Excitation of radical anions of naphthalene diimides in consecutive‐ and electro‐photocatalysis

ChemCatChem ◽  
2021 ◽  
Author(s):  
Sofia Caby ◽  
Lydia M. Bouchet ◽  
Juan E. Argüello ◽  
Roberto A. Rossi ◽  
Javier Bardagi
ChemCatChem ◽  
2021 ◽  
Author(s):  
Sofia Caby ◽  
Lydia M. Bouchet ◽  
Juan E. Argüello ◽  
Roberto A. Rossi ◽  
Javier I. Bardagi

2020 ◽  
Author(s):  
Sofia Caby ◽  
Lydia M. Bouchet ◽  
Juan E. Argüello ◽  
Roberto A. Rossi ◽  
Javier Bardagi

<p>Photo- and electrochemical transformations represent excellent opportunities for the development of methodologies environmentally friendly and combination of both techniques would result in improved methodologies. Recently, photochemical transformations involving the excitation of open-shell species has become a reality. Photostimulated electron transfer (PET) from radical anions of organic dyes have been used in consecutive photoredox catalysis and electro-photocatalysis transformation, allowing the transformation of aryl halides in valuable compounds under mild conditions. The similarities of both techniques raises the question of the convenience of using one or other related and a close evaluation is necessary to drive further development and have been shyly done in previous works. However, an objective comparison of both approaches will require using the same chemical system. We present here a direct comparison of a “pure” photochemical and an electrophotochemical transformartion studying a model transformation, namely, a C-H substitution in (hetero)aromatic systems with a C-C bond formation through reaction of halogenated substrates. Through a detailed investigation of both mechanisms, we identify a system that could be applied in both approaches with minor (necessaries) changes in the reaction conditions and clearly identify the excitation of radical anion of naphthalene diimides as the key intermediates. Both approaches are comparable in yields and kinetics with slightly better yields for the consecutive PET reaction and better selectivity for the electro-PET process. Our work offers a system that could be used for a more profound comparison of the experimental setups which could include, for instance, the important factor of energy consumption.<br></p>


2020 ◽  
Author(s):  
Sofia Caby ◽  
Lydia M. Bouchet ◽  
Juan E. Argüello ◽  
Roberto A. Rossi ◽  
Javier Bardagi

<p>Photo- and electrochemical transformations represent excellent opportunities for the development of methodologies environmentally friendly and combination of both techniques would result in improved methodologies. Recently, photochemical transformations involving the excitation of open-shell species has become a reality. Photostimulated electron transfer (PET) from radical anions of organic dyes have been used in consecutive photoredox catalysis and electro-photocatalysis transformation, allowing the transformation of aryl halides in valuable compounds under mild conditions. The similarities of both techniques raises the question of the convenience of using one or other related and a close evaluation is necessary to drive further development and have been shyly done in previous works. However, an objective comparison of both approaches will require using the same chemical system. We present here a direct comparison of a “pure” photochemical and an electrophotochemical transformartion studying a model transformation, namely, a C-H substitution in (hetero)aromatic systems with a C-C bond formation through reaction of halogenated substrates. Through a detailed investigation of both mechanisms, we identify a system that could be applied in both approaches with minor (necessaries) changes in the reaction conditions and clearly identify the excitation of radical anion of naphthalene diimides as the key intermediates. Both approaches are comparable in yields and kinetics with slightly better yields for the consecutive PET reaction and better selectivity for the electro-PET process. Our work offers a system that could be used for a more profound comparison of the experimental setups which could include, for instance, the important factor of energy consumption.<br></p>


2020 ◽  
Author(s):  
Sofia Caby ◽  
Lydia M. Bouchet ◽  
Juan E. Argüello ◽  
Roberto A. Rossi ◽  
Javier Bardagi

