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首页> 外文期刊>The journal of physical chemistry, A. Molecules, spectroscopy, kinetics, environment, & general theory >Chemistry of the Superoxide Radical (O_2~-) in Seawater: Reactions with Inorganic Copper Complexes
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Chemistry of the Superoxide Radical (O_2~-) in Seawater: Reactions with Inorganic Copper Complexes

机译：海水中超氧自由基（O_2〜-）的化学性质：与无机铜络合物的反应

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摘要

Copper-catalyzed dismutation has been proposed as an important sink of photoproduced superoxide radical (O_2~-) in seawater. We have determined the effective rate constants of the reactions of superoxide with Cu(I) and Cu(II) in seawater, using pulse radiolysis and kinetic spectrophotometry. Due to the effects of ionic strength and complexation, the observed rate constants, 1.98(±0.05) * 10~9 M~(-1) s~(-1) and 0.663(±0.071) * 10~9 M~(-1) s~(-1), for Cu(I) and Cu(II), respectively, are 1 order of magnitude lower than those reported for Cu~+ and Cu~(2+) in low ionic strength media. Measurements of the rate of O_2~- decay in the presence of catalytic concentrations of dissolved Cu agreed well with predictions based on the independently measured rate constants. Observed steady-state concentrations of Cu(I) in solutions exposed to a constant flux of O_2~- were also consistent with the measured rate constants. From these results and available data regarding Cu speciation in coastal and open oceans, we calculate that O_2~- reactions with Cu will be a more important sink of O_2~- than bimolecular dismutation, even if all organically complexed Cu species are unreactive.
机译：铜催化的歧化被认为是海水中光生超氧化物自由基（O_2〜-）的重要汇。我们已经使用脉冲辐射分解和动力学分光光度法确定了海水中超氧化物与Cu（I）和Cu（II）反应的有效速率常数。由于离子强度和络合作用的影响，观测到的速率常数为1.98（±0.05）* 10〜9 M〜（-1）s〜（-1）和0.663（±0.071）* 10〜9 M〜（- 1）在低离子强度介质中，Cu（I）和Cu（II）的s〜（-1）分别比Cu〜+和Cu〜（2+）的s〜（-1）低1个数量级。在溶解的铜的催化浓度下，O_2〜-衰变速率的测量与基于独立测量的速率常数的预测吻合得很好。暴露于恒定流量的O_2〜-的溶液中，Cu（I）的稳态浓度也与测得的速率常数一致。根据这些结果和有关沿海和远洋海洋中铜形成的现有数据，我们计算出，即使所有有机络合的铜物种都没有反应性，与双分子歧化相比，与铜发生的O_2〜-反应将是更重要的O_2〜-吸收体。

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