Organoalkoxysilanes (e.g. R–SiMe3-n(OR’)n, 1 ≤ n ≤ 3 with R=alkyl or aryl) have found various applications in synthetic chemistry and materials science because the silicon-bound alkoxy groups provide unique opportunities for further derivatization and transformations. Among the few catalytic strategies that allow the direct and intermolecular introduction of an alkoxysilyl unit onto an organic substrate, the alkoxysilylation of unactivated C–H bonds has barely been achieved despite its synthetic potential and the atom-economy it conveys. In particular, a catalytic and transition metal-free C–H silylation protocol towards this class of organosilicon compounds has yet to be reported. We herein describe the first general alkoxysilylation of (hetero)arene C(sp2)–H and benzylic C(sp3)–H bonds under ambient, transition metal-free conditions using newly-prepared tert-butyl-substituted alkoxysilyldiazenes (tBu–N=N–SiMe3-n(OR’)n, 1 ≤ n ≤ 3 with R’=Et, iPr or tBu) as silylating reagents and tBuOK as catalytic promoter.
{"title":"Catalytic Alkoxysilylation of C–H bonds with tert-Butyl-Substituted Alkoxysilyldiazenes","authors":"Lamine Saadi, Loïc Valade, Clément Chauvier","doi":"10.1039/d5sc02059j","DOIUrl":"https://doi.org/10.1039/d5sc02059j","url":null,"abstract":"Organoalkoxysilanes (e.g. R–SiMe<small><sub>3-n</sub></small>(OR’)<small><sub>n</sub></small>, 1 ≤ n ≤ 3 with R=alkyl or aryl) have found various applications in synthetic chemistry and materials science because the silicon-bound alkoxy groups provide unique opportunities for further derivatization and transformations. Among the few catalytic strategies that allow the direct and intermolecular introduction of an alkoxysilyl unit onto an organic substrate, the alkoxysilylation of unactivated C–H bonds has barely been achieved despite its synthetic potential and the atom-economy it conveys. In particular, a catalytic and transition metal-free C–H silylation protocol towards this class of organosilicon compounds has yet to be reported. We herein describe the first general alkoxysilylation of (hetero)arene C(sp<small><sup>2</sup></small>)–H and benzylic C(sp<small><sup>3</sup></small>)–H bonds under ambient, transition metal-free conditions using newly-prepared <em>tert</em>-butyl-substituted alkoxysilyldiazenes (<em>t</em>Bu–N=N–SiMe<small><sub>3-n</sub></small>(OR’)<small><sub>n</sub></small>, 1 ≤ n ≤ 3 with R’=Et, <em>i</em>Pr or <em>t</em>Bu) as silylating reagents and <em>t</em>BuOK as catalytic promoter.","PeriodicalId":9909,"journal":{"name":"Chemical Science","volume":"80 1","pages":""},"PeriodicalIF":8.4,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143866912","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}
Ammonia, as a carbon-free fuel and promising hydrogen carrier, has attracted significant attention in the context of a net-zero-emission scenario. Photocatalytic ammonia decomposition is a promising approach for hydrogen production, and much attention has been given to this area in recent years. This mini-review summarizes the latest research progress in photocatalytic ammonia decomposition for hydrogen production. We mainly focus on the photocatalytic decomposition of aqueous ammonia solution and gaseous ammonia. For aqueous ammonia solution, various semiconductor-based catalysts are introduced, and the role of water is discussed. The formation of the ∙NH2 radical as a key species in the decomposition was proposed by different groups. In the case of gaseous ammonia, different types of catalysts, including semiconductor-based and localized surface plasmon resonance (LSPR)-based ones, are described. The mechanisms of ammonia decomposition, such as the N−N recombination and the N2Hy dehydrogenation, are discussed. Methods for accurate temperature measurement in the photocatalytic process are summarized. We conclude that photocatalytic ammonia decomposition has unique advantages in high activity, mild conditions, green process, and fast response. Moreover, the excellent catalyst, efficient utilization of light, and suitable reactor design are critically important for the practical application of photocatalytic ammonia decomposition.
