The structural, photophysical, and photochemical properties of Ln(depma)(hmpa)2(NO3)3 (Ln = La, Ce, Nd, Sm, Eu, Tb, Ho, Er, and Yb) complexes 1-Ln were investigated with a multidisciplinary approach involving synthesis, photocycloaddition-based crystal engineering, spectroscopic analytical techniques and quantum chemical ab initio calculations. Depending on the Ln3+ ion the isostructural 1-Ln complexes exhibit quite different behavior upon excitation at 350–400 nm. Some 1-Ln complexes (Ln = La, Ce, Sm, Tb, Yb) emit a broad and strong band near 533 nm arising from paired anthracene moieties, whereas others (Ln = Nd, Eu, Ho, Er) do not. 1-Eu is not emissive at all, whereas 1-Nd, 1-Ho, and 1-Er exhibit a Ln3+ based luminescence. Upon irradiation with 365 nm ultraviolet (UV) light 1-Ln (Ln = La, Ce, Sm, Tb, Yb) dimerize by means of a photochemically induced [4 + 4] cycloaddition of the anthracene moieties, whereas 1-Ln (Ln = Nd, Eu, Ho, Er) remain monomers. We propose three models, based on the matching of the energy levels between the Ln3+ ion and the paired or dimerized anthracene units in the energy-resonance crossing region, as well as on internal conversion-driven and intersystem crossing-driven energy transfer, which explain the Ln3+ ion regulated photophysics and photochemistry of the 1-Ln complexes.
{"title":"Lanthanide-Dependent Photochemical and Photophysical Properties of Lanthanide–Anthracene Complexes: Experimental and Theoretical Approaches","authors":"Liangliang Wu, Xin-Da Huang, Weijia Li, Xiaoyan Cao, Wei-Hai Fang, Li-Min Zheng, Michael Dolg, Xuebo Chen","doi":"10.1021/jacsau.4c00540","DOIUrl":"https://doi.org/10.1021/jacsau.4c00540","url":null,"abstract":"The structural, photophysical, and photochemical properties of Ln(depma)(hmpa)<sub>2</sub>(NO<sub>3</sub>)<sub>3</sub> (Ln = La, Ce, Nd, Sm, Eu, Tb, Ho, Er, and Yb) complexes <b>1-Ln</b> were investigated with a multidisciplinary approach involving synthesis, photocycloaddition-based crystal engineering, spectroscopic analytical techniques and quantum chemical ab initio calculations. Depending on the Ln<sup>3+</sup> ion the isostructural <b>1-Ln</b> complexes exhibit quite different behavior upon excitation at 350–400 nm. Some <b>1-Ln</b> complexes (Ln = La, Ce, Sm, Tb, Yb) emit a broad and strong band near 533 nm arising from paired anthracene moieties, whereas others (Ln = Nd, Eu, Ho, Er) do not. <b>1-Eu</b> is not emissive at all, whereas <b>1-Nd</b>, <b>1-Ho</b>, and <b>1-Er</b> exhibit a Ln<sup>3+</sup> based luminescence. Upon irradiation with 365 nm ultraviolet (UV) light <b>1-Ln</b> (Ln = La, Ce, Sm, Tb, Yb) dimerize by means of a photochemically induced [4 + 4] cycloaddition of the anthracene moieties, whereas <b>1-Ln</b> (Ln = Nd, Eu, Ho, Er) remain monomers. We propose three models, based on the matching of the energy levels between the Ln<sup>3+</sup> ion and the paired or dimerized anthracene units in the energy-resonance crossing region, as well as on internal conversion-driven and intersystem crossing-driven energy transfer, which explain the Ln<sup>3+</sup> ion regulated photophysics and photochemistry of the <b>1-Ln</b> complexes.","PeriodicalId":14799,"journal":{"name":"JACS Au","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142214362","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Over the past several decades, there has been a surge of interest in harnessing the functionalization of C(sp3)–H bonds due to their promising applications across various domains. Yet, traditional methodologies have heavily leaned on stoichiometric quantities of costly and often environmentally harmful metal oxidants, posing sustainability challenges for C–H activation chemistry at large. In stark contrast, the emergence of electro-photocatalytic-driven C(sp3)–H bond activation presents a transformative alternative. This approach offers a viable route for forging carbon–carbon and carbon–heteroatom bonds. It stands out by directly engaging inert C(sp3)–H bonds, prevalent in organic compounds, without the necessity for prefunctionalization or harsh reaction conditions. Such methodology simplifies the synthesis of intricate organic compounds and facilitates the creation of novel chemical architectures with remarkable efficiency and precision. This review aims to shed light on the notable strides achieved in recent years in the realm of C(sp3)–H bond functionalization through organic electro-photochemistry.
