Mechanism and Origin of Stereoselectivity of N-Heterocyclic Carbene (NHC)-Catalyzed Transformation Reaction of Benzaldehyde with o-QDM as Key Intermediate: A DFT Study

The Journal of Physical Chemistry A, Journal Year: 2024, Volume and Issue: 128(30), P. 6190 - 6198

Published: July 18, 2024

N-heterocyclic carbene (NHC)-bound

Language: Английский

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NHC-catalyzed enantioselective radical reactions of enal and pyridinium salt: mechanism and origin of regio- and stereoselectivities

Catalysis Science & Technology, Journal Year: 2023, Volume and Issue: 13(18), P. 5259 - 5266

Published: Jan. 1, 2023

The origin of regio- and stereoselectivities NHC-catalyzed enantioselective radical reactions an enal a pyridinium salt has been explored via theory for the first time.

Language: Английский

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Theoretical study of an N-heterocyclic carbene-catalyzed annulation reaction between an enal and a β-silyl enone: Mechanism and origin of stereoselectivity

Molecular Catalysis, Journal Year: 2023, Volume and Issue: 551, P. 113621 - 113621

Published: Oct. 27, 2023

Language: Английский

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Mechanistic studies on an isothiourea-catalyzed reaction of an aromatic ester with an imine

Molecular Catalysis, Journal Year: 2024, Volume and Issue: 567, P. 114445 - 114445

Published: Aug. 10, 2024

Language: Английский

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Theoretical investigation on the reaction mechanism and origin of stereoselectivity of a three-component coupling reaction under organocatalysis

Molecular Catalysis, Journal Year: 2025, Volume and Issue: 573, P. 114819 - 114819

Published: Jan. 6, 2025

Language: Английский

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Redox-Driven Magnetic Regulation in a Series of Couplers in Bridged Nitroxide Diradicals

Molecules, Journal Year: 2025, Volume and Issue: 30(3), P. 576 - 576

Published: Jan. 27, 2025

Redox-induced magnetic regulation in organic diradicals is distinctly attractive. In this work, taking nitroxide radicals as spin sources, we predict the properties of 9, 10-anthraquinone, 10-phenaquone, 10-diazanthracene and 10-diazepine-bridged molecular diradical structures which couplers are prone to dihydrogenation reduction at positions 9 10. As evidenced both B3LYP M06-2X levels theory, calculations confirm that transitions between ferromagnetism antiferromagnetism can take place for 10-anthraquinone 10-diazanthracene-bridged after dihydrogenation. The differences behaviors magnitudes before could be attributed their noticeably different spin-interacting pathways. 10-phenaquone diradicals, calculated results indicate signs exchange coupling constants J do not change, but remarkably change connecting bond character polarization crucial explaining these designed diradicals. detail, shorter bonds larger responsible strong coupling. addition, with an extensively π-conjugated structure effectively promote McConnell’s alternation rule key understanding observed work provides useful information rational design redox-regulated switches.

Language: Английский

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Mechanisms of C(sp³)-H Functionalization of Acetonitrile or Acetone with Alkynes: A DFT Investigation

Journal of Chemical Information and Modeling, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 6, 2025

The mechanisms for the C(sp3)-H activation and addition reactions between acetonitrile (or acetone) alkynes have been investigated with M06-2X-D3/ma-def2-TZVP method basis set. SMD (solvation model based on solute electron density) was applied to simulate solvent effect. In first second reactions, 2-phenylbut-3-yn-2-ol reacted acetone, respectively. First, activations of acetone could be achieved by PhCOO• t-BuO• radicals. Then, converted into final products P1 P2. Gibbs free energy surfaces these two suggest that blue lines would favorable paths lower barriers, terminal C atom C≡C bond is best reactive site. Moreover, analysis IRI (Interaction Region Indicator) reveals Z- E-configuration transformations. While in third fourth methyl(2-(phenylethynyl)phenyl)sulfane has interactions via some paths, profiles show C10 atom, rather than C11 priority, are favorable. Furthermore, action mode Na2HPO4 reduce barrier benefit reaction. vdW (van der Waals) play an important role choice fifth sixth) reaction, it happened 1-(2-(methylthio)phenyl)-3-phenylprop-2-yn-1-one acetontrile yield product P5 P6). computational results uncovered line path, site depends interactions, which origin selectivity. addition, investigation byproducts carried out, can explain reason only main produced. Both those agree experimental results. localized orbital locator (LOL) isosurfaces, Laplacian order (LBO), density critical point (ρBCP), spin isosurface graphs, graphs used analyze structure reveal reaction substances.