{"title":"Hydrogen Production via Photocatalytic Ammonia Decomposition","authors":"Qijun Pei, Yongyu Wang, Khai Chen Tan, Jianping Guo, Teng He, Ping Chen","doi":"10.1039/d5sc01834j","DOIUrl":"https://doi.org/10.1039/d5sc01834j","url":null,"abstract":"Ammonia, as a carbon-free fuel and promising hydrogen carrier, has attracted significant attention in the context of a net-zero-emission scenario. Photocatalytic ammonia decomposition is a promising approach for hydrogen production, and much attention has been given to this area in recent years. This mini-review summarizes the latest research progress in photocatalytic ammonia decomposition for hydrogen production. We mainly focus on the photocatalytic decomposition of aqueous ammonia solution and gaseous ammonia. For aqueous ammonia solution, various semiconductor-based catalysts are introduced, and the role of water is discussed. The formation of the ∙NH<small><sub>2</sub></small> radical as a key species in the decomposition was proposed by different groups. In the case of gaseous ammonia, different types of catalysts, including semiconductor-based and localized surface plasmon resonance (LSPR)-based ones, are described. The mechanisms of ammonia decomposition, such as the N−N recombination and the N<small><sub>2</sub></small>H<small><sub>y</sub></small> dehydrogenation, are discussed. Methods for accurate temperature measurement in the photocatalytic process are summarized. We conclude that photocatalytic ammonia decomposition has unique advantages in high activity, mild conditions, green process, and fast response. Moreover, the excellent catalyst, efficient utilization of light, and suitable reactor design are critically important for the practical application of photocatalytic ammonia decomposition.","PeriodicalId":9909,"journal":{"name":"Chemical Science","volume":"31 1","pages":""},"PeriodicalIF":8.4,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143866921","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}
Zhichao Zeng, Xiaomeng Shi, Hongtu Zhang, Yaping Du
All-solid-state lithium-ion batteries (ASLIBs) are important and promising electric energy storage devices with high stabilities and energy densities. As burgeoning key materials in ASLIBs, rare earth (RE) halide solid-state electrolytes (SEs) have better overall electrochemical performance than do oxide and sulfide SEs. Technologies for the efficient preparation, mass production and recycling of RE halide SEs (HSEs) are challenges that urgently need to be overcome. In this study, products and byproducts can be separated in an orderly manner via a vacuum evaporation-assisted reactor for the green synthesis of 15 kinds of RE HSEs and nine kinds of RE halide perovskites. The as-prepared HSEs have high ionic conductivity (mS cm-1 level) and wide electrochemical windows (1.4 – 4.2 V). The assembled Li–S ASLIBs were stable for up to 550 cycles. This work realized massive preparation and recycling of RE HSEs and crucial metal resources.
{"title":"Vacuum evaporation-assisted reaction: sustainable solution for application of rare earth-based halide solid-state electrolytes","authors":"Zhichao Zeng, Xiaomeng Shi, Hongtu Zhang, Yaping Du","doi":"10.1039/d5sc00003c","DOIUrl":"https://doi.org/10.1039/d5sc00003c","url":null,"abstract":"All-solid-state lithium-ion batteries (ASLIBs) are important and promising electric energy storage devices with high stabilities and energy densities. As burgeoning key materials in ASLIBs, rare earth (RE) halide solid-state electrolytes (SEs) have better overall electrochemical performance than do oxide and sulfide SEs. Technologies for the efficient preparation, mass production and recycling of RE halide SEs (HSEs) are challenges that urgently need to be overcome. In this study, products and byproducts can be separated in an orderly manner via a vacuum evaporation-assisted reactor for the green synthesis of 15 kinds of RE HSEs and nine kinds of RE halide perovskites. The as-prepared HSEs have high ionic conductivity (mS cm-1 level) and wide electrochemical windows (1.4 – 4.2 V). The assembled Li–S ASLIBs were stable for up to 550 cycles. This work realized massive preparation and recycling of RE HSEs and crucial metal resources.","PeriodicalId":9909,"journal":{"name":"Chemical Science","volume":"22 1","pages":""},"PeriodicalIF":8.4,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143866910","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}
Junmei Du, Yifan Yan, Jiao Chen, Xiumei Li, Chunsheng Guo, Yuanzheng Chen, Hongyan Wang
Selecting effective catalysts for the hydrogen evolution reaction (HER) among MXenes remains a complex challenge. While machine learning (ML) paired with density functional theory (DFT) can streamline this search, issues with training data quality, model accuracy, and descriptor selection limit its effectiveness. These hurdles often arise from incomplete understanding of the catalytic mechanisms. Here, we introduce a mechanism-guided descriptor (δ) for HER, designed to enhance catalyst screening among ordered transition metal carbonitride MXenes. This descriptor integrates structural and energetic characteristics, derived from an in-depth analysis of orbital interactions and the relationship between Gibbs free energy of hydrogen adsorption (ΔGH) and structural features. The proposed model (ΔGH = -0.49δ - 2.18) not only clarifies structure-activity links but also supports efficient, resource-effective identification of promising catalysts. Our approach offers a new framework for developing descriptors and advancing catalyst screening.
