Red-Light-Driven Atom Transfer Radical Polymerization for High-Throughput Polymer Synthesis in Open Air

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(44), P. 24315 - 24327

Published: Oct. 25, 2023

Photoinduced reversible-deactivation radical polymerization (photo-RDRP) techniques offer exceptional control over polymerization, providing access to well-defined polymers and hybrid materials with complex architectures. However, most photo-RDRP methods rely on UV/visible light or photoredox catalysts (PCs), which require multistep synthesis. Herein, we present the first example of fully oxygen-tolerant red/NIR-light-mediated photoinduced atom transfer (photo-ATRP) in a high-throughput manner under biologically relevant conditions. The method uses commercially available methylene blue (MB+) as PC [X-CuII/TPMA]+ (TPMA = tris(2-pyridylmethyl)amine) deactivator. mechanistic study revealed that MB+ undergoes reductive quenching cycle presence TPMA ligand used excess. formed semireduced MB (MB•) sustains by regenerating [CuI/TPMA]+ activator together provides polymerization. This dual catalytic system exhibited excellent oxygen tolerance, enabling polymerizations high monomer conversions (>90%) less than 60 min at low volumes (50-250 μL) synthesis library DNA-polymer bioconjugates narrow molecular weight distributions (Đ < 1.30) an open-air 96-well plate. In addition, broad absorption spectrum allowed ATRP be triggered UV NIR irradiation (395-730 nm). opens avenues for integration orthogonal reactions. Finally, MB+/Cu catalysis showed good biocompatibility during cells, expands potential applications this method.

Language: Английский

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Visible-Light Photoredox Catalysis in Water

The Journal of Organic Chemistry, Journal Year: 2022, Volume and Issue: 88(10), P. 6284 - 6293

Published: June 14, 2022

The use of water in organic synthesis draws attention to its green chemistry features and unique ability unveil unconventional reactivities. Herein, literature about the as a reaction medium under visible-light photocatalytic conditions is summarized order highlight challenges opportunities. Accordingly, this Synopsis has been divided into four different sections focused on (1) role reactions, (2) in-/on-water (3) water-soluble photocatalysts, (4) photomicellar catalytic systems.

Language: Английский

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Organophotocatalytic Mechanisms: Simplicity or Naïvety? Diverting Reactive Pathways by Modifications of Catalyst Structure, Redox States and Substrate Preassemblies

ChemCatChem, Journal Year: 2023, Volume and Issue: 15(11)

Published: Feb. 21, 2023

Abstract Photocatalysis is a powerful tool to assemble diverse chemical scaffolds, yet bottleneck on its further development the understanding of multitude possible pathways when practitioners rely only oversimplified thermodynamic and optical factors. Recently, there growing number studies in field that exploit, inter alia , kinetic parameters organophotocatalysts are synthetically more programmable terms their redox states opportunities for aggregation with target substrate. Non‐covalent interactions play key role enables access new generation reactivities such as those open‐shell organophotocatalysts. In this review, we discuss how targeted structural modifications influence organophotocatalytic mechanisms together underlying principles. We also highlight benefits strategies preassembly static quenching overcome common reactivity issues (e. g., diffusion rate limits energetic limits).

Language: Английский

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Super-Reducing Behavior of Benzo[b]phenothiazine Anion Under Visible-Light Photoredox Condition

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(41), P. 22403 - 22412

Published: Oct. 3, 2023

Herein we describe the anion of benzo[b]phenothiazine as a super reductant species upon excitation by visible light. In contrary to N-substituted phenothiazines or benzophenothiazines, this molecule holds extreme reducing power promote single electron transfer-based reductive cleavage at potential -3.51 V vs SCE. As proof, plethora aryl chloride substrates have been reductively cleaved fabricate molecules class isoindolinone and oxindole. Moreover, an aryl-chloride bond has homolytically generate radicals that utilized for C-C cross-coupling C-P formation reactions. To prove its ability, some fluoride bonds radicals. A detailed photophysical study including steady-state time-resolved spectroscopic techniques explain molecule's behavior light excitation, correlates with reactivity pattern. Theoretical calculations disclose benzophenothiazine be slightly puckered ground state is antiaromatic in nature. contrast, excited-state geometry planar, which also close intermediate after one transfer. Abating antiaromaticity anionic partially responsible highly behavior.

