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  1. Article ; Online: Vibrational synchronization and its reaction pathway influence from an entropic intermediate in a dirhodium catalyzed allylic C-H activation/Cope rearrangement reaction.

    Schaefer, Anthony J / Ess, Daniel H

    Physical chemistry chemical physics : PCCP

    2024  Volume 26, Issue 15, Page(s) 11386–11394

    Abstract: ... cyclohexadiene and prior experiments by Davies showed competitive allylic C-H insertion and Cope products ... reaction pathway C-H insertion ...

    Abstract In reactions with consecutive transition states without an intermediate, and an energy surface bifurcation, atomic motion generally determines product selectivity. Understanding this dynamic-based selectivity can be straightforward if there is extremely fast descent from the first transition state to a product. However, in cases where a nonstatistical roaming/entropic intermediate occurs prior to product formation the motion that influences selectivity can be difficult to identify. Here we report quasiclassical direct dynamics trajectories for the dirhodium catalyzed reaction between styryldiazoacetate and 1,4-cyclohexadiene and prior experiments by Davies showed competitive allylic C-H insertion and Cope products. Trajectories confirmed the proposed energy surface bifurcation and revealed that dirhodium vinylcarbenoid when reacting with 1,4-cyclohexadiene can induce either a dynamically concerted pathway or a dynamically stepwise pathway with a nonstatistical entropic tight ion-pair intermediate. In the dynamically stepwise reaction pathway C-H insertion
    Language English
    Publishing date 2024-04-17
    Publishing country England
    Document type Journal Article
    ZDB-ID 1476244-4
    ISSN 1463-9084 ; 1463-9076
    ISSN (online) 1463-9084
    ISSN 1463-9076
    DOI 10.1039/d4cp00657g
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: Quasiclassical Direct Dynamics Trajectory Simulations of Organometallic Reactions.

    Ess, Daniel H

    Accounts of chemical research

    2021  Volume 54, Issue 23, Page(s) 4410–4422

    Abstract: ... organometallic reactions, especially bond activation reactions. For example, in the C-H activation reaction ...

    Abstract Homogeneous metal-mediated organometallic reactions represent a very large and diverse reaction class. Density functional theory calculations are now routinely carried out and reported for analyzing organometallic mechanisms and reaction pathways. While density functional theory calculations are extremely powerful to understand the energy and structure of organometallic reactions, there are several assumptions in their use and interpretation to define reaction mechanisms and to analyze reaction selectivity. Almost always it is assumed that potential energy structures calculated with density functional theory adequately describe mechanisms and selectivity within the framework of statistical theories, for example, transition state theory and RRKM theory. However, these static structures and corresponding energy landscapes do not provide atomic motion information during reactions that could reveal nonstatistical intermediates without complete intramolecular vibrational redistribution and nonintrinsic reaction coordinate (non-IRC) pathways. While nonstatistical intermediates and non-IRC reaction pathways are now relatively well established for organic reactions, these dynamic effects have heretofore been highly underexplored in organometallic reactions. Through a series of quasiclassical density functional theory direct dynamics trajectory studies, my group has recently demonstrated that dynamic effects occur in a variety of fundamental organometallic reactions, especially bond activation reactions. For example, in the C-H activation reaction between methane and [Cp*(PMe
    Language English
    Publishing date 2021-11-11
    Publishing country United States
    Document type Journal Article ; Research Support, U.S. Gov't, Non-P.H.S.
    ZDB-ID 1483291-4
    ISSN 1520-4898 ; 0001-4842
    ISSN (online) 1520-4898
    ISSN 0001-4842
    DOI 10.1021/acs.accounts.1c00575
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  3. Article ; Online: Direct Dynamics Trajectories Demonstrate Dynamic Matching and Nonstatistical Radical Pair Intermediates during Fe-Oxo-Mediated C-H Functionalization Reactions.

    Joy, Jyothish / Ess, Daniel H

    Journal of the American Chemical Society

    2023  Volume 145, Issue 13, Page(s) 7628–7637

    Abstract: The generally proposed mechanism for the reaction between non-heme Fe-oxo complexes and alkane C-H ... the inherent reaction pathway selectivity for non-heme Fe-oxo-mediated C-H functionalization reactions. ...

