Nickel(II) Analogues of Phosphorescent Platinum(II) Complexes with Picosecond Excited‐State Decay DOI Creative Commons
Tomohiro Ogawa, Oliver S. Wenger

Angewandte Chemie, Journal Year: 2023, Volume and Issue: 135(46)

Published: Sept. 21, 2023

Abstract Square‐planar Ni II complexes are interesting as cheaper and more sustainable alternatives to Pt luminophores widely used in lighting photocatalysis. We investigated the excited‐state behavior of two complexes, which isostructural with luminescent complexes. The initially excited singlet metal‐to‐ligand charge transfer ( 1 MLCT) states decay metal‐centered 3 MC) within less than picosecond, followed by non‐radiative relaxation MC electronic ground state 9–21 ps. This contrasts population an emissive triplet ligand‐centered LC) upon excitation analogues. Structural distortions responsible for this discrepant lead dark far lower energy LC compounds. Our findings suggest that if these structural could be restricted rigid coordination environments stronger ligand fields, four‐coordinate decelerated such or MLCT become accessible. These insights relevant make fit photophysical photochemical applications relied on until now.

Language: Английский

Mechanistic Investigation of Ni-Catalyzed Reductive Cross-Coupling of Alkenyl and Benzyl Electrophiles DOI Creative Commons
Raymond F. Turro, Julie L. Hofstra Wahlman, Zhengjia Tong

et al.

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(27), P. 14705 - 14715

Published: June 26, 2023

Mechanistic investigations of the Ni-catalyzed asymmetric reductive alkenylation

Language: Английский

Citations

49
Enantioselective C(sp2)–C(sp3) Bond Construction by Ni Catalysis DOI Creative Commons
Liming Chen, Sarah E. Reisman

Accounts of Chemical Research, Journal Year: 2024, Volume and Issue: 57(5), P. 751 - 762

Published: Feb. 12, 2024

ConspectusAfter decades of palladium dominating the realm transition-metal-catalyzed cross-coupling, recent years have witnessed exciting advances in development new nickel-catalyzed cross-coupling reactions to form C(sp3) centers. Nickel possesses distinct properties compared with palladium, such as facile single-electron transfer electrophiles and rapid C–C reductive elimination from NiIII. These properties, among others, make nickel particularly well-suited for (RCC) which two are coupled an exogenous reductant is used turn over metal catalyst. Ni-catalyzed RCCs use readily available stable starting materials exhibit good functional group tolerance, makes them appealing applications synthesis complex molecules. Building upon foundational work by groups Kumada, Durandetti, Weix, well advancements enantioselective redox-neutral cross-couplings led Fu co-workers, we initiated a program explore feasibility developing highly RCCs. Our research has also been driven keen interest unraveling factors contributing enantioinduction electrophile activation seek avenues advancing our understanding further these reactions.In first part this Account, organize reported methods on basis identity electrophiles, including benzylic chlorides, N-hydroxyphthalimide (NHP) esters, α-chloro esters nitriles. We highlight how selection specific chiral ligands plays pivotal role achieving high cross-selectivity enantioselectivity. In addition, show that reduction can be accomplished not only heterogeneous reductants, Mn0, but soluble organic tetrakis(dimethylamino)ethylene (TDAE), electrochemically. The homogeneous TDAE, suited studying mechanism transformation. Although Account primarily focuses RCCs, using trifluoroborate (BF3K) salts radical precursors dual-Ni/photoredox systems.At end summarize relevant mechanistic studies closely related asymmetric alkenylation developed laboratory provide context between others. discuss ligand influence rates mechanisms mode generation optimize yield RCC. endeavors offer insights intricate at play goal rate improve substrate scope anticipate share guidance field.

Language: Английский

Citations

44
Mechanisms of Photoredox Catalysis Featuring Nickel–Bipyridine Complexes DOI Creative Commons
David A. Cagan, Daniel Bím, Nathanael P. Kazmierczak

et al.

ACS Catalysis, Journal Year: 2024, Volume and Issue: 14(11), P. 9055 - 9076

Published: May 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.

Language: Английский

Citations

23
Nickel(II) Analogues of Phosphorescent Platinum(II) Complexes with Picosecond Excited‐State Decay DOI Creative Commons
Tomohiro Ogawa, Oliver S. Wenger

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(46)

Published: Sept. 21, 2023

Square-planar NiII complexes are interesting as cheaper and more sustainable alternatives to PtII luminophores widely used in lighting photocatalysis. We investigated the excited-state behavior of two complexes, which isostructural with luminescent complexes. The initially excited singlet metal-to-ligand charge transfer (1 MLCT) states decay metal-centered (3 MC) within less than 1 picosecond, followed by non-radiative relaxation 3 MC electronic ground state 9-21 ps. This contrasts population an emissive triplet ligand-centered LC) upon excitation analogues. Structural distortions responsible for this discrepant lead dark far lower energy LC compounds. Our findings suggest that if these structural could be restricted rigid coordination environments stronger ligand fields, four-coordinate decelerated such or MLCT become accessible. These insights relevant make fit photophysical photochemical applications relied on until now.