{"title":"Electro-photochemical Functionalization of C(sp3)–H bonds: Synthesis toward Sustainability","authors":"Puja Singh, Burkhard König, Aslam C. Shaikh","doi":"10.1021/jacsau.4c00496","DOIUrl":"https://doi.org/10.1021/jacsau.4c00496","url":null,"abstract":"Over the past several decades, there has been a surge of interest in harnessing the functionalization of C(sp<sup>3</sup>)–H bonds due to their promising applications across various domains. Yet, traditional methodologies have heavily leaned on stoichiometric quantities of costly and often environmentally harmful metal oxidants, posing sustainability challenges for C–H activation chemistry at large. In stark contrast, the emergence of electro-photocatalytic-driven C(sp<sup>3</sup>)–H bond activation presents a transformative alternative. This approach offers a viable route for forging carbon–carbon and carbon–heteroatom bonds. It stands out by directly engaging inert C(sp<sup>3</sup>)–H bonds, prevalent in organic compounds, without the necessity for prefunctionalization or harsh reaction conditions. Such methodology simplifies the synthesis of intricate organic compounds and facilitates the creation of novel chemical architectures with remarkable efficiency and precision. This review aims to shed light on the notable strides achieved in recent years in the realm of C(sp<sup>3</sup>)–H bond functionalization through organic electro-photochemistry.","PeriodicalId":14799,"journal":{"name":"JACS Au","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142214361","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kelvin Wong, Runzhang Qi, Ye Yang, Zhi Luo, Stefan Guldin, Keith T. Butler
Small-angle X-ray scattering (SAXS) is a characterization technique that allows for the study of colloidal interactions by fitting the structure factor of the SAXS profile with a selected model and closure relation. However, the applicability of this approach is constrained by the limited number of existing models that can be fitted analytically, as well as the narrow operating range for which the models are valid. In this work, we demonstrate a proof of concept for using an artificial neural network (ANN) trained on SAXS curves obtained from Monte Carlo (MC) simulations to predict values of the effective macroion valency (Zeff) and the Debye length (κ–1) for a given SAXS profile. This ANN, which was trained on 200,000 simulated SAXS curves, was able to predict values of Zeff and κ–1 for a test set containing 25,000 simulated SAXS curves, where most predicted values had errors smaller than 20%. Subsequently, an ANN was used as a surrogate model in a Markov chain Monte Carlo sampling algorithm to obtain maximum a posteriori estimates of Zeff and κ–1, as well as the associated confidence intervals and correlations between Zeff and κ–1 for an experimentally obtained SAXS profile.
{"title":"Predicting Colloidal Interaction Parameters from Small-Angle X-ray Scattering Curves Using Artificial Neural Networks and Markov Chain Monte Carlo Sampling","authors":"Kelvin Wong, Runzhang Qi, Ye Yang, Zhi Luo, Stefan Guldin, Keith T. Butler","doi":"10.1021/jacsau.4c00368","DOIUrl":"https://doi.org/10.1021/jacsau.4c00368","url":null,"abstract":"Small-angle X-ray scattering (SAXS) is a characterization technique that allows for the study of colloidal interactions by fitting the structure factor of the SAXS profile with a selected model and closure relation. However, the applicability of this approach is constrained by the limited number of existing models that can be fitted analytically, as well as the narrow operating range for which the models are valid. In this work, we demonstrate a proof of concept for using an artificial neural network (ANN) trained on SAXS curves obtained from Monte Carlo (MC) simulations to predict values of the effective macroion valency (<i>Z</i><sub>eff</sub>) and the Debye length (κ<sup>–1</sup>) for a given SAXS profile. This ANN, which was trained on 200,000 simulated SAXS curves, was able to predict values of <i>Z</i><sub>eff</sub> and κ<sup>–1</sup> for a test set containing 25,000 simulated SAXS curves, where most predicted values had errors smaller than 20%. Subsequently, an ANN was used as a surrogate model in a Markov chain Monte Carlo sampling algorithm to obtain maximum a posteriori estimates of <i>Z</i><sub>eff</sub> and κ<sup>–1</sup>, as well as the associated confidence intervals and correlations between <i>Z</i><sub>eff</sub> and κ<sup>–1</sup> for an experimentally obtained SAXS profile.","PeriodicalId":14799,"journal":{"name":"JACS Au","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142226847","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jeremy Seidel, Patrick Diep, Ziye Dong, Joseph A. Cotruvo, Jr., Dan M. Park
