology with structural flexibility, a fully exposed molecular plane and active sites, and excellent dispersibility and processability. However, the efficient and scalable production of high-quality 2D-TPs and the investigation of their unique properties and functions remain largely unexplored.</p><p >In this Account, we summarize our recent contributions to the synthesis and application exploration of crystalline CTFs and 2D-TPs. We first introduce the design, synthesis, and polymerization mechanism of the crystalline CTFs. In order to synthesize high-quality CTFs, we have successively used a series of new synthetic methods including a solution polymerization strategy, microwave-assisted superacid-catalyzed polymerization strategy, polyphosphoric acid-catalyzed polymerization strategy, and solvent-free FeCl<sub>3</sub>-catalyzed polymerization strategy, achieving the production of highly crystalline layered CTFs from the gram level to the hundred-gram level and then to the kilogram level and realizing new CTF molecular structures. We also reveal a direct ordered 2D polymerization mechanism that provided meaningful guidance for the controllable preparation of functional CTFs. Next, we introduce the design, synthesis, and formation mechanism of 2D-TPs. We have developed effective bottom-up and top-down strategies to prepare 2D-TPs for different needs. On one hand, we have established the dynamic interface polymerization method, the monomer-dependent method, and the solvent-free salt-catalyzed polymerization strategy for the direct synthesis of ultrathin 2D-TPs with thickness down to the single-layer limit and provided important insights into the 2D polymerization mechanism. On the other hand, we have o","PeriodicalId":1,"journal":{"name":"Accounts of Chemical Research","volume":"58 3","pages":"474–487 474–487"},"PeriodicalIF":16.4,"publicationDate":"2025-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143090210","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Elucidating the Origins of High Capacity in Iron-Based Conversion Materials: Benefit of Complementary Advanced Characterization toward Mechanistic Understanding","authors":"Ryan C. Hill,  and , Kenneth J. Takeuchi*, ","doi":"10.1021/acs.accounts.4c0071710.1021/acs.accounts.4c00717","DOIUrl":"https://doi.org/10.1021/acs.accounts.4c00717https://doi.org/10.1021/acs.accounts.4c00717","url":null,"abstract":"<p >Lithium-ion batteries are recognized as an important electrochemical energy storage technology due to their superior volumetric and gravimetric energy densities. Graphite is widely used as the negative electrode, and its adoption enabled much of the modern portable electronics technology landscape. However, developing markets, such as electric vehicles and grid-scale storage, have increased demands, including higher energy content and a diverse materials supply chain. Alternatives that provide the opportunity to increase capacity and address supply chain concerns are of interest.</p><p >Understanding the fundamental mechanisms that govern battery function is crucial to driving further improvements in the field. Advanced characterization techniques, such as those enabled by synchrotron light sources and high-resolution electron microscopes, that can uncover these mechanisms have become a necessity for elucidating structural evolution upon electrochemical conversion at the nano- to mesoscales. Performing these experiments with relevant electrochemistry using <i>in situ</i> and <i>operando</i> experiments imparts the ability to identify critical reaction pathways and capture intermediate (dis)charge products not discernible by traditional experiments.</p><p >This Account describes a series of recent studies focused on the advanced characterization of spinel-type iron oxide-based anode materials. These studies begin with magnetite (Fe<sub>3</sub>O<sub>4</sub>), a low cost iron oxide which, when synthesized with appropriate coprecipitation based crystallite size control, provides opportunity to realize eight electrons per formula unit via electrochemical reduction. We then transition to bi- and trimetallic ferrites (such as ZnFe<sub>2</sub>O<sub>4</sub> and CoMnFeO<sub>4</sub>) and conclude with high-entropy spinel ferrite oxides (HEOs) that contain at least 5 transition metals. For each material type, a variety of characterization techniques are utilized to describe the fundamental reaction mechanisms and rationalize electrochemical behavior. X-ray absorption spectroscopy (XAS) is featured prominently, as it allows for element specific analysis of electronic structure and local atomic environments, including nanocrystalline products of electrochemical conversion. Combining XAS-based techniques with diffraction and microscopy, the transition of iron