In Situ NMR and Kinetics Reveal Origins of Regioselectivity Differences for Epichlorohydrin Ring-Opening in Lewis and Brønsted Acid Zeolites DOI
David W. Flaherty, David M. Potts, Huston Locht

и другие.

Research Square (Research Square), Год журнала: 2025, Номер unknown

Опубликована: Апрель 30, 2025

Abstract Altering the quantities and organization of reactive species at active sites enables control turnover rates regioselectivities (rate ratios) for ring-opening epichlorohydrin (C3H5ClO) across two orders magnitude. Kinetic analysis suggests that parallel monomolecular (SN1) bimolecular (SN2) substitution mechanisms contribute to observed C3H5ClO reactions with methanol (CH3OH) over both Lewis (Sn-BEA) Brønsted acid (Al-BEA) zeolites in liquid solvents. In situ solid-state 13C-nuclear magnetic resonance spectroscopy (SS-NMR) measurements give direct evidence proposed ring-opened carbocations activated CH3OH intermediates these catalysts. Interpretation time-resolved operando 13C-SS-NMR spectra show C3H5ClO-derived CH3OH-derived surface convert products through SN1 SN2 reaction subsequently form distinct produce regioisomers. These NMR also reveal a concomitant shift from increases coverage achieved by local concentrations CH3OH, C3H5ClO, diluting CH3CN. This knowledge provides new insight into roles confinement on regioselectivity catalytic organic solid-liquid interfaces.

Язык: Английский

Modulating the Reaction Configuration by Breaking the Structural Symmetry of Active Sites for Efficient Photocatalytic Reduction of Low‐concentration CO2 DOI

Wenyuan Lyu,

Yang Liu,

Jingyi Zhou

и другие.

Angewandte Chemie International Edition, Год журнала: 2023, Номер 62(42)

Опубликована: Авг. 29, 2023

Photocatalytic conversion of low-concentration CO2 is considered as a promising way to simultaneously mitigate the environmental and energy issues. However, weak adsorption tough activation process seriously compromise CO production, due chemical inertness molecule formed fragile metal-C/O bond. Herein, we designed fabricated oxygen vacancy contained Co3 O4 hollow nanoparticles on ordered macroporous N-doped carbon framework (Vo-HCo3 /OMNC) towards photoreduction . In situ spectra ab initio molecular dynamics simulations reveal that constructed able break local structural symmetry Co-O-Co sites. The formation asymmetric active site switches configuration from single-site linear model multiple-sites bending one with highly stable configuration, enhancing binding polarization molecules. As result, Vo-HCo3 /OMNC shows unprecedent activity in photocatalytic (10 % /Ar) under laboratory light source or even natural sunlight, affording syngas yield 337.8 95.2 mmol g-1 h-1 , respectively, an apparent quantum up 4.2 %.

Язык: Английский

Процитировано

79
Open-Framework Vanadate as Efficient Ion Exchanger for Uranyl Removal DOI
Cheng Meng, Mingyang Du, Zhibin Zhang

и другие.

Environmental Science & Technology, Год журнала: 2024, Номер 58(21), С. 9456 - 9465

Опубликована: Май 15, 2024

The elimination of uranium from radioactive wastewater is crucial for the safe management and operation environmental remediation. Here, we present a layered vanadate with high acid/base stability, [Me2NH2]V3O7, as an excellent ion exchanger capturing uranyl highly complex aqueous solutions. material possesses indirect band gap, ferromagnetic characteristic flower-like morphology comprising parallel nanosheets. structure [Me2NH2]V3O7 predominantly upheld by H-bond interaction between anionic framework [V3O7]nn– intercalated [Me2NH2]+. [Me2NH2]+ within can be readily exchanged UO22+. exhibits exchange capacity (qm = 176.19 mg/g), fast kinetics (within 15 min), removal efficiencies (>99%), good selectivity against excess interfering ions. It also displays activity UO22+ over wide pH range (2.00–7.12). More importantly, has capability to effectively remove low-concentration uranium, yielding residual U concentration 13 ppb, which falls below EPA-defined acceptable limit 30 ppb in typical drinking water. efficiently separate Cs+ or Sr2+ achieving highest separation factors (SFU/Cs 589 SFU/Sr 227) date. BOMD DFT calculations reveal that driving force dominated [V3O7]nn–, whereas rate influenced mobility Our experimental findings indicate considered promising scavenger Additionally, simulation results provide valuable mechanistic interpretations serve reference designing novel exchangers.

Язык: Английский

Процитировано

25
Automated Quantification of Hydroxyl Reactivities: Prediction of Glycosylation Reactions DOI
Chun‐Wei Chang, Mei‐Huei Lin, Chieh‐Kai Chan

и другие.

Angewandte Chemie International Edition, Год журнала: 2021, Номер 60(22), С. 12413 - 12423

Опубликована: Фев. 26, 2021

Abstract The stereoselectivity and yield in glycosylation reactions are paramount but unpredictable. We have developed a database of acceptor nucleophilic constants (Aka) to quantify the nucleophilicity hydroxyl groups influenced by steric, electronic structural effects, providing connection between experiments computer algorithms. subtle reactivity differences among on various carbohydrate molecules can be defined Aka, which is easily accessible simple convenient automation system assure high reproducibility accuracy. A diverse range donors acceptors with well‐defined promoters were organized processed designed software program “GlycoComputer” for prediction without involving sophisticated computational processing. importance Aka was further verified random forest algorithm, applicability tested synthesis Lewis skeleton show that accurately estimated.

