Unveiling N-Fused Nitreniums as Potent Catalytic Photooxidants

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(6), P. 3603 - 3608

Published: Jan. 31, 2024

The first example of a hitherto-unknown facet catalytic photooxidant capability nitrenium cations is reported herein. fundamental limitation inability the traditional and nitreniums to achieve excited-state redox potential beyond +2.0 V (vs Ag/AgCl), primary requirement for powerful photooxidant, addressed in this work by developing structurally unique class N-fused cations, with required structural engineering involving extensive π-conjugation through ring fusion at site, which enabled significant lowering LUMO energy easy reduction excited state (excited-state up +2.5 vs facilitated effective delocalization/stabilization generated radical. This finding opens new way discover novel useful (photo)catalytic properties just Lewis acidity.

Language: Английский

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N-Heterocyclic Nitreniums Can Be Employed as Photoredox Catalysts for the Single-Electron Reduction of Aryl Halides

Organic Letters, Journal Year: 2022, Volume and Issue: 24(25), P. 4598 - 4602

Published: June 16, 2022

N-Heterocyclic nitrenium (NHN) salts, the analogues of N-heterocyclic carbenes, have attracted considerable interest. However, relatively little is known about their catalytic ability beyond Lewis acid catalysis. Herein, we describe that NHNs can serve as electron acceptors for charge transfer complex photoactivations. We showcase that, under blue light irradiation, NHN salts could catalyze generation aryl radicals from halides.

Language: Английский

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New Generation of Nitrenium Salts: Catalytic Hydrosilylation of Imines and a Mechanism of Action of Nitrogen Lewis Acids

ACS Catalysis, Journal Year: 2022, Volume and Issue: 12(12), P. 6831 - 6839

Published: May 25, 2022

Nitrogen Lewis acids (NLAs) are emerging as a powerful tool in strong bond activation and catalysis. Till now, N,N-dialkyl-nitrenium salts were known utilized chemical transformations. In this article, we report on the synthesis characterization of next generation nitrenium-based acids─N,N-diaryl-substituted naphthotriazinium salts─,which opens door to libraries stereoelectronically modifiable catalysts. We exemplify potency these acidic catalysts gram-scale hydrosilylation various ketimines aldimines yields up 99% catalyst loading low 0.1 mol %. Notably, dialkyl-nitrenium proved inefficient reaction. Based our experimental theoretical studies, elucidated mechanistic action nitrenium such reduction-type reactions, demonstrating unique hydridic behavior N–H bonds triazanes.

Language: Английский

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Additive free, N-heterocyclic nitrenium catalyzed photoreduction of cycloketone oxime esters

Organic Chemistry Frontiers, Journal Year: 2023, Volume and Issue: 10(5), P. 1160 - 1165

Published: Jan. 1, 2023

N-Heterocyclic nitrenium iodide salts can be used as ideal charge transfer complex catalysts for the photoreduction of cycloketone oxime esters.

Language: Английский

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N-Heterocyclic Nitrenium-Catalyzed Photohomolysis of CF₃SO₂Cl for Alkene Trifluoromethylation

Organic Letters, Journal Year: 2023, Volume and Issue: 25(33), P. 6189 - 6194

Published: Aug. 14, 2023

N-Heterocyclic nitreniums (NHNs) have been utilized as Lewis acid catalysts to activate substrates with lone pairs. Alternative their conventional applications, we discovered that NHNs can also serve charge transfer complex catalysts. Herein, present another potential of by utilizing a weak interaction between and CF3SO2Cl. The method promotes CF3SO2Cl undergo photohomolysis, resulting in the CF3 radical. Mechanistic studies suggested could be due π-hole effect NHNs.