oxide-type electrodes from spinel to rock-salt to metal nanoparticles upon full lithiation can be deciphered. For magnetite and its bi- and trimetallic ferrite analogues, delithiation results in return to a highly disordered network of FeO-like domains. Notably, while magnetite and the bi- and trimetallic ferrites appear to be limited to reoxidation of Fe to the 2+ state, through introduction of entropy-induced structural stability, higher Fe oxidation states (up to 2.6+) can be accessed upon electrochemical oxidation. These materials may hold promise as alternatives to traditional graphite electrodes ","PeriodicalId":1,"journal":{"name":"Accounts of Chemical Research","volume":"58 3","pages":"463–473 463–473"},"PeriodicalIF":16.4,"publicationDate":"2025-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/acs.accounts.4c00717","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143090087","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Using NMR Spectroscopy to Evaluate Metal–Ligand Bond Covalency for the f Elements","authors":"Trevor W. Hayton*,  and , Jochen Autschbach*, ","doi":"10.1021/acs.accounts.4c0072710.1021/acs.accounts.4c00727","DOIUrl":"https://doi.org/10.1021/acs.accounts.4c00727https://doi.org/10.1021/acs.accounts.4c00727","url":null,"abstract":"<p >Understanding f element-ligand covalency is at the center of efforts to design new separations schemes for spent nuclear fuel, and is therefore of signficant fundamental and practical importance. Considerable effort has been invested into quantifying covalency in f element-ligand bonding. Over the past decade, numerous studies have employed a variety of techniques to study covalency, including XANES, EPR, and optical spectroscopies, as well as X-ray crystallography. NMR spectroscopy is another widely available spectroscopic technique that is complementary to these more established methods; however, its use for measuring 4f/5f covalency is still in its infancy. This Account describes efforts in the authors’ laboratories to develop and validate multinuclear NMR spectroscopy as a tool for studying metal–ligand covalency in the actinides and selected lanthanide complexes. Thus far, we have quantified M–L covalency for a variety of ligand types, including chalcogenides, carbenes, alkyls, acetylides, amides, and nitrides, and for a variety of isotopes, including <sup>13</sup>C, <sup>15</sup>N, <sup>77</sup>Se, and <sup>125</sup>Te. Using NMR spectroscopy to probe M-C and M-N covalency is particularly attractive because of the ready availability of the<sup>13</sup>C and <sup>15</sup>N isotopes (both <i>I</i> = 1/2), and also because these elements are found in some of the most important f element ligand classes, including alkyls, carbenes, polypyridines, amides, imidos, and nitrides.</p><p >The covalency analysis is based on the chemical shift (δ) and corresponding nuclear shielding constant (σ) of the metal-bound nucleus. The diamagnetic (σ<sub>dia</sub>), paramagnetic (σ<sub>para</sub>), and spin–orbit contributions (σ<sub>SO</sub>) to σ can be obtained and analyzed by relativistic density functional theory (DFT). Of particular importance is σ<sub>SO</sub>, which arises from the combination of spin–orbit coupling, the magnetic field, and chemical bonding. Its magnitude correlates with the amount of ligand s-character and metal <i>n</i>f (and (<i>n</i>+1)d) character in the M–L bond. In practice, Δ<sub>SO</sub>, the total difference between calculated chemical shift for the ligand nucleus including vs excluding SO effects, provides a more convenient metric for analysis. For the examples discussed herein, Δ<sub>SO</sub> accounts primarily for σ<sub>SO</sub> in an f-element complex, but also includes minor SO effects on the other shielding mechanisms and (usually) minor SO effects on the reference shielding. Δ<sub>SO</sub> can be very large, as in the case of [U(CH<sub>2</sub>SiMe<sub>3</sub>)<sub>6</sub>] (348 ppm), which is not surprising as the An–C bonds in this example exhibits a high degree of covalency (e.g., 20% 5f character). However, even small values of Δ<sub>SO</sub> can indicate profound bonding effects, as shown by our analysis of [La(C<sub>6</sub>Cl<sub>5</sub>)<sub>4</sub>]<sup>−</sup>. In this case, Δ<sub>SO</sub> is only 9 ppm, cons","PeriodicalId":1,"journal":{"name":"Accounts of Chemical Research","volume":"58 3","pages":"488–498 488–498"},"PeriodicalIF":16.4,"publicationDate":"2025-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143090069","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Bistable Functions and Signaling Motifs in Systems Chemistry: Taking the Next Step Toward Synthetic Cells","authors":"Indrajit Maity, Nathaniel Wagner, Dharm Dev, Gonen Ashkenasy","doi":"10.1021/acs.accounts.4c00703","DOIUrl":"https://doi.org/10.1021/acs.accounts.4c00703","url":null,"abstract":"A