<p>Photo- and electrochemical transformations represent excellent opportunities for the development of methodologies environmentally friendly and combination of both techniques would result in improved methodologies. Recently, photochemical transformations involving the excitation of open-shell species has become a reality. Photostimulated electron transfer (PET) from radical anions of organic dyes have been used in consecutive photoredox catalysis and electro-photocatalysis transformation, allowing the transformation of aryl halides in valuable compounds under mild conditions. The similarities of both techniques raises the question of the convenience of using one or other related and a close evaluation is necessary to drive further development and have been shyly done in previous works. However, an objective comparison of both approaches will require using the same chemical system. We present here a direct comparison of a “pure” photochemical and an electrophotochemical transformartion studying a model transformation, namely, a C-H substitution in (hetero)aromatic systems with a C-C bond formation through reaction of halogenated substrates. Through a detailed investigation of both mechanisms, we identify a system that could be applied in both approaches with minor (necessaries) changes in the reaction conditions and clearly identify the excitation of radical anion of naphthalene diimides as the key intermediates. Both approaches are comparable in yields and kinetics with slightly better yields for the consecutive PET reaction and better selectivity for the electro-PET process. Our work offers a system that could be used for a more profound comparison of the experimental setups which could include, for instance, the important factor of energy consumption.<br></p>


2020 ◽  
Author(s):  
Sofia Caby ◽  
Lydia M. Bouchet ◽  
Juan E. Argüello ◽  
Roberto A. Rossi ◽  
Javier Bardagi

<p>Photo- and electrochemical transformations represent excellent opportunities for the development of methodologies environmentally friendly and combination of both techniques would result in improved methodologies. Recently, photochemical transformations involving the excitation of open-shell species has become a reality. Photostimulated electron transfer (PET) from radical anions of organic dyes have been used in consecutive photoredox catalysis and electro-photocatalysis transformation, allowing the transformation of aryl halides in valuable compounds under mild conditions. The similarities of both techniques raises the question of the convenience of using one or other related and a close evaluation is necessary to drive further development and have been shyly done in previous works. However, an objective comparison of both approaches will require using the same chemical system. We present here a direct comparison of a “pure” photochemical and an electrophotochemical transformartion studying a model transformation, namely, a C-H substitution in (hetero)aromatic systems with a C-C bond formation through reaction of halogenated substrates. Through a detailed investigation of both mechanisms, we identify a system that could be applied in both approaches with minor (necessaries) changes in the reaction conditions and clearly identify the excitation of radical anion of naphthalene diimides as the key intermediates. Both approaches are comparable in yields and kinetics with slightly better yields for the consecutive PET reaction and better selectivity for the electro-PET process. Our work offers a system that could be used for a more profound comparison of the experimental setups which could include, for instance, the important factor of energy consumption.<br></p>


1979 ◽  
Vol 44 (12) ◽  
pp. 3632-3643 ◽  
Author(s):  
Karel Mach ◽  
Igor Janovský ◽  
Karel Vacek

Total yields of paramagnetic species, their optical bleaching and thermal annealing in acetic, propionic, a-butyric, isobutyric, and pivalic acid γ-irradiated at 77 K were followed by ESR spectroscopy. Radical anions, always found after irradiation, disappear during optical bleaching without formation of any paramagnetic product. During thermal annealing they are converted almost quantitatively into the α-radicals of the respective acid, with the exception of pivalic acid. Amounts of radical anions were estimated from the difference of integrated ESR spectra taken before and after optical bleaching. The results show that approximately equal amounts of the reduction and oxidation paramagnetic products of the γ-irradiation can be detected.


1985 ◽  
Vol 50 (7) ◽  
pp. 1594-1601 ◽  
Author(s):  
Jiří Klíma ◽  
Larisa Baumane ◽  
Janis Stradinš ◽  
Jiří Volke ◽  
Romualds Gavars

It has been found that the decay in dimethylformamide and dimethylformamide-water mixtures of radical anions in five of the investigated 5-nitrofurans is governed by a second-order reaction. Only the decay of the radical anion generated from 5-nitro-2-furfural III may be described by an equation including parallel first- and second-order reactions; this behaviour is evidently caused by the relatively high stability of the corresponding dianion, this being an intermediate in the reaction path. The presence of a larger conjugated system in the substituent in position 2 results in a decrease of the unpaired electron density in the nitro group and, consequently, an increase in the stability of the corresponding radical anions.


2021 ◽  
Author(s):  
Jhon Enrique Zapata Rivera ◽  
Carmen J. Calzado

This work explores the relationship between the magnetic properties of salts based on the [Ni(dmit)2]− radicals and the different arrangement that these radicals can adopt in the crystals, induced by...


2018 ◽  
Vol 148 (23) ◽  
pp. 234306 ◽  
Author(s):  
Steven J. Kregel ◽  
Glen K. Thurston ◽  
Etienne Garand

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