4971-41-9Relevant articles and documents
Example of Diffusion-Limited Behavior in the Reaction of a Geminate Radical Pair in Micelles
Bohne, C.,Alnajjar, M. S.,Griller, D.,Scaiano, J. C.
, p. 1444 - 1445 (1991)
-
Laser Flash Photolysis Study of the Hydrogen Atom Transfer Reaction from Triplet 1-Naphthol to Ground Benzophenone
Shizuka, Haruo,Hagiwara, Hiroyuki,Fukushima, Masaru
, p. 7816 - 7823 (1985)
Laser flash photolyses at 337 nm have been carried out methanol solutions of the 1-naphthol and benzophenone system.It is found that hydrogen atom transfer reaction from the triplet 1-naphthol 3ROH* (produced by triplet sensitization
Hydrogen Abstraction in the Neutral Molecular Cluster of Benzophenone and Hydrogen Domors Formed in a Supersonic Free Jet Expansion
Matsushita, Yoshihisa,Kajii, Yoshizumi,Obi, Kinichi
, p. 6566 - 6570 (1992)
Photochemical reactions of benzophenone with hydrogen donors in neutral molecular clusters formed in a supersonic free jet expansion were studied.It was found that benzophenone undergoes photoreduction to form benzophenone ketyl radical in the benzophenon
Laser Flash Photolysis Studies on Proton-Enhanced Hydrogen Atom Transfer Reaction from Triplet Naphthol to Benzophenone via a Triplet Exciplex
Kaneko, Shouichi,Yamaji, Minoru,Hoshino, Mikio,Shizuka, Haruo
, p. 8028 - 8033 (1992)
The laser flash photolysis study at 355 nm in the 1-naphthol (ROH) and benzophenone (BP) system with and without H2SO4 has been carried out in acetonitrile-water (4:1 v/v) or methanol at 290 K.For the ROH (3.0 * 10-3 M)-BP (6.7 * 10-3/sup
Photochemical Reaction of Excited Benzophenone in the Gas Phase
Matsushita, Yoshihisa,Kajii, Yoshizumi,Obi, Kinichi
, p. 4455 - 4458 (1992)
Photochemical reactions of benzophenone with hydrogen-donating compounds have been studied in the gas phase.It has been found that the photoreduction of excited benzophenone proceeds to form benzophenone ketyl radical without contributions from surroundin
Time-Resolved Fluorescence Monitoring of Aromatic Radicals in Photoinitiated Processes
Shield, Stephanie R.,Harris, Joel M.
, p. 2576 - 2583 (1998)
Photolytic initiation of free radical reactions is important to many areas of technology; time-resolved monitoring of submicromolar concentrations of radicals produced during the course of these reactions is needed to provide information about the rate of initiation and its competition with radical recombination. In this work, time-resolved laser-induced fluorescence is evaluated for monitoring of diphenylketyl radicals produced by photoreduction of the triplet state of benzophenone. Fluorescence from the doublet-doublet transition of the radical is excited with a continuous wave laser and provides a sensitive method to detect these intermediates at nanomolar concentrations and to study their kinetics in solution on time scales from a few microseconds to hundreds of milliseconds. The ketyl radical fluorescence measurements of radical initiation reactions allowed the H atom abstraction rate constant by triplet benzophenone from both 2-propanol and benzhydrol to be determined, where kH = (2.1 ± 0.1) × 106 M-1 s-1 for 2-propanol and kH = (4.4 ± 0.1) × 106 M-1 s-1 for benzhydrol. The diphenylketyl radical recombination rate constant was also determined by time-resolved fluorescence monitoring of the decay of the radical population and found to be kr = (1.9 ± 0.2) × 108 M-1 s-1. Formation kinetics could be measured on a microsecond time scale from radical populations as low as 45 nM; decay kinetics could be followed on a millisecond time scale from 20 nM radical concentrations.
Picosecond and Nanosecond Studies of the Photoreduction of Benzophenone by N,N-Diethylaniline and Triethylamine
Devadoss, C.,Fessenden, Richard W.
, p. 7253 - 7260 (1991)
The photoreduction of benzophenone by N,N-diethylaniline and trimethylamine has been examined in a number of solvents by both nano- and picosecond laser photolysis.With diethylaniline, electron transfer is the primary step and the spectrum of the ion pair has been detected even in nonpolar solvents such as benzene and cyclohexane.Rapid proton transfer then takes place to form a high yield of the ketyl radical.The lifetime of the ion pair in benzene is about 900 ps.In acetonitrile the ion pair dissociates into individual ions which then decay by back electron transfer and proton transfer.A spectral shift to the red occurs over 100 ps as the contact ion pair dissociates.In acidic alcohols such as methanol and trifluoroethanol proton transfer from the alcohol occurs to produce the ketyl radical.In the case of triethylamine, no distinct absorption band for benzophenone anion was seen in picosecond experiments but difference spectra, which removed much of the spectrum of benzophenone triplet, clearly showed some contribution from the anion.For this compound, it is likely that electron transfer occurs first followed by very fast proton transfer.