key challenge in modern chemistry research is to mimic life-like functions using simple molecular networks and the integration of such networks into the first functional artificial cell. Central to this endeavor is the development of signaling elements that can regulate the cell function in time and space by producing entities of code with specific information to induce downstream activity. Such artificial signaling motifs can emerge in nonequilibrium systems, exhibiting complex dynamic behavior like bistability, multistability, oscillations, and chaos. However, the <i>de novo</i>, bottom-up design of such systems remains challenging, primarily because the kinetic characteristics and energy aspects yielding bifurcation have not yet been globally defined. We herein review our recent work that focuses on the design and functional analysis of peptide-based networks, propelled by replication reactions and exhibiting bistable behavior. Furthermore, we rationalize and discuss their exploitation and implementation as variable signaling motifs in homogeneous and heterogeneous environments.","PeriodicalId":1,"journal":{"name":"Accounts of Chemical Research","volume":"206 1","pages":""},"PeriodicalIF":18.3,"publicationDate":"2025-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143020333","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Catalytic Asymmetric Dehydrogenative Si–H/X–H Coupling toward Si-Stereogenic Silanes","authors":"Yicong Ge,&nbsp;Jie Ke and Chuan He*,&nbsp;","doi":"10.1021/acs.accounts.4c0066710.1021/acs.accounts.4c00667","DOIUrl":"https://doi.org/10.1021/acs.accounts.4c00667https://doi.org/10.1021/acs.accounts.4c00667","url":null,"abstract":"&lt;p &gt;Chiral organosilicon compounds bearing a Si-stereogenic center have attracted increasing attention in various scientific communities and appear to be a topic of high current relevance in modern organic chemistry, given their versatile utility as chiral building blocks, chiral reagents, chiral auxiliaries, and chiral catalysts. Historically, access to these non-natural Si-stereogenic silanes mainly relies on resolution, whereas their asymmetric synthetic methods dramatically lagged compared to their carbon counterparts. Over the past two decades, transition-metal-catalyzed desymmetrization of prochiral organosilanes has emerged as an effective tool for the synthesis of enantioenriched Si-stereogenic silanes. Despite the progress, these catalytic reactions usually suffer from limited substrate scope, poor functional-group tolerance, and low enantioselectivity. The growing demand for Si-stereogenic silanes with structural diversity has continued to drive the development of new practical methods for the assembly of these chiral molecules.&lt;/p&gt;&lt;p &gt;Five years ago, our research group embarked on a project aimed at developing a general catalytic approach that can unlock access to various functionalized Si-stereogenic organosilanes with high efficiency. This Account describes our laboratory’s endeavor in the exploration and development of catalytic asymmetric dehydrogenative Si–H/X–H coupling toward Si-stereogenic silanes. This approach features (1) readily accessible dihydrosilane starting materials; (2) diverse X–H (X═C, N, O, etc.) coupling partners; (3) platform transformable Si-stereogenic monohydrosilane products; and (4) high efficiency and atomic economy.&lt;/p&gt;&lt;p &gt;At the initial stage of the research, a biaryl dihydrosilane was selected as the model substrate to conduct an enantioselective intramolecular C–H/Si–H dehydrogenative coupling reaction. Rh/Josiphos catalytic system was found to be effective at the early stage of this process, while the final enantiocontrol was elusive. Mechanistic studies indicated that a rhodium silyl dihydride complex is the resting state in the catalytic cycle, which may undergo racemization of the Si-stereogenic center. Enlightened by the mechanistic investigations, two strategies, the tandem alkene hydrosilylation strategy and bulky alkene-assisted dehydrogenative strategy, were adopted to avoid racemization, delivering the corresponding Si-stereogenic 9-silafluorenes with excellent yields and enantioselectivities. Further enantioselective intramolecular C(sp&lt;sup&gt;2&lt;/sup&gt;)–H or C(sp&lt;sup&gt;3&lt;/sup&gt;)–H silylation gave access to a series of five-, six- and seven-membered Si-stereogenic heterocycles with high efficiency. Next, we extended the reaction to an intermolecular version, realizing asymmetric Si–H/C–H, Si–H/O–H, and Si–H/N–H dehydrogenative coupling reactions toward a variety of acyclic Si-stereogenic monohydrosilanes, silyl ethers, siloxanes, silanols, and silazanes. We also presented our endeavors to apply the ","PeriodicalId":1,"journal":{"name":"Accounts of Chemical Research","volume":"58 3","pages":"375–398 375–398"},"PeriodicalIF":16.4,"publicationDate":"2025-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143089927","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Bistable Functions and Signaling Motifs in Systems Chemistry: Taking the Next Step Toward Synthetic Cells","authors":"Indrajit Maity,&nbsp;Nathaniel Wagner,&nbsp;Dharm Dev and Gonen Ashkenasy*,&nbsp;","doi":"10.1021/acs.accounts.4c0070310.1021/acs.accounts.4c00703","DOIUrl":"https://doi.org/10.1021/acs.accounts.4c00703https://doi.org/10.1021/acs.accounts.4c00703","url":null,"abstract":"&lt;p &gt;A key challenge in modern chemistry research is to mimic life-like functions using simple molecular networks and the integration of such networks into the first functional artificial cell. Central to this endeavor is the development of signaling elements that can regulate the cell function in time and space by producing entities of code with specific information to induce downstream activity. Such artificial signaling motifs can emerge in nonequilibrium systems, exhibiting complex dynamic behavior like bistability, multistability, oscillations, and chaos. However, the &lt;i&gt;de novo&lt;/i&gt;, bottom-up design of such systems remains challenging, primarily because the kinetic characteristics and energy aspects yielding bifurcation have not yet been globally defined. We herein review our recent work that focuses on the design and functional analysis of peptide-based networks, propelled by replication reactions and exhibiting bistable behavior. Furthermore, we rationalize and discuss their exploitation and implementation as variable signaling motifs in homogeneous and heterogeneous environments.&lt;/p&gt;&lt;p &gt;The bistable reactions constitute reversible second-order autocatalysis as positive feedback to generate two distinct product distributions at steady state (SS), the low-SS and high-SS. Quantitative analyses reveal that a phase transition from simple reversible equilibration dynamics into bistability takes place when the system is continuously fueled, using a reducing agent, to keep it far from equilibrium. In addition, an extensive set of experimental, theoretical, and simulation studies highlight a defined parameter space where bistability operates.&lt;/p&gt;&lt;p &gt;Analogous to the arrangement of protein-based bistable motifs in intracellular signaling pathways, sequential concatenation of the synthetic bistable networks is used for signal processing in homogeneous media. The cascaded network output signals are switched and erased or transduced by manipulating the order of addition of the components, allowing it to reach “on demand” either the low-SS or high-SS. The pre-encoded bistable networks are also useful as a programming tool for the downstream regulation of nanoscale materials properties, bridging together the Systems Chemistry and Nanotechnology fields. In such heterogeneous cascade pathways, the outputs of the bistable network serve as input signals for consecutive nanoparticle formation reaction and growth processes, which–depending on the applied conditions–regulate various features of (Au) nanoparticle shape and assembly.&lt;/p&gt;&lt;p &gt;Our work enables the design and production of various signaling apparatus that feature higher complexity than previously observed in chemical networks. Future studies, briefly discussed at the end of the Account, will be directed at the design and analysis of more elaborate functionality, such as bistability under flow conditions, multistability, and oscillations. We propose that a profound understanding of the design princip","PeriodicalId":1,"journal":{"name":"Accounts of Chemical Research","volume":"58 3","pages":"428–439 428–439"},"PeriodicalIF":16.4,"publicationDate":"2025-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/acs.accounts.4c00703","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143090065","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exploring Singlet Carbyne Anions and Related Low-Valent Carbon Species Utilizing a Cyclic Phosphino Substituent","authors":"Chaopeng Hu, Xin-Feng Wang, Chenyang Hu, Rui Wei, Hongyu Wang, Liu Leo Liu","doi":"10.1021/acs.accounts.4c00714","DOIUrl":"https://doi.org/10.1021/acs.accounts.4c00714","url":null,"abstract":"The advancement of synthetic methodologies is fundamentally driven by a deeper understanding of the structure–reactivity relationships of reactive key intermediates. Carbyne anions are compounds featuring a monovalent anionic carbon possessing four nonbonding valence electrons, which were historically confined to theoretical constructs or observed solely within the environment of gas-phase studies. These species possess