scholarly journals Unveiling Extreme Photoreduction Potentials of Donor-Acceptor Cyanoarenes to Access Aryl Radicals from Aryl Chlorides

2021 ◽  
Author(s):  
Jinhui Xu ◽  
Jilei Cao ◽  
Xiangyang Wu ◽  
Han Wang ◽  
Xiaona Yang ◽  
...  
Keyword(s):  
Limited Range ◽  
Redox Potentials ◽  
Aryl Chlorides ◽  
Aryl Radicals ◽  
Reduction Potentials ◽  
Anion Form ◽  
Donor Acceptor ◽  
High Reduction ◽  
Very High ◽  
Excited Radical

Since the seminal work of Zhang in 2016, donor-acceptor cyanoarene-based fluorophores, such as 1,2,3,5-tetrakis(carbazol-9-yl)-4,6-dicyanobenzene (4CzIPN), have been widely applied in photoredox catalysis, and used as excellent metal-free alternatives to noble metal Ir- and Ru-based photocatalysts. However, all the reported photoredox reactions involving this chromophore family are based on harnessing the energy from a single visible light photon, with a limited range of redox potentials from -1.92 V to +1.79 V. Here, we document the unprecedented discovery that this family of fluorophores can undergo consecutive photoinduced electron transfer (ConPET) to achieve very high reduction potentials. One of the newly synthesized catalysts, 2,4,5-tri(9H-carbazol-9-yl)-6-(ethyl(phenyl)amino)isophthalonitrile (3CzEPAIPN), possesses a long-lived (12.95 ns) excited radical anion form, 3CzEPAIPN<sup>•</sup><sup>−</sup>*, which can be used to activate reductively recalcitrant aryl chlorides (E<sub>red </sub>≈ -1.9 to -2.9 V) under mild conditions. The resultant aryl radicals can be engaged in synthetically valuable aromatic C-B, C-P, and C-C bond formation to furnish arylboronates, arylphosphonium salts, arylphosphonates, and spirocyclic cyclohexadienes, respectively.

scholarly journals Unveiling Extreme Photoreduction Potentials of Donor-Acceptor Cyanoarenes to Access Aryl Radicals from Aryl Chlorides

2021 ◽  
Author(s):  
Jinhui Xu ◽  
Jilei Cao ◽  
Xiangyang Wu ◽  
Han Wang ◽  
Xiaona Yang ◽  
...  
Keyword(s):  
Limited Range ◽  
Redox Potentials ◽  
Aryl Chlorides ◽  
Aryl Radicals ◽  
Reduction Potentials ◽  
Anion Form ◽  
Donor Acceptor ◽  
High Reduction ◽  
Very High ◽  
Excited Radical

Since the seminal work of Zhang in 2016, donor-acceptor cyanoarene-based fluorophores, such as 1,2,3,5-tetrakis(carbazol-9-yl)-4,6-dicyanobenzene (4CzIPN), have been widely applied in photoredox catalysis, and used as excellent metal-free alternatives to noble metal Ir- and Ru-based photocatalysts. However, all the reported photoredox reactions involving this chromophore family are based on harnessing the energy from a single visible light photon, with a limited range of redox potentials from -1.92 V to +1.79 V. Here, we document the unprecedented discovery that this family of fluorophores can undergo consecutive photoinduced electron transfer (ConPET) to achieve very high reduction potentials. One of the newly synthesized catalysts, 2,4,5-tri(9H-carbazol-9-yl)-6-(ethyl(phenyl)amino)isophthalonitrile (3CzEPAIPN), possesses a long-lived (12.95 ns) excited radical anion form, 3CzEPAIPN<sup>•</sup><sup>−</sup>*, which can be used to activate reductively recalcitrant aryl chlorides (E<sub>red </sub>≈ -1.9 to -2.9 V) under mild conditions. The resultant aryl radicals can be engaged in synthetically valuable aromatic C-B, C-P, and C-C bond formation to furnish arylboronates, arylphosphonium salts, arylphosphonates, and spirocyclic cyclohexadienes, respectively.

Reductive Electrophotocatalysis: Merging Electricity and Light to Achieve Extreme Reduction Potentials

2019 ◽  
Author(s):  
Hyunwoo Kim ◽  
Hyungjun Kim ◽  
Tristan Lambert ◽  
Song Lin
Keyword(s):  
Radical Anion ◽  
Aryl Radicals ◽  
Reduction Potentials ◽  
High Reduction ◽  
Very High ◽  
Excited Radical ◽  
Reducing Potential

We describe a new electrophotocatalytic strategy that harnesses the power of light and electricity to generate an excited radical anion with a reducing potential of –3.2 V vs. SCE, which can be used to activate substrates with very high reduction potentials (<i>E</i><sub>red</sub> ~ –1.9 to –2.9 V). The resultant aryl radicals can be engaged in various synthetically useful transformations to furnish arylboronate, arylstannane, and biaryl products.<br>

scholarly journals Reductive Electrophotocatalysis: Merging Electricity and Light to Achieve Extreme Reduction Potentials

2019 ◽  
Author(s):  
Hyunwoo Kim ◽  
Hyungjun Kim ◽  
Tristan Lambert ◽  
Song Lin
Keyword(s):  
Radical Anion ◽  
Aryl Radicals ◽  
Reduction Potentials ◽  
High Reduction ◽  
Very High ◽  
Excited Radical ◽  
Reducing Potential