The lanmodulin (LanM) protein has emerged as an effective means for rare earth element (REE) extraction and separation from complex feedstocks without the use of organic solvents. Whereas the binding of LanM to individual REEs has been well characterized, little is known about the thermodynamics of mixed metal binding complexes (i.e., heterogeneous ion complexes), which limits the ability to accurately predict separation performance for a given metal ion mixture. In this paper, we employ the law of mass action to establish a theory of perfect cooperativity for LanM-REE complexation at the two highest-affinity binding sites. The theory is then used to derive an equation that explains the nonintuitive REE binding behavior of LanM, where separation factors for binary pairs of ions vary widely based on the ratio of ions in the aqueous phase, a phenomenon that is distinct from single-ion-binding chemical chelators. We then experimentally validate this theory and perform the first quantitative characterization of LanM complexation with heterogeneous ion pairs using resin-immobilized LanM. Importantly, the resulting homogeneous and heterogeneous constants enable accurate prediction of the equilibrium state of LanM in the presence of mixtures of up to 10 REEs, confirming that the perfect cooperativity model is an accurate mechanistic description of REE complexation by LanM. We further employ the model to simulate separation performance over a range of homogeneous and heterogeneous binding constants, revealing important insights into how mixed binding differentially impacts REE separations based on the relative positioning of the ion pairs within the lanthanide series. In addition to informing REE separation process optimization, these results provide mathematical and experimental insight into competition dynamics in other ubiquitous and medically relevant, cooperative binding proteins, such as calmodulin.
{"title":"EF-Hand Battle Royale: Hetero-ion Complexation in Lanmodulin","authors":"Jeremy Seidel, Patrick Diep, Ziye Dong, Joseph A. Cotruvo, Jr., Dan M. Park","doi":"10.1021/jacsau.4c00628","DOIUrl":"https://doi.org/10.1021/jacsau.4c00628","url":null,"abstract":"The lanmodulin (LanM) protein has emerged as an effective means for rare earth element (REE) extraction and separation from complex feedstocks without the use of organic solvents. Whereas the binding of LanM to individual REEs has been well characterized, little is known about the thermodynamics of mixed metal binding complexes (i.e., heterogeneous ion complexes), which limits the ability to accurately predict separation performance for a given metal ion mixture. In this paper, we employ the law of mass action to establish a theory of perfect cooperativity for LanM-REE complexation at the two highest-affinity binding sites. The theory is then used to derive an equation that explains the nonintuitive REE binding behavior of LanM, where separation factors for binary pairs of ions vary widely based on the ratio of ions in the aqueous phase, a phenomenon that is distinct from single-ion-binding chemical chelators. We then experimentally validate this theory and perform the first quantitative characterization of LanM complexation with heterogeneous ion pairs using resin-immobilized LanM. Importantly, the resulting homogeneous and heterogeneous constants enable accurate prediction of the equilibrium state of LanM in the presence of mixtures of up to 10 REEs, confirming that the perfect cooperativity model is an accurate mechanistic description of REE complexation by LanM. We further employ the model to simulate separation performance over a range of homogeneous and heterogeneous binding constants, revealing important insights into how mixed binding differentially impacts REE separations based on the relative positioning of the ion pairs within the lanthanide series. In addition to informing REE separation process optimization, these results provide mathematical and experimental insight into competition dynamics in other ubiquitous and medically relevant, cooperative binding proteins, such as calmodulin.","PeriodicalId":14799,"journal":{"name":"JACS Au","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142214363","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Shuangshuang Cha, Yuxin Chen, Wei Du, Jianxiang Wu, Ran Wang, Tao Jiang, Xuejing Yang, Cheng Lian, Honglai Liu, Ming Gong
Degradable polymers are an effective solution for white plastic pollution. Polycaprolactone is a type of degradable plastic with desirable mechanical and biocompatible properties, and its monomer, ε-caprolactone (ε-CL), is often synthesized by Baeyer–Villiger (B–V) oxidation that demands peroxyacids with low safety and low atom-efficiency. Herein, we devised an electrochemical B–V oxidation system simply driven by H2O2 for the efficient production of ε-CL. This system involves two steps with the direct oxidation of H2O2 into •OOH radicals at the electrode surface and the indirect oxidation of cyclohexanone by the generated reactive oxygen species. The modulation of the interfacial ionic environment by amphipathic sulfonimide anions [e.g., bis(trifluoromethane)sulfonimide (TFSI–)] is highly critical. It enables the efficient B–V oxidation into ε-caprolactone with ∼100% selectivity and 68.4% yield at a potential of 1.28 V vs RHE, much lower than the potentials applied for electrochemical B–V oxidation systems using water as the O sources. On hydrophilic electrodes with the action of sulfonimide anions, hydrophilic H2O2 can be enriched within the double layer for direct oxidation while hydrophobic cyclohexanone can be simultaneously accumulated for rapidly reacting with the reactive oxygen species. This work not only enriches the electrified method of the ancient B–V oxidation by using only H2O2 toward monomer production of biodegradable plastics but also emphasizes the critical role of the interfacial ionic environment for electrosynthesis systems that may extend the scope of activity optimization.