potential for applications across diverse domains of synthetic chemistry and ancillary fields. This Account details our focused efforts to isolate singlet carbyne anions and explores our isolation of a range of related low-valent carbon species. Our achievements include the synthesis and characterization, under normal laboratory conditions, of gold-substituted free carbenes, copper carbyne anion complexes, ketenyl anions, keteniminyl anions, and a free stannyne. These have been accomplished using a bulky cyclic phosphino substituent, which effectively stabilizes these reactive species.","PeriodicalId":1,"journal":{"name":"Accounts of Chemical Research","volume":"61 1","pages":""},"PeriodicalIF":18.3,"publicationDate":"2025-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143020338","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exploring Singlet Carbyne Anions and Related Low-Valent Carbon Species Utilizing a Cyclic Phosphino Substituent","authors":"Chaopeng Hu,&nbsp;Xin-Feng Wang,&nbsp;Chenyang Hu,&nbsp;Rui Wei,&nbsp;Hongyu Wang and Liu Leo Liu*,&nbsp;","doi":"10.1021/acs.accounts.4c0071410.1021/acs.accounts.4c00714","DOIUrl":"https://doi.org/10.1021/acs.accounts.4c00714https://doi.org/10.1021/acs.accounts.4c00714","url":null,"abstract":"&lt;p &gt;The advancement of synthetic methodologies is fundamentally driven by a deeper understanding of the structure–reactivity relationships of reactive key intermediates. Carbyne anions are compounds featuring a monovalent anionic carbon possessing four nonbonding valence electrons, which were historically confined to theoretical constructs or observed solely within the environment of gas-phase studies. These species possess potential for applications across diverse domains of synthetic chemistry and ancillary fields. This Account details our focused efforts to isolate singlet carbyne anions and explores our isolation of a range of related low-valent carbon species. Our achievements include the synthesis and characterization, under normal laboratory conditions, of gold-substituted free carbenes, copper carbyne anion complexes, ketenyl anions, keteniminyl anions, and a free stannyne. These have been accomplished using a bulky cyclic phosphino substituent, which effectively stabilizes these reactive species.&lt;/p&gt;&lt;p &gt;Our journey commenced with the isolation of gold-substituted phosphinocarbenes, characterized by a robust carbon–gold covalent single bond, and progressed to the isolation of copper carbyne anion complexes featuring a carbon–copper ionic bond. This was realized through the synergistic combination of a bulky cyclic phosphino group and a closed-shell electron-rich late transition metal. The robustness of the carbon–gold bond contrasts markedly with the susceptibility of the carbon–copper bond, which imparts to the copper complexes the behavior characteristic of a phosphinocarbyne anion within the coordination sphere of copper, thereby enabling unique carbyne anion transfer reactions. The tri-active ambiphilic nature of the anionic carbon in these copper carbyne complexes enables the formation of three chemical bonds at the carbon center through one-pot reactions. Subsequent investigations unveiled ligand exchange reactions at the carbyne anion site, leading to the generation of stable crystalline ketenyl and keteniminyl anions. These species emerge as potent synthons capable of producing a diverse array of derivatives. In addition, we isolated a free phosphinostannyne, a rare species featuring a carbon–tin multiple bond and two adjacent ambiphilic centers. Collectively, these compounds have demonstrated a remarkable propensity for engaging in a spectrum of unique reactions, underscoring their versatility and confirming their utility in synthesizing uncharted, unique main group species.&lt;/p&gt;&lt;p &gt;The methodologies and insights derived from our research contribute to the broader understanding of low-valent carbon species and may provide a platform for future innovations in synthetic chemistry, catalytic processes, and novel materials. As we continue to explore and develop this area of study, we hope that these low-valent carbon species might follow in the footsteps of stable singlet carbenes, potentially finding applications across various field","PeriodicalId":1,"journal":{"name":"Accounts of Chemical Research","volume":"58 3","pages":"452–462 452–462"},"PeriodicalIF":16.4,"publicationDate":"2025-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143090181","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Catalytic Asymmetric Dehydrogenative Si–H/X–H Coupling toward Si-Stereogenic Silanes","authors":"Yicong Ge, Jie Ke, Chuan He","doi":"10.1021/acs.accounts.4c00667","DOIUrl":"https://doi.org/10.1021/acs.accounts.4c00667","url":null,"abstract":"Chiral