Language: Английский

Citations

25
Nickel-Catalyzed Enantioselective Reductive Arylation of Common Ketones DOI
Shuai Huang, Jianrong Steve Zhou

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(19), P. 12895 - 12900

Published: May 2, 2024

A nickel complex of chiral bisoxazolines catalyzed the stereoselective reductive arylation ketones in high enantioselectivity. range common acyclic and cyclic reacted without aid directing groups. Mechanistic studies using isolated a bis(oxazoline) (L)Ni(Ar)Br revealed that Mn reduction was not needed, while Lewis acidic titanium alkoxides were critical to ketone insertion.

Language: Английский

Citations

11
Ni-Catalyzed Regioselective and Site-divergent Reductive Arylalkylations of Allylic Amines DOI Creative Commons
Huan Meng, Jun-Song Jia, Pengfei Yang

et al.

Chemical Science, Journal Year: 2025, Volume and Issue: 16(10), P. 4442 - 4449

Published: Jan. 1, 2025

Catalytic methods by switching the least parameters for regioselective and site-divergent transformations to construct different architectures from identical readily available starting materials are among most ideal catalytic protocols. However, associated challenge precisely control both regioselectivity site diversity renders this strategy appealing yet challenging. Herein, Ni-catalyzed cross-electrophile 1,2- 1,3-arylalkylations of N-acyl allylic amines have been developed. This reductive three-component protocol enables 1,2-arylalkylation 1,3-arylalkylation with aryl halides alkyl excellent chemo-, regio- site-selectivity, representing first example controlled migratory difunctionalization alkenes under conditions. A wide range terminal internal unactivated amines, precursors were tolerated, providing straightforward efficient access diverse C(sp3)-rich branched aliphatic materials.

Language: Английский

Citations

0
New reactivity of late 3d transition metal complexes in catalytic reactions of alkynes DOI
Shenghan Teng,

Peiyao Liang,

Jianrong Steve Zhou

et al.

Chemical Society Reviews, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 1, 2025

This review summarizes seven types of new reactivities found in late 3d metal complexes and catalytic examples recent years.

Language: Английский

Citations

0
Influence of the Counterion on the Activation of Nickel(σ-Aryl) Precatalysts DOI Creative Commons

Ivo H. Lindenmaier,

Anna S. Harzer,

Markus Ströbele

et al.

Organometallics, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 2, 2025

Language: Английский

Citations

0
Electrochemical Nickel-Catalyzed 1,2-Diarylation of 1,3-Dienes DOI

Wangzhe Chen,

Lei Yu, Yi Pan

et al.

Organic Letters, Journal Year: 2023, Volume and Issue: 25(51), P. 9225 - 9230

Published: Dec. 19, 2023

Due to the presence of carbon–carbon double bonds, 1,3-dienes exhibit great reactivity. A protocol for site-selective diarylation terminal is reported here. The transformation facilitated by Ni catalyst without need additional ligands, utilizing an electrochemical setup. Preliminary results indicate that introducing chiral ligands moderate enantioselective products can be obtained. This method affords diversely substituted diarylated occur as structural motifs in various natural products.

Language: Английский

Citations

6
Mechanistic Interrogation of Photochemical Nickel-Catalyzed Tetrahydrofuran Arylation Leveraging Enantioinduction Data DOI

Brennan D. McManus,

Lang Hung,

Olivia R. Taylor

et al.

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(46), P. 32135 - 32146

Published: Nov. 11, 2024

This manuscript details the development of an asymmetric variant for Ni-photoredox α-arylation tetrahydrofuran (THF), which was originally reported in a racemic fashion by Doyle and Molander. Leveraging enantioselectivity data that we obtained, complex mechanistic scenario different from those proposed is uncovered. Specifically, unexpected dependence product enantiomeric ratio observed on both halide identity (aryl chloride vs bromide substrates) Ni source. Stoichiometric experiments time course analyses evolution with revealed initial behavior reactions carried out Ni(II) Ni(0) precatalysts later converge into common mechanism. For studying predominant pathway, this paper describes rare example syntheses chiral bisoxazoline aryl complexes, proved essential probing via stochiometric experiments. These identify as primary species involved key THF radical trapping event. A multivariate linear regression model presented further validates dominant mechanism delineates structure-selectivity relationships between ligand properties enantioselectivity. EPR analysis Ni(0)/aryl mixtures highlights fast access to variety complexes 0, +1, +2 oxidation states are be responsible divergence when using precatalysts. More broadly, beyond advancing understanding arylation protocol, work underscores potential leveraging unravel intricate manifolds within catalysis.

Language: Английский

Citations

2