{"title":"Interfacial Anion-Induced Dispersion of Active Species for Efficient Electrochemical Baeyer–Villiger Oxidation","authors":"Shuangshuang Cha, Yuxin Chen, Wei Du, Jianxiang Wu, Ran Wang, Tao Jiang, Xuejing Yang, Cheng Lian, Honglai Liu, Ming Gong","doi":"10.1021/jacsau.4c00585","DOIUrl":"https://doi.org/10.1021/jacsau.4c00585","url":null,"abstract":"Degradable polymers are an effective solution for white plastic pollution. Polycaprolactone is a type of degradable plastic with desirable mechanical and biocompatible properties, and its monomer, ε-caprolactone (ε-CL), is often synthesized by Baeyer–Villiger (B–V) oxidation that demands peroxyacids with low safety and low atom-efficiency. Herein, we devised an electrochemical B–V oxidation system simply driven by H<sub>2</sub>O<sub>2</sub> for the efficient production of ε-CL. This system involves two steps with the direct oxidation of H<sub>2</sub>O<sub>2</sub> into •OOH radicals at the electrode surface and the indirect oxidation of cyclohexanone by the generated reactive oxygen species. The modulation of the interfacial ionic environment by amphipathic sulfonimide anions [e.g., bis(trifluoromethane)sulfonimide (TFSI<sup>–</sup>)] is highly critical. It enables the efficient B–V oxidation into ε-caprolactone with ∼100% selectivity and 68.4% yield at a potential of 1.28 V vs RHE, much lower than the potentials applied for electrochemical B–V oxidation systems using water as the O sources. On hydrophilic electrodes with the action of sulfonimide anions, hydrophilic H<sub>2</sub>O<sub>2</sub> can be enriched within the double layer for direct oxidation while hydrophobic cyclohexanone can be simultaneously accumulated for rapidly reacting with the reactive oxygen species. This work not only enriches the electrified method of the ancient B–V oxidation by using only H<sub>2</sub>O<sub>2</sub> toward monomer production of biodegradable plastics but also emphasizes the critical role of the interfacial ionic environment for electrosynthesis systems that may extend the scope of activity optimization.","PeriodicalId":14799,"journal":{"name":"JACS Au","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142226848","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
It remains challenging to construct C═N bonds due to their facile hydrogenation. Herein, a single Co atom catalyst was discovered to be active for the selective construction of C═N bonds toward the synthesis of imines and N-heterocycles via reductive coupling of nitroarenes with various alcohols, including inert aliphatic ones. DFT calculations and experimental data revealed that the transfer hydrogenation proceeded via the intramolecular hydride transfer and the transfer of H from the α-Csp3-H bond to the nitro group was the rate-determining step. The single Co atoms served as a bridge to transfer the electrons from the catalyst to the adsorbed alcohol molecules, resulting in the activation of the α-Csp3-H bond. Unlike metal nanoparticles, the C═N bonds in imine products can be reserved due to the large steric hindrance from substituents on C and N. DFT calculation also confirmed that transfer hydrogenation of the C═N bonds in imines is thermodynamically unfavored with a much higher energy barrier compared with the transfer hydrogenation of the –NO2 group (1.47 vs 1.15 eV).
