Machine learning dihydrogen activation in the chemical space surrounding Vaska's complex

Chemical Science, Год журнала: 2020, Номер 11(18), С. 4584 - 4601

Опубликована: Янв. 1, 2020

Homogeneous catalysis using transition metal complexes is ubiquitously used for organic synthesis, as well technologically relevant in applications such water splitting and CO2 reduction. The key steps underlying homogeneous require a specific combination of electronic steric effects from the ligands bound to center. Finding optimal challenging task due exceedingly large number possibilities non-trivial ligand-ligand interactions. classic example Vaska's complex, trans-[Ir(PPh3)2(CO)(Cl)], illustrates this scenario. species activate iridium oxidative addition hydrogen, yielding dihydride cis-[Ir(H)2(PPh3)2(CO)(Cl)] complex. Despite simplicity system, thousands derivatives can be formulated activation H2, with limited belonging same general categories found original In work, we show how DFT machine learning (ML) methods combined enable prediction reactivity within chemical spaces containing complexes. space 2574 derived data calculations are train test ML models that predict H2-activation barrier. contrast experiments requiring several days completed, were trained on laptop time-scale minutes. As first approach, Bayesian-optimized artificial neural networks (ANN) features autocorrelation deltametric functions. resulting ANNs achieved high accuracies, mean absolute errors (MAE) between 1 2 kcal mol-1, depending size training set. By Gaussian process (GP) model set selected features, including fingerprints, accuracy was further enhanced. Remarkably, GP minimized MAE below by only 20% or less available training. gradient boosting (GB) method also assess relevance which both feature selection interpretation purposes. Features accounting composition, atom electronegativity most determinant predictions. Further, ligand fragments strongest influence barrier identified.

Язык: Английский

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Chiral Carboxylic Acid Assisted Enantioselective C–H Activation with Achiral Cp^xM^III (M = Co, Rh, Ir) Catalysts

ACS Catalysis, Год журнала: 2021, Номер 11(11), С. 6455 - 6466

Опубликована: Май 17, 2021

Enantioselective C–H functionalization is a powerful tool for synthesizing chiral molecules. In the past few years, combination of high-valent group 9 metals with achiral Cpx ligands and carboxylic acids (CCA) has emerged as promising catalytic system to enable selective cleavage enantiotopic bonds. This Perspective summarizes background, catalyst design, applied reactions in detail, followed by discussion future directions.

Язык: Английский

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The continuum of carbon–hydrogen (C–H) activation mechanisms and terminology

Communications Chemistry, Год журнала: 2021, Номер 4(1)

Опубликована: Дек. 10, 2021

Abstract As a rapidly growing field across all areas of chemistry, C-H activation/functionalisation is being used to access wide range important molecular targets. Of particular interest the development sustainable methodology for alkane functionalisation as means reducing hydrocarbon emissions. This Perspective aims give an outline community with respect commonly terminology in activation, well mechanisms that are currently understood operate (cyclo)alkane activation/functionalisation.

Язык: Английский

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Cobalt(III)/Chiral Carboxylic Acid‐Catalyzed Enantioselective Synthesis of Benzothiadiazine‐1‐oxides via C−H Activation

Angewandte Chemie International Edition, Год журнала: 2022, Номер 61(28)

Опубликована: Май 2, 2022

Abstract Among sulfoximine derivatives containing a chiral sulfur center, benzothiadiazine‐1‐oxides are important for applications in medicinal chemistry. Here, we report that the combination of an achiral cobalt(III) catalyst and pseudo‐ C 2 ‐symmetric H 8 ‐binaphthyl carboxylic acid enables asymmetric synthesis from sulfoximines dioxazolones via enantioselective C−H bond cleavage. With optimized protocol, with several functional groups can be accessed high enantioselectivity.

Язык: Английский

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C4–H indole functionalisation: precedent and prospects

Chemical Science, Год журнала: 2018, Номер 9(18), С. 4203 - 4216

Опубликована: Янв. 1, 2018

This Perspective article traces the evolution of modern approaches to functionalise indole C4–H bond.

Язык: Английский

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