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Solar Photochemistry in Flow
摘要： In recent years, photochemistry has been a highly active research field. This renaissance is linked to the upsurge of photoredox catalysis, a versatile platform for synthetic methodologies using visible light photons as a traceless reagent. In contrast with UV, visible light constitutes almost half of the ground solar irradiance, making the use of solar light in chemistry a sustainable and viable possibility. However, the direct use of sunlight to power chemical reactions is still little explored. This can be explained by both the hurdles associated with solar radiation (e.g., its variability, irreproducibility, high IR content, etc.) and the need for a specialized photoreactor. Most of these issues can be tackled with technological solutions, and especially with the recourse to flow chemistry. Flow chemistry goes hand in hand with photochemistry thanks to the uniform irradiation it provides to the reaction. Furthermore, a continuous-flow reactor can be easily integrated with different solar collectors (including compound parabolic concentrators and luminescent solar concentrators) and constitutes the most efficient approach to solar photochemistry. After a description of the characteristics of the solar radiation relevant to chemistry, this chapter critically describes the different type of solar photoreactors and their applications in synthetic organic chemistry. Finally, an outlook on the future of solar photochemistry in flow is included.
关键词： Green chemistry,Solar photochemistry,Solar energy,Flow chemistry
更新于2025-09-10 09:29:36
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Manipulating azobenzene photoisomerization through strong light–molecule coupling
摘要： The formation of hybrid light–molecule states (polaritons) offers a new strategy to manipulate the photochemistry of molecules. To fully exploit its potential, one needs to build a toolbox of polaritonic phenomenologies that supplement those of standard photochemistry. By means of a state-of-the-art computational photochemistry approach extended to the strong-coupling regime, here we disclose various mechanisms peculiar of polaritonic chemistry: coherent population oscillations between polaritons, quenching by trapping in dead-end polaritonic states and the alteration of the photochemical reaction pathway and quantum yields. We focus on azobenzene photoisomerization, that encompasses the essential features of complex photochemical reactions such as the presence of conical intersections and reaction coordinates involving multiple internal modes. In the strong coupling regime, a polaritonic conical intersection arises and we characterize its role in the photochemical process. Our chemically detailed simulations provide a framework to rationalize how the strong coupling impacts the photochemistry of realistic molecules.
关键词： azobenzene,photochemistry,polaritons,photoisomerization,strong coupling
更新于2025-09-10 09:29:36
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Concurrent Asymmetric Reactions Combining Photocatalysis and Enzyme Catalysis: Direct Enantioselective Synthesis of 2,2-Disubstituted Indol-3-ones from 2-Arylindoles
摘要： The combination of photoredox and enzymatic catalysis for the direct asymmetric one-pot synthesis of 2,2-disubstituted indol-3-ones from 2-arylindoles through concurrent oxidization and alkylation reactions is described. 2-Arylindoles can be photocatalytically oxidized to 2-arylindol-3-one with subsequent enantioselective alkylation with ketones catalyzed by wheat germ lipase (WGL). The chiral quaternary carbon center at C2 of the indoles was directly constructed. This mode of concurrent photobiocatalysis provides a mild and powerful strategy for one-pot enantioselective synthesis of complex compounds. The experiments proved that other lipases containing structurally analogous catalytic triad in the active site also can catalyze the reaction in the same way. This reaction is the first example of combining the non-natural catalytic activity of hydrolases with visible-light catalysis for enantioselective organic synthesis and it does not require any cofactors.
关键词： photochemistry,enzymes,heterocycles,synthetic methods,asymmetric catalysis
更新于2025-09-10 09:29:36
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Visible Light-Driven MADIX Polymerisation via a Reusable, Low-Cost and Non-Toxic Bismuth Oxide Photocatalyst
摘要： The continuous amalgamation of photocatalysis into existing reversible deactivation radical polymerisation processes has initiated a rapidly propagating area of polymer research in recent years. We introduce bismuth oxide (Bi2O3) as a heterogeneous photocatalyst for polymerisations, operating at room temperature with visible light. We demonstrate formidable control over degenerative chain-transfer polymerisations, such as macromolecular design by interchange of xanthate (MADIX) and reversible addition-fragmentation chain transfer (RAFT) polymerisation. We achieved narrow molecular weight distributions and attribute the excellent temporal control to a photo-induced electron transfer (PET) process. This methodology was employed to synthesise diblock copolymers combining differently activated monomers. The Bi2O3 catalyst system has the additional benefits of low toxicity, reusability, low-cost, and ease of removal from the reaction mixture.
关键词： polymerisation,photochemistry,block copolymers,RDRP,PET-RAFT
更新于2025-09-10 09:29:36
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Visible Light-Driven MADIX Polymerisation via a Reusable, Low-Cost and Non-Toxic Bismuth Oxide Photocatalyst
摘要： The continuous amalgamation of photocatalysis into existing reversible deactivation radical polymerisation processes has initiated a rapidly propagating area of polymer research in recent years. We introduce bismuth oxide (Bi2O3) as a heterogeneous photocatalyst for polymerisations, operating at room temperature with visible light. We demonstrate formidable control over degenerative chain-transfer polymerisations, such as macromolecular design by interchange of xanthate (MADIX) and reversible addition-fragmentation chain transfer (RAFT) polymerisation. We achieved narrow molecular weight distributions and attribute the excellent temporal control to a photo-induced electron transfer (PET) process. This methodology was employed to synthesise diblock copolymers combining differently activated monomers. The Bi2O3 catalyst system has the additional benefits of low toxicity, reusability, low-cost, and ease of removal from the reaction mixture.