    Abstract The generally proposed mechanism for the reaction between non-heme Fe-oxo complexes and alkane C-H bonds involves a hydrogen atom transfer (HAT) reaction step with a radical pair intermediate that then has competitive radical rebound, dissociation, or desaturation pathways. Here, we report density functional theory-based quasiclassical direct dynamics trajectories that examine post-HAT reaction dynamics. Trajectories revealed that the radical pair intermediate can be a nonstatistical type intermediate without complete internal vibrational redistribution and post-HAT selectivity is generally determined by dynamic effects. Fast rebound trajectories occur through dynamic matching between the rotational motion of the newly formed Fe-OH bond and collision with the alkane radical, and all of this occurs through a nonsynchronous dynamically concerted process that circumvents the radical pair intermediate structure. For radical pair dissociation, trajectories proceeded to the radical pair intermediate for a very brief time, followed by complete dissociation. These trajectories provide a new viewpoint and model to understand the inherent reaction pathway selectivity for non-heme Fe-oxo-mediated C-H functionalization reactions.
    Language English
    Publishing date 2023-03-23
    Publishing country United States
    Document type Journal Article
    ZDB-ID 3155-0
    ISSN 1520-5126 ; 0002-7863
    ISSN (online) 1520-5126
    ISSN 0002-7863
    DOI 10.1021/jacs.3c01196
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article ; Online: Electro/Ni Dual-Catalyzed Decarboxylative C(sp

    Luo, Jian / Davenport, Michael T / Ess, Daniel H / Liu, T Leo

    Angewandte Chemie (International ed. in English)

    2024  , Page(s) e202403844

    Abstract: Paired redox-neutral electrolysis offers an attractive green platform for organic synthesis by avoiding sacrificial oxidants and reductants. Carboxylates are non-toxic, stable, inexpensive, and widely available, making them ideal nucleophiles for C-C ... ...

    Abstract Paired redox-neutral electrolysis offers an attractive green platform for organic synthesis by avoiding sacrificial oxidants and reductants. Carboxylates are non-toxic, stable, inexpensive, and widely available, making them ideal nucleophiles for C-C cross-coupling reactions. Here, we report the electro/Ni dual-catalyzed redox-neutral decarboxylative C(sp
    Language English
    Publishing date 2024-03-22
    Publishing country Germany
    Document type Journal Article
    ZDB-ID 2011836-3
    ISSN 1521-3773 ; 1433-7851
    ISSN (online) 1521-3773
    ISSN 1433-7851
    DOI 10.1002/anie.202403844
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  5. Article ; Online: Dynamical Origin of Rebound versus Dissociation Selectivity during Fe-Oxo-Mediated C-H Functionalization Reactions.

    Joy, Jyothish / Schaefer, Anthony J / Teynor, Matthew S / Ess, Daniel H

    Journal of the American Chemical Society

    2024  Volume 146, Issue 4, Page(s) 2452–2464

    Abstract: The mechanism of catalytic C-H functionalization of alkanes by Fe-oxo complexes is often suggested ...

    Abstract The mechanism of catalytic C-H functionalization of alkanes by Fe-oxo complexes is often suggested to involve a hydrogen atom transfer (HAT) step with the formation of a radical-pair intermediate followed by diverging pathways for radical rebound, dissociation, or desaturation. Recently, we showed that in some Fe-oxo reactions, the radical pair is a nonstatistical-type intermediate and dynamic effects control rebound versus dissociation pathway selectivity. However, the effect of the solvent cage on the stability and lifetime of the radical-pair intermediate has never been analyzed. Moreover, because of the extreme complexity of motion that occurs during dynamics trajectories, the underlying physical origin of pathway selectivity has not yet been determined. For the reaction between [(TQA_Cl)Fe
    Language English
    Publishing date 2024-01-19
    Publishing country United States
    Document type Journal Article
    ZDB-ID 3155-0
    ISSN 1520-5126 ; 0002-7863
    ISSN (online) 1520-5126
    ISSN 0002-7863
    DOI 10.1021/jacs.3c09891
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  6. Article: Dynamic-dependent selectivity in a bisphosphine iron spin crossover C-H insertion/π-coordination reaction.

    Davenport, Michael T / Kirkland, Justin K / Ess, Daniel H

    Chemical science

    2023  Volume 14, Issue 35, Page(s) 9400–9408

    Abstract: ... trajectories demonstrate nonstatistical intermediates and that C-H insertion ...

    Abstract Reaction pathway selectivity is generally controlled by competitive transition states. Organometallic reactions are complicated by the possibility that electronic spin state changes rather than transition states can control the relative rates of pathways, which can be modeled as minimum energy crossing points (MECPs). Here we show that in the reaction between bisphosphine Fe and ethylene involving spin state crossover (singlet and triplet spin states) that neither transition states nor MECPs model pathway selectivity consistent with experiment. Instead, single spin state and mixed spin state quasiclassical trajectories demonstrate nonstatistical intermediates and that C-H insertion
    Language English
    Publishing date 2023-08-21
    Publishing country England
    Document type Journal Article
    ZDB-ID 2559110-1
    ISSN 2041-6539 ; 2041-6520
    ISSN (online) 2041-6539
    ISSN 2041-6520
    DOI 10.1039/d3sc02078a
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  7. Article ; Online: Chemical design by artificial intelligence.