Language: Английский

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An analysis method including orbital overlap directions for predicting π electron properties and reactivity vectors

Nature Communications, Journal Year: 2025, Volume and Issue: 16(1)

Published: March 27, 2025

An analysis method with the name of Projection Orbital Coefficient Vector (POCV) has been proposed for predicting π electronic properties, aromaticity, and directional reactivity molecules including vectors. This approach significantly differs from previous computational methods by explicitly accounting orbital overlap directions. Using POCV method, accurate predictions electron properties indices have successfully demonstrated across various unsaturated molecules. To illustrate advantages over conventional methods, we present several case studies involving computation vectors diverse molecular systems, non-planar axially chiral molecules, nucleophilic electrophilic carbenes, linear conjugated Here show, enables prediction chemical reaction sites multiple directions, facilitates calculations properties. Predicting chemo- regioselectivity is crucial understanding designing reactions. Here, authors introduce projection coefficient vector to predict

Language: Английский

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Understanding the Key Roles of pH Buffer in Accelerating Lignin Degradation by Lignin Peroxidase

JACS Au, Journal Year: 2023, Volume and Issue: 3(2), P. 536 - 549

Published: Jan. 24, 2023

pH buffer plays versatile roles in both biology and chemistry. In this study, we unravel the critical role of accelerating degradation lignin substrate peroxidase (LiP) using QM/MM MD simulations nonadiabatic electron transfer (ET) proton-coupled (PCET) theories. As a key enzyme involved degradation, LiP accomplishes oxidation via two consecutive ET reactions subsequent C–C cleavage cation radical. The first one involves from Trp171 to active species Compound I, while second Differing common view that = 3 may enhance oxidizing power Cpd I protonation protein environment, our study shows intrinsic electric fields have minor effects on step. Instead, tartaric acid during Our can form strong H-bond with Glu250, which prevent proton Trp171-H•+ radical thereby stabilizing for oxidation. addition, proximal Asp264 second-sphere Glu250. Such synergistic facilitate thermodynamics step reduce overall barrier by ∼4.3 kcal/mol, corresponds rate acceleration 103-fold agrees experiments. These findings not only expand understanding pH-dependent redox chemistry but also provide valuable insights into tryptophan-mediated biological reactions.

Language: Английский

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Direct Proton-Coupled Electron Transfer between Interfacial Tyrosines in Ribonucleotide Reductase

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(8), P. 4784 - 4790

Published: Feb. 20, 2023

Ribonucleotide reductase (RNR) regulates DNA synthesis and repair in all organisms. The mechanism of Escherichia coli RNR requires radical transfer over a proton-coupled electron (PCET) pathway spanning ∼32 Å across two protein subunits. A key step along this is the interfacial PCET reaction between Y356 β subunit Y731 α subunit. Herein, tyrosines an aqueous interface explored with classical molecular dynamics quantum mechanical/molecular mechanical (QM/MM) free energy simulations. simulations suggest that water-mediated involving double proton through intervening water molecule thermodynamically kinetically unfavorable. direct becomes feasible when flipped toward predicted to be approximately isoergic relatively low barrier. This facilitated by hydrogen bonding both Y731. These provide fundamental insights into interfaces.

Language: Английский

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