Photogenerated Ni(I)–Bipyridine Halide Complexes: Structure-Function Relationships for Competitive C(sp2)–Cl Oxidative Addition and Dimerization Reactivity Pathways DOI Creative Commons
David A. Cagan, Daniel Bím, Brendon J. McNicholas

и другие.

Опубликована: Март 21, 2023

We report the facile photochemical generation of a library Ni(I)–bpy halide complexes (Ni(I)(Rbpy)X (R = t-Bu, H, MeOOC; X Cl, Br, I) and benchmark their relative reactivity toward competitive oxidative addition off-cycle dimerization pathways. Structure-function relationships between ligand set are developed, with particular emphasis on rationalizing previously uncharacterized ligand-controlled high energy challenging C(sp2)–Cl bonds. Through dual Hammett computational analysis, mechanism formal is found to proceed through an SNAr-type pathway, consisting nucleophilic two-electron transfer Ni(I) 3d(z2) orbital Caryl–Cl σ* orbital, which contrasts observed for activation weaker C(sp2)–Br/I The bpy substituent provides strong influence reactivity, ultimately determining whether or even occur. Here we elucidate origin this as arising from perturbations effective nuclear charge (Zeff) center. Electron donation metal decreases Zeff, leads significant destabilization entire 3d manifold. Decreasing electron binding energies powerful donor activate These changes also prove have analogous effect dimerization, in Zeff leading more rapid dimerization. Ligand-induced modulation thus tunable target by can be altered, providing direct route stimulate stronger C–X bonds potentially unveiling new ways accomplish Ni-mediated photocatalytic cycles.

Язык: Английский

Mechanisms of Photoredox Catalysis Featuring Nickel–Bipyridine Complexes DOI Creative Commons
David A. Cagan, Daniel Bím, Nathanael P. Kazmierczak

и другие.

ACS Catalysis, Год журнала: 2024, Номер 14(11), С. 9055 - 9076

Опубликована: Май 29, 2024

Metallaphotoredox catalysis can unlock useful pathways for transforming organic reactants into desirable products, largely due to the conversion of photon energy chemical potential drive redox and bond transformation processes. Despite importance these processes cross-coupling reactions other transformations, their mechanistic details are only superficially understood. In this review, we have provided a detailed summary various photoredox mechanisms that been proposed date Ni-bipyridine (bpy) complexes, focusing separately on photosensitized direct excitation reaction By highlighting multiple key findings, depict how mechanisms, which ultimately define substrate scope, themselves defined by ground- excited-state geometric electronic structures Ni-based intermediates. We further identify knowledge gaps motivate future studies development synergistic research approaches spanning physical, organic, inorganic chemistry communities.

Язык: Английский

Процитировано

24
Cross-Electrophile Coupling: Principles, Methods, and Applications in Synthesis DOI Creative Commons
Lauren E. Ehehalt, Omar M. Beleh, Isabella C. Priest

и другие.

Chemical Reviews, Год журнала: 2024, Номер unknown

Опубликована: Ноя. 26, 2024

Cross-electrophile coupling (XEC), defined by us as the cross-coupling of two different σ-electrophiles that is driven catalyst reduction, has seen rapid progression in recent years. As such, this review aims to summarize field from its beginnings up until mid-2023 and provide comprehensive coverage on synthetic methods current state mechanistic understanding. Chapters are split type bond formed, which include C(sp

Язык: Английский

Процитировано

24
Mechanism of Ni-Catalyzed Photochemical Halogen Atom-Mediated C(sp3)–H Arylation DOI
Alexander Q. Cusumano, Braden C. Chaffin, Abigail G. Doyle

и другие.

