Cage-escape of geminate radical pairs can produce peroxynitrate from peroxynitrite under a wide variety of experimental conditions
Cage-escape of geminate radical pairs can produce peroxynitrate from peroxynitrite under a wide variety of experimental conditions
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DOI：
10.1021/ja991077u
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发表时间：
1999-11-24
影响因子：
15
通讯作者：
Ingold, KU
中科院分区：
文献类型：
--
作者：
Hodges, GR;Ingold, KU
过亚硝酸根的自发分解和二氧化碳催化分解产生了HO。和(-CO3.)自由基分别与(NO2)-N-..双酯Ho./NO2和-CO3./(NO2)-N-。对经历了竞争性的笼内坍塌和扩散分离。自由的何。和-CO3。自由基与过氧化氢反应。在O-2存在下，合适的醇或甲酸盐生成超氧化物，它被(NO2)-N-捕获。形成过氧硝酸根。过氧硝酸盐的形成可能会影响302 nm处光密度的变化率，该波长通常用于监测过氧亚硝酸根的衰变，导致误导动力学痕迹。用四硝基甲烷(TNM)作为超氧化物的比色探针，对游离HO的产率进行了定量。(27-28%)和游离CO3。(32-33%)。这两种自由基的产率与最近的其他估计非常一致。在一些氧醛催化的过氧亚硝酸盐分解反应中也检测到了超氧化物，这既是通过过氧硝酸根的形成，也是通过它与TNM的反应。用TNM测定的超氧化物产率与醛(RCHO)有关(R=-O2CC6H4、CH3、CH3CH2、(CH3)(3)C和HOCH2CHOH；产率分别为15、9、0.8、0和30%)。
The spontaneous and CO2-catalyzed decomposition of peroxynitrite yields HO. and (-CO3.) radicals, respectively, together with (NO2)-N-.. The geminate HO./NO2 and -CO3./(NO2)-N-. pairs undergo competitive in-cage collapse to nitrate and diffusive separation. Free HO. and -CO3. radicals react with H2O2 and. in the presence of O-2, suitable alcohols or formate to produce superoxide, which is trapped by the (NO2)-N-. to form peroxynitrate. The formation of peroxynitrate may influence the rate of change in optical density at 302 nm, the wavelength normally employed to monitor peroxynitrite decay, leading to misleading kinetic traces. Tetranitromethane (TNM) was used as a colorimetric probe for superoxide to quantify the yield of free HO. (27-28%) and free -CO3. (32-33%). The yields of both of these free radicals are in excellent agreement with other recent estimates. Superoxide was also detected in some oxygenated aldehyde-catalyzed peroxynitrite decompositions both by peroxynitrate formation and by its reaction with TNM. Superoxide yields, measured with TNM, were aldehyde (RCHO) dependent (R = -O2CC6H4, CH3, CH3CH2, (CH3)(3)C and HOCH2CHOH; yields were 15, 9, 0.8, 0, and 30%, respectively).