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首页> 外文期刊>Proceedings of the National Academy of Sciences of the United States of America >Anions dramatically enhance proton transfer through aqueous interfaces
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Anions dramatically enhance proton transfer through aqueous interfaces

机译：阴离子极大地增强了质子通过水界面的转移

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摘要

Proton transfer (PT) through and across aqueous interfaces is a fundamental process in chemistry and biology. Notwithstanding its importance, it is not generally realized that interfacial PT is quite different from conventional PT in bulk water. Here we show that, in contrast with the behavior of strong nitric acid in aqueous solution, gas-phase HNO_3 does not dissociate upon collision with the surface of water unless a few ions (>1 per 10~6 H_2O) are present. By applying online electrospray ionization mass spectrometry to monitor in situ the surface of aqueous jets exposed to HNO_(3(G)) beams we found that NO_3~- production increases dramatically on >30-μM inert electrolyte solutions. We also performed quantum mechanical calculations confirming that the sizable barrier hindering HNO_3 dissociation on the surface of small water clusters is drastically lowered in the presence of anions. Anions electrostatically assist in drawing the proton away from NO_3~- lingering outside the cluster, whose incorporation is hampered by the energetic cost of opening a cavity therein. Present results provide both direct experimental evidence and mechanistic insights on the counterintuitive slowness of PT at water-hydrophobe boundaries and its remarkable sensitivity to electrostatic effects.
机译：通过和穿过水界面的质子转移（PT）是化学和生物学的基本过程。尽管它很重要，但在散装水中，界面PT与常规PT并没有很大的不同。在这里，我们发现，与水溶液中的强硝酸行为相反，气相HNO_3在与水表面碰撞时不会离解，除非存在少量离子（每10〜6 H_2O中有1个以上）。通过应用在线电喷雾电离质谱法原位监测暴露于HNO_（3（G））束的水射流的表面，我们发现在>30μM的惰性电解质溶液中，NO_3〜-的产生显着增加。我们还进行了量子力学计算，确认了在存在阴离子的情况下，阻碍小水团簇表面HNO_3分解的相当大的势垒大大降低了。阴离子在静电上有助于将质子从团簇外部徘徊的NO_3吸走，其引入由于在其中打开腔体的高能成本而受到阻碍。目前的结果为PT在水-疏水物边界处的反直觉缓慢性及其对静电效应的显着敏感性提供了直接的实验证据和机理上的见解。

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  • 作者

    Himanshu Mishra; Shinichi Enami; Robert J. Nielsen; Michael R. Hoffmann; William A. Goddard lll; Agustin J. Colussi;

  • 作者单位

    Ronald and Maxine Linde Center for Global Environmental Science, California Institute of Technology, Pasadena, CA 91125, Materials Science, and California Institute of Technology, Pasadena, CA 91125, Materials and Process Simulation Center, California Institute of Technology, Pasadena, CA 91125;

    Ronald and Maxine Linde Center for Global Environmental Science, California Institute of Technology, Pasadena, CA 91125, The Hakubi Center, Kyoto University, Kyoto 606-8302, Japan;

    Materials and Process Simulation Center, California Institute of Technology, Pasadena, CA 91125;

    Ronald and Maxine Linde Center for Global Environmental Science, California Institute of Technology, Pasadena, CA 91125;

    Materials Science, and California Institute of Technology, Pasadena, CA 91125, Materials and Process Simulation Center, California Institute of Technology, Pasadena, CA 91125;

    Ronald and Maxine Linde Center for Global Environmental Science, California Institute of Technology, Pasadena, CA 91125;

  • 收录信息 美国《科学引文索引》(SCI);美国《生物学医学文摘》(MEDLINE);美国《化学文摘》(CA);
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

    air-water interface; acid-base; catalysis; nitric acid dissociation;

    机译：空气-水界面;酸碱催化;硝酸离解;

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