On the role of water in intermolecular proton transfer reactions
On the role of water in intermolecular proton transfer reactions
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DOI：
10.1021/ja069265p
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发表时间：
2007-10
影响因子：
15
通讯作者：
B. Siwick;H. Bakker
中科院分区：
文献类型：
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作者：
B. Siwick;H. Bakker
利用飞秒振动光谱研究了水溶液中8-羟基-1，3，6-吡喃三磺酸(HPTS)与碱乙酸酯之间的质子转移(PT)机理。通过对光酸、受体碱和水合质子的振动共振的研究，我们发现，在这个模型体系中，分子间PT涉及到质子在几个水分子之间的转移，这些水分子通过氢键(H键)将给体-受体对连接起来。我们发现，在高碱浓度下，PT的速率不是由酸和碱的相互扩散决定的，而是由分子间质子的格洛特斯传导速率决定的。这种长程PT需要活化的溶剂配置来促进电荷转移。
We study the mechanism of proton transfer (PT) between the photoacid (8-hydroxy-1,3,6-pyrenetrisulfonic acid (HPTS)) and the base acetate in aqueous solution using femtosecond vibrational spectroscopy. By probing the vibrational resonances of the photoacid, the accepting base, and the hydrated proton we find that intermolecular PT in this model system involves the transfer of the proton across several water molecules linking the donor-acceptor pair by hydrogen bonds (H-bonds). We find that at high base concentration the rate of PT is not determined by the mutual diffusion of acid and base but rather by the rate of Grotthuss-like conduction of the proton between molecules. This long-range PT requires an activated solvent configuration to facilitate the charge transfer.