{"title":"Mechanism-Guided Descriptor for Hydrogen Evolution Reaction in 2D Ordered Double Transition-Metal Carbide MXenes","authors":"Junmei Du, Yifan Yan, Jiao Chen, Xiumei Li, Chunsheng Guo, Yuanzheng Chen, Hongyan Wang","doi":"10.1039/d4sc08725a","DOIUrl":"https://doi.org/10.1039/d4sc08725a","url":null,"abstract":"Selecting effective catalysts for the hydrogen evolution reaction (HER) among MXenes remains a complex challenge. While machine learning (ML) paired with density functional theory (DFT) can streamline this search, issues with training data quality, model accuracy, and descriptor selection limit its effectiveness. These hurdles often arise from incomplete understanding of the catalytic mechanisms. Here, we introduce a mechanism-guided descriptor (<em>δ</em>) for HER, designed to enhance catalyst screening among ordered transition metal carbonitride MXenes. This descriptor integrates structural and energetic characteristics, derived from an in-depth analysis of orbital interactions and the relationship between Gibbs free energy of hydrogen adsorption (Δ<em>G</em><small><sub>H</sub></small>) and structural features. The proposed model (Δ<em>G</em><small><sub>H</sub></small> = -0.49<em>δ</em> - 2.18) not only clarifies structure-activity links but also supports efficient, resource-effective identification of promising catalysts. Our approach offers a new framework for developing descriptors and advancing catalyst screening.","PeriodicalId":9909,"journal":{"name":"Chemical Science","volume":"91 1","pages":""},"PeriodicalIF":8.4,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143866923","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}
Juhee Ha, Jiwon Kang, Suk Hyun Lim, Dae Won Cho, Kwang-Im Oh, Youngsoo Kim
The selective oxidation and degradation of lignin are crucial for realizing its potential as a biofuel or petroleum substitute. Despite the importance of C–C bond cleavage for lignin valorization, this process is significantly challenging. Herein, we present plasmonic gold nanoparticles (Au NPs) as environmentally friendly and reusable photocatalysts for the chemoselective oxidation of the benzylic hydroxyl groups of lignin and subsequent lignin degradation. The oxidation process is driven by the generation of superoxide ions (O2•−), leading to proton release and initiating lignin photooxidation through a mechanism termed plasmon-driven hydrogen atom abstraction and degradation (p-HAADe). Our results demonstrate the significant suppression of lignin oxidation and degradation in acetonitrile-rich environments, while aqueous conditions notably enhance these processes. Furthermore, two distinct time-dependent regimes are identified, namely, the "oxidation dominant" regime, where lignin oxidation is predominant, and the "degradation dominant" regime, favoring Cα–Cβ bond cleavage. These findings provide crucial insights into optimizing lignin conversion in biofuel applications, highlighting the potential of Au NPs for use in sustainable chemical processes.