{"title":"Single-Atom Co–N4 Sites Mediate C═N Formation via Reductive Coupling of Nitroarenes with Alcohols","authors":"Xixi Liu, Liang Huang, Yurong He, Peng Zhou, Xuedan Song, Zehui Zhang","doi":"10.1021/jacsau.3c00825","DOIUrl":"https://doi.org/10.1021/jacsau.3c00825","url":null,"abstract":"It remains challenging to construct C═N bonds due to their facile hydrogenation. Herein, a single Co atom catalyst was discovered to be active for the selective construction of C═N bonds toward the synthesis of imines and <i>N-</i>heterocycles via reductive coupling of nitroarenes with various alcohols, including inert aliphatic ones. DFT calculations and experimental data revealed that the transfer hydrogenation proceeded via the intramolecular hydride transfer and the transfer of H from the α-C<sub>sp3</sub>-H bond to the nitro group was the rate-determining step. The single Co atoms served as a bridge to transfer the electrons from the catalyst to the adsorbed alcohol molecules, resulting in the activation of the α-C<sub>sp3</sub>-H bond. Unlike metal nanoparticles, the C═N bonds in imine products can be reserved due to the large steric hindrance from substituents on C and N. DFT calculation also confirmed that transfer hydrogenation of the C═N bonds in imines is thermodynamically unfavored with a much higher energy barrier compared with the transfer hydrogenation of the –NO<sub>2</sub> group (1.47 vs 1.15 eV).","PeriodicalId":14799,"journal":{"name":"JACS Au","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142214364","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yunqiang Bian, Fangyi Lv, Hai Pan, Weitong Ren, Weiwei Zhang, Yanwei Wang, Yi Cao, Wenfei Li, Wei Wang
Biomolecular condensation involving proteins and nucleic acids has been recognized to play crucial roles in genome organization and transcriptional regulation. However, the biophysical mechanisms underlying the droplet fusion dynamics and microstructure evolution during the early stage of liquid–liquid phase separation (LLPS) remain elusive. In this work, we study the phase separation of linker histone H1, which is among the most abundant chromatin proteins, in the presence of single-stranded DNA (ssDNA) capable of forming a G-quadruplex by using molecular simulations and experimental characterization. We found that droplet fusion is a rather stochastic and kinetically controlled process. Productive fusion events are triggered by the formation of ssDNA-mediated electrostatic bridges within the droplet contacting zone. The droplet microstructure is size-dependent and evolves driven by maximizing the number of electrostatic contacts. We also showed that the folding of ssDNA to the G-quadruplex promotes LLPS by increasing the multivalency and strength of protein–DNA interactions. These findings provide deep mechanistic insights into the growth dynamics of biomolecular droplets and highlight the key role of kinetic control during the early stage of ssDNA–protein condensation.
{"title":"Fusion Dynamics and Size-Dependence of Droplet Microstructure in ssDNA-Mediated Protein Phase Separation","authors":"Yunqiang Bian, Fangyi Lv, Hai Pan, Weitong Ren, Weiwei Zhang, Yanwei Wang, Yi Cao, Wenfei Li, Wei Wang","doi":"10.1021/jacsau.4c00690","DOIUrl":"https://doi.org/10.1021/jacsau.4c00690","url":null,"abstract":"Biomolecular condensation involving proteins and nucleic acids has been recognized to play crucial roles in genome organization and transcriptional regulation. However, the biophysical mechanisms underlying the droplet fusion dynamics and microstructure evolution during the early stage of liquid–liquid phase separation (LLPS) remain elusive. In this work, we study the phase separation of linker histone H1, which is among the most abundant chromatin proteins, in the presence of single-stranded DNA (ssDNA) capable of forming a G-quadruplex by using molecular simulations and experimental characterization. We found that droplet fusion is a rather stochastic and kinetically controlled process. Productive fusion events are triggered by the formation of ssDNA-mediated electrostatic bridges within the droplet contacting zone. The droplet microstructure is size-dependent and evolves driven by maximizing the number of electrostatic contacts. We also showed that the folding of ssDNA to the G-quadruplex promotes LLPS by increasing the multivalency and strength of protein–DNA interactions. These findings provide deep mechanistic insights into the growth dynamics of biomolecular droplets and highlight the key role of kinetic control during the early stage of ssDNA–protein condensation.","PeriodicalId":14799,"journal":{"name":"JACS Au","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142226850","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sara Gutkin, Omri Shelef, Zuzana Babjaková, Laura Anna Tomanová, Matej Babjak, Tal Kopp, Qingyang Zhou, Pengchen Ma, Micha Fridman, Urs Spitz, Kendall N. Houk, Doron Shabat
