Electron spin resonance spectra and structure of bridgehead adamantyl and bicyclo[2.2.2]octyl free radicals

Krusic, Paul J.; Rettig, T. A.; Schleyer, Paul von Ragué

doi:10.1021/ja00758a050

Cited by 47 publications

(17 citation statements)

References 2 publications

(2 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Even if a fluorine atom is placed on the other bridgehead carbon atom, no measurable coupling is observed between the radical and the opposite atom. This indicates that the actual through‐space coupling for BCO and cubane, which share similar bridgehead–bridgehead distances (2.60 and 2.72 Å, respectively), is an insignificant effect. Further investigation on related systems confirmed that a through‐space coupling mechanism is only valid for distances below 2.1 Å .…”

Section: Physical Propertiesmentioning

confidence: 99%

Nonconjugated Hydrocarbons as Rigid‐Linear Motifs: Isosteres for Material Sciences and Bioorganic and Medicinal Chemistry

Locke

Bernhard

Senge

2019

Chemistry A European J

197

143

View full text Add to dashboard Cite

Nonconjugated hydrocarbons, like bicyclo[1.1.1]pentane, bicyclo[2.2.2]octane, triptycene, and cubane are a unique class of rigid linkers. Due to their similarity in size and shape they are useful mimics of classic benzene moieties in drugs, so‐called bioisosteres. Moreover, they also fulfill an important role in material sciences as linear linkers, in order to arrange various functionalities in a defined spatial manner. In this Review article, recent developments and usages of these special, rectilinear systems are discussed. Furthermore, we focus on covalently linked, nonconjugated linear arrangements and discuss the physical and chemical properties and differences of individual linkers, as well as their application in material and medicinal sciences.

show abstract

Section: Physical Propertiesmentioning

confidence: 99%

Nonconjugated Hydrocarbons as Rigid‐Linear Motifs: Isosteres for Material Sciences and Bioorganic and Medicinal Chemistry

Locke

Bernhard

Senge

2019

Chemistry A European J

197

143

View full text Add to dashboard Cite

show abstract

“…Beckwith and co-workers showed that, as expected, cyclization of the 4-cyclopentenylbutyl radical (1 3) occurred most rapidly in the exo mode to give the spiro intermediate (14), but that formation of the bridgehead radical (1 5 ) was only about a factor of five slower. In the case of the 3-(2-methylenecyclohex-y1)propyl radical (16), where the pattern of substitution disfavours exo-cyclization, the bridgehead radical (1 7) was actually the major cyclized intermediate. 8 In a particularly interesting study Yurchenko et ~1 .…”

Section: Generation Of Bridgehead Radicalsmentioning

confidence: 99%

Bridgehead radicals

Walton¹

1992

Chem. Soc. Rev.

View full text Add to dashboard Cite

“…Ainsi, la concentration de l'adduit DMPO-alkyle dans le milieu reactionnel est trop faible pour permettre l'enregistrement de son spectre rpe. Dans le cas de l'adamantyl-1 cobaloxime 23, le radical adamantyle-1, suffisarnment stable pour 2tre detect6 directernent par rpe dans certaines conditions (28,29) …”

Section: @ C H =~-~-B~unclassified

Utilisation des pièges à radicaux en vue de mettre en évidence des intermédiaires dans la photolyse de complexes contenant une liaison Co^III—C

Maillard¹,

Giannotti²

1982

Can. J. Chem.

View full text Add to dashboard Cite

Using the spin trapping technique with 5,5′-dimethyl 1-pyrroline N-oxide (DMPO), phenyl-N-tert-butyl nitrone (PBN), nitrosodurene (ND), and α-4-pyridyl 1-oxide N-tert-butl nitrone (4-POBN), or their mixtures, we have been able to detect two types of radicals, one is a hydrogen atom spin adduct and the other is the corresponding alkyl of the alkylcobaloximes, salens or cobalamines.By the use of selective deuteration and the preparation of the benzyl bis(diphenylglyoximato)-pyridinato cobaloxime, we have shown that the spin trapped hydrogen atom comes from the chelated hydrogen of the dimethylglyoximato anion of the equatorial ligand of CoIII complexes. Using a mixture of two spin traps gives rise to an esr spectrum containing, at the same time, the hydrogen atom and alkyl spin adducts.To explain such an efficient spin trapping reaction while the homolysis is in competition with a β-elimination process, it should be postulated that the photolysis of such compounds proceeds through a solvent cage environment. This hypothesis explains the strong influence of solvents on the nature of the free radicals trapped. Also the spin trap diffuses in the solvent cage, and is able to trap in a very efficient manner any free radicals occurring in the solvent cage. The excited CoIII complexes and the spin trap in the solvent cage behave like an exciplex, which could explain the spin trapping of the hydrogen atom.

show abstract

Electron spin resonance spectra and structure of bridgehead adamantyl and bicyclo[2.2.2]octyl free radicals

Cited by 47 publications

References 2 publications

Nonconjugated Hydrocarbons as Rigid‐Linear Motifs: Isosteres for Material Sciences and Bioorganic and Medicinal Chemistry

Nonconjugated Hydrocarbons as Rigid‐Linear Motifs: Isosteres for Material Sciences and Bioorganic and Medicinal Chemistry

Bridgehead radicals

Utilisation des pièges à radicaux en vue de mettre en évidence des intermédiaires dans la photolyse de complexes contenant une liaison Co^III—C

Contact Info

Product

Resources

About

Electron spin resonance spectra and structure of bridgehead adamantyl and bicyclo[2.2.2]octyl free radicals

Cited by 47 publications

References 2 publications

Nonconjugated Hydrocarbons as Rigid‐Linear Motifs: Isosteres for Material Sciences and Bioorganic and Medicinal Chemistry

Nonconjugated Hydrocarbons as Rigid‐Linear Motifs: Isosteres for Material Sciences and Bioorganic and Medicinal Chemistry

Bridgehead radicals

Utilisation des pièges à radicaux en vue de mettre en évidence des intermédiaires dans la photolyse de complexes contenant une liaison CoIII—C

Contact Info

Product

Resources

About

Utilisation des pièges à radicaux en vue de mettre en évidence des intermédiaires dans la photolyse de complexes contenant une liaison Co^III—C