{"title":"Water-Accelerated Photooxidation and Degradation of Lignin Linkages Mediated by Plasmonic Catalysts","authors":"Juhee Ha, Jiwon Kang, Suk Hyun Lim, Dae Won Cho, Kwang-Im Oh, Youngsoo Kim","doi":"10.1039/d4sc08401b","DOIUrl":"https://doi.org/10.1039/d4sc08401b","url":null,"abstract":"The selective oxidation and degradation of lignin are crucial for realizing its potential as a biofuel or petroleum substitute. Despite the importance of C–C bond cleavage for lignin valorization, this process is significantly challenging. Herein, we present plasmonic gold nanoparticles (Au NPs) as environmentally friendly and reusable photocatalysts for the chemoselective oxidation of the benzylic hydroxyl groups of lignin and subsequent lignin degradation. The oxidation process is driven by the generation of superoxide ions (O<small><sub>2</sub></small><small><sup>•−</sup></small>), leading to proton release and initiating lignin photooxidation through a mechanism termed plasmon-driven hydrogen atom abstraction and degradation (<em>p</em>-HAADe). Our results demonstrate the significant suppression of lignin oxidation and degradation in acetonitrile-rich environments, while aqueous conditions notably enhance these processes. Furthermore, two distinct time-dependent regimes are identified, namely, the \"oxidation dominant\" regime, where lignin oxidation is predominant, and the \"degradation dominant\" regime, favoring C<small><sub>α</sub></small>–C<small><sub>β</sub></small> bond cleavage. These findings provide crucial insights into optimizing lignin conversion in biofuel applications, highlighting the potential of Au NPs for use in sustainable chemical processes.","PeriodicalId":9909,"journal":{"name":"Chemical Science","volume":"35 1","pages":""},"PeriodicalIF":8.4,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143866913","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}
Victor V Volkov, Graham Hickman, Carole Celia Perry
Confocal microscopy using silicaphilic molecular probes is a promising approach to identify the ionic character of silica interfaces. Using ab initio and density functional theory we model the structural and electronic properties of the (2-(4-pyridyl)-5((4-(2-dimethyl-aminoethyl-aminocarbamoyl)-methoxy)phenyl)-oxazole (PDMPO) chromophore at different protonation states, in vacuum, and when next to silica of different ionicity. For protonated chromophores next to anionic silica sites, theory suggests strong emission in the visible spectral range from higher excited states and the probability of weaker near infrared fluorescence from a lower energy manifold. Using theory insights, we conduct single- and two-color confocal microscopy in the visible and in the near infrared, respectively, to study open and closed stomata of Equisetum arvense, a heavily silicified primitive plant. Three-dimensional ionic tomography resolves sub-micron neighbouring regions of high and low ionic charges of exo/endo-skeletal silica components according to whether they are open or closed. Considering the variance of methane and carbon dioxide levels prior to, during and after the Silurian, we discuss the observed high ionic contrast of stomatal apertures upon opening as a signature of bioinorganic machinery able to moderate methane and carbon dioxide transport for optimal growth under a range of atmospheric conditions.
