Quantification of Conventional and Nonconventional Charge-Assisted Hydrogen Bonds in the Condensed and Gas Phases

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• 作者：Sergey A. Katsyuba ; Mikhail V. Vener ; Elena E. Zvereva ; Zhaofu Fei ; Rosario Scopelliti ; Jan Gerit Brandenburg ; Sviatlana Siankevich ; Paul J. Dyson
• 刊名：The Journal of Physical Chemistry Letters
• 出版年：2015
• 出版时间：November 5, 2015
• 年：2015
• 卷：6
• 期：21
• 页码：4431-4436
• 全文大小：365K
• ISSN：1948-7185

文摘

Charge-assisted hydrogen bonds (CAHBs) play critical roles in many systems from biology through to materials. In none of these areas has the role and function of CAHBs been explored satisfactorily because of the lack of data on the energy of CAHBs in the condensed phases. We have, for the first time, quantified three types of CAHBs in both the condensed and gas phases for 1-(2鈥?hydroxylethyl)-3-methylimidazolium acetate ([C₂OHmim][OAc]). The energy of conventional OH路路路[OAc]^{鈭?/sup> CAHBs is 鈭?0 kcal路mol鈥?, whereas nonconventional C(sp2)H路路路[OAc]鈭?/sup> and C(sp3)H路路路[OAc]鈭?/sup> CAHBs are weaker by 鈭?鈥? kcal路mol鈥?. In the gas phase, the strength of the nonconventional CAHBs is doubled, whereas the conventional CAHBs are strengthened by <20%. The influence of cooperativity effects on the ability of the [OAc]鈭?/sup> anion to deprotonate the imidazolium cation is evaluated. The ability to quantify CAHBs in the condensed phase on the basis of easier accessible gas-phase estimates is highlighted.}