The hydrogen atom transfer reactivity of sulfinic acids
Griesser, Markus,Chauvin, Jean-Philippe R.,Pratt, Derek A.
, p. 7218 - 7229 (2018)
Sulfinic acids (RSO2H) have a reputation for being difficult reagents due to their facile autoxidation. Nevertheless, they have recently been employed as key reagents in a variety of useful radical chain reactions. To account for this paradox and enable further development of radical reactions employing sulfinic acids, we have characterized the thermodynamics and kinetics of their H-atom transfer reactions for the first time. The O-H bond dissociation enthalpy (BDE) of sulfinic acids was determined by radical equilibration to be ～78 kcal mol?1; roughly halfway between the RS-H BDE in thiols (～87 kcal mol?1) and RSO-H BDE in sulfenic acids (～70 kcal mol?1). Regardless, RSH, RSOH and RSO2H have relatively similar inherent H-atom transfer reactivity to alkyl radicals (～106 M?1 s?1). Counter-intuitively, the trend in rate constants with more reactive alkoxyl radicals follows the reaction energetics: ～108 M?1 s?1 for RSO2H, midway between thiols (～107 M?1 s?1) and sulfenic acids (～109 M?1 s?1). Importantly, since sulfinic and sulfenic acids are very strong H-bond donors (αH2 ～ 0.63 and 0.55, respectively), their reactivity is greatly attenuated in H-bond accepting solvents, whereas the reactivity of thiols is largely solvent-independent. Efforts to measure rate constants for the reactions of sulfinic acids with alkylperoxyl radicals were unsuccessful. Computations predict these reactions to be surprisingly slow; ～1000-times slower than for thiols and ～10?000?000-times slower than for sulfenic acids. On the other hand, the reaction of sulfinic acids with sulfonylperoxyl radicals-which propagate sulfinic acid autoxidation-is predicted to be almost diffusion-controlled. In fact, the rate-determining step in sulfinic acid autoxidation, and the reason they can be used for productive chemistry, is the relatively slow reaction of propagating sulfonyl radicals with O2 (～106 M?1 s?1).
Femtosecond-Picosecond Laser Photolysis Studies on Reduction Process of Excited Benzophenone with N-Methyldiphenylamine in Acetonitrile Solution
Miyasaka, Hiroshi,Nagata, Toshihisa,Kiri, Manabu,Mataga, Noboru
, p. 8060 - 8065 (1992)
Photoreduction processes of benzophenone (BP)-N-methyldiphenylamine (MDPA) system in acetonitrile solution were studied by means of femtosecond-picosecond laser photolysis and time-resolved transient absorption spectroscopy.The reaction processes includin
Reaction of Benzophenone Triplets with Allylic Hydrogens. A Laser Flash Photolysis Study
Encinas, M.V.,Scaiano, J.C.
, p. 6393 - 6397 (1981)
The quenching of benzophenone by olefins having allylic hydrogens leads to hydrogen abstraction in addition to guenching by the ? system.The fraction of quenching events that leads to hydrogen abstraction in benzene at 27 deg C ranges from ca. 0 for conju
Effect of nitroxide radicals on chemically induced dynamic electron polarization of spin-correlated radical pairs in aqueous micellar solutions of sodium dodecyl sulfate
Gorelik,Tarasov,Shakirov,Bagryanskaya
experimental part, p. 1416 - 1427 (2009/09/30)
The multispin systems consisting of spin-correlated radical pairs (SCRPs) and stable nitroxide radicals, localized in micelles of sodium dodecyl sulfate (SDS), were studied by ESR and pulse laser photolysis techniques. In all the systems studied, the stab
Kinetic study of the hydrogen abstraction reaction of the benzotriazole-N-oxyl radical (BTNO) with H-donor substrates
Brandi, Paolo,Galli, Carlo,Gentili, Patrizia
, p. 9521 - 9528 (2007/10/03)
The aminoxyl radical (>N-O.) BTNO (benzotriazole-N-oxyl) has been generated by the oxidation of 1-hydroxybenzotriazole (HBT; >N-OH) with a CeIV salt in MeCN. BTNO presents a broad absorption band with λmax 474 nm and e 184