{"title":"Stomata biosilica and equisetum photosynthesis: ionic tomography insight using PDMPO silicaphilic probe","authors":"Victor V Volkov, Graham Hickman, Carole Celia Perry","doi":"10.1039/d4sc07973f","DOIUrl":"https://doi.org/10.1039/d4sc07973f","url":null,"abstract":"Confocal microscopy using silicaphilic molecular probes is a promising approach to identify the ionic character of silica interfaces. Using ab initio and density functional theory we model the structural and electronic properties of the (2-(4-pyridyl)-5((4-(2-dimethyl-aminoethyl-aminocarbamoyl)-methoxy)phenyl)-oxazole (PDMPO) chromophore at different protonation states, in vacuum, and when next to silica of different ionicity. For protonated chromophores next to anionic silica sites, theory suggests strong emission in the visible spectral range from higher excited states and the probability of weaker near infrared fluorescence from a lower energy manifold. Using theory insights, we conduct single- and two-color confocal microscopy in the visible and in the near infrared, respectively, to study open and closed stomata of Equisetum arvense, a heavily silicified primitive plant. Three-dimensional ionic tomography resolves sub-micron neighbouring regions of high and low ionic charges of exo/endo-skeletal silica components according to whether they are open or closed. Considering the variance of methane and carbon dioxide levels prior to, during and after the Silurian, we discuss the observed high ionic contrast of stomatal apertures upon opening as a signature of bioinorganic machinery able to moderate methane and carbon dioxide transport for optimal growth under a range of atmospheric conditions.","PeriodicalId":9909,"journal":{"name":"Chemical Science","volume":"8 1","pages":""},"PeriodicalIF":8.4,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143866918","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}
Etienne LaPierre, Roope A. Suvinen, Brian O. Patrick, Heikki M. Tuononen, Ian Manners
Facile one and two site reduction of hexachlorophosphazene using cyclic (alkyl)(amino)carbene substituents is shown to yield P-CAACMe-cyclo-(PNP(Cl)2NP(Cl)2N) 1 and P,P’-bis-CAACMe-cyclo-(PNPNP(Cl)2N) 2 (CAACMe=1-[2,6-bis(isopropyl)phenyl]-3,3,5,5-tetramethyl-2-pyrrolidinylidene). Compound 1 is characterized by its predominantly phosphorus centered HOMO, which results in typical phosphine-type nucleophilic and reductive reactivity; however, the resultant compounds of such reactions feature properties distinct from their classical phosphine analogues due to the CAAC centered LUMO, which acts as acceptor for both intramolecular interactions and photophysical excitations. In contrast, compound 2 exhibits π-conjugation spanning the endocyclic PNP moiety and the two CAACMe substituents, despite its non-planar structure. Treatment of 2 with [Cp*RuCl]4 results in the electrophilic displacement of one of the CAACMe¬ moieties by two Cp*RuCl fragments to yield the spirocyclic compound 3. Preliminary results show that the methodology used to reduce hexachlorophosphazene to 1 can be directly transposed to the regiospecific reduction of poly-chlorophosphazene, to yield poly-1, a fundamentally new class of inorganic polymer that possesses a phosphorus center with chemically active lone pairs in the main chain.
{"title":"Multi-Site Reduction of Hexachlorophosphazene to Low-Valent PN Heterocycles and Extension to the Reduction of poly-Chlorophosphazene","authors":"Etienne LaPierre, Roope A. Suvinen, Brian O. Patrick, Heikki M. Tuononen, Ian Manners","doi":"10.1039/d4sc07559e","DOIUrl":"https://doi.org/10.1039/d4sc07559e","url":null,"abstract":"Facile one and two site reduction of hexachlorophosphazene using cyclic (alkyl)(amino)carbene substituents is shown to yield P-CAACMe-cyclo-(PNP(Cl)2NP(Cl)2N) 1 and P,P’-bis-CAACMe-cyclo-(PNPNP(Cl)2N) 2 (CAACMe=1-[2,6-bis(isopropyl)phenyl]-3,3,5,5-tetramethyl-2-pyrrolidinylidene). Compound 1 is characterized by its predominantly phosphorus centered HOMO, which results in typical phosphine-type nucleophilic and reductive reactivity; however, the resultant compounds of such reactions feature properties distinct from their classical phosphine analogues due to the CAAC centered LUMO, which acts as acceptor for both intramolecular interactions and photophysical excitations. In contrast, compound 2 exhibits π-conjugation spanning the endocyclic PNP moiety and the two CAACMe substituents, despite its non-planar structure. Treatment of 2 with [Cp*RuCl]4 results in the electrophilic displacement of one of the CAACMe¬ moieties by two Cp*RuCl fragments to yield the spirocyclic compound 3. Preliminary results show that the methodology used to reduce hexachlorophosphazene to 1 can be directly transposed to the regiospecific reduction of poly-chlorophosphazene, to yield poly-1, a fundamentally new class of inorganic polymer that possesses a phosphorus center with chemically active lone pairs in the main chain.","PeriodicalId":9909,"journal":{"name":"Chemical Science","volume":"48 1","pages":""},"PeriodicalIF":8.4,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143866591","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}
