Anion radicals of beta diketonates

1983 ◽  
Vol 48 (9) ◽  
pp. 2525-2530 ◽  
Author(s):  
Andrej Staško ◽  
Ľubomír Malík ◽  
Peter Pelikán ◽  
Ján Reguli
Keyword(s):  
Anion Radical ◽  
Methine Proton ◽  
Grignard Reagents ◽  
Indo Calculations ◽  
Splitting Constant ◽  
Anion Radicals

Formation of anion radicals [RCOCHCOR']- with R ≡ R' = Me, i-Pr, t-Bu, and with R = Me, R' = Ph has been observed in reactions of beta diketonates wih Grignard reagents. The splitting constant of the methine proton is 0.26 mT, and that of the methyl protons is 1.2 mT if R ≡ R' = Me. According to INDO calculations the anion radical is stabilized with Ni2+ counterion in tetrahedral arrangement.

Alkyl 1-[2-(oxido anion)-, 3-, 4-, 5-alkyl substituted]phenyl ketyl radicals

1979 ◽  
Vol 44 (6) ◽  
pp. 1731-1741 ◽  
Author(s):  
Andrej Staško ◽  
Ľubomír Malík ◽  
Alexander Tkáč ◽  
Vladimír Adamčík ◽  
Eva Maťašová
Keyword(s):  
Electron Donor ◽  
Unpaired Electron ◽  
Grignard Reagents ◽  
Slight Effect ◽  
Benzene Nucleus ◽  
Alkyl Groups ◽  
Splitting Constant

Reactions of R2,R3-alkyl substituted 2-hydroxybenzenecarboxylic acids 2-HO-C6H2R2-COOH with Grignard reagents R1MgBr in the presence of nickel give stable aryl alkyl ketyl radicals 2-O--R2-, R3-C6H2-CO--R1 where R1 = CH3, C2H5, C2D5, n-C3H7 and R2,R3 = CH3, C2H5, i-C3H7, t-C4H9. The β protons of ketyl group are equivalent (splitting constant 1.25 mT) and non-equivalent (splitting constants within 0.5 to 1.5 mT) for R1 = methyl and other alkyl groups, respectively. Interaction of the γ protons with the unpaired electron was only observed in the case of R1 = n-propyl (splitting constants about 0.07 mT). The substituents R1 have but slight effect on values of splitting constants of the protons in R2,R3 and vice versa. Also splitting constants of the benzene nucleus (a4H = 0.55 mT, a6H = 0.44 mT) are only slightly affected by the substituents R1,R2,R3, which indicates dominant electron-donor effect of the oxido-anion group eliminating the relatively smaller contributions of the alkyl substituents.

scholarly journals Reactions of Aromatic Anion Radicals and Dianions. VIII. Reversible Potentials and Spectra of Perylene Anion Radical Undergoing Rapid Chemical Follow-up Reactions.

1978 ◽  
Vol 32b ◽  
pp. 363-369 ◽  
Author(s):  
Elisabet Ahlberg ◽  
Bo Svensmark ◽  
David P. Parker ◽  
Vernon D. Parker ◽  
André Babadjamian ◽  
...  
Keyword(s):  
Anion Radical ◽  
Anion Radicals

Does the reaction between fluorenone and grignard reagents involve free fluorenone anion radicals?

1994 ◽  
Vol 35 (49) ◽  
pp. 9225-9226 ◽  
Author(s):  
Torben Lund ◽  
Morten L. Pedersen ◽  
Lars A. Frandsen
Keyword(s):  
Grignard Reagents ◽  
Anion Radicals

Properties of electrochemically generated primary anion radicals of 2,5-dimethyl-1-nitrophenylpyrroles

1981 ◽  
Vol 46 (10) ◽  
pp. 2494-2502 ◽  
Author(s):  
Pavel Kubáček
Keyword(s):  
Nitrogen Atom ◽  
Carbon Atom ◽  
Anion Radical ◽  
Platinum Electrode ◽  
Spin Population ◽  
Kinetics Of Decomposition ◽  
Primary Anion ◽  
Stable Anion ◽  
Kinetics Of ◽  
Anion Radicals

The first step of electrochemical reduction of 2,5-dimethyl-1-nitrophenylpyrroles on a platinum electrode in anhydrous acetonitrile consists in an one-electron process producing relatively stable anion radicals. The prediction based on HMO calculations concerning an almost complete localization of the LFMO in the nitrophenyl part of the studied molecules is fully confirmed by means of EPR spectroscopy. Magnitude of the found proton splitting constants is very close to the values found for anion radical of nitrobenzene. The splitting by nucleus of nitrogen atom of pyrrole cycle can be explained exclusively by the mechanism of π-σ spin polarization of σ C-N bond and by the spin population at the carbon atom. The EPR method has also been used for following the kinetics of decomposition of anion radicals of the molecules studied.

Luminescent closed shell nickel(ii) pyridyl-azo-oximates and the open shell anion radical congener: molecular and electronic structure, ligand redox behaviour and biological activity

2017 ◽  
Vol 41 (10) ◽  
pp. 4157-4164 ◽  
Author(s):  
Shuvam Pramanik ◽  
Suhana Dutta ◽  
Sima Roy ◽  
Soumitra Dinda ◽  
Tapas Ghorui ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Biological Activity ◽  
Anion Radical ◽  
Closed Shell ◽  
Open Shell ◽  
Redox Behaviour ◽  
Redox Active ◽  
Molecular And Electronic Structure ◽  
Anion Radicals

Luminescent nickel(ii) complexes have been synthesized using redox-active azo-oximes. The superior π-acidity of the organic backbone is a key to the isolation of Ni(ii) anion radicals.

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