We describe a new electrophotocatalytic strategy that harnesses the power of light and electricity to generate an excited radical anion with a reducing potential of –3.2 V vs. SCE, which can be used to activate substrates with very high reduction potentials (<i>E</i><sub>red</sub> ~ –1.9 to –2.9 V). The resultant aryl radicals can be engaged in various synthetically useful transformations to furnish arylboronate, arylstannane, and biaryl products.<br>

scholarly journals Reductive Electrophotocatalysis: Merging Electricity and Light to Achieve Extreme Reduction Potentials

2019 ◽  
Author(s):  
Hyunwoo Kim ◽  
Hyungjun Kim ◽  
Tristan Lambert ◽  
Song Lin
Keyword(s):  
Radical Anion ◽  
Aryl Radicals ◽  
Reduction Potentials ◽  
High Reduction ◽  
Very High ◽  
Excited Radical ◽  
Reducing Potential

We describe a new electrophotocatalytic strategy that harnesses the power of light and electricity to generate an excited radical anion with a reducing potential of –3.2 V vs. SCE, which can be used to activate substrates with very high reduction potentials (<i>E</i><sub>red</sub> ~ –1.9 to –2.9 V). The resultant aryl radicals can be engaged in various synthetically useful transformations to furnish arylboronate, arylstannane, and biaryl products.<br>

Photoswitching of Redox Potentials and Spectroscopic Properties in the UV/vis Region

2005 ◽  
Vol 60 (1) ◽  
pp. 75-82 ◽  
Author(s):  
Nedko Drebov ◽  
Nikolai Tyutyulkov ◽  
Stojan Karabunarliev ◽  
Fritz Dietz
Keyword(s):  
Spectroscopic Properties ◽  
Visible Spectral Region ◽  
Redox Potentials ◽  
Electron Systems ◽  
Excitation Energies ◽  
Reduction Potentials ◽  
Open Ring ◽  
Wavelength Absorption ◽  
Donor Acceptor ◽  
Ct Transitions

The photoswitching of optical and electrochemical properties of di-donor, di-acceptor and donor-acceptor substituted photochromic tetrahydropyrene - [2,2]metacyclophanene and dihydropyrene - [2,2]metacyclophanediene systems has been studied theoretically. A switching of the halfwave oxidation and reduction potentials should be possible in the case of bis(pyridinium) and bis(hydroxyphenyl) substituted systems. Because of the relatively great perturbation of the planarity of the π-electron systems by large torsion of the substituents out of the π-electron structure of the photochromic system and the stair-like structure of the ring-opened isomer, relatively large excitation energies for CT transitions have been calculated with the AM1-CI procedure. The ring-closed structures should absorb in the visible spectral region, and the open-ring isomers should have a longest-wavelength absorption in the UV region.

Phosphoryl- and Phosphonium-Bridged Viologens as Stable Two- and Three-Electron Acceptors for Organic Electrodes

2020 ◽  
Author(s):  
Colin R. Bridges ◽  
Andryj M. Borys ◽  
Vanessa Béland ◽  
Joshua R. Gaffen ◽  
Thomas Baumgartner
Keyword(s):  
Molecular Weight ◽  
Organic Molecules ◽  
Electrode Materials ◽  
High Energy ◽  
Electron Acceptors ◽  
Low Molecular Weight ◽  
Reduction Potentials ◽  
Organic Electrode ◽  
High Reduction ◽  
High Specific Energy

Low molecular weight organic molecules that can accept multiple electrons at high<br>reduction potentials are sought after as electrode materials for high-energy sustainable batteries. To date their synthesis has been difficult, and organic scaffolds for electron donors significantly outnumber electron acceptors. Herein, we report two highly electron deficient phosphaviologen derivatives from a phosphorus-bridged 4,4-bipyridine and characterize their electrochemical properties. Phosphaviologen sulfide (PVS) and P-methyl phosphaviologen (PVM) accept two and three electrons at high reduction potentials, respectively. PVM can reversibly accept 3 electrons between 3-3.6 V vs. Li/Li+ with an equivalent molecular weight of 102 g/(mol e-) (262 mAh/g), making it a promising scaffold for sustainable organic electrode materials having high specific energy densities.

scholarly journals Intermolecular oxyarylation of olefins with aryl halides and TEMPOH catalyzed by the phenolate anion under visible light

2020 ◽  
Vol 11 (27) ◽  
pp. 6996-7002
Author(s):  
Kangjiang Liang ◽  
Qian Liu ◽  
Lei Shen ◽  
Xipan Li ◽  
Delian Wei ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Visible Light ◽  
Aryl Halides ◽  
Single Electron ◽  
Single Electron Transfer ◽  
Strong Reduction ◽  
Aryl Radicals ◽  
Reduction Potentials

The phenolate anion was developed as a new photocatalyst with strong reduction potentials (−3.16 V vs. SCE) to reduction of aryl halides to aryl radicals through single electron transfer.

Synthesis and hydrolysis of gas-phase lanthanide and actinide oxide nitrate complexes: a correspondence to trivalent metal ion redox potentials and ionization energies

2015 ◽  
Vol 17 (15) ◽  
pp. 9942-9950 ◽  
Author(s):  
Ana F. Lucena ◽  
Célia Lourenço ◽  
Maria C. Michelini ◽  
Philip X. Rutkowski ◽  
José M. Carretas ◽  
...  
Keyword(s):  
Gas Phase ◽  
Metal Ion ◽  
Oxidation States ◽  
Redox Potentials ◽  
Trivalent Metal ◽  
Ionization Energies ◽  
Reduction Potentials ◽  
Hydrolysis Of ◽  
Nitrate Complexes

Gas-phase hydrolysis of lanthanide/actinide MO3(NO3)3−ions relates to the stabilities of the MIVoxidation states, which correlate with IV/III solution reduction potentials and 4th ionization energies.

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