关键词： polymerisation,photochemistry,block copolymers,RDRP,PET-RAFT
更新于2025-09-10 09:29:36
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Radiochemistry in a flash: photochemical conjugation and one-pot radiolabelling of antibodies for immuno-PET
摘要： Monoclonal antibodies (mAbs), immunoglobulin fragments and other proteins are important scaffolds in the development of radiopharmaceuticals for diagnostic immuno-positron emission tomography (immuno-PET) and targeted radioimmunotherapy (RIT). Conventional methods for radiolabelling proteins with metal ions like 68Ga, 64Cu, 89Zr, and 90Y etc require multi-step procedures involving pre-purification, functionalisation with a chelate, and subsequent radiolabelling. Standard coupling chemistries are time consuming, difficult to automate, and involve synthesis, isolation and storage of an intermediate, new molecular entity (the conjugated mAb) whose biochemical properties can differ from those of the parent protein. To circumvent these issues, we developed a photoradiochemical approach that uses fast, chemoselective, light-induced protein modification under mild conditions with novel metal ion binding chelates derivatised with arylazide (ArN3) groups. Experiments show that one-pot photochemical conjugation and radiolabelling of formulated mAbs can be achieved in <20 min.
关键词： Radiochemistry,photochemistry,antibody conjugates,positron emission tomography,arylazides
更新于2025-09-10 09:29:36
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Photoactivatable Reaction for Covalent Nanoscale Patterning of Multiple Proteins
摘要： This article describes a photochemical approach for independently patterning multiple proteins to an inert substrate, particularly for studies of cell adhesion. A photoactivatable chloropyrimidine ligand was employed for covalent immobilization of SnapTag fusion proteins on self-assembled monolayers of alkanethiolates on gold. A two-step procedure was used: first, patterned UV illumination of the surface activated protein capture ligands, and second, incubation with a SnapTag fusion protein bound to the surface in illuminated regions. Two different fluorescent proteins were patterned in registry with features of 400 nm in size over a 1 mm2 area. An example is given wherein an anti-carcinoembryonic antigen (anti-CEA) scFv antibody was patterned to direct the selective attachment of a human cancer cell line that express the CEA antigen. This method enables the preparation of surfaces with control over the density and activity of independently patterned proteins.
关键词： immobilization,photochemistry,monolayers,surface chemistry,proteins
更新于2025-09-10 09:29:36
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An Investigation on the Unexplored Photochemistry of 5,5-Dimethyl-1-Pyrroline 1-Oxide (DMPO)
摘要： A comparative study of 5,5-dimethyl-1-pyrroline 1-oxide (DMPO) and its 2-methyl-substituted analogue (2-Me-DMPO) has revealed their contrasting reaction pathways of oxaziridine and lactam (pyrrolidone) formation. The initial photo-excitation populates the second excited singlet states (S2) in both the systems with S0-S2 transition moment value of 3 Debye (oscillator strength 0.4); this subsequently undergoes (S0/S1) conical intersection through a structure having a CNO-kink and situated around 35-40 kcal / mol below the vertically excited geometry of the first excited singlet state (S1). This conical intersection is found to be responsible for the formation of the oxaziridine photoproduct in these systems. In DMPO, this oxaziridine eventually forms the corresponding lactam compound through a [1,2] H shift after overcoming a barrier of 35 kcal / mol and following the imaginary frequency of 1517i cm-1. The reverse thermal process of parent nitrone formation proceeds through a transition state situated at 60 kcal / mol above the oxaziridine geometry and the corresponding imaginary frequency is 1514i cm-1. On the other hand, in 2-Me-DMPO, the oxaziridine formed is more stable and lactam formation does not happen from it in a similar manner.
关键词： Quantum Chemistry,Oxaziridine,Lactam,DMPO,Photochemistry,Spectroscopy,Molecular Structure
更新于2025-09-10 09:29:36
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Near <scp>IR</scp> Photochemistry for Biology: Exploiting the Optical Window of Tissue
摘要： Photoactive molecules enable much of modern biology and biochemistry – a vast library of fluorescent chromophores is used to track and label cellular structures and macromolecules. However, photochemistry is better-known to the synthetic or physical organic chemist as a “light switch” that turns on unusual excited-state reactivity, isomerization, or dynamic adjustment of structure. This review details a rapidly growing approach to bio-photochemistry that uses low-energy near-IR wavelengths not only for imaging, but for close spatial control over chemical switching events in biosystems. Emphasis is placed on topics of biomedical interest: release of gaseous biological messengers, uncaging of drugs, nano-therapeutics, and modification of biomaterials.
关键词： drug uncaging,bio-photochemistry,nano-therapeutics,biomaterials modification,optical window of tissue,biomedical applications,gasotransmitters,Near IR photochemistry
更新于2025-09-09 09:28:46
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Metal-Ligand Cooperative Synthesis of Benzonitrile via Electrochemical Reduction and Photolytic Splitting of Dinitrogen
摘要： Thermal nitrogen fixation relies on strong reductants to overcome the extraordinarily large N–N bond energy. Photochemical strategies that drive N2 fixation are scarcely developed. Here, the synthesis of a dinuclear N2-bridged complex is presented upon reduction of a rhenium(III) pincer platform. Photochemical splitting into terminal nitride complexes is triggered by visible light. Clean N-transfer with benzoyl chloride to free benzamide and benzonitrile is enabled by cooperative 2H+/2e– transfer of the pincer ligand. A three-step cycle is demonstrated for N2 to nitrile fixation that relies on electrochemical reduction, photochemical N2-splitting and thermal N-transfer.
关键词： Rhenium,Photochemistry,Electrochemistry,Nitrogen Fixation,Pincer Ligand
更新于2025-09-09 09:28:46