Journal of the American Chemical Society, Год журнала: 2024, Номер 146(22), С. 15331 - 15344

Опубликована: Май 23, 2024

Within the context of Ni photoredox catalysis, halogen atom photoelimination from has emerged as a fruitful strategy for enabling hydrogen transfer (HAT)-mediated C(sp3)–H functionalization. Despite numerous synthetic transformations invoking this paradigm, unified mechanistic hypothesis that is consistent with experimental findings on catalytic systems and accounts radical formation facile C(sp2)–C(sp3) bond remains elusive. We employ kinetic analysis, organometallic synthesis, computational investigations to decipher mechanism prototypical Ni-catalyzed photochemical arylation reaction. Our revise previous proposals, first by examining relevance SET EnT processes intermediates relevant HAT-based investigation highlights ability blue light promote efficient Ni–C(sp2) homolysis cationic NiIII reductive elimination bipyridine NiII complexes. However interesting, rates selectivities these do not account productive pathway. Instead, our studies support involves evolution in situ generated dihalide intermediates, capture NiII(aryl)(halide) resting state, key C–C NiIII. Oxidative addition NiI, opposed Ni0, rapid NiIII/NiI comproportionation play roles process. The presented herein offer fundamental insight into reactivity broader catalysis.

Язык: Английский

Процитировано

19
Dual nickel- and photoredox-catalyzed carbon-carbon bond formations via reductive cross-coupling involving organohalides DOI

Hepan Wang,

Tao Xu

Chem Catalysis, Год журнала: 2024, Номер 4(3), С. 100952 - 100952

Опубликована: Март 1, 2024

Язык: Английский

Процитировано

10
Metallaphotoredox deuteroalkylation utilizing thianthrenium salts DOI Creative Commons

Mengjie Jiao,

Jie Zhang, Minyan Wang

и другие.

Nature Communications, Год журнала: 2024, Номер 15(1)

Опубликована: Июнь 13, 2024

Abstract Deuterium labeling compounds play a crucial role in organic and pharmaceutical chemistry. The synthesis of such typically involves deuterated building blocks, allowing for the incorporation deuterium atoms functional groups into target molecule single step. Unfortunately, limited availability synthetic approaches to synthons has impeded progress this field. Here, we present an approach utilizing alkyl-substituted thianthrenium salts that efficiently selectively introduce at α position alkyl chains through pH-dependent HIE process, using D 2 O as source. resulting α-deuterated salts, which bear two atoms, exhibit excellent selectivity electrophilic substitution reactions. Through situ formation isotopically labelled halides, these demonstrate compatibility series metallaphotoredox cross-electrophile coupling with (hetero)aryl, alkenyl, bromides, other salts. Our technique allows wide range substrates, high incorporation, precise control over site insertion within benzyl position, allylic or any chain between, well neighboring heteroatoms. This makes it invaluable synthesizing various deuterium-labeled compounds, especially those significance.

Язык: Английский

Процитировано

10
Photochemical Formation of Trifluoroacetic Acid: Mechanistic Insights into a Fluoxetine-Related Aryl-CF3 Compound DOI

Zhefei Guo,

Azka A. Attar,

Qiqige Qiqige

и другие.

Environmental Science & Technology, Год журнала: 2025, Номер unknown

Опубликована: Янв. 10, 2025

Trifluoroacetic acid (TFA) is a ubiquitous environmental contaminant; however, its sources are poorly constrained. One understudied source from the photochemical reactions of aromatic compounds containing -CF

Язык: Английский

Процитировано

2
Photogenerated Ni(I)–Bipyridine Halide Complexes: Structure–Function Relationships for Competitive C(sp2)–Cl Oxidative Addition and Dimerization Reactivity Pathways DOI
David A. Cagan, Daniel Bím, Brendon J. McNicholas

и другие.