The chemiluminescent light-emission pathway of phenoxy-1,2-dioxetane luminophores is increasingly attracting the scientific community’s attention. Dioxetane probes that undergo rapid, flash-type chemiexcitation demonstrate higher detection sensitivity than those with a slower, glow-type chemiexcitation rate. This is primarily because the rapid flash-type produces a greater number of photons within a given time. Herein, we discovered that dioxetanes fused to 7-norbornyl and homocubanyl units present accelerated chemiexcitation rates supported by DFT computational simulations. Specifically, the 7-norbornyl and homocubanyl spirofused dioxetanes exhibited a chemiexcitation rate 14.2-fold and 230-fold faster than that of spiro-adamantyl dioxetane, respectively. A turn-ON dioxetane probe for the detection of the enzyme β-galactosidase, containing the 7-norbornyl spirofused unit, exhibited an S/N value of 415 at a low enzyme concentration. This probe demonstrated an increase in detection sensitivity toward β-galactosidase expressing bacteria E. coli with a limit-of-detection value that is 12.8-fold more sensitive than that obtained by the adamantyl counterpart. Interestingly, the computed activation free energies of the homocubanyl and 7-norbornyl units were correlated with their CCsC spiro-angle to corroborate the measured chemiexcitation rates.
{"title":"Boosting Chemiexcitation of Phenoxy-1,2-dioxetanes through 7-Norbornyl and Homocubanyl Spirofusion","authors":"Sara Gutkin, Omri Shelef, Zuzana Babjaková, Laura Anna Tomanová, Matej Babjak, Tal Kopp, Qingyang Zhou, Pengchen Ma, Micha Fridman, Urs Spitz, Kendall N. Houk, Doron Shabat","doi":"10.1021/jacsau.4c00493","DOIUrl":"https://doi.org/10.1021/jacsau.4c00493","url":null,"abstract":"The chemiluminescent light-emission pathway of phenoxy-1,2-dioxetane luminophores is increasingly attracting the scientific community’s attention. Dioxetane probes that undergo rapid, flash-type chemiexcitation demonstrate higher detection sensitivity than those with a slower, glow-type chemiexcitation rate. This is primarily because the rapid flash-type produces a greater number of photons within a given time. Herein, we discovered that dioxetanes fused to 7-norbornyl and homocubanyl units present accelerated chemiexcitation rates supported by DFT computational simulations. Specifically, the 7-norbornyl and homocubanyl spirofused dioxetanes exhibited a chemiexcitation rate 14.2-fold and 230-fold faster than that of spiro-adamantyl dioxetane, respectively. A turn-ON dioxetane probe for the detection of the enzyme β-galactosidase, containing the 7-norbornyl spirofused unit, exhibited an S/N value of 415 at a low enzyme concentration. This probe demonstrated an increase in detection sensitivity toward β-galactosidase expressing bacteria <i>E. coli</i> with a limit-of-detection value that is 12.8-fold more sensitive than that obtained by the adamantyl counterpart. Interestingly, the computed activation free energies of the homocubanyl and 7-norbornyl units were correlated with their CC<sub>s</sub>C spiro-angle to corroborate the measured chemiexcitation rates.","PeriodicalId":14799,"journal":{"name":"JACS Au","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142214387","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Till Schmidt-Räntsch, Hendrik Verplancke, Annemarie Kehl, Jian Sun, Marina Bennati, Max C. Holthausen, Sven Schneider
Photolysis of a platinum(II) azide complex in the presence of styrenes enables C═C double bond cleavage upon dissociative olefin imination to aldimido (PtII–N═CHPh) and formimido (PtII–N═CH2) complexes as the main products. Spectroscopic and quantum chemical examinations support a mechanism that commences with the decay of the metallonitrene photoproduct (PtII–N) via bimolecular coupling and nitrogen loss as N2. The resulting platinum(I) complex initiates a radical chain mechanism via a dinuclear radical-bridged species (PtII–CH2CHPhN•–PtII) as a direct precursor to C–C scission. The preference for the PtI mediated route over styrene aziridination is attributed to the distinct nucleophilicity of the triplet metallonitrene.