Douglas E. Soutar, Ho Fung Mack, Melissa Ligorio, Akalabya Bissoyi, Alexander N. Baker, Matthew I. Gibson
The (bio)conjugation of polymers onto proteins enhances their pharmacokinetics and stability, most commonly using PEG (polyethylene glycol), but there is a need for alternatives. Poly(vinyl alcohol), PVA, is a water-soluble, biocompatible and environmentally degradable polymer, which also has the unique function of ice recrystallisation inhibition (IRI) which can aid the cryopreservation of biologics. Site-specific PVA bioconjugation (“PVAylation”) is underexplored due to the challenge of obtaining homogenous mono end-functional PVA. Here we show that following deprotection of the acetate (from the precursor poly(vinyl acetate)), the concurrent xanthate end-group reduction leads to a diversity of ambiguous end-groups which prevented precision conjugation. This is overcome by using a photo-catalyzed reduction of the omega-terminal xanthates to C–H, which is orthogonal to active-ester bioconjugation functionality at the alpha-chain terminus, demonstrated by MALDI-TOF mass spectrometry. This strategy enabled the preparation of well-defined mono-functional PVA displaying alkyne, biotin and O6-benzylguanine chain-end functionalities, which are each then used for covalent or non-covalent site-specific modification of three model proteins, introduce ice-binding function. These results will enable the synthesis of new bioconjugates containing PVA and be of particular benefit for low-temperature applications.
{"title":"PVAylation: precision end-functionalized poly(vinyl alcohol) for site-selective bioconjugation","authors":"Douglas E. Soutar, Ho Fung Mack, Melissa Ligorio, Akalabya Bissoyi, Alexander N. Baker, Matthew I. Gibson","doi":"10.1039/d5sc00772k","DOIUrl":"https://doi.org/10.1039/d5sc00772k","url":null,"abstract":"The (bio)conjugation of polymers onto proteins enhances their pharmacokinetics and stability, most commonly using PEG (polyethylene glycol), but there is a need for alternatives. Poly(vinyl alcohol), PVA, is a water-soluble, biocompatible and environmentally degradable polymer, which also has the unique function of ice recrystallisation inhibition (IRI) which can aid the cryopreservation of biologics. Site-specific PVA bioconjugation (“PVAylation”) is underexplored due to the challenge of obtaining homogenous mono end-functional PVA. Here we show that following deprotection of the acetate (from the precursor poly(vinyl acetate)), the concurrent xanthate end-group reduction leads to a diversity of ambiguous end-groups which prevented precision conjugation. This is overcome by using a photo-catalyzed reduction of the omega-terminal xanthates to C–H, which is orthogonal to active-ester bioconjugation functionality at the alpha-chain terminus, demonstrated by MALDI-TOF mass spectrometry. This strategy enabled the preparation of well-defined mono-functional PVA displaying alkyne, biotin and O<small><sup>6</sup></small>-benzylguanine chain-end functionalities, which are each then used for covalent or non-covalent site-specific modification of three model proteins, introduce ice-binding function. These results will enable the synthesis of new bioconjugates containing PVA and be of particular benefit for low-temperature applications.","PeriodicalId":9909,"journal":{"name":"Chemical Science","volume":"31 1","pages":""},"PeriodicalIF":8.4,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143866917","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}
Yan Hu, Hongshuai Zhang, Yiteng Ding, Weirui Chen, Changqie Pan, Longwei He, Dan Cheng, Lin Yuan
Diabetes and its complications have drawn growing research attention due to their detrimental effects on human health. Although optical probes have been used to help understand many aspects of diabetes, the lung diseases caused by diabetes remain unclear and have rarely been explored. Herein, a tandem-reaction (TR) strategy is proposed based on the adjacent diol esterification-crosslinking reaction and the nicotinamide reduction reaction of nicotinamide adenine dinucleotide (NADH) to design a lung-targeting near-infrared (NIR) small molecule probe (NBON) for accurate imaging of diabetic lung diseases. NBON was designed by coupling a phenylboronic acid analog that can form borate ester bonds by reversibly binding with NADH via an esterification-crosslinking reaction. Streptozotocin (STZ)-induced diabetic mice and metformin (MET)/epalrestat (EPS)-repaired model studies demonstrated that NBON allowed the sensitive imaging of NADH for lung disease diagnosis and therapeutic monitoring. The proposed antioxidant mechanism by which EPS alleviates diabetic lung disease was studied for the first time in living cells and in vivo. Furthermore, NBON was successfully applied in the detection of NADH in tumors and lung metastases. Overall, this work provides a general platform for an NIR NADH probe design, and advances the development of NADH probes for mechanistic studies in lung diseases.
