12169-67-4Relevant articles and documents
Laser flash photolysis of 2,2′-dithiobis(pyridine N-oxide): Reactivity of N-oxypyridyl-2-thio radical
Alam, Maksudul M.,Watanabe, Akira,Ito, Osamu
, p. 53 - 59 (1996)
Reaction kinetics of radicals produced by the nanosecond laser flash photolysis of 2,2′-dithiobis(pyridine N-oxide) and related compounds have been studied. The transient absorption band at 360 nm was attributed to the radical in which the unpaired electron mainly localizes on the S atom (N-oxypyridyl-2-thio radical). The reactivities of the radical for conjugated dienes are lower than those of the pyridyl-2-thio radical, suggesting that a considerable unpaired electron density on the S atom delocalizes onto the N-oxypyridine moiety. The addition reaction rate of the radical to the conjugating diene was accelerated with hydrogen-bonding solvents and with addition of the cation, which may stabilize the N+-O- canonical structure, increasing the unpaired electron density on the S atom. By the photolysis of N-hydroxypyridine-2-thione, the N-O bond was predominantly dissociated producing a pyridy1-2-thio radical. By the photolysis of its anion, photoejection took place followed by the N-O bond fission, yielding pyridine-2-thione.
Hydrogen atom abstraction by radical cations. The reactions of 9-substituted acridine radical cations with cyclohexa-1,4-diene
Handoo,Cheng,Parker
, p. 1476 - 1480 (2001)
9-Substituted acridine radical cations undergo facile hydrogen atom abstraction reactions with cyclohexa-1,4-diene in dichloromethane-Bu4NPF6 (0.2 M). The kinetics of the reaction were studied by derivative cyclic voltammetry and obs
Radical-Type Reactivity of the Methylenedimethylsulfonium Ion, (CH3)2S(+)-CH2(.)
Smith, Rebecca L.,Chyall, Leonard J.,Stirk, Krista M.,Kenttaemaa, Hilkka I.
, p. 1623 - 1631 (1993)
Ab initio molecular orbital calculations at the MP2/6-31G*//6-31G* + ZPVE level of theory suggest that the ion (CH3)2S(+)-CH2(.) is 75 kJ mol-1 higher in energy than ionized ethyl methyl sulfide.However, this distonic ion is stable toward isome
Laser flash photolysis study of the photochemistry of 4,5-diaza-9-fluorenone
Bertoti, Ada R.,Guimar?es, Alexandre K.,Netto-Ferreira, José Carlos
, p. 166 - 171 (2015)
The triplet excited state of 4,5-diaza-9-fluorenone (1) shows absorption maxima at 410 and 470 nm and a lifetime of 3 μs, in acetonitrile. Its intersystem crossing quantum yield was determined using 9-fluorenone as a secondary standard and a value of 0.41 ± 0.01 was obtained. The reactivity of the triplet excited state of 1 towards several quenchers, in acetonitrile, was investigated employing the laser flash photolysis technique quenching rate constants ranging from 7.9 × 104 M-1 s-1 (2-propanol) to 1.0 × 1010 M-1 s-1 (triethylamine) were obtained. From the quenching rate constants obtained one can conclude that 4,5-diaza-9-fluorenone has a ππ? triplet excited state. A Hammett plot for the quenching rate constants of triplet 1 by phenols containing polar substituents against σ + gave a reaction constant ρ of -1.54 ± 0.10, which demonstrates the electrophilic character of the 4,5-diaza-9-fluorenone triplet excited state.
Electronic transitions of protonated benzene and fulvene, and of C 6H7 isomers in neon matrices
Garkusha, Iryna,Fulara, Jan,Nagy, Adam,Maier, John P.
experimental part, p. 14979 - 14985 (2011/01/07)
Electronic transitions of protonated benzene (A 1B 2X 1A1, origin at 325 nm) and ±-protonated fulvene (A 1A′X 1A′, at 335 nm) trapped in 6 K neon matrices have been detected. The cations were produced from several different precursors, mass-selected, and co-deposited with neon. After neutralization of the cations, the electronic transitions of cyclohexadienyl (onsets at 549 and 310 nm) and ±-hydrogenated fulvene (532 and 326 nm) radicals were identified. Upon excitation of cyclohexadienyl to the B 2B1 state, photoisomerization to an open-chain structure and ±-hydrogenated fulvene was observed.