organosilicon compounds bearing a Si-stereogenic center have attracted increasing attention in various scientific communities and appear to be a topic of high current relevance in modern organic chemistry, given their versatile utility as chiral building blocks, chiral reagents, chiral auxiliaries, and chiral catalysts. Historically, access to these non-natural Si-stereogenic silanes mainly relies on resolution, whereas their asymmetric synthetic methods dramatically lagged compared to their carbon counterparts. Over the past two decades, transition-metal-catalyzed desymmetrization of prochiral organosilanes has emerged as an effective tool for the synthesis of enantioenriched Si-stereogenic silanes. Despite the progress, these catalytic reactions usually suffer from limited substrate scope, poor functional-group tolerance, and low enantioselectivity. The growing demand for Si-stereogenic silanes with structural diversity has continued to drive the development of new practical methods for the assembly of these chiral molecules.","PeriodicalId":1,"journal":{"name":"Accounts of Chemical Research","volume":"24 1","pages":""},"PeriodicalIF":18.3,"publicationDate":"2025-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143020679","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Molecular Photoelectrocatalysis for Radical Reactions.","authors":"Peng Xiong, Hai-Chao Xu","doi":"10.1021/acs.accounts.4c00739","DOIUrl":"10.1021/acs.accounts.4c00739","url":null,"abstract":"&lt;p&gt;&lt;p&gt;ConspectusMolecular photoelectrocatalysis, which combines the merits of photocatalysis and organic electrosynthesis, including their green attributes and capacity to offer novel reactivity and selectivity, represents an emerging field in organic chemistry that addresses the growing demands for environmental sustainability and synthetic efficiency. This synergistic approach permits access to a wider range of redox potentials, facilitates redox transformations under gentler electrode potentials, and decreases the use of external harsh redox reagents. Despite these potential advantages, this area did not receive significant attention until 2019, when we and others reported the first examples of modern molecular photoelectrocatalysis. These studies showcased the immense synthetic potential of this hybrid strategy, which not only inherits the strengths of its parent fields but also unlocks unprecedented reactivity and selectivity, enabling challenging transformations under mild conditions while minimizing the reliance on external stoichiometric harsh oxidants or reductants.In this Account, we present our efforts to develop photoelectrocatalytic strategies that leverage homogeneous catalysts to facilitate diverse radical reactions. By integrating electrocatalysis with key photoinduced processes such as single electron transfer (SET), ligand-to-metal charge transfer (LMCT), and hydrogen atom transfer (HAT), we have established photoelectrocatalytic methods to transform substrates such as organotrifluoroborates, arenes, carboxylic acids, and alkanes into reactive radical intermediates. These intermediates subsequently engage in heteroarene C-H functionalization reactions. Importantly, under these photoelectrochemical conditions with homogeneous catalysts, reactive radical intermediates generated in the bulk solution readily participate in efficient radical reactions without undergoing further overoxidation into carbocations, a common challenge in conventional electrochemical systems.By further integration of photoelectrocatalysis with asymmetric catalysis, we have developed photoelectrochemical asymmetric catalysis (PEAC), which proves to be efficient in the enantioselective synthesis of chiral nitriles. This approach involves two relay catalytic cycles: the initial photoelectrocatalytic process engenders benzylic radicals from precursors such as alkyl arenes, benzylic carboxylic acids, and aryl alkenes, and these C-radicals are then subjected to enantioselective cyanation in a subsequent copper-electrocatalytic cycle.Within the realm of oxidative photoelectrochemical transformations, the anode serves as a crucial component for recycling or generating the photocatalyst, while the cathode promotes proton reduction. This dual functionality enables oxidative transformations via H&lt;sub&gt;2&lt;/sub&gt; evolution, eliminating the reliance on external chemical oxidants. Furthermore, the adaptability of electrochemical systems, achieved through precise manipulation","PeriodicalId":1,"journal":{"name":"Accounts of Chemical Research","volume":" ","pages":"299-311"},"PeriodicalIF":16.4,"publicationDate":"2025-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142968669","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}