{"title":"Tandem Reaction-Powered Near-Infrared Fluorescent Molecular Reporter for Real-Time Imaging of Lung Diseases","authors":"Yan Hu, Hongshuai Zhang, Yiteng Ding, Weirui Chen, Changqie Pan, Longwei He, Dan Cheng, Lin Yuan","doi":"10.1039/d5sc01488c","DOIUrl":"https://doi.org/10.1039/d5sc01488c","url":null,"abstract":"Diabetes and its complications have drawn growing research attention due to their detrimental effects on human health. Although optical probes have been used to help understand many aspects of diabetes, the lung diseases caused by diabetes remain unclear and have rarely been explored. Herein, a tandem-reaction (TR) strategy is proposed based on the adjacent diol esterification-crosslinking reaction and the nicotinamide reduction reaction of nicotinamide adenine dinucleotide (NADH) to design a lung-targeting near-infrared (NIR) small molecule probe (<strong>NBON</strong>) for accurate imaging of diabetic lung diseases. <strong>NBON</strong> was designed by coupling a phenylboronic acid analog that can form borate ester bonds by reversibly binding with NADH via an esterification-crosslinking reaction. Streptozotocin (STZ)-induced diabetic mice and metformin (MET)/epalrestat (EPS)-repaired model studies demonstrated that <strong>NBON</strong> allowed the sensitive imaging of NADH for lung disease diagnosis and therapeutic monitoring. The proposed antioxidant mechanism by which EPS alleviates diabetic lung disease was studied for the first time in living cells and <em>in vivo</em>. Furthermore, <strong>NBON</strong> was successfully applied in the detection of NADH in tumors and lung metastases. Overall, this work provides a general platform for an NIR NADH probe design, and advances the development of NADH probes for mechanistic studies in lung diseases.","PeriodicalId":9909,"journal":{"name":"Chemical Science","volume":"22 1","pages":""},"PeriodicalIF":8.4,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143866954","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}
Hou-Ji Cao, Jia-Xin Li, Jia-Hui Yan, Miao-Xin Liu, Qianyi Zhao, Jie Zhang, Ju Zhang, Hong Yan
Despite significant progress in the B–H functionalization of carboranes, the development of cost-effective catalytic systems devoid of noble metals, coupled with mechanistic validation of regioselectivity control, remains a formidable challenge. Herein, we disclose an Ag salt-free, redox-neutral, and inexpensive ruthenium(II)-catalyzed protocol that enables exclusive B(4)–H acylmethylation of o-carboranes through a novel post-coordination strategy. By exploiting weakly coordinating carboxylic acid as a traceless directing group, this method achieves excellent mono-site selectivity for B–C(sp³) bond formation using diverse sulfoxonium ylides, demonstrating both functional group tolerance and synthetic scalability. This work not only establishes a practical synthetic platform but also addresses critical mechanistic questions unresolved in prior analogous studies. Through deuterium labeling, in situ high-resolution mass spectrometry (HRMS) tracking, and single-crystal X-ray analysis of critical Ru intermediates, we unequivocally demonstrate that the mono-site selectivity originates from a unique post-coordination mode of Ru(II). The Ru catalyst simultaneously engages both the carboxylic acid and the enolizable acylmethyl moiety in the mono-acylated intermediate, thereby dictating the B(4)–H activation trajectory. Our findings establish a generalizable platform for regiocontrolled carborane functionalization while defining mechanistic paradigms in transition metal-mediated B–H activation chemistry.
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