Language: Английский

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Recent Advances in Combining Photo- and N-Heterocycle Nitrenium Catalysis

Synthesis, Journal Year: 2024, Volume and Issue: unknown

Published: Sept. 19, 2024

Abstract N-Heterocyclic nitreniums (NHNs) are isoelectronic and isostructural analogues of N-heterocyclic carbenes (NHCs). Unlike NHCs, NHNs much less developed. While a comprehensive understanding NHN reactivity remains elusive, recent advancements have demonstrated their utility as Lewis acid catalysts, photoreductants, photooxidants, leading to several reaction patterns. In this short review, we focus on the applications in photoredox reactions. We also discuss mechanisms behind these transformations outline future research directions. 1 Introduction 2 Application Nitreniums Photoreductants 3 Facilitate Photohomolysis 4 Photooxidants 5 Conclusion

Language: Английский

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Synthesis of a Carbene-Stabilized (Diphospha)aminyl Radical and Its One Electron Oxidation and Reduction to Nonclassical Nitrenium and Amide Species

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(16), P. 9223 - 9232

Published: April 17, 2023

Herein, we report the synthesis of an acyclic carbene-stabilized diphospha(aminyl) PNP radical CAACMePNPCAACMe4 (CAACMe = 1-[2,6-bis(isopropyl)phenyl]-3,3,5,5-tetramethyl-2-pyrrolidinylidene) by a facile one-pot, seven-electron reduction hexachlorophosphazene chloride [Cl3PNPCl3][Cl]. The 4 features conjugated framework with spin density primarily localized on central nitrogen atom as well flanking carbenes. Unlike other tripnictogen radicals, undergoes one-electron oxidation and to yield nonclassical nitrenium amide species [5]+ [6]-, respectively. cation exhibits conformational flexibility in solution state between expected W-shaped geometry [5b]+ previously unobserved linear heteroallene-type structure [5a]+, which was characterized solid state. equilibrium explored both computationally experimentally, showing that [5a]+ is favored over enthalpically (ΔH -2.9 × 103 ± 80 J mol-1) entropically (ΔS 4.2 0.25 mol-1 K-1). formal [6]- displays remarkable its coordination chemistry due presence multiple Lewis basic centers, evidenced potassium complex K262, μ, κ-P, η3-PNP modes. Protonation leads formation amine 7, trigonal planar around nitrogen.

Language: Английский

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The Reactivity of Isomeric Nitrenium Lewis Acids with Phosphines, Carbenes, and Phosphide

Chemistry - A European Journal, Journal Year: 2020, Volume and Issue: 27(8), P. 2861 - 2867

Published: Nov. 2, 2020

Alkylation of spiro[fluorene-9,3'-indazole] at N(1) and N(2) with tBuCl affords the nitrenium cations [C

Language: Английский

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Nitrenium ions as new versatile reagents for electrophilic amination

Chemical Science, Journal Year: 2023, Volume and Issue: 14(43), P. 12034 - 12040

Published: Jan. 1, 2023

Bench-stable N-heterocyclic nitrenium ions were used for the efficient electrophilic amination of organometallic nucleophiles. The previously unexplored N -alkyl/aryl triazane intermediates reduced to produce a diverse scope primary amines.

Language: Английский

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Stable, aromatic, and electrophilic azepinium ions: Design using quantum chemical methods

Journal of Computational Chemistry, Journal Year: 2024, Volume and Issue: unknown

Published: Oct. 30, 2024

Abstract Cyclic nitrenium ions containing five‐membered and six‐membered rings are available, however, the seven‐membered cyclic (azepinium ions) rare. The chemistry of these species is related to their stability originating from aromaticity due 6π electrons. Very few theoretical experimental studies have been conducted on azepinium ions. Related clozapine olanzapine cations (diazepinium were observed during drug metabolism studies. In this work, quantum chemical analysis has carried out estimate stability, aromaticity, electrophilicity several derivatives A designed carry Δ E S‐T values in range 50 kcal/mol favoring singlet state; π donating groups at 2nd position increase singlet‐triplet energy differences. Most substituents reduce NICS(1) compared parent system. Ring fusion with heterocyclic generally increases ion ring systems. parameters estimated terms HIA, FIA, ω indicate that it possible fine‐tune properties appropriate modulation.

Language: Английский

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