Inorganic Chemistry, Год журнала: 2023, Номер 62(24), С. 9538 - 9551

Опубликована: Июнь 6, 2023

We report the facile photochemical generation of a library Ni(I)-bpy halide complexes (Ni(I)(Rbpy)X (R = t-Bu, H, MeOOC; X Cl, Br, I) and benchmark their relative reactivity toward competitive oxidative addition off-cycle dimerization pathways. Structure-function relationships between ligand set are developed, with particular emphasis on rationalizing previously uncharacterized ligand-controlled high energy challenging C(sp2)-Cl bonds. Through dual Hammett computational analysis, mechanism formal is found to proceed through an SNAr-type pathway, consisting nucleophilic two-electron transfer Ni(I) 3d(z2) orbital Caryl-Cl σ* orbital, which contrasts observed for activation weaker C(sp2)-Br/I The bpy substituent provides strong influence reactivity, ultimately determining whether or even occurs. Here, we elucidate origin this as arising from perturbations effective nuclear charge (Zeff) center. Electron donation metal decreases Zeff, leads significant destabilization entire 3d manifold. Decreasing electron binding energies powerful donor activate These changes also prove have analogous effect dimerization, in Zeff leading more rapid dimerization. Ligand-induced modulation thus tunable target by can be altered, providing direct route stimulate stronger C-X bonds potentially unveiling new ways accomplish Ni-mediated photocatalytic cycles.

Язык: Английский

Процитировано

21
A Visible Light Driven Nickel Carbonylation Catalyst: The Synthesis of Acid Chlorides from Alkyl Halides DOI

Kristian El Chami,

Yi Liu,

Mohammed A. Belahouane

и другие.

Angewandte Chemie International Edition, Год журнала: 2022, Номер 62(10)

Опубликована: Дек. 28, 2022

We describe here the development of a visible light driven nickel carbonylation catalyst. The combination large bite-angle Xantphos ligand with nickel(0) generates catalyst capable activating alkyl halides toward at ambient temperature in presence blue irradiation, and reductive elimination high energy acid chloride products. Unlike classical carbonylations, where coordination carbon monoxide inhibits reactivity earth abundant catalysts, CO-associated is found to be active reaction. Coupling build-up chlorides nucleophile addition can used access various amides, esters thioesters, including those sterically encumbered substrates or metal-reactive functionalities.

Язык: Английский

Процитировано

27
Harnessing Sulfur(VI) Fluoride Exchange Click Chemistry and Photocatalysis for Deaminative Benzylic Arylation DOI Creative Commons

Deepta Chattapadhyay,

Akın Aydoğan,

Katarzyna Doktor

и другие.

ACS Catalysis, Год журнала: 2023, Номер 13(11), С. 7263 - 7268

Опубликована: Май 15, 2023

While being among the most common functional handles present in organic molecules, amines are a widely underutilized linchpin for C–C bond formation. To facilitate C–N cleavage, large activating groups typically used but result generation of stoichiometric amounts waste. Herein, we report an atom-economical activation benzylic primary relying on sulfur(VI) fluoride exchange (SuFEx) click chemistry and aza-Ramberg–Bäcklund reaction. This two-step sequence allows high-yielding 1,2-dialkyldiazenes from via loss SO2. Excitation diazenes with blue light Ir photocatalyst afford radical pairs upon expulsion N2, which can be coaxed into formation C(sp3)–C(sp2) bonds diffusion capture by Ni catalyst. arylative strategy traceless approach was harnessed variety examples, its mechanism investigated.

Язык: Английский

Процитировано

17
Mechanistic and kinetic studies of visible light photoredox reactions DOI Open Access
Eric D. Talbott,

Nora L. Burnett,

John R. Swierk

и другие.

Chemical Physics Reviews, Год журнала: 2023, Номер 4(3)

Опубликована: Сен. 1, 2023

The use of visible light to enable small molecule synthesis has grown substantially over the last 15 years. While much focus been on development new methods, mechanistic and kinetic studies can provide valuable information about reaction steps highlight directions for optimization methods. This review focuses reports light, homogenous photoredox reactions that emphasize direct observation intermediates and/or contain a significant studies. How these types improve yields rates are highlighted. Finally, quantum 200 summarized first time. often-neglected parameter provides insights into efficiency as well clues underlying mechanism.

Язык: Английский

Процитировано

15