Thioxanthone: a powerful photocatalyst for organic reactions

Nikitas, Nikolaos F.; Gkizis, Petros; Kokotos, Christoforos G.

doi:10.1039/d1ob00221j

Cited by 136 publications

(104 citation statements)

References 105 publications

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“…Unlike other aromatic ketone photocatalysts, TX has high singlet and triplet state energies, and relatively long triplet lifetimes [estimated τ 0 = 77 μs, one hundred times longer that benzophenone ( τ 0 = 0.7 μs)], 90 and has the potential to participate in dual catalysis with metal complexes. 91 The conformation of TX is not static; it undergoes interconversion from a planar to a non-planar conformation (known as the “butterfly motion”). 91,92 Each conformation possesses a discrete absorption band in the UV-Vis spectrum.…”

Section: Photocatalysismentioning

confidence: 99%

“…91 The conformation of TX is not static; it undergoes interconversion from a planar to a non-planar conformation (known as the “butterfly motion”). 91,92 Each conformation possesses a discrete absorption band in the UV-Vis spectrum. These various physical chemical properties allow TX to mediate reaction via HAT, SET and triplet energy transfer (ENT).…”

Section: Photocatalysismentioning

confidence: 99%

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Direct decarboxylative Giese reactions

2022

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Section: Photocatalysismentioning

confidence: 99%

Section: Photocatalysismentioning

confidence: 99%

Direct decarboxylative Giese reactions

2022

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“…A deeper look into TX photophysics and photochemistry can be obtained from the literature (ref. [ 93 ]).…”

Section: Coupled Type I and Ii Photoinitiatorsmentioning

confidence: 99%

Surface-Immobilized Photoinitiators for Light Induced Polymerization and Coupling Reactions

2022

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Straightforward and versatile surface modification, functionalization and coating have become a significant topic in material sciences. While physical modification suffers from severe drawbacks, such as insufficient stability, chemical induced grafting processes efficiently modify organic and inorganic materials and surfaces due to covalent linkage. These processes include the “grafting from” method, where polymer chains are directly grown from the surface in terms of a surface-initiated polymerization and the “grafting to” method where a preformed (macro)-molecule is introduced to a preliminary treated surface via a coupling reaction. Both methods require an initiating species that is immobilized at the surface and can be triggered either by heat or light, whereas light induced processes have recently received increasing interest. Therefore, a major challenge is the ongoing search for suitable anchor moieties that provide covalent linkage to the surface and include initiators for surface-initiated polymerization and coupling reactions, respectively. This review containing 205 references provides an overview on photoinitiators which are covalently coupled to different surfaces, and are utilized for subsequent photopolymerizations and photocoupling reactions. An emphasis is placed on the coupling strategies for different surfaces, including oxides, metals, and cellulosic materials, with a focus on surface coupled free radical photoinitiators (type I and type II). Furthermore, the concept of surface initiation mediated by photoiniferters (PIMP) is reviewed. Regarding controlled radical polymerization from surfaces, a large section of the paper reviews surface-tethered co-initiators, ATRP initiators, and RAFT agents. In combination with photoinitiators or photoredox catalysts, these compounds are employed for surface initiated photopolymerizations. Moreover, examples for coupled photoacids and photoacid generators are presented. Another large section of the article reviews photocoupling and photoclick techniques. Here, the focus is set on light sensitive groups, such as organic azides, tetrazoles and diazirines, which have proven useful in biochemistry, composite technology and many other fields.

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“…Photochemistry is a fast-growing field, which is known for many years, but the last 13 years has met with exponential development [19][20][21][22][23][24][25]. Usually transition metal-based catalysts are employed, but in the last decade, a significant number of researchers have focused their attempts on the use of small organic molecules as photocatalysts, a field called Photoorganocatalysis [26][27][28][29][30][31][32][33]. In recent years, our group has focused its interest on utilizing effectively a variety of photocatalysts-photoinitiators in many different chemical tranformations [34][35][36][37].…”

Section: Introductionmentioning

confidence: 99%