    Ess, Daniel H / Jelfs, Kim E / Kulik, Heather J

    The Journal of chemical physics

    2022  Volume 157, Issue 12, Page(s) 120401

    MeSH term(s) Artificial Intelligence
    Language English
    Publishing date 2022-09-28
    Publishing country United States
    Document type Editorial
    ZDB-ID 3113-6
    ISSN 1089-7690 ; 0021-9606
    ISSN (online) 1089-7690
    ISSN 0021-9606
    DOI 10.1063/5.0123281
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  8. Article ; Online: Coordination-induced O-H/N-H bond weakening by a redox non-innocent, aluminum-containing radical.

    Sinhababu, Soumen / Singh, Roushan Prakash / Radzhabov, Maxim R / Kumawat, Jugal / Ess, Daniel H / Mankad, Neal P

    Nature communications

    2024  Volume 15, Issue 1, Page(s) 1315

    Abstract: ... ammonia as energy reservoirs. Because the O-H and N-H bonds are quite strong (>100 kcal/mol), it is ... of coordination-induced bond weakening of O-H and N-H bonds. The multisite proton-coupled electron transfer ...

    Abstract Several renewable energy schemes aim to use the chemical bonds in abundant molecules like water and ammonia as energy reservoirs. Because the O-H and N-H bonds are quite strong (>100 kcal/mol), it is necessary to identify substances that dramatically weaken these bonds to facilitate proton-coupled electron transfer processes required for energy conversion. Usually this is accomplished through coordination-induced bond weakening by redox-active metals. However, coordination-induced bond weakening is difficult with earth's most abundant metal, aluminum, because of its redox inertness under mild conditions. Here, we report a system that uses aluminum with a redox non-innocent ligand to achieve significant levels of coordination-induced bond weakening of O-H and N-H bonds. The multisite proton-coupled electron transfer manifold described here points to redox non-innocent ligands as a design element to open coordination-induced bond weakening chemistry to more elements in the periodic table.
    Language English
    Publishing date 2024-02-13
    Publishing country England
    Document type Journal Article
    ZDB-ID 2553671-0
    ISSN 2041-1723 ; 2041-1723
    ISSN (online) 2041-1723
    ISSN 2041-1723
    DOI 10.1038/s41467-024-45721-1
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  9. Article ; Online: Directing-Group-Free Arene C(sp

    Behnke, Nicole Erin / Kwon, Young-Do / Davenport, Michael T / Ess, Daniel H / Kürti, László

    The Journal of organic chemistry

    2023  Volume 88, Issue 16, Page(s) 11847–11854

    Abstract: A hydroxylamine-derived electrophilic aminating reagent produces a transient and bulky aminium radical intermediate ... ...

    Abstract A hydroxylamine-derived electrophilic aminating reagent produces a transient and bulky aminium radical intermediate upon
    Language English
    Publishing date 2023-07-28
    Publishing country United States
    Document type Journal Article
    ZDB-ID 123490-0
    ISSN 1520-6904 ; 0022-3263
    ISSN (online) 1520-6904
    ISSN 0022-3263
    DOI 10.1021/acs.joc.3c01127
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    In stock of ZB MED Cologne/Königswinter

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  10. Article ; Online: Understanding Formation and Roles of Ni

    Luo, Jian / Davenport, Michael T / Callister, Chad / Minteer, Shelley D / Ess, Daniel H / Liu, T Leo

    Journal of the American Chemical Society

    2023  Volume 145, Issue 29, Page(s) 16130–16141

    Abstract: Ni-catalyzed electrochemical aryl amination (e-amination) is an attractive, emerging approach to building C-N bonds. Here, we report in-depth experimental and computational studies that examined the mechanism of Ni-catalyzed e-amination reactions. Key ... ...

    Abstract Ni-catalyzed electrochemical aryl amination (e-amination) is an attractive, emerging approach to building C-N bonds. Here, we report in-depth experimental and computational studies that examined the mechanism of Ni-catalyzed e-amination reactions. Key Ni
    Language English
    Publishing date 2023-07-11
    Publishing country United States
    Document type Journal Article
    ZDB-ID 3155-0
    ISSN 1520-5126 ; 0002-7863
    ISSN (online) 1520-5126
    ISSN 0002-7863
    DOI 10.1021/jacs.3c04610
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