Reliable reduction potentials of diaryliodonium cations and aryl radicals in acetonitrile from high-level ab initio computations

Romańczyk, Piotr P.; Kurek, Stefan S.

doi:10.1016/j.electacta.2020.136404

Cited by 27 publications

(27 citation statements)

References 66 publications

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“…Specifically, the def2-tzvp basis set and cam-b3lyp functional were used in an implicit solvation model to compute the HOMO and LUMO energy levels. Following literature precedent for diphenyliodinium, 47,48 accurate estimations for the D and A initiators were achieved by using a concerted ionization and bond cleaving process (see "computational methods/data" in the SI for more details). As shown in Table 1 Figure S31).…”

Section: Resultsmentioning

confidence: 99%

Catalyst Halogenation Enables Rapid and Efficient Polymerizations with Visible to Near-Infrared Light

Stafford¹,

Ahn²,

Raulerson³

et al. 2020

Preprint

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Driving rapid polymerizations with visible to near-infrared (NIR) light will enable nascent technologies in the emerging fields of bio- and composite-printing. However, current photopolymerization strategies are limited by long reaction times, high light intensities, and/or large catalyst loadings. Improving efficiency remains elusive without a comprehensive, mechanistic evaluation of photocatalysis to better understand how composition relates to polymerization metrics. With this objective in mind, a series of methine- and aza-bridged boron dipyrromethene (BODIPY) derivatives were synthesized and systematically characterized to elucidate key structure-property relationships that facilitate efficient photopolymerization driven by visible to NIR light. For both BODIPY scaffolds, halogenation was shown as a general method to increase polymerization rate, quantitatively characterized using a custom real-time infrared spectroscopy setup. Furthermore, a combination of steady-state emission quenching experiments, electronic structure calculations, and ultrafast transient absorption revealed that efficient intersystem crossing to the lowest excited triplet state upon halogenation was a key mechanistic step to achieving rapid photopolymerization reactions. Unprecedented polymerization rates were achieved with extremely low light intensities (< 1 mW/cm<sup>2</sup>) and catalyst loadings (< 50 μM), exemplified by reaction completion within 60 seconds of irradiation using green, red, and NIR light-emitting diodes.

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Section: Resultsmentioning

confidence: 99%

Catalyst Halogenation Enables Rapid and Efficient Polymerizations with Visible to Near-Infrared Light

Stafford¹,

Ahn²,

Raulerson³

et al. 2020

Preprint

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show abstract

“…The two triaryl sulfonium salts appear much less efficient than DAIS-B. This is due to the decrease in reduction of potential properties of sulfonium (E • (Ar 3 S + /Ar 2 S + Ar • ) −1.2 V vs. SCE) compared to the iodonium cation (E • (Ar 2 I + /ArI + Ar • ) −0.8 V vs. SCE) [24,25]. The recorded temperature profile (Figure 4) shows that after a short period of latency, during which the sample is warmed up by conversion of the incoming beam into heat while the first acidic species to be generated in situ are quenched by basic contaminants and moisture, the temperature in the irradiated sample rises up to 180 °C within about 10 s, the peak being observed as the sample has already moved away from the irradiation zone.…”

Section: Monitoring Of Epoxy Polymerizationmentioning

confidence: 99%

Cationic Curing of Epoxy–Aromatic Matrices for Advanced Composites: The Assets of Radiation Processing

2022

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Cross-linking polymerization of multifunctional aromatic monomers initiated by exposure to high energy radiation continues to be explored as a promising alternative to thermal curing for the production of high-performance composite materials. High-energy radiation processing offers several advantages over thermosetting technology by allowing for fast and out-of-autoclave curing operations and for its adaptability in the manufacturing of large and complex structures at reduced energy costs. The present article covers the basic aspects of radiation curing by cationic polymerization of epoxy resins, providing a status report on recent investigations conducted in our group to improve the properties of epoxy matrices and gain better control over the process for producing composites. A selection of results based on blends prepared with different composition of epoxy aromatics, transfer agents, thermoplastic toughening agents and onium salt initiators exemplifies the importance of the composition on polymerization kinetics and on the properties of resulting materials. The superiority of radiation-triggered polymerization-induced phase separation of thermoplastic additives is emphasized by the obtained morphology of toughened materials. The low initial temperature and fast curing of the reactive blends limits the expansion of phase-separated thermoplastic domains, resulting in an enhancement of the toughness.

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“…Aryl halides [46] Aryl sulfonyl chlorides [46] Diaryliodonium salts [47] Aryl diazonium salts [48] E 1/2 red (V vs SCE) À 1.9 to À 1. Then in 2018, Reiser's group demonstrated Ir(III)catalysed radical tandem cyclization of ortho-isocyano-α-bromocinnamates 86 with diaryldiazonium salts 87 to access 2-aryl or 2-phenylthio-indole-ethyl-3glyoxylates 88 (Scheme 18).…”

Section: Arylating Reagentsmentioning

confidence: 99%

Photocatalytical and Photochemical Generation of Imidoyl Radicals: Synthetic Applications

2020

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In the last few decades, the development in the field of radical chemistry has gained great attention. The majority of these radical strategies mainly depend on the in situ generation of reactive radical species by employing radical initiators such as oxidants and metal salts or methods such as photocatalysis and electrochemistry etc. This review covers the literature on the generation of imidoyl radicals using photoredox catalysis. In the majority of the reactions, the spontaneity of the underlying SET transitions is correlated by the compiled redox potential data of the reacting species for a better understanding of the readers. Besides, the applications of these reactive imidoyl radicals to access a variety of heterocycles such as benzothiazoles, indoles, quinoxalines, phenanthridines, isoquinolines, pyridines, and amides are also addressed.

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Reliable reduction potentials of diaryliodonium cations and aryl radicals in acetonitrile from high-level ab initio computations

Cited by 27 publications

References 66 publications

Catalyst Halogenation Enables Rapid and Efficient Polymerizations with Visible to Near-Infrared Light

Catalyst Halogenation Enables Rapid and Efficient Polymerizations with Visible to Near-Infrared Light

Cationic Curing of Epoxy–Aromatic Matrices for Advanced Composites: The Assets of Radiation Processing

Photocatalytical and Photochemical Generation of Imidoyl Radicals: Synthetic Applications

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