Reactivity Patterns of Radical Ions–A Unifying Picture of Radical‐Anion and Radical‐Cation Transformations

Schmittel, Michael; Ghorai, Manas K.

doi:10.1002/9783527618248.ch15

Cited by 22 publications

(21 citation statements)

References 632 publications

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“…As an example, the largely positive reduction potential of aromatic nitriles [5,8–9] and cyanophthalimides [10] in the singlet excited state or of aromatic esters in the triplet state [5,11] makes PET a common occurrence upon irradiation of such substrates in the presence of a variety of donors (D–X, step a). In all of the above cases, the generated radical anion (A–Y •− ) is a persistent species easily detected by laser flash photolysis.…”

Section: Introductionmentioning

confidence: 99%

Spectroscopic characterization of photoaccumulated radical anions: a litmus test to evaluate the efficiency of photoinduced electron transfer (PET) processes

Fagnoni¹,

Protti²,

Ravelli³

et al. 2013

Beilstein J. Org. Chem.

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SummarySteady-state irradiation in neat acetonitrile of some aromatic nitriles, imides and esters (10−5–10−3 M solution) in the presence of tertiary amines allowed the accumulation of the corresponding radical anions, up to quantitative yield for polysubstituted benzenes and partially with naphthalene and anthracene derivatives. The condition for such an accumulation was that the donor radical cation underwent further evolution that precluded back electron transfer and any chemical reaction with the radical anion. In fact, no accumulation occurred with 1,4-diazabicyclo[2.2.2]octane (DABCO), for which this condition is not possible. The radical anions were produced from benzene polyesters too, but decomposition began early. Ipso substitution was one of the paths with secondary amines and the only reaction with tetrabutylstannane. The results fully support the previously proposed mechanism for electron transfer (ET) mediated photochemical alkylation of aromatic acceptors via radical ions and radical intermediates.

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Section: Introductionmentioning

confidence: 99%

Spectroscopic characterization of photoaccumulated radical anions: a litmus test to evaluate the efficiency of photoinduced electron transfer (PET) processes

Fagnoni¹,

Protti²,

Ravelli³

et al. 2013

Beilstein J. Org. Chem.

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“…[1,2] In other cases the expected products are formed, but the reactions are greatly accelerated (electron transfer catalysis [3] ). In particular, many studies have been devoted to elucidate the kinetic and mechanistic effects of removing an electron from reagents involved in pericyclic reactions.…”

Section: Introductionmentioning

confidence: 99%

“…Abstract: Three tricyclic vinylcyclobutanes (3-methylenetricyclo[5.3.0.0 2,6 ]-decanes 1-3) have been subjected to ionization by photoinduced electron transfer in solution and by X-irradiation in Ar matrices. All three compounds undergo oxidative cycloreversion; the cleavage of the four-membered ring, however, occurs in a different direction depending on the presence of a methyl group in position 6 of the tricyclic framework.…”

Section: Introductionmentioning

confidence: 99%

“…Therefore the question arises in what way the main product which was found in these experiments, [24] that is, 1-methyl-8-methylenetricyclo[4.4.0.0 2,7 ]decane (6), is formed.…”

mentioning

confidence: 99%

“…[33] Conversely, the reduction of 5 bC + to the triplet state of 5 is strongly exergonic (DG = À125.7 kcal mol À1 according to B3LYP/6-31G*). As the triplet sensitized [2+2] cycloaddition of a 8-methylene-1,6-cyclodecadiene derivative to give the corresponding 8-methylenetricyclo[4.4.0.0 2,7 ]decane is known, [34] we assume that 6 is formed after back electron transfer from 5C + to the sensitizer radical anion. Compound 2: The syn-isomer of 1, compound 2, exists also in different conformations, but, to simplify the calculations, only the lowest-energy conformer 2 a was considered (where one of the peripheral methylene groups is in an endo-and the other in an exo-position).…”

mentioning

confidence: 99%

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Oxidative Rearrangements of Tricyclic Vinylcyclobutane Derivatives

Grota

Mattay

Piech

et al. 2006

Chemistry A European J

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Three tricyclic vinylcyclobutanes (3‐methylenetricyclo[5.3.0.02,6]decanes 1–3) have been subjected to ionization by photoinduced electron transfer in solution and by X‐irradiation in Ar matrices. All three compounds undergo oxidative cycloreversion; the cleavage of the four‐membered ring, however, occurs in a different direction depending on the presence of a methyl group in position 6 of the tricyclic framework. In those derivatives, cycloreversion is found to lead to 1‐methyl‐8‐methylene‐1,6‐cyclodecadiene radical cations (5.+ from 1, 8.+ from 2) which upon back electron transfer yield two different hydrocarbons (6 from 5.+, 9 from 8.+), depending on the configuration around the endocyclic double bonds of the respective cyclodecadiene derivative. In the absence of a methyl group on C6, the cycloreversion leads to a radical cation complex between 1‐methylenecyclopent‐2‐ene and cyclopentene (12.+) which appears to revert to 3 on back electron transfer. The intermediate radical cations 5.+, 8.+, and 12.+ have been identified and characterized by UV/Vis and IR spectra in Ar matrices. The mechanism of their formation is elucidated by quantum chemical calculations.

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Photoinduced Reactions of Radical Ions via Charge Separation

Fukuzumi

Ohkubo

2012

Encyclopedia of Radicals in Chemistry, Biology and Materials

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This article describes the recent development of photocatalytic reactions using a simple donor‐acceptor‐linked dyad, 9‐mesityl‐10‐methylacridinium ion (Acr + –Mes). The electron‐transfer state of Acr + –Mes (Acr · –Mes ·+ ), produced on visible light irradiation, acts as an efficient oxidant and reductant. The use of Acr + –Mes, which has an extremely long‐lived charge‐separated state, enables the construction of highly efficient photocatalytic systems such as oxygenation, bromination, and carbon‐carbon bond formation of aromatic compounds.

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Reactivity Patterns of Radical Ions–A Unifying Picture of Radical‐Anion and Radical‐Cation Transformations

Cited by 22 publications

References 632 publications

Spectroscopic characterization of photoaccumulated radical anions: a litmus test to evaluate the efficiency of photoinduced electron transfer (PET) processes

Spectroscopic characterization of photoaccumulated radical anions: a litmus test to evaluate the efficiency of photoinduced electron transfer (PET) processes

Oxidative Rearrangements of Tricyclic Vinylcyclobutane Derivatives

Photoinduced Reactions of Radical Ions via Charge Separation

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