Infrared spectroscopy of the hydrated clusters of cationic pentane, which are generated through the vacuum ultraviolet photoionization in the gas phase, is carried out to probe the acidic properties of their CH bonds. The monohydrated pentane cation forms the proton-shared structure, in which the proton of CH in cationic pentane is shared between the pentyl radical and water molecule. In the di- and trihydrated clusters, the proton of CH is completely transferred to the water moiety so that the clusters are composed of the pentyl radical and protonated water cluster. These results indicate that two water molecules are enough to cause the proton transfer from CH of cationic pentane, and thus its acidity is highly enhanced with the ionization.

中文翻译：

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阳离子戊烷水合簇中酸性CH键的红外光谱研究

通过气相气相真空紫外光电离产生的阳离子戊烷水合簇的红外光谱，以探测其CH键的酸性。一水合戊烷阳离子形成质子共享的结构，其中阳离子戊烷中的CH的质子在戊基和水分子之间共享。在二水合和三水合簇中，CH的质子完全转移到水部分，因此簇由戊基和质子化水簇组成。这些结果表明，两个水分子足以引起质子从阳离子戊烷的CH转移，因此其酸度随电离而大大提高。