Language: Английский

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Is Micellar Catalysis Green Chemistry?

Molecules, Journal Year: 2023, Volume and Issue: 28(12), P. 4809 - 4809

Published: June 16, 2023

Many years ago, twelve principles were defined for carrying out chemical reactions and processes from a green chemistry perspective. It is everyone’s endeavor to take these points into account as far possible when developing new or improving existing ones. Especially in the field of organic synthesis, area research has thus been established: micellar catalysis. This review article addresses question whether catalysis by applying reaction media. The shows that many can be transferred an solvent medium, but surfactant also crucial role solubilizer. Thus, carried much more environmentally friendly manner with less risk. Moreover, surfactants are being reformulated their design, degradation add extra advantages match all chemistry.

Language: Английский

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Copper-Catalyzed General and Selective α-C(sp³)–H Silylation of Amides via 1,5-Hydrogen Atom Transfer

ACS Catalysis, Journal Year: 2024, Volume and Issue: 14(3), P. 1725 - 1732

Published: Jan. 18, 2024

The development of a general and selective method for α-C(sp3)–H silylation feedstock amines has been long-standing challenge. In this paper, we disclose mild, general, practical, highly regio- diastereoselective various readily available acyclic, cyclic, aromatic with silylboranes through copper-catalyzed intramolecular 1,5-hydrogen atom transfer (HAT) strategy. mild activation 2-iodobenzamide to generate an aryl radical enabled by ligand-coordinated silyl copper complex without additional heating or photoinduced conditions, as well the 1,5-HAT process produce crucial α-aminoalkyl species, is key success chemistry. This protocol demonstrated its potential utility in late-stage modification structurally drugs bioactive molecules. Therefore, it expected that will find applications synthetic chemistry drug discovery.

Language: Английский

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A survey of the iron ligand-to-metal charge transfer chemistry in water

Green Chemistry, Journal Year: 2024, Volume and Issue: 26(6), P. 3058 - 3071

Published: Jan. 1, 2024

Fully hydrated! – Iron photocatalysis tests the waters.

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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Regulating Donor–Acceptor Interactions within 2-Methylpyridine-Mediated Vinylene-Linked Covalent–Organic Frameworks for Enhanced Photocatalysis

ACS Materials Letters, Journal Year: 2024, Volume and Issue: 6(4), P. 1120 - 1129

Published: Feb. 26, 2024

Vinylene-linked covalent–oganic frameworks (COFs), as novel photocatalysts, have garnered considerable attention due to their exceptional stability, remarkable π-electron delocalization, and precisely customizable structures. However, the design of monomers for constructing vinylene-linked COFs with tunable electronic structures is still in its early stages poses a number challenges. Addressing this, tritopic monomer was developed by attaching 3-fold 2-methylpyridine unit triphenyl-1,3,5-triazine core. The further condensed aromatic dialdehydes via solid-state Knoevenagel polycondensation reaction form two 2D (TP-PB TP-PT COF), which exhibited excellent crystallinity, preeminent outstanding delocalization. More importantly, modulation donor–acceptor (D–A) interaction within COFs, semiconducting properties could be optimized. Due stronger D–A interactions TP-PB COF containing 1,3,5-triphenylbenzene than unit, broader visible light absorption, narrower band gap, photocurrent response, lower charge transfer resistance, makes more efficient photocatalyst photocatalytic selective conversions organic sulfides sulfoxides C-3 thiocyanation indole derivatives high catalytic activity recyclability. This work not only demonstrates construction but also presents facile strategy regulating such fine-tuning matrices.

Language: Английский

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Role of micellar nanoreactors in organic chemistry: Green and synthetic surfactant review

Sustainable Chemistry and Pharmacy, Journal Year: 2022, Volume and Issue: 30, P. 100875 - 100875

Published: Oct. 30, 2022

Language: Английский

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