Kinetic Study of the Phthalimide <i>N</i>-Oxyl Radical in Acetic Acid. Hydrogen Abstraction from Substituted Toluenes, Benzaldehydes, and Benzyl Alcohols
作者:Nobuyoshi Koshino、Basudeb Saha、James H. Espenson
DOI:10.1021/jo0348017
日期:2003.11.1
N-oxyl (PINO) radical was generated by the oxidation of N-hydroxyphthalimide (NHPI) with Pb(OAc)4 in acetic acid. The molar absorptivity of PINO* is 1.36 x 10(3) L mol(-1) cm(-1) at lambda(max) 382 nm. The PINO radical decomposes slowly with a second-order rate constant of 0.6 +/- 0.1 L mol(-1) s(-1) at 25 degrees C. The reactions of PINO(*) with substituted toluenes, benzaldehydes, and benzyl alcohols
邻苯二甲酰亚胺N-氧基(PINO)自由基是通过在乙酸中用Pb(OAc)4氧化N-羟基邻苯二甲酰亚胺(NHPI)生成的。PINO *在λ(最大)382 nm处的摩尔吸收率为1.36 x 10(3)L mol(-1)cm(-1)。PINO自由基在25摄氏度下以0.6 +/- 0.1 L mol(-1)s(-1)的二级速率常数缓慢分解。PINO(*)与取代的甲苯,苯甲醛和苄醇的反应在氩气气氛下进行了研究。通过Hammett分析将二阶速率常数关联起来。与甲苯和苄醇的反应与sigma +的相关性更好(rho = -1.3和-0.41),与苯甲醛的反应与sigma +的相关性更好(rho = -0.91)。还研究了动力学同位素效应,并获得了相当大的k(H)/ k(D)值:25.0(对二甲苯),27。在25摄氏度下为1(甲苯),27.5(苯甲醛)和16.9(苄醇)。从与对二甲苯和对二甲苯-d(10)
Intramolecular electron transfer and dehalogenation of nitroaromatic anion radicals
作者:J. P. Bays、S. T. Blumer、S. Baral-Tosh、D. Behar、P. Netav
DOI:10.1021/ja00341a003
日期:1983.2
series of nitroaromatic compounds, containingCl, Br, or tosyl groups at various positions, were synthesized and studied by pulse radiolysis in aqueous alcohol solutions. One-electron reduction of the compounds produces the anion radicals which then undergo an intramolecular electron transfer and eliminate X/sup -/ (Cl/sup -/, Br/sup -/, or TsO/sup -/). The rates of X/sup -/ elimination vary over six orders
Proton-transfer and electron-transfer processes in reaction of p-nitrotoluene with bases. A spectrophotometric study
作者:E. Buncel、B. C. Menon
DOI:10.1021/ja00530a032
日期:1980.5
Secondary α-Deuterium Kinetic Isotope Effects Signifying a Polar Transition State in the Thermolysis of Ring-Substituted <i>tert</i>-Butyl Phenylperacetates
作者:Sung Soo Kim、Alexey Tuchkin
DOI:10.1021/jo9814492
日期:1999.5.1
Several ring-substituted tert-butyl phenylperacetates (YC6H4CH2CO3But) and their deuterated versions (YC6H4CD2CO3But) were prepared (Y: p-OCH3, P-CH3, p-H; and p-NO2). Thermolyses at 80 degrees C in CDCl3 showed excellent first-order kinetics. The rates have been measured as k(YH) x 10(4) and k(YD) x 10(4) s(-1): 11.9 and 9.20 (p-OCH3), 2.64 and 2.22 (p-CH3), 1.06 and 0.93 (p-H), 0.164 and 0.156 (p-NO2). Hammett correlations were derived to yield rho(YH)(+) = -1.17 and rho(YD)(+) = -1.12. However, better Hammett plots were obtained with three points (p-OCH3, p-CH3, and p-H) showing rho(YH)(+) = -1.35 and rho(YD)(+) = -1.28. SDKIE was calculated as 1.293 (p-OCH3), 1.189 (p-CH3), 1.140 (p-H), and 1.051 (p-NO2), showing substantial substituent effects. Values of k(YH)/k(YD) for p-NO2 showed little temperature dependence. Hammett correlations and SDKIE were derived from the same kinetic entity that is the band cleavage.
Denisov, Russian Journal of Physical Chemistry, 1996, vol. 70, # 2, p. 238 - 241