RE-EVALUATION OF SPECTRAL AND KINETIC-PROPERTIES OF HO2 AND (0--)2 FREE-RADICALS
RE-EVALUATION OF SPECTRAL AND KINETIC-PROPERTIES OF HO2 AND (0--)2 FREE-RADICALS
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DOI：
10.1111/j.1751-1097.1978.tb06986.x
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发表时间：
1978-01-01
影响因子：
3.3
通讯作者：
BIELSKI, BHJ
中科院分区：
文献类型：
--
作者：
BIELSKI, BHJ
通过脉冲和停流辐解以及60 Co γ射线研究，在甲酸水溶液中重新测定了HO 2和O2-自由基的光谱和摩尔吸光度。在相应的最大值和23°C时的消光系数分别为225 = 1400 ± 80 M-1cm-1和225 = 2350 ± 120 M-1cm-1。根据新的消光系数重新评估早期发表的速率数据，得出HO 2和O2-的自发衰变速率常数如下：KHo 2 + HO 2 =（8.60 ± 0.62）× 105 M-1 s-1; KHo 2 +O2-=（1.02 ± 0.49）× 108 M-1 s-1; KHo 2 +O2-< 0.35M-1 s-1。对于平衡的HO 2 → O2-+ H+，解离常数为KHO 2 =（2.05 ± 0.39）× 10 - 5 M或pKHO 2 = 4.69 ± 0.08。
The spectra and molar absorbances of the HO2and O2‐free radicals have been redetermined in aqueous formate solutions by pulse and stopped‐flow radiolysis as well as by60Co gamma‐ray studies. The extinction coefficients at the corresponding maxima and 23°C are225= 1400 ± 80M‐1cm‐1and225= 2350 ± 120M‐1cm‐1respectively. Reevaluation of earlier published rate data in terms of the new extinction coefficients yielded the following rate constants for the spontaneous decay of HO2and O2‐:KHo2+HO2= (8.60 ± 0.62) × 105M‐1s‐1;KHo2+O2‐= (1.02 ± 0.49) × 108M‐1s‐1;KHo2+O2‐< 0.35M‐1s‐1. For the equilibrium HO2→ O2‐+ H+the dissociation constant isKHo2= (2.05 ± 0.39) × 10‐5Mor pKHO2= 4.69 ± 0.08.G(O2‐) has been evaluated as a function of formate concentration.