Язык: Английский

Процитировано

65
Mimicry of the proton wire mechanism of enzymes inside a supramolecular capsule enables β-selective O-glycosylations DOI
Tian‐Ren Li, Fabian Huck, GiovanniMaria Piccini

и другие.

Nature Chemistry, Год журнала: 2022, Номер 14(9), С. 985 - 994

Опубликована: Июль 7, 2022

Язык: Английский

Процитировано

46
Recent Advances in Stereoselective Chemical O-Glycosylation Reactions DOI Creative Commons
M. Mukherjee, Rina Ghosh, John A. Hanover

и другие.

Frontiers in Molecular Biosciences, Год журнала: 2022, Номер 9

Опубликована: Июнь 14, 2022

Carbohydrates involving glycoconjugates play a pivotal role in many life processes. Better understanding toward glycobiological events including the structure–function relationship of these biomolecules and for diagnostic therapeutic purposes tailor-made vaccine development synthesis structurally well-defined oligosaccharides (OS) become important. Efficient chemical glycosylation high yield stereoselectivity is however challenging depends on fine tuning protection profile to get matching glycosyl donor–acceptor reactivity along with proper use other important external factors like catalyst, solvent, temperature, activator, additive. So far, methods have been reported several reviews also. In present review, we will concentrate our discussion recent trend α- β-selective reactions during past decade.

Язык: Английский

Процитировано

33
Type-II van der Waals heterostructures of GeC, ZnO and Al2SO monolayers for promising optoelectronic and photocatalytic applications DOI
Sheraz Ahmad,

Khumal Sohail,

Letian Chen

и другие.

International Journal of Hydrogen Energy, Год журнала: 2023, Номер 48(65), С. 25354 - 25365

Опубликована: Апрель 5, 2023

Язык: Английский

Процитировано

22
Accelerating explicit solvent models of heterogeneous catalysts with machine learning interatomic potentials DOI Creative Commons
Benjamin W. J. Chen, Xinglong Zhang, Jia Zhang

и другие.

Chemical Science, Год журнала: 2023, Номер 14(31), С. 8338 - 8354

Опубликована: Янв. 1, 2023

Realistically modelling how solvents affect catalytic reactions is a longstanding challenge due to its prohibitive computational cost. Typically, an explicit atomistic treatment of the solvent molecules needed together with molecular dynamics (MD) simulations and enhanced sampling methods. Here, we demonstrate utility machine learning interatomic potentials (MLIPs), coupled active learning, enable fast accurate adsorption on heterogeneous catalysts. MLIPs trained on-the-fly were able accelerate ab initio MD by up 4 orders magnitude while reproducing high fidelity geometrical features water in bulk at metal-water interfaces. Using these ML-accelerated simulations, accurately predicted key quantities such as energies CO*, OH*, COH*, HCO*, OCCHO* Cu surfaces free energy barriers C-H scission ethylene glycol over Pd surfaces, validated calculations. We envision that will pave way towards detailed realistic studies solvated catalysts large time- length-scales.

Язык: Английский

Процитировано

20
Stereospecific alkenylidene homologation of organoboronates by SNV reaction DOI
Miao Chen,

Christian D. Knox,

Mithun C. Madhusudhanan

и другие.

Nature, Год журнала: 2024, Номер 631(8020), С. 328 - 334

Опубликована: Май 23, 2024

Язык: Английский

Процитировано

7
Glycosidase mechanisms: Sugar conformations and reactivity in endo- and exo-acting enzymes DOI Creative Commons
M.A.B. Morais, Alba Nin‐Hill, Carme Rovira

и другие.

Current Opinion in Chemical Biology, Год журнала: 2023, Номер 74, С. 102282 - 102282

Опубликована: Март 15, 2023

The enzymatic breakdown of carbohydrates plays a critical role in several biological events and enables the development sustainable processes to obtain bioproducts biofuels. In this scenario, design efficient inhibitors for glycosidases that can act as drug targets engineering carbohydrate-active enzymes with tailored catalytic properties is remarkable importance. To guide rational approaches, it necessary elucidate enzyme molecular mechanisms, particular understanding how microenvironment modulates conformational space explored by substrate. Computer simulations, especially those based on ab initio methods, have provided suitable atomic description carbohydrate conformations reactions glycosidase families. review, we will focus active-site topology (pocket or cleft) mode cleavage (endo exo) affect mechanisms adopted glycosidases, substrate along reaction coordinate.

Язык: Английский

Процитировано

13
Unraveling the promoter effect and the roles of counterion exchange in glycosylation reaction DOI Creative Commons
Chun‐Wei Chang, Mei‐Huei Lin, Tsun-Yi Chiang

и другие.

Science Advances, Год журнала: 2023, Номер 9(42)

Опубликована: Окт. 18, 2023

The stereoselectivity of glycosidic bond formation continues to pose a noteworthy hurdle in synthesizing carbohydrates, primarily due the simultaneous occurrence S

Язык: Английский

Процитировано

13