{"title":"C═C Dissociative Imination of Styrenes by a Photogenerated Metallonitrene","authors":"Till Schmidt-Räntsch, Hendrik Verplancke, Annemarie Kehl, Jian Sun, Marina Bennati, Max C. Holthausen, Sven Schneider","doi":"10.1021/jacsau.4c00571","DOIUrl":"https://doi.org/10.1021/jacsau.4c00571","url":null,"abstract":"Photolysis of a platinum(II) azide complex in the presence of styrenes enables C═C double bond cleavage upon dissociative olefin imination to aldimido (Pt<sup>II</sup>–N═CHPh) and formimido (Pt<sup>II</sup>–N═CH<sub>2</sub>) complexes as the main products. Spectroscopic and quantum chemical examinations support a mechanism that commences with the decay of the metallonitrene photoproduct (Pt<sup>II</sup>–N) via bimolecular coupling and nitrogen loss as N<sub>2</sub>. The resulting platinum(I) complex initiates a radical chain mechanism via a dinuclear radical-bridged species (Pt<sup>II</sup>–CH<sub>2</sub>CHPhN<sup>•</sup>–Pt<sup>II</sup>) as a direct precursor to C–C scission. The preference for the Pt<sup>I</sup> mediated route over styrene aziridination is attributed to the distinct nucleophilicity of the triplet metallonitrene.","PeriodicalId":14799,"journal":{"name":"JACS Au","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142214388","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jiaqi Wang, Zihan Liu, Shuang Zhao, Yu Zhang, Tengyan Xu, Stan Z. Li, Wenbin Li
The elucidation of aggregation rules for short peptides (e.g., tetrapeptides and pentapeptides) is crucial for the precise manipulation of aggregation. In this study, we derive comprehensive aggregation rules for tetrapeptides and pentapeptides across the entire sequence space based on the aggregation propensity values predicted by a transformer-based deep learning model. Our analysis focuses on three quantitative aspects. First, we investigate the type and positional effects of amino acids on aggregation, considering both the first- and second-order contributions. By identifying specific amino acids and amino acid pairs that promote or attenuate aggregation, we gain insights into the underlying aggregation mechanisms. Second, we explore the transferability of aggregation propensities between tetrapeptides and pentapeptides, aiming to explore the possibility of enhancing or mitigating aggregation by concatenating or removing specific amino acids at the termini. Finally, we evaluate the aggregation morphologies of over 20,000 tetrapeptides, regarding the morphology distribution and type and positional contributions of each amino acid. This work extends the existing aggregation rules from tripeptide sequences to millions of tetrapeptide and pentapeptide sequences, offering experimentalists an explicit roadmap for fine-tuning the aggregation behavior of short peptides for diverse applications, including hydrogels, emulsions, or pharmaceuticals.
{"title":"Aggregation Rules of Short Peptides","authors":"Jiaqi Wang, Zihan Liu, Shuang Zhao, Yu Zhang, Tengyan Xu, Stan Z. Li, Wenbin Li","doi":"10.1021/jacsau.4c00501","DOIUrl":"https://doi.org/10.1021/jacsau.4c00501","url":null,"abstract":"The elucidation of aggregation rules for short peptides (e.g., tetrapeptides and pentapeptides) is crucial for the precise manipulation of aggregation. In this study, we derive comprehensive aggregation rules for tetrapeptides and pentapeptides across the entire sequence space based on the aggregation propensity values predicted by a transformer-based deep learning model. Our analysis focuses on three quantitative aspects. First, we investigate the type and positional effects of amino acids on aggregation, considering both the first- and second-order contributions. By identifying specific amino acids and amino acid pairs that promote or attenuate aggregation, we gain insights into the underlying aggregation mechanisms. Second, we explore the transferability of aggregation propensities between tetrapeptides and pentapeptides, aiming to explore the possibility of enhancing or mitigating aggregation by concatenating or removing specific amino acids at the termini. Finally, we evaluate the aggregation morphologies of over 20,000 tetrapeptides, regarding the morphology distribution and type and positional contributions of each amino acid. This work extends the existing aggregation rules from tripeptide sequences to millions of tetrapeptide and pentapeptide sequences, offering experimentalists an explicit roadmap for fine-tuning the aggregation behavior of short peptides for diverse applications, including hydrogels, emulsions, or pharmaceuticals.","PeriodicalId":14799,"journal":{"name":"JACS Au","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142214389","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：